This circuit with two 555s was found in the Encyclopedia of Electronic Circuits volume 5 of 1995. The power is high due to the use of 2N3055.
The Motorola MOC501O optocoupler has a complete amplifier inside the sensor, enabling the...
This circuit is suggested by the Texas Instruments manual of linear applications of the 90's. The...
This circuit was found in the Radio Electronics magazine of May 1990. The supply voltage depends on...