OVER LIGHT SENSOR ALARM CIRCUIT


Posted on Feb 4, 2014

The LDR is a variable resistor whose resistance decreases with increase in light intensity. When the light falling on an LDR has normal intensity, its Resistance is large enough and the voltage across R is insufficient to trigger the SCR. However, when light falling on LDR is of large intensity, the Resistance of LDR falls and voltage drop across


OVER LIGHT SENSOR ALARM CIRCUIT
Click here to download the full size of the above Circuit.

R becames large enough to trigger the SCR. Consequently the buzzer sounds the alarm. It may be noted that if the strong light disappears the buzzer continues to sound the alarm. It is because once the SCR is triggered the gate loses its control.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Electronic TIC TAC TOE
Plug-in speed control for tools or appliances
Urban Sensing Networks using Arduino
pic16f84a relay control board
simple precision current source circuit
100khz square wave generator
pll fm demodulator
in making incandescent lamps
Tilt Alarm Circuit
VHF Stability
Linear AC voltmeter circuit diagram



Top