Radio Frequency Millivoltmeter


This article will help you to build yourself a radio frequency probe. It is an useful plugin to any Digital Multimeter.
Most devices of this kind are simple full wave diode rectifiers. Their biggest drawbacks are the high input capacitance and low input impedance. These make it impossible to give right readings at high frequencies. In some cases, these probes change the parameters of the measured circuit so much, that it stops working.
Another major issue is that these devices do not operate with input voltages below 0.4V

The radio frequency probe described in this article, consists of a high frequency buffer with very low input capacitance and a transistor detector instead of diode one. These allow the specifications described.
rf probe Radio Frequency Millivoltmeter Radio Frequency Millivoltmeter circuit