The circuit shown in the figure allows a load to be switched on and off (through a relay) at regular intervals determined by the setting of P1. The active cycle is 50%. For other active cycles, we have circuits in this series with an appropriate configuration. The frequency also depends on C1, which can have its value changed over a wide range, reaching 1,500 uF when a total activation cycle of close to 1 hour is obtained. The power supply depends on the relay used and in the condition that the relay is not activated the consumption of the unit is very low.
