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Idiomas disponibles
KNS130
28
29
22
17
18
3
4
23
24
48
49
Complete all wiring connections as indicated in the sequence. Switch on the main switch. Dampen you
finger with water and touch the touch plate. Through only very little amount of electric current flows
through the touch plate (as shown in the last experiment), the LED is switched on brightly! It is because
in this circuit, the PNP transistor is the real gateway to the LED, and the touch plate 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 you touch the touch plate, 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!
12.9 A simple demonstration of the function of the NPN transistor
Wiring Sequence
28-25, 26-17, 18-3, 4-29-49, 48-27
28
29
25
17
18
3
4
27
26
48
49
Complete all wiring connections as indicated in the sequence. Switch on the main switch. Touch the touch
plate. Through only very little amount of electric current flows through the touch plate (as shown in the
last experiment), the LED is switched on brightly! This is pretty much the same as the case of the PNP
transistor. It is just the polarities of the transistor that are reversed.
12.10 Two LEDs in parallel connection
Wiring Sequence
4-49-51, 50-48-17, 18-3
V. 01 – 01/02/2024
14
©Velleman nv
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