The configuration shown was found in an old Poptronics but can be easily assembled using a common calculator photocell. The relay is according to the supply voltage.
This circuit is from an October 1963 Radio Electroncs. It uses a single 2N18383 transistor and a...
This circuit has a gain of 34 dB and a good power to be used as an audio booster in cars. The...
A flash of light directed at the LDR causes the SCR to fire and the motor to be activated in the...