This RF circuit measures transmission power from 0.25 W to 10 W. The maximum frequency depends on the diode and the gauge is an analog instrument. A multimeter can be used instead.
Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M...
We found this circuit in a 1995 documentation. It can measure frequencies from 100 kHz to over 100 MHz...
This circuit was obtained in a documentation from the 70s. The operational amplifiers used are...