This charger for small batteries was obtained from the 1982 Radio Experimenter Handbook. The circuit is low current.
This circuit was obtained in a Radio Electronics of the 90s. The circuit uses an integrated circuit...
This squelch is activated by its own noise, acting automatically. It is used in communications...
In this circuit of the 1980s, the T1 transformer has 30 turns of 28 primary wire and the secondary...