You tried to optimize the circuit for a full battery, without realizing that you’re cutting the useful duty from the other end of the battery voltage range. > At 2mA the Vf would be higher, that ...

The compact ac light dimmer module with zero-crossing detector described here is ideal for microcontroller-based ac voltage controlling applications and projects. This module contains a triac ...

Designed to illuminate the work area when tracing ac circuits in dark areas or behind equipment, the SenseLite is a battery-powered flashlight with a noncontact ac voltage detection circuit and a ...

The AC mains voltage is rectified by diode D1, and the resulting DC voltage is smoothed by capacitor C2. Zener diode ZD1 is added as a pre-regulator for total circuit protection. In case of an open ...

Circuit Combines DC High-Voltage Drop Detector, Undervoltage Alarm Dec. 14, 2010 Description of a circuit to tell if the high-voltage supply in an industrial smokestack precipitator is functioning ...

In the video embedded below, he shows off a homemade voltage detector circuit that he constructed using a trio of BC547 NPN transistors. The circuit is pretty simple though very useful all the same.

For those unfamiliar, it’s shown in Fig. 2. It’s an AC inductive probe that glows red when it senses AC voltage. Before reaching into any equipment, pass the volt pen around breakers and disconnects ...