This circuit covers 400 kHz to 40 MHz in three bands according to the selected coil. The double MOSFET allows equivalent, since the original is not easy to obtain.
This circuit generates 500 Hz rectangular signals. The circuit is from old American documentation. Neon...
The circuit shown is a documentation on 80's tunnel diodes. The frequency depends on the delay line...
In the figure we have a small general-purpose amplifier with the LM386 integrated circuit and...