PASCO WA-9867 User Manual
Instructions
Demonstrations
Experiments
Sample Data
Sine Wave Generator
Instruction Manual
No. 012-08678A
WA-9867
Sine Wave Generator Model No. WA-9867
Contents
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Operational Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Experiment 1:
Standing Waves In Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Experiment 2:
Resonance Tubes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Experiment 1:
Teachers’ Notes–Standing Waves in Strings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Experiment 2:
Teachers’ Notes–Resonance Tubes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Copyright and Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Model No. WA-9867 Sine Wave Generator
Power
Supply
Sine Wave
Generator
Sine Wave Generator
Model No. WA-9867
Included Eq ui pm e n t Replace m ent Pa rt Nu m ber
Sine Wave Generator
Power Supply
Suggested Accessories Model Number
String V ibrato r
Economy Wave Driver
Mechanical Wave Driver
Open Speaker
Economy Resonance Tube
Banana Patch Cords
WA-9867
540-057
WA-9858
WA-9854
SF-9324
WA-9900
WA-9495
SE-7123
Introduction
The PASCO Sine Wave Generator supplies adjustable-frequency AC power for applications such
as driving speakers, wave drivers and string vibrators. The digital display and easy-to-use
frequency and amplitude controls make this unit ideal for student labs.
The additional features of Auto Play and Advanced Mode with Record and Playback enhance
classroom demonstrations and permanent displays requiring automated signal variation.
The Sine Wave Generator outputs AC power at up to about 10 volts amplitude (20 V peak-topeak) and 1 amp. The output frequency, adjustable in increments of 0.1 Hz, ranges from 1 Hz to
800 Hz.
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3
Sine Wave Generator Setup
Power Input
On/Off
Switch
Increment
Keys
Amplitude
Knob
Fine Frequency
Knob
Course Frequency
Knob
Display
Output Jacks
Setup
Input Power
Connect the included power supply to the power input of the Sine Wave Generator. Slide the
ON/OFF switch to the right to turn it on.
Output Power
Connect a device such as a speaker or string vibrator to the output jacks of the Sine Wave
Generator with a pair of 4 mm banana patch cords. Both jacks produce AC signals with opposite
phases, so polarity is not important. (Note that the outputs do not float with respect to ground.)
If the Sine Wave Generator is connected to a short-circuit, the unit’s short-circuit protection will
shut off the output. Remove the short and cycle the input power to restore it.
Mounting and Storage
You can use the built-in clamp on the back of the unit to mount the Sine Wave Generator on a
vertical rod, as shown. Rod mounting makes the display more visible for demonstrations and
allows you to position the controls
conveniently when you set up an
experiment.
For storage, recessed dimples in the top
of the case align with the feet on the
bottom, allowing several units to be
stacked as shown.
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Model No. WA-9867 Operation
Operation
In addition to the description given here, there is a complete operational flow chart on page 10.
Manual Control
Amplitude
Adjust the amplitude of the output signal with the Amplitude knob. The amplitude range is
approximately 0 V to 10 V.
Frequency
Set the output frequency with the Coarse and Fine Frequency knobs (labeled “1.0” and “0.1”).
The LED display indicates the frequency to 0.1 Hz resolution. When the Sine Wave Generator is
first turned on, it outputs the default frequency of 100 Hz. You can adjust the output signal from 1
Hz to 800 Hz.
The Frequency knobs are mechanical encoders with 24 discrete detents, or clicks, per revolution.
One click of the Fine knob changes the frequency by 0.1 Hz. One click of the Coarse knob
changes the frequency by 1.0 Hz if the knob is turned slowly, or 4.0 Hz if the knob is turned
quickly. This allows you to change the frequency more quickly over a large range.
You can also use the Up and Down Increment keys to change the frequency. Each quick press of
the Up or Down key changes the frequency by the stored increment. By default the increment is
100 Hz. To change the stored increment, see the Increment Keys section below. (If you press and
hold the Increment keys, a different function will occur, so only use quick presses to change the
frequency.)
This following sections describe how to change the stored frequency increment and program the
Sine Wave Generator to play automatic sequences of notes. If you would like to skip to some
practical demonstrations, see the Applications se ction on page 11.
Incremen t Key s
The Up and Down arrow keys have multiple functions. The Increment function is activated by a
single quick press and release of either key . Other functions are activated when you press and hold
the keys. For example, to implement the Play function you would press and hold the Up arrow
key for about 1 second. The instructions may read, “press and hold the Play key,” or, “press the
Up Increment key.” Both refer to the same key , but different functions. The labels below the keys
(Store/Exit and Play) indicate the press-and-hold functions of the keys.
Changing the Output Frequency by the Stored Increment
Each quick press of the Up or Down Increment key changes the output frequency by the amount
stored as the increment. The default increment (when unit is initially turned on) is 100 Hz. Thus, a
single press of the Up Increment key will add 100 Hz to the output frequency. Try this:
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5
Sine Wave Generator Operation
1. Turn the Sine Wave Generator on (if it is already on, turn it off for a second, then back on).
The initial output frequency is 100 Hz.
2. Press the Up Increment key. The frequency changes to 200 Hz. Press it again and it changes to
300 Hz. Press the Down Increment key and the frequency changes back to 200 Hz.
3. Use the Frequency knobs to change the frequency to 220 Hz.
4. Press the Up Increment key; the frequency changes to 320 Hz.
5. Press the Up Increment key several more times so that the output is 720 Hz. Additional
presses of the Up Increment key will do nothing because the output will not exceed 800 Hz.
Setting the Stored Increment
The harmonics of a resonating device (such as a vibrating string or tube) are usually spaced at
equal frequency increments. It is useful to set the Sine Wave Generator’s stored increment to
match your device.
The label below the Up arrow key reads Store/Exit. When you press and hold this key, it will
function as a Store key; the stored increment will change to the value on the display (which is the
output frequency). Try this:
1. Use the Increment keys and the Frequency knobs to set the output to 120 Hz.
2. Press and hold the Store key. After 1 second the display will blink and you can release the key .
The stored increment is now 120 Hz.
3. Press the Up Increment key a few times; the frequency changes by 120 Hz with every press.
This value will remain stored until a new value replaces it or the unit is turned off.
Auto Play
In Auto Play mode you can program the Sine Wa ve Genera tor to scan automatically through the
harmonics of a device.
Setup
The label below the Up arrow key reads Play. When you press and hold it, this key will start
automatic play. Try this:
1. Set the stored increment to 120 Hz (as described above).
2. Use the Amplitude knobs to change the output frequency to 60 Hz.
3. Press and hold the Play key. The di splay will blink to show you that Auto Play has st arted, and
you can release the key .
4. The Sine Wave Generator will play the starting note (60 Hz), then increment to the next notes
(180 Hz, 300 Hz, 420 Hz, etc.), playing each note for 1.5 seconds. You can use the Amplitude
knob to adjust the output.
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Model No. WA-9867 Operation
Duration of Each Note
While in Auto Play mode, you can use the Frequency knobs to change the duration of each note.
By default, each note is played for 1.5 seconds. If you turn the Course (1.0) knob one click
clockwise, it will increase the duration by 1 se cond. The display will switch over to show the
duration (in seconds), and then switch back to showing the frequencies. One click of the Fine
(0.1) knob will change the duration by 0.1 second. The duration can be set from 0.1 to 99.9
seconds.
Wrap Around
Auto Play will continue to increment the frequency until it reaches the maximum (up to, but not
over 800 Hz); then it will wrap around and start the sequence again. To make Auto Play wrap
around at a lower frequency, press and hold the Play key when the sequence is at the highest note
that you want. (The display will blink after 1 second to indicate that you can release the key.)
Exit Auto Play
To stop Auto Play, press and hold the Store/Exit key. (The display will blink after 1 second to
indicate that you can release the key. ) The Sine Wave Generator will return to normal mode, and
the output frequency will return to the original starting frequency.
Advanced Mode: Record and Playback
In Advanced Mode you can set, store and play back a sequence of up to 80 notes. The Sine Wave
Generator will record the frequency and amplitude of each note. Advanced Mode is espec ially
useful when demonstrating resonance in vibrating strings because it allows you to set the optimal
amplitude and frequency for each harmonic.
This mode is a hidden sub-layer so as to not confuse the student with extra complexity in normal
lab use. It is intended for the teacher’s use in demonstrations. Although it is “hidden”, it is easily
accessible and straightfor war d to use.
Entering Advanced Mode
Press and hold both arrow keys simultaneously (as shown) until
the display changes to indicate the number of recorded notes. If
no sequence is stored it will display “0.”
After entering Advanced Mode there are 3 options:
Exit: Press and hold the Store/Exit key to leave Advanced
Mode and return to normal mode.
Play the St ored Sequence: Press and hold the Play key. The
Sine Wave Generator will enter Playback Mode and play the
sequence of recorded notes. (If there is no recorded seque nce, this action will exit Advanced Mode.)
Enter Record Mode: Press and hold both keys simultaneously again to enter Record Mode. The
display will show “0” (to denote tha t it has cleared out the previously stored sequence) and begin to
flicker to indicate that the unit is in Record Mode.
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7
Sine Wave Generator Operation
Record a Sequence of Notes
In Record Mode the display will always flicker. When you enter Record Mode, the display shows
the output frequency. Connect the apparatus (such as a string vibrator with a string) to the Sine
Wave Generator so that you can tune the frequency and amplitude for each harmonic.
1. Enter Record Mode (see above).
2. Set the frequency and amplitude of the first note in the sequence (usually the fundamental
resonance frequency of the apparatus).
The Frequency knobs and the Increment keys function as norma l. Use only a quick press and
release to implement the up and down increment. The increment value is what it was set to
before you entered Advanced Mode.
3. Press and hold the Store key until the display changes; for a moment the display will show the
total number of stored notes, then return to showing the frequency.
4. Adjust the frequency and amplitude for the next note in the sequence and return to step 3.
5. After you have stored the entire sequence of notes, press and hold the Play key until the
display stops flickering. The Sine Wave Generator will switch to Playback M ode and begin to
play the sequence that you have recorded.
While you are recording a sequence, be careful not to make a mist ake. There is no way to edit a
note in the sequence after it has been stored. When you enter Record Mode, all previous notes are
erased and you start over. Once you have stored a note, you can not change or erase it.
Playback of Stored Notes
With the Sine Wave Generator in Playback Mode and playing the stored sequence, you have
several options:
Amplitude: If you turn the Amplitude knob all the way up, the unit will play ba ck the stored
notes exactly as you recorded them. If you turn the knob down, it decreases all of the stored notes
by the same proportion.
Duration: You can use the Frequency knobs to change the duration of every note. The default
duration is 1.5 seconds. The Course (1.0) knob changes the duration by 1 second per click, the
Fine (0.1) changes the duration by 0.1 second per click. If you exit Advanced Mode and return
later, the Sine Wave Generator will remember the previous duration setting.
Pause: A quick press of the Down arrow key pauses the playback of the stored sequence. To
resume playback, press and hold Play until the display blinks.
While paused, a quick press of the Up or Down arrow key will cause the next or previous note in
the sequence to play.
While paused, you can use the Frequency knobs to vary the output frequency. This is useful to
show what happens when the driving frequency is slightly off resonance. Changing the frequency
with the knobs while playback is pause d does not change the stored notes.
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Model No. WA-9867 Specifications
Sequence S tar t-over: When the last stored note has been played, the Sine Wave Generator wraps
around and starts over with the first note. At any time during play mode, a quick press of the Up
arrow key will cause the sequence to start over with the first note.
S top Playback: Pre s s and hold the Store/Exit key to return to normal mode. The output
frequency will be set to the stored increment.
The sequence remains in storage. You can go back to Advanced Mode and play the sequence
again, even if you turned the unit off and unplug it in the interim.
Specifications
Frequency 1 to 800 Hz
Adjustable in 0.1 Hz increments
Output DC coupled push-pull
Short-circuit protected
Amplitude 0 to 10 V peak (approx.)
Current >1 A into 8 Ω load
Memory Up to 80 stored notes
Display 4 digit LED
Input Power 100–240 VAC, 50/60 Hz
Dimensions 12 × 11 × 5 cm
(not including separate power supply)
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9
Sine Wave Generator Operational Flow Chart
NORMAL
SHOW
NUMBER OF
STORED
NOTES
INC/DEC
FREQ by 1
INC/DEC
FREQ by 0.1
FREQ 0.1
FREQ 1.0,
(SLOW)
INC/DEC
FREQ by 4
FREQ 1.0,
(FAST)
MEMORIZE
INCREMENT
HOLD
STORE/EXIT
INCREASE
FREQ BY
INCREMENT
DECREASE
FREQ BY
INCREMENT
PRESS PLAY
PRESS STORE/
EXIT
HOLD PLAY
INC/DEC
INTERVAL BY
1 SEC
INC/DEC
INTERVAL BY
0.1 SEC
FREQ 1.0 FREQ 0.1
MAX INTERVAL = 99.5 SEC MIN INTERVAL = 0.5 SEC,
DISPLAY TEMPORARILY SHOWS INTERVAL, THEN
REVERTS TO NORMAL OPERATION.
PAUSED PLAY
PRESS STORE/EXIT
HOLD PLAY
STORED
NOTES:
BACKWARDS
STORED
NOTES:
FORWARDS
PRESS
PLAY
PRESS
STORE/EXIT
AMPLITUDE RAMPS DOWN
AND UP AT CHANGE OF
FREQUENCY. RAMP TURNED
OFF FOR INTERVALS LESS
THAN 1 SECOND.
RECORD
MODE
CLEAR
STORED
VALUES
ADJUST
FREQUENCY AND
AMPLITUDE THEN:
HOLD STORE/EXIT
SHOW #
STORED
NOTES X sec
IF NUMBER OF STORED NOTES
EXCEEDS CAPACITY (80), LAST
NOTE DISPLAYED THEN
RETURN.
HOLD PLAY
AND STORE/EXIT
HOLD PLAY
HOLD
STORE/EXIT
WA-9867 SINE WAVE GENERATOR OPERATIONAL FLOW CHART
Rev 1.01
05/07/2004
SET MAX
FREQ.
HOLD
PLAY
AUTOPLAY:
INCREMENT
PLAY STORED
NOTES
(STORED NOTES > 0)
(STORED NOTES= 0)
HOLD PLAY
AND STORE/EXIT
HOLD PLAY AND
STORE/EXIT
INITIAL PRESS 'FREEZES'
DISPLAY. IF HELD, MAX
FREQUENCY IS SET.
FREQUENCY
REVERTS TO POINT
WHEN NORMAL
MODE EXITED
RETURN AFTER DELAY
DISPLAY FLICKERS IN RECORD MODE
HOLD STORE/EXIT
HOLD
STORE/EXIT
INC/DEC
FREQ by 1
INC/DEC
FREQ by 0.1
FREQ 0.1
FREQ 1.0,
(SLOW)
INC/DEC
FREQ by 4
FREQ 1.0,
(FAST)
INC/DEC
FREQ by 1
INC/DEC
FREQ by 0.1
FREQ 0.1
FREQ 1.0,
(SLOW)
INC/DEC
FREQ by 4
FREQ 1.0,
(FAST TURN)
BUTTON PLAYS
FORWARDS
STORED NOTES.
INCREASE
FREQ BY
INCREMENT
DECREASE
FREQ BY
INCREMENT
PRESS PLAY
PRESS
STORE/EXIT
STORE/EXIT PLAY
AMPLITUDEFREQUENCY
0.11.0
INCREMENT
WA-9867
BUTTON PLAYS
BACKWARDS
THROUGH STORED
NOTES.
INC/DEC
INTERVAL BY
1 SEC
INC/DEC
INTERVAL BY
0.1 SEC
FREQ 1.0 FREQ 0.1
HOLD PLAY
HOLD PLAY AND STORE/EXIT
HOLD STORE/EXIT
MAX INTERVAL = 99.5 SEC, MIN INTERVAL = 0.1 SEC; DISPLAY TEMPORARILY
SHOWS INTERVAL, THEN REVERTS TO NORMAL OPERATION.
ADVANCED
OPERATION
BASIC OPERATION
AMPLITUDE RAMPS
DOWN AND UP AT
CHANGE OF
FREQUENCY. RAMP
TURNED OFF FOR
INTERVALS LESS
THAN 1 SECOND.
NOTES:
1. "PRESS" means press the button then immediately release.
2. "HOLD" means press and hold the button(s) for at least one
second, then release. In most modes the display will "blink" after
the key has been held for the required amount of time.
PRESS PLAY
SEQUENCE
RESTART
THROUGH
Operational Flow Chart
10
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