This filter for frequencies from 300 Hz to 3.4 kHz was found in the February 1995 Radio Electronics magazine. Other operational amplifiers can be experimented, and the source must be dual.
The components used in this 80's circuit are uncommon today. The circuit is intended for...
This experimental flip-flip changes its state by the command of two push-buttons. The state is...
This circuit was obtained from a 1986 Spanish magazine Resistor. The magazine no longer exists, but...