This car battery monitor was featured in the January 1988 issue of Radio Electronics magazine. The circuit uses common transistors and has 3 levels of indication made with common LEDs.
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...