This circuit can be used as an amplifier for musical instruments or even with your cell phone. The circuit is old and was found in the 1990 edition of Radio Electronics Experimenter magazine.
In this circuit, D.A. which is actually O. A. of an operational amplifier, which can be any type...
A narrow range of frequencies around 1 kHz is rejected by the high Q filter shown in the figure,...
This circuit, which uses a planar silicon sensor, is from a 1964 Electronic Design. The component...