basic cds photocell detector

Posted on Feb 6, 2014

This is a Basic Cadmium Sulfide (Cds) Photocell Detector circuit. In this circuit, when the light falling on the photocell (PC 1) is blocked, its resistance will increase and the voltage across PC 1 will rise. When the voltage rises above 1/2 of the supply voltage the output of the comparator will turn ON and the LED will be lit. Due to wide varia

basic cds photocell detector
Click here to download the full size of the above Circuit.

tions in CdS photocells it is usually best to install the cell and then measure its resistance under normal lighting conditions. A resistor with a value that is approximately 3 to 5 times the measured resistance of the cell is then selected for R1. For example; If the cell resistance is measured at 400 ohms then a 1200 to 2200 ohms resistor would be used. Increasing the value of R1 will cause the sensitivity of the sensor to decrease. This may be necessary when the light falling on the cell is not very strong or shadows can affect the photocell.

Leave Comment

characters left:

New Circuits



Popular Circuits

4W FM Transmitter with 2N2219
Capacitor Charger Lead Acid Battery
1 khz oscillator
Digital Pressure Gauge Circuit
DC motor 12V speed controller circuit with explanation
Double-Sideband Suppressed-Carrier (DSB-SC) Modulator
fm stereo decoder
uhf tv preamplifier circuit
Measurement Related
Doorbell Cascade
PA Time sequencer
USB audio DAC with PCM2704
grundig 5040w3d circuitry analysis
VCO Seiler 80Mhz-300Mhz
Vibration burglar alarm circuit
Adjustable from 3 to 9V 100mA power supply circuit