Automatic emergency lighting circuit

  
Automatic emergency lighting circuit shown, it is suitable for families install yourself. Because it uses smaller components, the price is cheaper. When the normal power supply mains, 220V AC mains voltage through capacitor CI ire.k pressure, and then by a
Automatic emergency lighting circuit - schematic

half-wave rectifier diode VD1 and capacitor C2, after filtering, pulse current of about 90mA to charge the battery. And this at the same time, since the transistors VT1 base with a forward bias state in the conduction state, so that a 2 is off, the bulb does not light EL.. Once the mains power network, turned on by the transistor VT1 goes off, VT2 off by the change to the conduction, EL light bulb. Diode VD2 role is to isolate the battery and VT1 base level, to ensure that electricity stops. VT1 turn HU indigo only. After mains power is restored, VT1 conduction, EI. Off, reset the circuit. Figure. To 6. 3V, 0.15A small electric startled, batteries can be used 4 1 battery, can also be used 6V batteries.




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