This filter was found in an American publication from the 1980s. The circuit can be implemented with any operational amplifier. The power supply must be symmetrical.
In the figure we show a trigger circuit for triacs with a unijunction transistor. The circuit is...
The oscillator in the figure has its frequency determined by the crystal. The indicated value is...
This circuit was found in the November 1959 Radio Electronics magazine; The circuit generates a...