We should have a system time delay. When a power failure, Then, not long typical power. This system is not connected to the AC line to the electrical appliances.
But it will time delay is period of time, when the surge electrical away, power system will continue to electrical appliances again. Our electrical appliances so safe. Without the worries. this surge protector circuit build simple and cheap as ever.
At first, not have a 220 volt AC
power into this circuit, The relay contacts-RY1 are connected to NC terminals. As shown in a circuit figure below. Thus making electrical appliances is not working. But after the powering the primary coil of the transformer T1 and then the secondary coil has AC voltage is 9 Volt, next it is So is rectified from AC to DCV by diodes D1-D4 and is filtered voltage with smooth by C1.
Circuit Delay System C1815
The C2 as acts the delay, by it will store slowly charged, until enough to Q1 works. The VR1 is used to adjust the time delay. (Time delay is electrical appliances, do not run immediately, After the AC line flowing into this
circuit.) when Q1 and Q2 transistors works. Contacts of the relay is switched to the NO. electrical appliances are ready to works now. In the event of a power failure the relay contact is connected to the NC, RY1a cut off electrical appliances out of ac line power. For the D5 to protect the transistor from the operation of relay.