Elenco Electronics CI-73 Instruction Manual And User Handbook

Copyright © 2014, 2004 by Elenco®Electronics, Inc. All rights reserved. No part of this book shall be reproduced by REV-E Revised 2014 753293
any means; electronic, photocopying, or otherwise without written permission from the publisher.

CI-73_REV-E_051314.qxp_CI-73_Manual_072213 5/13/14 4:01 PM Page 1

If you have any questions contact:

ELENCO

®

150 Carpenter Avenue

Wheeling, IL 60090

[phone]

Website: www.elenco.com • e-mail: [e-mail]

WARNING:

SHOCK HAZARD - NEVER connect
the probe to AC power or a wall
electricity outlet for any reason since
serious injury or damage may result.

-1-

CI-73 - READ THIS FIRST

The CI-73 is a set of 73 Snap Circuits®with special
software that allows you to “see” the electrical signals
in the circuits, just like electronics engineers do using
oscilloscopes and spectrum analyzers.

Requirements for your computer:

1. Windows

®

computer with internet connection.

2. A microphone input port.

INSTRUCTIONS:

1. Download our software from www.elenco.com/downloads/CI-

73.zip (Windows®may give you a warning, but our software is

safe to download). Go to the download and extract the
compressed files. Connect the plug end of our cable to the
microphone input (or microphone/USB adapter) on your
computer. With our cable connected, open the extracted files
folder and run file Winscope.exe.

2. Change the default settings for Winscope by selecting
<Options>. Then select <Timing> and change Sampling to
44100 and press <OK>. Then select <Options> again, then
<Colors> - <Y1 Trace> and pick a bright color like pink. Then
select <Options>, then <Save Setup> to save these settings
as your default.

3.

Follow the instructions through project PC3 before
moving on to any other circuits, since the main features
of the software are demonstrated.

!

Complies with CAN ICES-3 (B)/NMB-3 (B). This product
should only be connected to equipment of class II.

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-2-

Electronic engineers use specialized test equipment to “see”
electronic signals and make performance measurements. They
use an oscilloscope to look at the shape of the signal and use a
spectrum analyzer to look at its frequency content. This
equipment is specialized and usually very expensive.

The Winscope software simulates this equipment using your
personal computer. The PC-interface cable can be connected
across any 2 points in your circuit to look at the signal.

It is usually connected to the output of a circuit, as in the circuits
shown for the CI-73. Connect the plug end of the probe to the

microphone input on your personal computer. Run the

Winscope application (Winscope.exe). It will come up in Hold
mode looking like this:

Click on the On-Line button to turn it on. You should now get
one of the following 2 pictures, depending on whether your
microphone input is properly turned on:

If you get the picture shown in Example B, then your microphone
input is not properly turned on. Go to the “Turning On Your
Microphone Input” section to turn it on. There may also be other
sound card controls on your computer that you need to set.
When your input is properly configured, you will get a picture like
Example A above. Touch the red and black “alligator” clips on the
PC-interface cable to each other and you should see the random
pattern on the Winscope screen change as you do so. You are
now ready to proceed with the first CI-73 experiment or you may
investigate the Winscope software on your own.

Looking at Electronic Signals using the WINSCOPE Software

WARNING:

SHOCK HAZARD - NEVER connect the probe to AC power
or a wall electricity outlet for any reason since serious injury
or damage may result.

Example

A

Example

B

On-Line

button

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-3-

You may freeze a waveform on the screen by clicking on the

Hold mode button (just to the right of the On-Line button).

WARNING: Do not “save setup” in Winscope. Many of the

buttons on Winscope control features that this manual will not be
using. If you accidentally place the Winscope software into an
unknown mode, you may always close and re-start Winscope.
Doing so will reset all settings to those described in this booklet
unless you have done a “save setup”.

NOTES:

1. It is recommended that you disable or turn down the
volume to the speakers on your computer. CI-73’s use of
the microphone input port will also channel the same
signal to the speakers, and the result can be distracting.

2. It is recommended that you become familiar with the Snap
Circuits

®

parts and assembly methods before building

any of the circuits in this manual.

3. For some Windows

®

versions, you must plug in the PC­interface cable before you run Winscope, or you will not
be able to activate the Winscope on-line button.

Looking at Electronic Signals using the WINSCOPE Software (continued)

Hold mode button

PROJECTS PC1-PC3 SHOW
HOW TO USE THE MAIN
FUNCTIONS OF WINSCOPE SO
DO THEM FIRST!

Turning On Your Microphone

(For Windows®98 or XP, other Windows®versions may be
slightly different.)

If you don’t get any signal from the PC-interface cable then
your microphone may be disabled on your computer. To turn
it on, follow these instructions which begin by pressing the
<Start> button on the lower-left corner:

1. Select <Start> - <Programs> - <Accessories> ­<Entertainment> (or <Multimedia>) - <Volume Control>.

2. Select <Options>.

3. Select <Properties>.

4. Select <Recording> in the “Adjust Volume For” box.

5. In the “Show the Following Controls” box, check
<Microphone>.

6. Select <OK>.

7. In the “Microphone - Volume” box, check <Select> and set
volume to about 40% of max.

Your microphone should now be turned on.

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-4-

IMPORTANT NOTE: The designs for the microphone input port

vary throughout the computer industry. Hence you may get
waveforms different from those shown in your manual even
though the circuit is actually performing the same way. Here are
some types of differences:

A. The gain of your microphone input may be significantly

different from that indicated on pages 8-10 (and similarly
for the other circuits). Page 4 describes how to turn on the
microphone input and adjust its volume to about 40% of
max, you may want to adjust this volume higher or lower
so that your results better match those shown. Note that
having the volume set too high may “clip off” the top or
bottom portion of a waveform.

B. The oscilloscope waveforms shown on your display may

appear upside down (“inverted”) from those shown
throughout this document. For example the waveform
shown on the top of page 10 would look like this:

If this is the case then swap the connections of the red and black
clips of the Winscope probe in all circuits.

C. The shape of waveforms may appear distorted for some

circuits, due to protection circuitry that acts as a filter. For
example:

Looking at Electronic Signals using the WINSCOPE Software (continued)

This waveform . . .

might look like this.

And this waveform . . . might look like this.

And this waveform . . . might look like this.

Contact ELENCO®if you have any questions about this.

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-5-

By using the microphone audio input and the flexible processing
power of the personal computer, we have created an inexpensive
and easy-to-use way of looking at electronic signals. However,
no electronic oscilloscope or spectrum analyzer ever made
works on all electronic signals, and similarly Winscope has
limitations. The projects in this booklet were written to minimize
those limitations.

Winscope can only measure changing signals (AC voltages, >20
Hz frequency) and cannot measure fixed voltages (DC voltages,
such as a battery), due to the design of the microphone input.
Fixed voltages are not very exciting to look at anyway. Slow­changing or transient signals (such as when you first turn on
power to a circuit) will be displayed in a distorted form.

Winscope works best on signals up to about 5kHz, since its
sampling rate is limited to 44kHz. If you attempt to measure
higher frequency signals, then you will get wrong results due to
undersampling. This is a narrow range but it covers human voice
and most (but not all) music. AM and FM radio frequencies
cannot be measured. Every measurement you make will have
some amount of random “chatter” superimposed on the signal of
interest. This chatter is due to the limited sampling rate and from
the PC-interface cable picking up energy from other electronic
instruments in the vicinity (including room lights and your
computer), hence it cannot be avoided.

Limitations of WINSCOPE and Its Interface

Winscope has 2 input channels that can be displayed at the
same time. This is commonly done by electronic engineers using
an oscilloscope, to show the relationship of one (or more) signals
to another. However, use of this requires a second microphone
input, which most computers do not have. If the sound card in
your computer has this then you may use all of Winscope

features for 2 channels, which include X-Y and correlate modes.
Use of these Winscope capabilities is beyond the introductory
level of this product, use the Help menu in Winscope for
information about using these features (to make the help file work
on Windows Vista, you may need to download and install the
program (WinHlp32.exe) from the Microsoft Download Center).

Using WINSCOPE’s Full Capabilities

WARNING:

SHOCK HAZARD - NEVER connect the probe to AC power
or a wall electricity outlet for any reason since serious injury
or damage may result.

!

To make a copy of the Winscope display screen, hold down the Alt button and press the PrtScn button on your
computer when Winscope is the active window. You can then paste it into word processing programs such as
Microsoft Word.

Exporting Graphs from WINSCOPE

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-6-

Project # Description Page #

PC1 Pitch PC 7
PC2 Screaming Fan PC 11
PC3 Hissing Foghorn PC 14

PC4 Light and Sounds PC 16
PC5 Light and Sounds PC (II) 18
PC6 Light and Sounds PC (III) 18
PC7 Light and Sounds PC (IV) 18
PC8 Light and Sounds PC (V) 18
PC9 Light and Sounds PC (VI) 19
PC10 Modulation 19
PC11 Filtering 21
PC12 AM Radio PC 22
PC13 Space War PC 24
PC14 Microphone 25
PC15 Speaker Microphone 27
PC16 Symphony of Sounds PC 28
PC17 Doorbell PC 29
PC18 Periodic Sounds PC 30
PC19 Lasting Doorbell PC 31
PC20 Space War Flicker PC 33
PC21 Buzzing in the Dark PC 34
PC22 Trombone PC 35
PC23 Sound Pulse Oscillator PC 37
PC24 High Pitch Bell PC 38
PC25 Tone Generator PC 39
PC26 Tone Generator PC (II) 39
PC27 Tone Generator PC (III) 39
PC28 Old-Style Typewriter PC 40
PC29 Transistor Fading Siren PC 41
PC30 Fading Doorbell PC 41
PC31 Police Siren Amplifier PC 42
PC32 Music Amplifier PC 42
PC33 Space War Amplifier PC 43

PC34 Adjustable Tone Generator PC 43

PC35 Adjustable Tone Generator PC (II) 44
PC36 Adjustable Tone Generator PC (III) 44
PC37 Adjustable Tone Generator PC (IV) 44

Project # Description Page #

PC38 Adjustable FM Radio PC 44

PC39 Transistor AM Radio PC (II) 45
PC40 Playback & Record PC 45
PC41 Power Amplifier Playing Music PC 46
PC42 Music Meter PC 47
PC43 Oscillation Sounds PC 48
PC44 Oscillation Sounds PC (II) 48
PC45 Oscillation Sounds PC (III) 48
PC46 Oscillation Sounds PC (IV) 48
PC47 Oscillator Sounds PC 49
PC48 Oscillator Sounds PC (II) 49
PC49 Whistle Chip Sounds PC 49
PC50 Whistle Chip Sounds PC (II) 50

PC51 Whistle Chip Sounds PC (III) 50

PC52 Whistle Chip Sounds PC (IV) 50
PC53 Bird Sounds PC 50
PC54 Bird Sounds PC (II) 51
PC55 Electronic Cat PC 51
PC56 Electronic Cat PC (II) 51
PC57 Electronic Cat PC (III) 51
PC58 Electronic Cat PC (IV) 51
PC59 Variable Oscillator PC 52
PC60 Variable Oscillator PC (II) 52
PC61 Variable Oscillator PC (III) 52
PC62 Variable Oscillator PC (IV) 52
PC63 Electronic Sound PC 53
PC64 Electronic Sound PC (II) 53
PC65 Siren PC 54
PC66 Drawing Resistors PC 55
PC67 Electronic Noisemaker PC 55
PC68 Electronic Noisemaker PC (II) 56
PC69 Bee PC 56
PC70 Bee PC (II) 57
PC71 Space War Alarm Combo PC 57
PC72 Space War Music Combo PC 58
PC73 Sound Mixer PC 58

Project Listings

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-7-

Project #PC1

OBJECTIVE: To look at the output signal from a transistor oscillator while changing the pitch of the sound.

Pitch PC

You will now be introduced to the Winscope features, and thereby
become familiar with oscilloscopes and spectrum analyzers, and
see some of the most important concepts in electronics. It is
recommended that you already be familiar with the Snap Circuits

®

parts and assembly methods from the other manuals.

Build the circuit shown and connect the PC-interface cable to the
microphone input on your computer. Turn on the slide switch (S1)
and vary the adjustable resistor (RV). The frequency or pitch of
the sound is changed. Run the Winscope software and be sure
your microphone input is configured properly, as described
earlier.

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Note that your picture may not exactly match this picture due to
variances in the microphone input gain between computers, which
is beyond software control. You may want to adjust the volume
control of your microphone input to compensate, see note A on
page 4 for more details. You may also disable 1:1 mode by clicking
on its button again and then adjust the gain using the Y1 control.

The gain and position control features just described enable
electronic engineers and technicians to “see” the amplitude
(voltage level) of a signal. By adjusting the settings on an
oscilloscope, they can look at both very large and very small
voltage waveforms.

Move the adjustable resistor control (snap part RV) and watch how
it changes the waveform on the computer screen. Now click on the

0.5ms/div button to change the time scale on the display. (The
button to the left of it is for 5ms/div, the default.) Move the
adjustable resistor control around again. You may click on the Hold
button to freeze the waveform on the screen, then click on On­Line to restart.

-8-

Click on the On-Line button if Winscope is currently in Hold mode
and you should get a picture similar to this one:

On-Line

button

The waveform peak is off the top of the screen because the scope
gain (amplification) is set too high. You may adjust this gain by
moving the Y1 gain control around (try it).

Similarly, you may adjust the position of the waveform on the
screen by moving the Y1 position control around (try it).

Now click on the 1:1 button to set the gain to x1 and disable the
Y1 controls. You should now have a picture similar to this one:

1:1 button

Y1 position

control

Y1 gain

control

With the time scale at 0.5ms/div and the adjustable resistor set for
middle position, you should now have a picture similar to this one.

Your picture may appear different due to variations in the
microphone input designs between computers. Although this is
beyond software control, in some cases you may be able to
compensate externally. See notes B and C on page 4 for details.

Hold

button

0.5ms/div button

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The small slash “-” represents the trigger voltage, when the signal
reaches this voltage level it activates the display. This makes it
easy to observe a stream of pulses like you have now, and also to
record a single (non-repeating) pulse.

Move the adjustable resistor control (snap part RV) and watch how
it changes the waveform on the computer screen. Now you can
see how changing the adjustable resistor changes the time
between the pulses, which changes the tone of the sound you
hear.

The waveform you see here is the voltage across the speaker, the
peaks of the pulses occur when the transistors turn on and provide
current to the speaker. Changing the amplitude of the peaks
changes the loudness of the sound, changing their separation
changes the tone or “pitch” of the sound. The time scale and
trigger control features just described enable electronic engineers
and technicians to see the relationship between parts of a
waveform on their oscilloscope.

“Trigger positive level button

-9-

Notice that the waveform seems to be randomly dancing across the
screen, making it hard to study. We can fix this. Click on the
“trigger positive level” button and make sure the trigger bar is
in the position shown here. Notice that a small “-” appears on the
left of the display as you do so.

“-”

Trigger bar

Now its time to look at your electronic signal in a different way. The
oscilloscope features you have been using show you voltage
(amplitude) vs. time, now you will see voltage vs. frequency.
Engineers use expensive instruments called spectrum analyzers to
do this, but Winscope uses a mathematical transformation called
an FFT to do this. Set the Y1 gain control back to its default
position for now. Click on the 5ms/div button to display a wider
range, then click on the FFT button. Your display should be similar
to this:

You are seeing the frequency spectrum of your signal, up to 22kHz.
Notice that most of the energy is at the low frequencies (below
7kHz), and there is very little as you go higher.

5ms/div button FFT button

Y1 gain

control
default

position

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-10-

The 1:1 gain mode does not apply to the FFT screen, so move the
Y1 gain control down to here so you can see the peak energy at
the low frequencies.

Move the adjustable resistor control (snap part RV) and watch how
it changes the frequencies on the display.

Set the adjustable resistor control (snap part RV) to mid-range. In
addition to the 5ms/div and 0.5ms/div settings for the horizontal
scale, there is also a variable setting. See if you can set it so that
all the signal peaks line up with the grid lines, as shown.

Y1 gain
control

level

Variable

setting

As you can see, all the peaks are equally spaced in frequency.
Move your computer mouse directly over the first peak, the
software displays the frequency you are pointing at. Move the
mouse to the other peaks and you see they are multiples of the first
frequency.

Frequency

Now you can see that the tone you hear is actually a range of
related frequencies combined together. The first peak is considered
to be the main signal (and it is usually but not always the highest),
the energy at all the other peaks determine the waveform of the
signal you see on an oscilloscope.

Now modify your circuit by placing the 0.1mF capacitor (C2) on top
of the 0.02mF capacitor (C1).

By increasing circuit capacitance, you lower the oscillation
frequency and your display should now look something like this:

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Now adjust the horizontal scale so the peaks line up with the
gridlines as they did before.

Notice that all the peaks went down in frequency by a
corresponding amount and many changed in amplitude, that is why
your ears hear a different sound. Notice also that in this case the
left-most frequency peak no longer is the highest in voltage (your
results may vary).

Horizontal scale

-11-

Now you can click on the FFT box to return to oscilloscope mode
and look at the waveform with the 0.1mF capacitor in the circuit. You
can observe it with the same settings as before for comparison, but
these settings usually work best:

Project #PC2

OBJECTIVE: To demonstrate storage mode.

Screaming Fan PC

!

WARNING: Moving parts.

Do not touch the fan or
motor during operation. Do
not lean over the motor.

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-12-

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
switch (snap part S1). Set Winscope to the settings shown below,
and move the lever on the adjustable resistor (snap part RV)
around to change the waveform and the sound. A sample
waveform is shown here, but the pattern and shape of the pulses
depends on the adjustable resistor setting.

WaveformOn-Line

button

Without Storage Mode

Winscope has a mode that can display multiple scans at the same
time, called Storage mode. Set the adjustable resistor lever to a
low-middle position, place Winscope in this mode, and watch the
results.

With Storage Mode

Storage

mode

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-13-

What you see here is the effect of timing variations on the trigger
used for synchronization. Turn off the trigger and you will see how
much variation there is without using the trigger:

Trigger

You can use Storage mode on any of the other circuit waveforms if
desired.

Now turn off storage mode and turn on FFT mode to look at the
frequency spectrum, try the settings shown here.

Moving the adjustable resistor lever will change the spectrum
shown.

You can also use storage mode when in FFT mode, so turn it on
now.

Storage mode

In this way you can show the peak energy achieved at each
frequency. But this is only useful on a stable waveform, so if you
move the adjustable resistor lever now the signal will fill the screen
as the peaks move across the display.

Most oscilloscopes and spectrum analyzers have a storage mode
like this of some form.

Settings

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-14-

Project #PC3

OBJECTIVE: To demonstrate wait mode with multiple colors.

Hissing Foghorn PC

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
switch (snap part S1). Set Winscope to the settings shown on the
right, and move the lever on the adjustable resistor (snap part RV)
around to change the waveform and the sound. At some positions
there may be no sound. A sample waveform is shown here, but the
pattern and shape of the pulses depends on the adjustable resistor
setting.

On-Line

button

Settings

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Place Winscope in Wait mode by clicking on the button for it, then
slowly press the On-Line button several times. Now turn off the
slide switch (snap part S1) and press On-Line again. Then turn the
switch back on. You see that in Wait mode Winscope scans
(“waits”) until it sees a waveform that exceeds the trigger level you
set, then stops. With a strong signal it will make one scan and then
stop, whereas if no signal is present it keeps scanning until it finds
one. You could use this to sense when someone has turned on the
circuit.

-15-

On-Line

button

Wait

mode

You can change the color of the waveform: select <Options>, then
select <Colors>, then select <Y1 Trace>. Now select the color you
like and click <OK>.

Now we will combine the wait and storage modes to display several
waveforms that this circuit can create. You should have the circuit
on with the adjustable resistor at mid-range and Winscope in Wait
mode. Now turn on Storage mode. Now change the color of the
Y1 trace. Move the adjustable resistor control lever a little, then
press On-Line once to record another waveform. Now change the
color of Y1 again. Move the resistance control again and press On­Line once. Change the Y1 color, adjust the resistance and press
On-Line. Change the Y1 color, adjust the resistance and press On­Line. Do this several more times if you like. Note that at some
resistance settings there may be no waveform to trigger on, move
the resistance control until it does.

Now your display should look something like this:

Storage mode

Now you see the range of waveforms this circuit can create, all at
the same time. Engineers often do this to compare signals during
analysis.

You can use Wait mode and different colors like this on the other
circuits if you like.

Now turn off storage mode and turn on FFT mode to look at the
frequency spectrum, try the settings shown here. Wait mode does
not apply in FFT mode, so it has no effect here. Moving the
adjustable resistor lever will change the spectrum shown.

Settings

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-16-

Project #PC4

OBJECTIVE: To look at the output signal from a circuit that makes alarm sounds.

Light & Sounds PC

Build the circuit and connect the Winscope PC-interface cable as
shown, the cable should still be connected to the microphone input
on your computer.

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If continuing from the previous experiment then close the Winscope
program and run it again, to reset the settings. Then use the mouse
to set it up as shown here, and turn on the switch (snap part S1).
Click on the On-Line button to activate.

You should see a waveform similar to that shown here, but it will be
constantly changing. This is because the siren sound you hear is
not a continuous tone but instead is constantly changing. Note the
differences in the waveshape for this circuit compared to the circuit
in Project PC1.

Your picture may appear different due to variations in the
microphone input designs between computers. See the notes on
page 4 for details.

On-Line

button

Set up

Click on the FFT button to look at the frequency spectrum.
Also set the amplitude and time scales (really amplitude and
frequency scales in FFT mode) to be as shown here.

You should see a fuzzy spectrum similar to that shown here, but it
will be constantly changing. This is because the siren sound you
hear is not a continuous tone but instead is constantly changing
frequency, and it spends more time at some frequencies than at
others. Note the differences in the spectrum for this circuit
compared to the circuit in Project PC1.

FFT button

Amplitude

Time scales

-17-

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-18-

Sample Frequency Spectrum

Modify the circuit for project PC4 by connecting points X and Y on the
snap diagram. Now the sound is a machine gun, it shuts off between
bursts.

Look at the waveform and frequency spectrum using the same
settings as for project PC4, and compare them to those for the siren.

Project #PC5

Light & Sounds PC (II)

Modify the circuit by removing the connection between X and Y and
then make a connection between T and U. It makes a fire engine
sound.

Look at the waveform and frequency spectrum using the same
settings as for project PC4. The waveform slowly rises and falls in
pitch, and gives a clear spectrum that slowly rises and falls in
frequency.

Project #PC6

Light & Sounds PC (III)

Remove the connection between T and U and then make a
connection between U and Z. It makes an ambulance sound.

Look at the waveform and frequency spectrum using the same
settings as for project PC4. It alternates between two frequencies.

Project #PC7

Light & Sounds PC (IV)

Remove the connections between U and Z and between V and W,
then make a connection between T and U. It makes a water faucet
sound.

Look at the waveform and frequency spectrum using the same
settings as for project PC4. This sound is different from the others
and seems to have little or no pattern.

Project #PC8

Light & Sounds PC (V)

Sample Frequency Spectrum

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-19-

Look at the waveform in oscilloscope mode using the same
settings as earlier in PC4. Replace the whistle chip with the
speaker and remove the lamp. Compare the waveform you see
now with that from the whistle chip. The amplitude of the
waveforms are similar but yet the sound from the speaker is much
louder, since the speaker is drawing more current.

Project #PC9

Light & Sounds PC (VI)

Project #PC10

Modulation

OBJECTIVE: To demonstrate AM and FM modulation.

Build the circuit shown. If continuing from the previous
experiment then close the Winscope program and run it again, to
reset the settings. Click on the On-Line button to activate, and
turn on the switch (snap part S1). If you press the key (snap part
S2) then you will hear a siren sound, but it will not be very loud.
Click on the 1:1 button to set the gain automatically, then talk or
hum into the microphone (snap part X1) and observe how the
waveform changes. You may freeze the waveform by pressing
the Hold button if desired.

Hold button 1:1 button

When you are quiet you just get a stream of pulses with roughly
equal height and width, as shown at left.

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The waveform shown here is from humming into the microphone,
notice how the tops of the pulses show a regular pattern of dips
now.

Look ahead to the Microphone project PC14 on page 25, and note
the waveform shown there for humming into the microphone:

Notice that you can see roughly the same pattern in the peaks of
the waveform at left. If you hum at a similar tone and at a similar
distance from the microphone, you will get similar results.

If you talk into the microphone now you will get different patterns
depending on what words you say, how loudly you say them, and
your distance from the microphone. Words produce a more
“random” pattern than humming, but less random than blowing into
the microphone. The waveform at left is an example of talking into
the microphone. Observe the waveforms you get and compare with
what you get in project PC14.

And so you see that your voice is being superimposed onto the
peaks of the stream of pulses, this is called Amplitude Modulation
or AM. At AM radio stations music or voice is superimposed on a
high frequency waveform (similar to the pulse stream here),
filtered, amplified, and transmitted. Doing this allows the music to
be transmitted over great distances.

You can place Winscope into FFT mode to view the frequency
spectrum if you like, but it will be confusing to look at.

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You probably noticed that the width of the pulses in the pulse
stream is constantly changing, that is because there is actually a
second type of modulation occurring here. Press the key again and
you hear a siren. A siren is not a stable tone but rather is constantly
changing in frequency. Change the time scale to 0.5ms/div and
observe the range of waveforms:

Time scale

The width of the pulses (or frequency of the signal) is slowly being
changed, at a regular and repetitive rate. This is an example of
Frequency Modulation, or FM. In AM you use a controlling signal
(voice or music) to vary the amplitude of a second signal, in FM you
use the controlling signal to vary the frequency of the other signal.
In this circuit the output frequency from the alarm IC is being
controlled by a signal created inside the alarm IC, but it could have
been controlled by humming like you did for the AM (you don’t have
the parts needed to do this).

Look back at the Light & Sounds project PC4 on page 16. It shows
several different ways of configuring the alarm IC to make different
sounds, all of these are examples of frequency modulation using
different controlling signals created within the alarm IC. It also
shows examples of the frequency spectrum.

Project #PC11

Filtering

With the same circuit as PC10 and the same settings as shown at
the end of PC10, look at the waveform again and then press the
key. Notice how the pulses become more “rounded” when the key
is pressed. The whistle chip (snap part WC) has capacitance that
filters or smoothes the output signal. Now replace the whistle chip
with the 0.02mF capacitor (snap part C1) and it should look similar
though you won’t hear any sound. You can also look at the
frequency spectrum in FFT mode like in the other projects.

Typical waveform using

whistle chip

Typical waveform using

0.02

mF capacitor

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Project #PC12

OBJECTIVE: To look at the output signal from an AM radio.

Build the circuit shown and
connect the PC-interface
cable to the microphone
input on your computer.
Turn on the slide switch
(snap part S1), tune the
variable capacitor (snap
part CV) to a local radio
station that gives good
reception, and set the
adjustable resistor (snap
part RV) to a comfortable
volume. The integrated
circuit (snap part U5)
detects and amplifies the
AM radio waves all around
you. The power amplifier IC
(snap part U4) drives the
speaker (snap part SP) to
complete the circuit.

In this project you will study
the audio signal at the
radio’s output to the
speaker. The actual AM
radio transmission is at
high frequencies that
cannot be viewed using
Winscope.

AM Radio PC

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If continuing from the previous experiment then close the Winscope
program and run it again, to reset the settings. Then use the mouse
to set the scale to 1:1 mode. Click on the On-Line button to activate.

You should see a waveform similar to that shown here, but it will be
constantly changing as the music or talking you hear is changing.
Try tuning the adjustable capacitor (snap part CV) to different radio
stations and compare the waveforms.

This shows you what talking or music look like in electrical form.
Every word that every person says looks different, though there are
many patterns. The waveform will be fuzzier if there is lots of static
on the station. Here are some other examples of talking and music
using the same settings above:

On-Line button 1:1 mode

Click on the FFT button to look at the frequency spectrum. Set the
time scale (really frequency scale in FFT mode) and amplitude
scale to be as shown here.

You should see a spectrum similar to that shown here, but it will be
constantly changing as the music or talking you hear is changing.
Try tuning the adjustable capacitor (snap part CV) to different radio
stations and compare the waveforms.

This shows you the frequency spectrum of talking or music. Every
word that every person says looks different, though there are many
patterns. The spectrum will be fuzzier if there is lots of static on the
station. Here are some other examples of talking and music using
the same settings above:

FFT button Time scaleAmplitude scale

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Build the circuit shown and connect the PC-interface cable to the
microphone input on your computer.

Project #PC13

Space War PC

OBJECTIVE: To look at the output signal from a circuit that
makes space war sounds.

If continuing from the previous experiment then close the Winscope
program and run it again, to reset the settings. Then use the mouse
to set it up as shown here, and turn on the switch (snap part S1).
Click on the On-Line button to activate.

Press the press switch (snap part S2) several times to step through
the eight different sounds from the space war integrated circuit.
Hold it down for a few seconds each time so you can see the
waveform representing the sound you hear.

It is also interesting to switch to the 5ms/div time scale setting to
see more of the waveform at one time. Here are some example
waveforms using the same settings as above:

On-Line

button

Set upTime scale

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Click on the FFT button to look at the frequency spectrum for these
signals. For best viewing set the amplitude and time scales (really
amplitude and frequency scales in FFT mode) to be as shown here.

FFT button Amplitude scale

Time scale

Press the press switch (snap part S2) several times to step through
the eight different sounds from the space war integrated circuit.
Hold it down for a few seconds each time so you can see the
frequency spectrum representing the sound you hear.

Here are sample spectrums from some of the other sounds using
the same settings as above:

Build the circuit shown and connect the PC-interface cable to the
microphone input on your computer.

Project #PC14

Microphone

OBJECTIVE: To see what your voice looks like in electrical
form.

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If continuing from the previous experiment then close the Winscope
program and run it again, to reset the settings. Click on the On-Line
button to activate Winscope, and turn on the switch (snap part S1).

Talk into the microphone (snap part X1) and see what your voice
looks like after the microphone converts it to electrical energy.
Adjust the Y1 gain control to get the best view of it, since the
amplitude is greater if you talk louder or are closer to the
microphone. Notice how the waveform is different depending on
which words or tones you say.

Here are some example waveforms using the same settings as
above. Try not to blow on the microphone while you talk into it.

On-Line button Y1 gain control

Blowing into
microphone

Whistling into
microphone

Ahhhhhh
sound

Humming into
microphone

Click on the FFT button to look at the frequency spectrum for
these signals. Try the amplitude and time scales shown here to
start, but your best settings will depend on what sounds you make,
how loud you speak, and how close you are to the microphone.

Notice that most women have higher-frequency voices than most men,
and so their frequency peaks are further to the right on your display.

Here are some example waveforms using the same settings as above:

On-Line button Amplitude and time scales

Blowing into
microphone

Whistling into
microphone

Ahhhhhh
sound

Humming into
microphone

The above frequency spectrum pictures correspond directly to the
waveform pictures on the preceding page. Notice that the
spectrums for the hum and whistle have only a single big peak.
Smooth, well-rounded, and repetitive waveforms (in oscilloscope

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mode) have nearly all of their energy at a specific frequency like for
the hum. “Square” or “rectangular” looking waveforms (like in
Project PC1) and most music have a series of mathematically­related peaks, while “random” waveforms (like from blowing into
the microphone or several people talking at the same time) have a
frequency “blob” instead of distinct peaks.

Project #PC15

Speaker Microphone

OBJECTIVE: To see what your voice looks like in electrical
form.

A speaker uses electrical energy to create mechanical vibrations.
These vibrations create variations in air pressure, called sound
waves, which travel across the room. You “hear” sound when your
ears feel these air pressure variations. But if air pressure variations
reach the speaker from another source, they will cause it to vibrate
too. This, in turn, causes the speaker to create a small electrical
signal just like a microphone does (though not very efficiently, since
speakers were not designed to be microphones).

-27-

Connect the PC-interface cable directly onto the speaker as shown;
no other parts are needed here. If continuing from the previous
experiment then close the Winscope program and run it again, to
reset the settings. Click on the On-Line button to activate.

Hold the speaker next to your mouth and talk into it to see what
your voice looks like after the speaker converts it to electrical
energy. Adjust the Y1 gain control to get the best view of it.

Notice that you need to set the gain control higher here than in the
preceding project using the microphone, since speakers were not
designed to be used in the same way.

You may switch to FFT mode and view the frequency spectrum in
the same manner as for the microphone project PC14.

On-Line button Y1 gain control

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Project #PC16

Symphony of Sounds PC

OBJECTIVE: To see the waveforms for a complex signal.

The Symphony of Sounds project combines waveforms from the
Music, Alarm, and Space War integrated circuits. Build the circuit
shown. If continuing from the previous experiment then close the
Winscope program and run it again, to reset the settings. Click on
the On-Line button to activate, and turn on the switch (snap part
S1). Press the press switch (S2) and wave your hand over the
photosensitive resistor (RP).

Due to the combination of sounds, the waveform is complex. Set
Winscope to the settings shown, or as you prefer.

Settings

Click on the FFT button to look at the frequency spectrum for the
signal. Try the settings shown here, or as you prefer.

Settings

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Project #PC17

Doorbell PC

OBJECTIVE: To look at the output of a musical circuit.

-29-

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
slide switch (snap part S1). Try the settings shown here. When the
music stops, press the press switch (part S2) and it will resume.

Settings

Click on the 5ms/div time scale button and on the FFT button to
look at the frequency spectrum for the signal. The Y1 gain control
is set for high gain now, so the higher peaks are off the screen but
lots of the lower peaks are visible.

Note that the sound is music and the oscilloscope waveform has a
“square” shape, as a result the frequency spectrum has a lot of
peaks with equal spacing.

Now adjust the gain lower until you see the higher peaks.

5ms/div time
scale button

Y1 gain controlFFT button

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Project #PC18

Periodic Sounds PC

OBJECTIVE: To look at the output of an alternately changing
circuit.

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
slide switch (snap part S1). Try the settings shown here.

The oscilloscope display alternates between 2 waveforms, the one
shown here and the one on the next page. This one shows some
pulses followed by a flat signal, then more pulses, then flat, then
pulses, then flat . . .

This is the second oscilloscope waveform, using the same settings.
It is a continuous series of pulses. You can use the Hold button to
freeze the display for easier viewing.

Settings

Hold button

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Now change to FFT mode to look at the frequency spectrums
corresponding to the 2 waveforms above. Try the settings shown
here.

Settings

This is the spectrum for the oscilloscope waveform shown on the
preceding page, which alternates between pulses and flat.
Because of the transition between pulses and flat, the spectrum is
the irregular shape shown here.

This is the spectrum for the oscilloscope waveform shown at the
top of this page, which has a continuous series of pulses. There are
only pulses there, with no transition between pulses and flat.
Hence the frequency spectrum is very “clean”, with the energy
concentrated at a few tall peaks instead of being spread out like in
the other spectrum display.

Project #PC19

Lasting Doorbell PC

OBJECTIVE: To look at the output of an alternately changing
circuit.

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Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, turn on the switch
(snap part S1), and press the press switch (part S2). Try the
settings shown here.

The waveform at left shows the signal just after pressing the press
switch, the waveform below uses the same settings and shows the
waveform just before the sound stops. You see the pulses slowly
spread out as the tone of the sound changes.

Settings

Now change to FFT mode to look at the frequency spectrum as the
sound fades away. Try the settings shown here.

Settings

The spectrum at left is for just after pressing the press switch. The
spectrum below uses the same settings and shows the spectrum
just before the sound stops. The frequencies and amplitude slowly
get lower as the sound fades away.

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Project #PC20

Space War Flicker PC

OBJECTIVE: To continuously show the patterns created by the
space war IC.

Click on the On-Line button to activate, and turn on the switch
(snap part S1). Set Winscope to the settings shown below. The
signal from the alarm IC (snap part U2) causes the space war IC
(part U3) to step through the 8 different patterns it can create. A
sample waveform is shown here.

Settings Wait modeOn-Line button

You can also activate Wait mode and press the On-Line button
several times to view one scan of the signal at a time, instead of
seeing continuous scans.

Turn on FFT mode to look at the frequency spectrum, try the
settings shown here. You can see the spectrums for the different
patterns produced by the space war IC, a sample is shown here.

Settings

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings.

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Project #PC21

Buzzing in the Dark PC

OBJECTIVE: To build a circuit that buzzes.

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Set Winscope to the settings shown below and click on
the On-Line button to activate. A sample waveform is shown here.

The actual waveform will vary depending on how much light is
shining on the photoresistor (snap part RP). If you cover the
photoresistor then the circuit shuts off.

Settings

The waveform above is weak and
erratic, so replace the 0.02mF
capacitor (snap part C1) with the

0.1mF capacitor. A sample of the
new waveform is at left, with the
same settings. It is lower in
frequency but higher in amplitude.

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Turn on FFT mode to look at the frequency spectrum, try the
settings shown here.

Now put the 0.02mF capacitor back
in place of the 0.1mF capacitor to
compare its spectrum. A sample is
on the left, with the same
Winscope settings as above. As
with the oscilloscope mode, its
spectrum is weaker and more
erratic.

Settings

Project #PC22

Trombone PC

OBJECTIVE: To build a circuit that sounds like a trombone.

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Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
switch (snap part S1). Set Winscope to the settings shown below,
and move the lever on the adjustable resistor (snap part RV)
around to change the waveform and the sound. At some positions
there may be no sound. A sample waveform is shown here.

Settings

Note that in the above display
the Y1 Gain is set high to show
the low energy levels of the
higher frequency components of
the signal, even though the
stronger peaks of the lower
frequency components are off
the top of the display. This can
be deceiving. Now change the
Y1 Gain so that the highest
peak can be seen, this is shown
on the right. Now you see how
the main signal frequency
dominates the others.

Turn on FFT mode to look at the frequency spectrum, try the

settings shown here.

Settings

Y1 Gain

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Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
slide switch (snap part S1). Set Winscope to the settings shown
on the upper right, and move the lever on the adjustable resistor
(snap part RV) around to change the waveform and the sound. At
some positions there may be no sound. A sample waveform is
shown on the upper right.

You can also change to the

0.5ms/div scale to take a closer
look at one of the pulses, shown on
the right:

Settings

0.5ms/div scale

Turn on FFT mode to look at the frequency spectrum, try the

settings shown here.

Settings

Project #PC23

Sound Pulse

Oscillator PC

OBJECTIVE: To build a pulse oscillator.

LED (D1) is on
layer 1 directly

beneath the

speaker (SP).

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Project #PC24

High Pitch Bell PC

OBJECTIVE: To build a high pitch bell.

Build the circuit shown. If continuing from the previous
experiment then close the Winscope program and run it
again, to reset the settings. Click on the On-Line button to
activate, and hold down the press switch (snap part S2). Set
Winscope to the settings shown on the upper right. A sample
waveform is shown on the upper right.

Settings

Turn on FFT mode to look at the frequency spectrum, try the

settings shown here.

Settings

You can change some of the Winscope settings around to view the
waveform and spectrum in different ways if desired. You can also
place the 0.02mF capacitor on top of the whistle chip to lower the
frequency.

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Project #PC25

Tone Generator PC

OBJECTIVE: To build a high frequency oscillator.

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
switch. Set Winscope to the settings shown below. A sample
waveform is shown here.

Settings

Turn on FFT mode to look at the frequency spectrum, try the

settings shown here.

Settings

Modify the circuit for project PC25 by placing the 0.02mF capacitor
(C1) on top of the whistle chip (WC). Look at the waveform and
frequency spectrum using the same settings as for project PC19,
the frequency is lower now.

Modify the circuit for project PC25 by placing the 0.1mF capacitor
(C2) on top of the whistle chip (WC). Look at the waveform and
frequency spectrum using the same settings as for project PC19,
but you may want to change the time scale since the frequency is
much lower now.

Project #PC26

Tone Generator PC (II)

Project #PC27

Tone Generator PC (III)

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Project #PC28

Old-Style Typewriter PC

OBJECTIVE: To build a circuit that sounds like a typewriter.

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Click on the On-Line button to activate, and turn on the
switch. Set Winscope to the settings shown on the upper right.
Turn the motor (snap part M1) slowly with your fingers and watch
the waveforms generated. They are very erratic and unpredictable.
A sample is shown on the upper right.

Settings

Turn on FFT mode to look at the frequency spectrum, try the
settings shown here.

You can also turn on Storage
mode to see the peaks recorded
as you turn the motor, a sample
of this is at right.

Settings Storage mode

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Project #PC29

Transistor Fading Siren PC

OBJECTIVE: To build a siren that slowly fades away.

Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Set Winscope to the settings shown on the right. Click on
the On-Line button to activate, turn on the switch, and press the
press switch (snap part S2). You hear a siren that slowly fades
away.

This display shows the siren just after pressing the press switch.

Settings

This display (at the same settings)
shows the siren when it has almost
faded out. The waveform has
become weak and sometimes
erratic.

Turn on FFT mode to look at the frequency spectrum, try the
settings shown here. The display on the left shows the signal just
after pressing the press switch and on the right shows it just before
it fades out.

Settings

Modify the circuit in PC29 by replacing the alarm IC (U2) with the
music IC (U1), use a 1-snap and a 2-snap to make a connection
across D6-E6 on top of the music IC. The music slowly fades away
and stops. Use the same settings as in PC29 to view the waveform
and frequency spectrum.

Project #PC30

Fading Doorbell PC

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Project #PC31

Police Siren Amplifier PC

OBJECTIVE: To show the output of an amplifier.

You may also make different alarm sounds by connecting the
alarm IC using the configurations shown in projects #23-26.

Build the circuit shown and set Winscope to the settings shown
below. The siren sound is very loud. In most cases the waveform
will have flat edges on the top and bottom, indicating the voltage
is too high for the microphone input stage on your computer and is
being distorted. You may sometimes correct for this if you like by
reducing the volume control of your microphone input (see p. 3),
but it is recommended that you return the volume to the normal
level before doing other projects.

Settings

Flat edges

Modify the circuit in PC31 by replacing the alarm IC (U2) with the
music IC (U1). Use the same settings as in PC31 to view the
waveform, you may also use the FFT button to view the frequency
spectrum.

Project #PC32

Music Amplifier PC

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Project #PC33

Space War Amplifier PC

-43-

Build the circuit shown and use the same settings as in PC31 to
view the waveform. Press the switch (S2) to change the sounds
and waveform.

Project #PC34

Adjustable Tone Generator PC

Build the circuit shown, and try the settings below. Move the
adjustable resistor lever to change the frequency. A sample
waveform is shown here.

Settings

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-44-

Try these settings to
see the spectrum:

Modify the circuit for project PC34 by placing the 0.02mF capacitor
(C1) on top of the whistle chip (WC). Look at the waveform and
frequency spectrum using the same settings as for project PC34,
the frequency is lower now.

Project #PC35

Adjustable Tone Generator PC (II)

Modify the circuit for project PC34 by
placing the 0.1mF capacitor (C2) on top of
the whistle chip (WC). Look at the
waveform and frequency spectrum using
the same settings as for project PC34, but
you may want to change the time scale
since the frequency is much lower now.

Project #PC36

Adjustable Tone Generator PC (III)

Project #PC37

Adjustable Tone Generator PC (IV)

Modify the circuit for project PC34 by replacing the 10KW (R4)
resistor with the photoresistor (RP). Look at the waveform and
frequency spectrum using the same settings as for project PC34,
and wave your hand over the photoresistor to change the sound
and pattern. There will not always be sound.

Turn on the slide switch (S1) and press the R button. Now press
the T button and the FM module scans for a radio station. When a
station is found, it locks on to it and you hear it on the speaker.
Press the T button again for the next radio station.

Connect the PC-interface cable as shown. Set up Winscope as
desired or use the same Winscope settings to view the waveform
and frequency spectrum as for project PC12 (AM radio), since the
output signal to the speaker is music or talking just like in PC12.
(AM and FM radio transmit the same types of information using
different modulation methods.) Adjust the volume using the
adjustable resistor (RV) so that all of the waveform is shown on the
Winscope screen.

Project #PC38

Adjustable FM Radio PC

OBJECTIVE: To show the output of an FM Radio.

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Turn on the switch and adjust the variable capacitor (CV) for a
radio station, then adjust the loudness using the adjustable resistor
(RV). Use the same Winscope settings as for project PC12 (AM
radio) to view the waveform and frequency spectrum. The
waveform will be different from that in projects PC12 and PC38,
because those circuits use the power amplifier IC (U4) instead of
the NPN transistor for amplification.

Project #PC39

Transistor AM Radio PC (II)

OBJECTIVE: To show the output of an AM Radio.

-45-

Build the circuit shown. Turn on the slide switch (S1), you hear a
beep signaling that you may begin recording. Talk into the
microphone (X1) up to 8 seconds, and then turn off the slide switch
(it also beeps after the 8 seconds expires).

Press the press switch (S2) for playback. It plays the recording you
made followed by one of three songs. If you press the press switch
before the song is over, the music will stop. You may press the
press switch several times to play all three songs.

Project #PC40

Playback & Record PC

OBJECTIVE: To show the waveforms for music and your voice.

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Use Winscope to view the waveform and frequency spectrum
when playing back your recording and music. A sample music

waveform is shown here.

Sample music waveform

Build the circuit shown. Turn on the slide switch (S1), you hear a
beep signaling that you may begin recording. Talk into the
microphone (X1) up to 8 seconds, and then turn off the slide switch
(it also beeps after the 8 seconds expires).

Press the switch S2 for playback. It plays the recording you made
followed by one of three songs. If you press the press switch (S2)
before the song is over, the music will stop. You may press the
press switch several times to play all three songs.

Project #PC41

Power Amplifier

Playing Music IC

OBJECTIVE: To show how high amplification can distort

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This recorder IC circuit works the same as in project PC40 except
that the power amplifer IC (U4) used here makes the sound much
louder than in project PC40. If viewed with the same Winscope
settings as in PC40, then the waveform appears as shown below.
The output from the recorder IC has not changed, but the flat
edges at the top and bottom of the waveform indicate that the
higher amplification is distorting the sound.

Flat edges

Project #PC42

Music Meter PC

OBJECTIVE: To show how high amplification can distort

Use the LOW (or 10mA) setting on the meter (M2). Set the
adjustable resistor (RV) to the bottom position and turn on the slide
switch (S1), you will see a waveform like that shown below. Set the
adjustable resistor to the top, and the waveform looks like that
shown on the bottom left, due to lower resistance in the circuit. A
sample frequency spectrum is also shown on the bottom right.

Settings

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Project #PC43

Oscillation Sounds PC

OBJECTIVE: To view the output of an oscillator circuit.

You may look at a pulse close-up by changing the time scale and
slightly adjusting the delay, as shown.

You may look at the frequency spectrum on your own if desired.

Build the circuit and try the settings shown here. This circuit
produces a series of pulses (shown below), representing when the
transistor is activated.

Settings

Time scale Delay

Project #PC44

Oscillation

Sounds PC (II)

Using the circuit from PC43,
connect the whistle chip across
points C & D. Notice how the shape
of the pulse has changed from that
shown in PC43 (using the same
settings):

Project #PC45

Oscillation

Sounds PC (III)

Using the circuit from PC43,
connect the whistle chip across
points B & E. Notice how the shape
of the pulse has changed.

Project #PC46

Oscillation

Sounds PC (IV)

Using the circuit from PC43, install
the whistle chip under capacitor
C2. Notice how the shape of the
pulse has changed.

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Project #PC47

Oscillator Sounds PC

OBJECTIVE: To view the output of an oscillator circuit.

Build the circuit and try the settings shown.

Settings

Project #PC48

Oscillation

Sounds PC (II)

Using the circuit from PC47, install
the whistle chip on top of capacitor
C1. Notice how the spacing
between the pulses has changed.

Project #PC49

Whistle Chip Sounds PC

OBJECTIVE: To view the output of an oscillator circuit.

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Build the circuit and try the settings shown. You may try other
settings to zoom in or look at the frequency spectrum.

Settings

Project #PC50

Whistle Chip

Sounds PC (II)

Connect the whistle chip (with the
PC-interface cable still connected
across it) across points B & C. The
circuit oscillates in short intervals.

Project #PC51

Whistle Chip

Sounds PC (III)

Connect the whistle chip (with PC cable) across points C & D using a
1-snap, the sound and waveforms are different.

Project #PC52

Whistle Chip

Sounds PC (IV)

Place the 470mF capacitor C5 on top of
the 100mF capacitor C4, and connect the
whistle chip across points A & B. The
circuit oscillates in 2-second intervals.

Project #PC53

Bird Sounds PC

OBJECTIVE: To view the output of an oscillator circuit.

Build the circuit and try the settings shown. The oscillator
activates about once-a-second, sounding like a bird chirping. You
may look at the frequency spectrum if you like.

Settings

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Project #PC54

Bird Sounds PC (II)

Replace the 100mF capacitor (C4) with the 10mF capacitor (C3). The
frequency of the oscillator is the same as before (and so the pulses look
the same), but the oscillator activates in shorter intervals (so the bursts of
pulses are shorter but closer together). You could use the 470mF
capacitor to increase the oscillation interval.

Project #PC55

Electronic Cat PC

OBJECTIVE: To view the output of an oscillator circuit.

Build the circuit and try the settings shown. Start with the
adjustable resistor set to the left but then adjust to change the
tone. The signal dies out after you release the switch.

Settings

Project #PC56

Connect the whistle chip across points A & B, then B & C, then C & D and
observe how the waveform changes as the sound changes.

Project #PC57

Remove the speaker. Connect the PC
interface cable across the whistle chip
and install the whistle chip across
points A & B, then B & C, then C & D
and observe how the waveform
changes as the sound changes. Try
different settings of the adjustable
resistor. The waveform for B & C is
shown.

Electronic Cat

PC (III)

Electronic Cat

PC (II)

Project #PC58

Replace the 100mF capacitor with the 470mF capacitor and repeat projects PC55­PC57. The signal dies out at a much slower rate now, making it easier to observe.
You can also use FFT mode to view the frequency spectrum as desired.

Electronic Cat

PC (IV)

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Project #PC59

Variable Oscillator PC

OBJECTIVE: To view the output of an oscillator circuit.

Build the circuit and try the settings shown. Move the adjustable
resistor lever to change the pitch of the sound and pulse
separation in the waveform.

Settings

Project #PC60

Connect the whistle chip across points A & B, then B & C, then D & E and
observe how the waveform changes as the sound changes. Sometimes
the speaker sound and waveform are unchanged, but the whistle chip
itself makes new sound.

Project #PC61

Remove the speaker. Connect the PC
interface cable across the whistle chip
and install the whistle chip across
points A & B, then B & C, then D & E
and observe how the waveform
changes as the sound changes. Try
different settings of the adjustable
resistor. The waveform for A & B is
shown.

Variable Oscillator

PC (III)

Variable Oscillator

PC (II)

Project #PC62

Replace the 100KW resistor R5 with the photoresistor RP, wave your hand or
a piece of paper over it and observe how the sound and waveform change.

Variable Oscillator

PC (IV)

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Project #PC63

Electronic Sound PC

OBJECTIVE: To view the output of an oscillator circuit.

Build the circuit and try the settings shown. Press the press switch
to lower the frequency of the signal by increasing the capacitance
in the oscillator. You can replace the 0.1mF capacitor C2 with the
10mF capacitor C3 (“+” on the right) to further lower the frequency
of the tone. You may try other settings to zoom in or look at the
frequency spectrum.

Settings

Project #PC64

Replace the 100KW resistor R5 with the 10KW resistor R4, place the

0.1mF capacitor back in the circuit as before. Now you change the
frequency by changing the resistance in the oscillator.

Electronic Sound

PC (II)

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Project #PC65

Siren PC

OBJECTIVE: To view the output of a fading siren circuit.

Build the circuit and try the settings shown. Flip on the slide switch
and press the press switch for a few seconds and release. View
the waveform as a siren starts up and then slowly fades away.

Settings

Note: Although the amplitude of the pulses appears to be varying

across the screen (the wider time scale shown below shows this
better), this is an illusion caused by the way Winscope measures
the signal. The amplitude of the pulses is not really varying.

Winscope makes measurements using a 44kHz sampling rate,
which is fast enough to measure the frequency of this signal
(varying from 1-5kHz). However these pulses have much of their
energy spread among higher frequencies that approach the
sampling rate (see the sample spectrum plots at right), where the
amplitude measurement becomes increasingly inaccurate.

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Use the circuit from the Drawing Resistors project #516, but
connect the PC-interface cable across the speaker. Use a pencil to
draw the shapes shown in projects #516-518, as per the directions
given in those projects. Use Winscope to see how the waveforms
and frequency spectrums vary as you move the jumper wires
across the shapes to change the sounds. A sample is shown here.

Next, place the loose ends of the jumper wires into a cup of water, as
per project #519. The waveforms and frequency spectrum you see
will be similar to the resistors you drew, just as the sounds are similar.

Project #PC66

Drawing Resistors PC

OBJECTIVE: To draw your own resistors.

Settings

Settings

Build the circuit and try the settings shown. Flip on the slide switch
and press the press switch a few times while moving the
adjustable resistor control around. View the waveform and
frequency spectrum.

Project #PC67

Electronic Noisemaker PC

OBJECTIVE: To view the output of an oscillator circuit.

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Sample frequency spectrum:

You can replace the 0.1mF capacitor C2 with the 10mF capacitor
C3 (“+” on the right) to change the sound.

Settings

Sample waveform:

Settings

Project #PC68

Replace the 10KW resistor R4 with the 100KW resistor R5. Now you
change the frequency by changing the resistance in the oscillator.

Electronic Noisemaker

PC (II)

Project #PC69

Bee PC

OBJECTIVE: To view the output of an oscillator circuit.

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Build the circuit and press the press switch a few times, you hear
cute sounds like a bumble bee. Use Winscope to see how the
waveform fades away after you release the switch, and try storage
mode as shown here.

You may replace the 0.02mF capacitor C1 with 0.1mF capacitor C2
or 10mF capacitor C3 (“+” on the right) to change the sound, but
you may want to change the time scale.
You may also replace the 100mF capacitor C4 with the 10mF
capacitor C3 or the 470mF capacitor C5 to change the duration of
the sound.

Settings

Time scale

Storage mode

Project #PC70

Remove the speaker from the circuit and place the whistle chip
(WC) across the transformer at points labeled A & B on the circuit
layout, connect the PC-interface cable across the whistle chip.
Listen to the sounds and view the waveforms as you press the
press switch. Replace the 0.02mF capacitor C1 with 0.1mF
capacitor C2 or 10mF capacitor C3 (“+” on the right) to change the
sound, or replace the 100mF capacitor C4 with the 10mF capacitor
C3 (“+” on the right) or the 470mF capacitor C5 to change the
duration.

Bee PC (II)

Build the circuit and try the settings shown. Turn it on, press the
press switch (S2) several times, and wave your hand over the
photoresistor (RP) to view all the sound combinations. You may
also use FFT mode to view the frequency spectrum.

Project #PC71

Space War Alarm Combo PC

OBJECTIVE: To view the output of the combined outputs from
the space war and alarm integrated circuits.

Settings

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Build the circuit and try the settings shown. Turn it on, press the
press switch (S2) several times, and wave your hand over the
photoresistor (RP) to view all the sound combinations. Compare
the waveform and spectrum to the alarm IC combo circuit.

Project #PC72

Space War Music Combo PC

OBJECTIVE: To view the output of the combined outputs from
the space war and music integrated circuits.

Settings

Build the circuit and try the settings shown. Turn it on and view the
waveforms.

Project #PC73

Sound Mixer PC

OBJECTIVE: To view the output of the music and alarm
integrated circuits.

Settings

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IMPORTANT NOTICE

Disclaimer Information

Oscilloscope for Windows95®or newer, version 2.51.

OSCILLOSCOPE IS SUPPLIED TO YOU AS IS, AND IN
NO CASE IS THE AUTHOR OF THIS PROGRAM
RESPONSIBLE FOR PERSONAL INJURY, HARDWARE
AND/OR DATA DAMAGE, PROPERTY DAMAGE OR
PROFIT LOSS ARISING FROM USE OR INABILITY TO
USE THIS SOFTWARE.

THERE IS NO GUARANTEE IMPLIED OR OTHERWISE
TO THE FITNESS OF THIS OSCILLOSCOPE PROGRAM
FOR ANY PARTICULAR PURPOSE. THIS SOFTWARE IS
NOT INTENDED FOR INDUSTRIAL OR COMMERCIAL
USE.

ELENCO

®

150 Carpenter Avenue

Wheeling, IL 60090

[phone]

Website: www.elenco.com

e-mail: [e-mail]

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