•  
  •  

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

New Cisco R200-1120402W UCS-C200-M2 N2XX-AIPCI02 Rack Mount Server A01-X0111
$25.0 New Cisco R200-1120402W UCS-C200-M2 N2XX-AIPCI02 Rack Mount Server A01-X0111 picture
PENTIUM III XEON MICROPRESSOR W/ HEATSINK-NOS
$9.95 PENTIUM III XEON MICROPRESSOR W/ HEATSINK-NOS picture
Intel Xeon E5-2680 2.7 GHz 8-Core Processor SR0KH
$149.99 Intel Xeon E5-2680 2.7 GHz 8-Core Processor SR0KH picture
16 Inch Light Under Cabinet Xeon 25 Watt Bulbs Included. Stainless Steel. H/W
$25.3 16 Inch Light Under Cabinet Xeon 25 Watt Bulbs Included. Stainless Steel. H/W picture
Supermicro 815-6 6016T-NTRF Server w 16GB RAM No Hard Drives
$179.99 Supermicro 815-6 6016T-NTRF Server w 16GB RAM No Hard Drives picture