This super regenerative detector circuit was found in an English documentation from 1963. The coil is frequency compliant. The transistors are germanium of the time.
This circuit was found in an Electronics Now from the 90s. The frequency depends on the crystal. The...
The figure shows an excellent benchtop isolation transformer system. This circuit was suggested by...
This circuit monitors the humidity of a pot or plant bed, providing indication on two LEDs. The...