•  
  •  

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


Johnson Controls Metasys MS-NCE2566-0  picture

Johnson Controls Metasys MS-NCE2566-0 

$1000.00



Johnson Controls Metasys - AP-VMA1420-0 VAV - Modular Controller - w/ Connector picture

Johnson Controls Metasys - AP-VMA1420-0 VAV - Modular Controller - w/ Connector

$200.00



Johnson Controls Metasys AP-VMA1410-0 VAV Modular Controller - VMA 1410 picture

Johnson Controls Metasys AP-VMA1410-0 VAV Modular Controller - VMA 1410

$129.00



Johnson Controls Metasys MS-NAE5510-2 picture

Johnson Controls Metasys MS-NAE5510-2

$2500.00



Johnson Controls Metasys DX-9100-8454 NEW picture

Johnson Controls Metasys DX-9100-8454 NEW

$1099.00