How To Make A Dark Sensor

 

Step 1: Things You Need

 

Parts:-
1) 1x BC547 transistor
2) 1x 220 k resistor
3) 1x 330 ohms resistor
4) 1- small perf board
5) 1x led (any colour )
6) wires
7) 9v battery
8) battery clip
9)ldr(light dependent resistor )

Tools:-
1) soldering rod and wire
2) wire stripper 

Step 2: Getting started

solder the transistor on the perf board and solder one wire of the ldr to the emitter and other to the base  , solder the negative wire of the led to the base of the transistor with a 330 ohms resistor and also solder 220k resistor with the one side of the 330 ohms resistor

 

 

Step 3: Finishing touches

 

you can use a SPDT switch it is optional, it used to pin headers as the connectors for the power .