This circuit allows the detection of RF signals using the lowest range of direct currents of a common multimeter. Equivalent diodes such as 1N34 can be used. The circuit is assembled in a ballpoint tube.
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
This project from a 1983 publication can be assembled using more modern transistors. We can use...
The circuit shown in the figure is the version activated at the low level, of the previous circuit...