Page 36 - Electronics Starter Kit_EN

Wiring diagram

8.4 Circuit Explanation

We have two modes for this circuit, to understand how this circuit works, let’s suppose the LED
is OFF, when the LED is OFF, the 100nF capacitor will be charged because it is connected to
5V through 2 MΩ resistors and connected directly to GND (All of the transistors are in
Cut-Off mode).

When you press on the push button, the current will flow from the capacitor to the base of
TR2, it will be in the saturation mode, immediately TR1 will be in the saturation mode too,
because the current will start to flow from the base of TR1(PNP) to the collector of TR2, we

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