Automatic periodic switching circuit 2

Automatic periodic switching circuit 2

It uses 555 time base integrated circuit A as the time control component} and uses a capacitor step-down circuit;
a bidirectional thyristor V is used to control the power-on and power-off time of the relay
or load.     Adjusting the potentiometers RPi and RP2 (or Cl) can change the pull-in and release time of relay KA respectively. For example, if RPi
is adjusted to 300k,0 and RPz is adjusted to 220kfl, the pull-in time of KA is 20s and the release time is 15s.