Using relay general the majority then to use power supply that have DC Voltage with the value volt that specify on relay. For relay work but , if , we have no power supply that want to feed give relay. This circuit helps to give relay can work.
How the circuit works
From the circuit uses two power supply from at for come to work give Relay 12V work. The power supply first use 6Volt when feed volt come in touch C1 charge take keep. The power supply that 2 use voltage more than 3V feed come in the way input make Q1 work. It make Q2-BC558 work go to with be make C pin of Q2 have voltage source 6V feed give relay Ry1 and When Q1 work will compared as something through the circuit down ground. It make C1 do something discharge 6Volt come out of the cathode of capacitor C1. Which build with a pole of relay RY1 again beside one make have drop voltage relay RY1 equal to 12V. Then make relay RY1 work and will work long ago only? that depend on something discharge of capacitor C1.
Replace Part: BC558 = BC327 = BC556 = 2N4403 PNP 40 Volt 0.6A
2SC458 = 2SC1815 =2SC828 = 2SC2675 = BC337 = 2N2222
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