The QROP Meter uses a directional coupler circuit connected between the transmitter and antenna. The directional coupler samples the antenna's RF voltage and RF current and produces the forward RF voltage sample and reflected RF voltage sample. These two RF voltages are fed into the rectifier stage, which converts them into DC voltages with the same values as their respective 0-to-peak RF voltages. The output display stage uses a microcontroller to process the rectified forward and reflected voltages and light the appropriate LEDs in the wattmeter and SWR displays. The power supply circuit provides 12V for the rectifier stage and 5V for the output display stage.