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.
This short-range experimental transmitter emits a signal with many harmonics, without modulation. It can...
The LM380 is not a modern component and in some cases not easy to find. But if you have one you...
This is the analog part of the previous circuit with the pressure sensor for the altimeter. The...