Using an LDR, this Philips circuit directly activates a relay when light strikes the sensor. The relay is 45 V with 20k coil resistance. The 220 nF capacitor must be polyester for 400 V.
We have articles on the site with the name “lamp test” for this configuration found in a Popular...
The circuit we present is suggested by Linear Technologies (www.linear.com) and makes use of an...
This current sensing circuit for applications up to 10 A has been found in a Linear Technology...