•  
  •  

Light Barrier Detector

Designed by Naveen P N

This simple circuit using a single transistor turns ON the relay when light falls on the LDR.
The potentiometer is adjusted for the required sensitivity.
The power supply is 6V.
Be careful about the impedance of the relay. Its impedance should not be less that 60ohm.
Its working can be explained as follows:
With the light falling on the LDR,its resistance is low and the transistor is saturated and turns the relay ON.
When light is obstructed, the LDRs resistance becomes very high. The potentiometer shorts the transistors
base to ground and it is cut off. Hence the relay is OFF.

Tested 11th Jan,2001 by Naveen P Nwebmaster@electronic-circuits-diagrams.com

If there are any problems please contact webmaster@electronic-circuits-diagrams.com

Please share & like

1Pcs New In Box Siemens Memory Card 512KB 6ES7 953-8LJ30-0AA0 6ES7953-8LJ30-0AA0
$223.68 1Pcs New In Box Siemens Memory Card 512KB 6ES7 953-8LJ30-0AA0 6ES7953-8LJ30-0AA0 picture
1Pcs New In Box Siemens Memory Card 2MB 6ES7 953-8LL20-0AA0 One year warranty
$318.18 1Pcs New In Box Siemens Memory Card 2MB 6ES7 953-8LL20-0AA0 One year warranty picture
New in box Mitsubishi Memory Module A3NMCA-16 One year warranty
$279.98 New in box Mitsubishi Memory Module A3NMCA-16 One year warranty picture
1PC Siemens S7-200 64k Memory 6ES7291-8GF23-0XA0 New In Box
$68.0 1PC Siemens S7-200 64k Memory 6ES7291-8GF23-0XA0 New In Box picture
New Mitsubishi Q series PLC module memory card Q2MEM-4MBF One-year warranty
$206.4 New Mitsubishi Q series PLC module memory card Q2MEM-4MBF One-year warranty picture