Light Relay Switch By BC547 & BC337

This circuit is simple form but can be useful various such as The alarm circuit, an more electronic control circuits such as ON-OFF electrical equipment, the flash light control circuit or etc. following with do you want.
Function of the circuit
From the circuit in Figure 1 that see two transistor Q1 BC547,Q2 BC337 join together in Darlington compound In order to have a higher increase rates.
When has a light on the photocell (LDR1) The resistance will reduce. The bias voltage is supplied to the transistor up, just enough to make transistors and relays it to work.
The VR1 is a base circuit of the transistor that controls the sensitivity of the circuit.
If the offer is less so. The sensitivity of the circuit is low, It provides very valuable. The high sensitivity.
Construction
To operate the device in the PCB properly. In Figure 1 soldered properly. Try entering a power source in the circuit. then adjusted the VR1 to sensitivity by do you want.

Circuit Light Relay Switch By BC547 & BC337

PCB Light Relay Switch By BC547 & BC337

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