Found in a 90s Popular Electronics, this circuit allows to select the operating ranges between short waves and VHF. MOSFET is uncommon today.
The circuit shown in the figure generates a rectangular signal whose frequency depends on C1. For...
This circuit suggested by Texas Instruments, operates with pulses, and is based on an operational...
This circuit captures, through a coil, the signals emitted by another coil under the mat connected to...