This 300 Hz to 3.4 kHz filter was found in the May 1989 Radio Electronics magazine. The circuit requires a symmetrical power supply.
This charger circuit provides an initial voltage of 2.5 V and when the current reaches 180 mA the...
The FET of this circuit of a 1971 publication may be the BF245. The circuit serves as a voltage...
This circuit was found in an American 1980s documentation. The transistors admit equivalents and the...