We found this circuit in documentation from the 90s. Instead of a voltmeter, you can use the voltage scale of a multimeter. The circuit tests batteries under load.
Capacitance to voltage converter (CB6075E) This Texas Instruments circuit can be used on a...
This circuit was obtained from an American 80's documentation. The transistors can be 2N2222 and...
This circuit is a small FM transmitter, capable of carrying its signals over short distances...