A simple timing circuit can be built using electronic diagram below. This electronic timer circuit is built using integrated circuit UAA3000 which has the following features: can be powered directly from the network; has built in stage to command triacs, triac coupled to the circuit is always lit when the voltage zero crossing network, a pause in supply does not affect the function of timing.
Time that can be programmed is quite large: 1 ... 15 minutes, in increments of one minute, or 1 ... 15 hours, in increments of one hour.
UAA3000 takes voltage directly from the outlet network and works with a negative voltage, which is why the positive terminal of capacitor C1 is connected to ground. This capacitor acts as a battery during brief interruptions of electricity.
Desired time is selected using jumpers J1 making proper connections ... J5. If they want to delay of hours, J5 jumper is not installed.
Once the timing scheduled, installation can be started by a short press S1 button. Immediately, the integrated circuit will provide triac gate pulses. Gate current is dictated by the resistance R4. The value of R4 in this diagram, provide a current of 15 mA, enough to control a triac type TIC206D. Internal zero crossing detector collects its information through the network of R3.
Without a heatsink for triac , it can control loads up to 200 W, while with a suitable radiator loads may increase to 800 W.