I have traced down a IR illuminator pcb which used in cctv cameras for night vision.
Can someone decode the logic flow of this circuit. I know what is LDR and transistor used for but still i need some help to decode this circuit.
I have mentioned a signal pin. This pin gives out the signal to main pcb to handle the camera shutter based on the light intensity.
And the input it actually 12DC. When light level goes low, the LEDs will turn ON and variable voltage(6v to 10v) is generated in signal pin which is transmitted to main pcb board.
Q1 is pnp
Q2 is npn
Q3 is power transistor.