Conrad 192230 Operation Manual

“Electronic Start” Learning Package

Item-No. 19 22 30

Version 07/09

OPERATING INSTRUCTIONS

These Operating Instructions accompany this product. They contain important information on setting up
and using it. You should refer to these instructions, even if you are buying this product for someone
else.

Please retain these Operating Instructions for future use!
A list of the contents can be found in the Table of contents, with the corresponding page number, on

page 2.

Table of contents

1 Getting started ....................................................................................................................3

2 First tries with LEDs............................................................................................................9

2.1 LED with series resistor ..................................................................................................9

2.2 Current direction ............................................................................................................11

2.3 Amperages ....................................................................................................................12

2.4 Signal lamp with pushbutton switch ..............................................................................13

3 LED circuit technology......................................................................................................15

3.1 Diode threshold voltage ................................................................................................15

3.2 Series connection ..........................................................................................................17

3.3 Little energy – a lot of light ............................................................................................19

3.4 Parallel connection ........................................................................................................20

3.5 Plays of colour ..............................................................................................................22

3.6 Flashlight ......................................................................................................................23

4 Test instruments with LEDs ............................................................................................24

4.1 Cable tester ..................................................................................................................24

4.2 Water detector ..............................................................................................................25

4.3 Alarm device..................................................................................................................26

4.4 Polarity tester ................................................................................................................27

4.5 Battery tester ................................................................................................................28

4.6 LED as temperature sensor ..........................................................................................29

5 Transistor circuits ............................................................................................................31

5.1 Amplification ..................................................................................................................31

5.2 Follow-up control ..........................................................................................................32

5.3 Touch sensor ................................................................................................................33

5.4 LED as light sensor........................................................................................................34

5.5 Constant brightness ......................................................................................................35

5.6 Temperature sensor ......................................................................................................36

5.7 On and off......................................................................................................................37

5.8 LED blinker ....................................................................................................................39

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1 Getting started

This learning package is an easy introduction to electronics. The following is a presentation of
the components.

Patch board

All experiments are conducted on a laboratory experimenting board.
The patch board with a total of 270 contacts in a 2.54-mm grid ensures safe connections of the
integrated circuits (ICs) and the individual components.

The patch board has 230 contacts in the middle section which are connected conductively
by vertical lines in groups of five. In addition, there are 40 contacts for the power supply on the
upper and lower edges consisting of two horizontal contact spring strips with 20 contacts each.
The patch board thus has two independent supply rails. Figure 1.2 shows all internal connections.
You can see the short contact rows in the middle section and the long supply rails on the edges.

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Figure 1.1: The experimenting board

Figure 1.2: The internal contact rows

Inserting components requires a good amount of force. The connecting wires might bend easily.
Therefore, make sure to insert the connecting wires exactly from the top. Use a pair of tweezers
or a small pair of pliers. Hold the connecting wires as closely as possible to the patch board and
press them down in a vertical movement. Proceed in the same way to insert sensitive connecting
wires such as the tinned ends of battery clips.

For your experiments, you require different lengths of wire which must be cut off from the provided
jumper wire. To strip the wire ends, it is a proven method to first cut into the insulation around the
wire using a sharp knife.

Battery

The following overview shows the components as they really look and the symbols used in cir­cuit diagrams. The battery can be replaced by e.g. a power supply.

You should not use alkali batteries or rechargeable batteries. Only use zinc-carbon batteries.
Although alkali batteries have a longer lifetime, they might – just like rechargeable batteries –
supply high currents above 5 A e.g. in case of a short circuit, which can cause the thin wires or
the battery itself to heat up considerably. The current supplied by a zinc-carbon battery during
a short circuit is usually below 1 A. This can destroy sensitive components but there is no
danger of fire.

The provided battery clip has a connecting cable with a flexible wire. The cable ends are stripped and
tinned. Therefore, they are rigid enough to be inserted into the contacts of the patch board. However,
they can lose shape if plugged in frequently. For this reason, we recommend leaving the battery
wires connected and just removing the clip from the battery.

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Figure 1.3: Battery and battery diagram symbol

A single zinc-carbon or alkali cell has a voltage of 1.5 V. Several cells are connected in series
in one battery. Accordingly, the symbols show the number of cells in a battery. For higher vol­tages, it is common practice to indicate the middle cells by a dotted line.

LED

The learning package includes two red LEDs, one green LED and one yellow LED. The polarity
of all LEDs must always be observed. The negative connection is called cathode. It is at the shor­ter connecting wire. The positive connection is called anode. The cup-shaped holder that holds
the LED crystal at the cathode is visible inside the LED. The anode connection is connected with
an extremely thin wire to a contact at the top of the crystal. Caution! Unlike light bulbs, LEDs
must never be directly connected to a battery. A series resistor is always required.

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Figure 1.4: Diagram symbols for different batteries

Figure 1.5: LED

- Cathode

+ Anode

Resistors

The resistors included in the learning package are carbon film resistors with tolerances of ±5 %.
The resistor material is applied on a ceramic rod and covered with a protective layer. Rings of
different colours indicate the resistor type. The resistance value and the accuracy class are
indicated.

Resistors with a tolerance of ±5 % are in the E24 list. Every decade includes 24 values with
about the same distance to the neighbouring values.

Table 1.1: Resistance values according to the E24 standard list

1,0 1,2 1,3 1,4 1,5 1,6
1,8 2,0 2,2 2,4 2,7 3,0
3,3 3,6 3,9 4,3 4,7 5,1
5,6 6,2 6,8 7,5 8,2 9,1

Begin reading the colour code from the ring closest to the edge of the resistor. The first two
rings represent digits whereas the third ring is a multiplier for the resistance value in ohms. The
fourth ring represents the tolerance.

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Figure 1.6: Resistor

Table 1.2: Resistance colour codes

Colour Ring 1 Ring 2 Ring 3 Ring 4

1. digit 2. digit Multiplier Tolerance

Black 0 1
Brown 1 1 10 1 %
Red 2 2 100 2 %
Orange 3 3 1.000
Yellow 4 4 10.000
Green 5 5 100.000
Blue 6 6 1.000.000
Purple 7 7 10.000.000
Grey 8 8
White 9 9

Gold 0,1 5 %
Silver 0,01 10 %

A resistor with the ring sequence yellow, purple, brown and gold has 470 ohms and a tolerance
of 5 %. The learning package includes two resistors of each of the following values:

100 Ω Brown, black, brown
220 Ω Red, red, brown
330 Ω Orange, orange, brown
470 Ω Yellow, purple, brown
1 kΩ Brown, black, red
10 kΩ Brown, black, orange
100 kΩ Brown, black, yellow

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Transistors

Transistors are components used for the amplification of small currents. The used BC547 resis­tors are silicon NPN transistors.

The connections on the transistor are called emitter (E), basis (B) and collector (C). The basis
connection for both transistors is in the middle. Looking at the label with the connection pointing
downwards, the emitter is on the right.

Capacitor

The capacitor is another important electronic component. A capacitor consists of two metal sur­faces and an insulating layer. When electric voltage is applied, an electric field in which energy is
stored builds up between the two capacitor plates. A capacitor with a big plate surface and a
small distance between the plates has a high capacity, i.e. it stores a lot of energy when voltage
is applied. The capacity of a capacitor is measured in Farad (F).

Electrolytic capacitors reach high capacities. The insulation consists of a very thin layer of alu­minium oxide. The electrolytic capacitor contains a fluid electrolyte and aluminium foil with a big
surface. Voltage must only be applied in one direction. In the wrong direction, leakage current
will gradually reduce the insulating layer and finally destroy the component. The negative
terminal is indicated by a white stripe and the connecting wire is shorter.

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Figure 1.7: Transistors

Figure 1.8: Electrolyte capacitor

2 First tries with LEDs

You can take a battery and a small light bulb and try different things until the bulb lights up. You
should not try the same with an LED as it will be destroyed quickly if connected directly to a battery.
You have to proceed a bit more systematically: Observe the correct voltage, the right polarity, and
use a suitable series resistor. It is not really difficult. Try out the circuits described below to become
familiar with working with LEDs.

2.1 LED with series resistor

Set up your first circuit with a battery, an LED and a series resistor. Use a red LED and a 9V
battery. Take the hightest resistance value (1 kΩ = 1000 Ω, colours: brown, black, red) from
the learning package to be on the safe side in terms of LED current. Figure 2.1 shows the cir­cuit as a circuit diagram.

Use the patch board to set up the circuit. Connect the upper supply rail with the positive terminal
of the battery, i.e. with the red connector on the battery clip. Connect he lower supply rail accor­dingly to the black clip connector, i.e. to the negative terminal of the battery. The actual circuit will
resemble the circuit diagram so that troubleshooting should not pose any problems. Bend the
connecting wires of the LEDs and the resistors so that they fit into the contacts. Some connecting
wires were shortened in this test setup for better illustration. You should, however, leave the
wires uncut to ensure that the components can be used for all other experiments as well.

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Figure 2.1: Circuit diagram of LED with series resistor

The first try will probably be successful. The LED lights up brightly. If not, look for the mistake.
Any interruption of the circuit prevents current flow. Therefore, check all lines and the position
of the components on the patch board. As another possible problem, the LED might have been
inserted the wrong way, or the battery is empty. You will notice, however, that even very old
batteries still provide enough power for the LED to light up weakly.

Try a different layout. Swap the LED and the resistor. The current will then flow through the LED
before flowing through the resistor. The effect is the same as in the first case, however. The
only important thing is that all three components are connected in a closed circuit.

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Figure 2.2: Setup on the patch board

Figure 2.3: Swapped components

2.2 Current direction

Turn the LED so that the anode is connected to the negative terminal of the battery. There is no
light! This means that current can only flow through the LED in one direction. The forward
direction is the current direction from anode to cathode, with the anode connected to the positi­ve terminal of the battery and the cathode to the negative terminal. In reverse direction, the LED
is blocked. A diode is like an electric valve. It only lights up when current is let through. Figure

2.5 shows the LED with reverse direction. It cannot light up.

The arrows in the LED circuit diagram in figure 2.6 indicate the direction of current. The direction
of current as well as the designation plus and minus was defined arbitrarily in history. This
means, current always flows from the positive terminal of the battery through the load to the
negative terminal of the battery. Today, it is common knowledge that negatively charged elect­rons inside the wires move exactly opposite to the direction indicated by the arrows in figure 2.6.
There are, however, positive charge carriers as well, as e.g. in fluids, that move with the direc­tion of the current. Even inside the LED itself there are negative and positive charge carriers.

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Figure 2.4: LED and resistor swapped

Figure 2.5: LED in reverse direction

2.3 Amperages

Instead of the 1-kΩ resistor, insert a smaller resistor of 470 Ω(yellow, purple, brown). The LED
lights up noticeably brighter. This indicates higher current. The rule is: The higher the resis­tance, the lower the current. More accurate calculations are stated below.

Test the brightness of all LEDs with resistors of 1 kΩ (brown, black, red), 470 Ω (yellow, purple,
brown) and 330 Ω (orange, orange, brown) each. However, do not use a resistance lower than
330 Ω, as this might result in a current too high for the circuit with a 9-V battery and consequently
harm the LED.

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Figure 2.6: Direction of current

Figure 2.7: More brightness with a lower series resistance