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.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...