PURPOSE: To obtain an electric timer circuit which features the steady operation in a miniature structure and an automatic breaking of the power supply in a fixed time after making the power supply.

CONSTITUTION: The timer circuit rectifies the AC power supply with diode 20 and then supplies the output voltage to the time constant circuit consisting of capacitor 10 and resistance 6. The serial circuit comprising discharge tube 12 and resistance 7 is connected to capacitor 10, and the output is supplied to the base of emitter- earthed type transistor 13. Then relay 15 is actuated by the rectified output voltage, and at the same time the input of the power voltage is held via the holding circuit consisting of relay contact 1. The voltage of the capacitor in the time constant voltage is raised up after application of the power voltage. After a fixed time, the voltage of capacitor 10 becomes higher than the discharge start voltage of tube 12. Thus, the discharging is started to supply the current and thus to actuate transistor 13. At this instant, the collector-emitter voltage of the transistor becomes near zero volt. In this connection, transistor 13 is connected in parallel to relay coil 15 to secure the switching action. As a result, the operation of the relay is stopped, and thus load 14 is broken from the power supply.