A blast from the Elektor archives: this 1998 battery tester uses a simple LED display to reveal a battery’s true condition ...

This circuit runs a fast battery test without the need of power supply or expensive moving-coil voltmeters. It features two ranges: when SW1 is set as shown in the circuit diagram, the device can test ...

Is the battery empty, or is there something wrong with the device? That’s always a difficult question when your walkman or some other battery-powered device appears to be dead when you switch it on.