Impulse switch made with transistors

Impulse switch made with transistors - Interruption of another circuit or electrical charges without timing

Reading time: <1 minut

How does the project work?

The assembly is based on two PNP transistors (BC557) and one NPN (BC337). Each time the SW1 button is pressed, the contact relay will be activated / deactivated.

At start-up (SW1 = ON), the voltage at the base of T1 and T2 is equal to the supply voltage. The base of T3 is grounded, which causes relay K1 to activate and LED1 to be active. The circuit shown absorbs a current of only 0.1uA in standby.

List of required components:

1 x Breadboard test board + connecting wires
1 x R1 = 2.7k
1 x R2 = 100k
1 x R3 = 1k
1 x R4 = 100k
1 x R5 = 1k
1 x R6 = 1k
1 x R7 = 2.7k
1 x Push-button (SW1)
1 x C1 = 10uF
1 x C2 = 220uF
1 x C3 = 1uF
1 x D1 = 1N4148
1 x LED1
1 x Relay (K1) = 5V
1 x T1 = BC557
1 x T2 = BC557
1 x T3 = BC337 / 2N2222
1 x Terminal contact

For a better understanding of the operation of the circuit and to make this assembly on the breadboard we will need the diagram electronics presented lower:

In order to better understand the operation of this montage, we have attached the videos below, in which they are presented some similar circuits:


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