Circuit Project Electronic

Detects 1.8 to 230 Volts DC or AC. This circuit is not a novelty, but it proved so useful, simple and cheap that it is worth building. When the positive (Red) probe is connected to a DC positive voltage and the Black probe to the negative, the Red LED will illuminate. Reversing polarities the Green [...]

Suitable for alerting purposes
Drives 12V Car bulbs
Derived from the Two-wire Lamp Flasher design, hosted on RED Free Circuit Designs since 1999, this astonishingly simple circuit allows one or two powerful 12V 21W car bulbs to be driven in flashing mode by means of a power MosFet.
Devices of this kind are particularly suited for road, traffic [...]

This circuit is Light Meter, use IC LM334 is easy circuit.
Supply Volt 1.5-20V, Meter : 1mA.
PC1 = CdS Photocell or LDR.
If you are looking for Light meter circuit that good and easy. I inviting for to advise this circuit , because use IC LM334 (3-Terminal Adjustable Current Source) use easy. follow [...]