This circuit is intended for detecting 3 levels power grid voltage, and it can be adapted to operate with the most diverse voltages. The circuit uses neon indicator lamps.
This circuit is a wireless temperature transmitter for RF signals in the range of 0.2 to 2 MHz...
The transistors of this circuit found in an English 1980s documentation may be the modern BC548...
Incandescent lamps of up to a few amps can be placed to flash with this circuit. The frequency depends...