With this circuit it is possible to measure RF signals with a common multimeter. Signals up to 200 MHz can be detected. The diode supports general-purpose equivalents.
We found this circuit in an old documentation. The indicated solenoid is of low current type,...
This commercial circuit of 3 transistors was found in Japanese documentation from the 1960s. The...
This circuit was found in National Semiconductor documentation from the 90s. The circuit uses two...