Circuit Diagram Using 555 Timer. Read or download gallery of led flasher circuit using 555 timer high voltage amplifier circuits led flasher circuit using 555 timer. We have used a variable resistor in place of fixed resistor for changing duty cycle of the output signal.
The npn transistor q 1 will be turned on if its base to emitter voltage is positive and greater than cut in voltage. As discussed in the above section the ic is in its standard monostable mode. Inside the 555 4.
When the trigger input is applied555 timer produces a pulse.
The circuit can give a time delay of 2 minutes to several hours. For 5 min 10 min and 15 min you just have to change the resistor value r1. The above circuit diagram is for the 1 minute timer circuit. Before going into detail of time delay circuit first we need to learn about 555 timer ic first.