Free Circuit Diagram

This circuit is another radio frequency (rf) field strength meter, similar with our previous field strength meter circuit, but with lower supply voltage (only a single cell 1.5V battery). Here is the schematic diagram of this rf strength meter circuit:

To use, turn on transmitter and meter; adjust C1 for peak reading. Turn off [...]

This instrument is very useful for radio frequency (rf) engineer and hobbyist, especially when he/she has to adjust the final rf transmission. Setting up an antenna impedance matcher is one of the example. Here is the schematic diagram of this rf meter circuit:

The circuit use only one transistor (MPSA18) as the active component. The signal [...]