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.
Originally this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...
This circuit was obtained in a 1967’s EEE. Transistors and integrated circuits can be replaced by...
In the figure we have a simple amplifier stage for BC547 series transistors. The gain is...