This amplifier for the 10 m (30 MHz) band has a gain of 12 to 15 dB having been found in an American documentation. Other RF transistors can be used like 2N2222 or 2N2218.
This simple metal detector was found in a 1960 Sylvania transistor manual. The phone must be high...
The figure shows how to obtain an 800 Hz astable circuit controlled by an external signal. The...
We find this circuit in an American 1980s documentation. It can be applied to any operational...