Complete all wiring connections as indicated in the sequence. Switch on the main switch. Access the reed
switch with the magnetic pole. The LED will light up as the circuit is connected. Move away the magnetic
pole, and the circuit will be disconnected, and the LED will be off.
12.4 Demonstration of resistance and current
Wiring Sequence
48-3, 4-52-17, 18-9, 10-49-8, 7-53
49
48
100Ω
8
7
10kΩ
10
Complete all wiring connections as indicated in the sequence. Switch on the main switch. The LED will
light up dimly. Switch off the main switch to turn it off. Now press the push switch. The LED will light up
more brightly. This is because the path of the main switch has a resistor of larger resistance. So the
current through this path will be less, and as a result the LED will be less bright. On the other hand, the
path of the push switch has a resistor of smaller resistance. So the current through this path will be
more, and the LED will be brighter.
12.5 Resistors in series connection
Wiring Sequence
4-12-16-53, 52-11-10, 9-15-8, 7-18, 17-49, 48-3
4
3
53
52
Ω
100k
12
11
16
15
Complete all wiring connections as indicated in the sequence. Switch on the main switch. The electric
current from the batteries will have to pass through 3 resistors, and therefore the LED will light up very
dimly, or apparently not light up at all. Press the push switch. This time, the current will have to pass
through 2 resistors only, so the LED will light up brighter than before. Access the reed switch with the
magnetic pole. This time, the current will have to pass through 1 resistor only, so the LED will light up
even more brightly. As an analogy, a resistor is like an obstacle. The fewer obstacles are there in the
circuit, the more current can flow through.
12.6 Resistors in parallel connection
Wiring Sequence
4-17, 18-11-52, 53-9-15, 16-7, 8-10-12-49, 48-3
V. 01 – 01/02/2024
3
53
52
9
18
49
48
10kΩ
100Ω
10
9
8
KNS130
4
17
17
18
7
12
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