555 Astable Multivibrator Circuit Diagram. Pin 2 and 6 are shorted and then connected to ground through the capacitor c to ground terminal pin 7 is connected to supply v cc through a resistor r a. On time off time frequency etc can be calculated using above formulas.
And between pin 6 and 7 a resistor r b is connected. I made a dedicated tutorial on astable multivibrator using 555 timer. 2 trigger and pin no.
You can find a lot of circuits and applications using astable mode in 555 timer circuits.
In this 555 astable multivibrator circuit led will switch on and off automatically with a particular duration. I made a dedicated tutorial on astable multivibrator using 555 timer. The 4th pin is reset pin which is active low and is connected to vcc to avoid accidental resets. 6 threshold are shorted together.