Found on an 80's Elektor, this circuit uses common components, being the diode a general purpose germanium. The coils select the frequency range of the indicator that reaches 60 MHz.
This circuit was obtained in an American documentation translated in the 80's. The circuit can be...
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...
This circuit was suggested by National Semiconductor in its Linear Application Handbook. The...