This circuit is from an ancient American documentation. The integrated circuit is 741 and the power supply must be symmetrical. The passing band is centered at 1 kHz.
The filter shown in the figure, suggested by National Semiconductor, only allows frequencies above...
This power supply that can supply current according to the LEC is suitable for small projects. The LED...
This PWM circuit was found in an American publication in 1978. It consists of a simple control that...