This circuit is based on learning of the discharge and charge of the C, which can be used as a timer circuit and can be applied in the off electrical appliances. The application has also put relay instead of LED can be enabled.
This circuit is working as video below:
When you click the switch S1 will cause LED1 light told state ready to run S2 is a timer switch. On press switch S2 current will flow to the C1 charge fully. Then to discharge out through R2 to limit current flow to the bias for transistor Q1. Q1 and Q2, which work together to Darlington Compound. To have growth rates high to drive the LED2 light over time as C1 discharge all Q1 and Q2 stops LED2 is off if you want the timer circuit is longer. Then add the C1 and if you want a little time. to reduce it to C1.
10 Second Fan on delay timer circuit by transistor
A friend of me wants 10 second delay timer circuit at can turn ON Fan 12V at use in an automobile. By fix the period of time about 10 second. He sets conditions that must use electronic part economize and seek easy with. I then choose transistors and relay be control electric fan equipment follow the circuit in a picture. The value delays can fix with R1 and C1 which there is a formula calculates 0.5 x R1 x C1 . When press S1 wait for about 10 second relay then work turn on give the electric fan works. The detail is other see in the circuit.
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