This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM backup battery. Resistor R1 determines the battery charge.
This amplifier uses common transistors in a phase inverter configuration. Transistors must be...
This is the same amplifier circuit as the previous circuit adapted to operate with a single...
In fact, this 1994 circuit uses a scale of LEDs to indicate the pulse rate applied to its input....