Velleman KNS120 Manual Del Usuario página 16

12.16 EXPERIMENT 16 - A simple demonstration of the light sensor
Wiring Sequence
2-34, 33-16, 15-13, 14-1
2 1
34 33
- Complete all wiring connections as indicated in the sequence.
- Switch on the main switch. You may notice that the LED lights up very dimly. This indicates only a very
small amount of current is flowing through it. It depends on the intensity of light falling onto the light
sensor. If you perform this experiment in a darker place, the LED may not light up at all.
- If you use a torch to shine on the light sensor, you can see that the LED light up brightly. This is
because when there is more light, more current will be able to pass through the light sensor and light up
the LED.
12.17 EXPERIMENT 17 – A simple demonstration of a function of the PNP
transistor
Wiring Sequence
2-7, 9-16, 8-34, 33-15-13, 14-1
34
8
2
9 7
16
- Complete all wiring connections as indicated in the sequence.
- Switch on the main switch. This time, even with a small amount of light, the LED will light up brightly!
- It is because in this circuit, the PNP transistor is the real gateway to the LED, and the light sensor is
only acting as a switch for opening the gateway! When the upper part of the circuit is not connected, no
current is flowing through the "Emitter" to the "Base" of the transistor. So the gateway of the "Emitter" to
the "Collector" is shut. When light falls on the light sensor, the upper circuit is connected; a very small
amount of current passes through the "Emitter" to the "Base", and then the gateway of the "Emitter" to
the "Collector" is opened! Electric current from the battery can then flow through the transistor to the
LED, and therefore the LED will light up brightly! This circuit makes the light sensor to become a sensitive
switch to detect light.
12.18 EXPERIMENT 18 – A simple demonstration of a function of the NPN
transistor
Wiring Sequence
2-34-16, 15-12, 11-33, 10-13, 14-1
V. 01 – 19/01/2024
14 13
16 15
33
1
14 13
15
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