The ZRLC meter

One feature that I did find fascinating though was a built-in ZRLC meter. This meter measures impedance (Z), resistance (R), inductance (L), and capacitance (C).

ZRLC meter

The software's author describes a simple test fixture for use with this feature. After some digging, I managed to find a schematic for the circuit he was referring to. The schematic is shown in the following diagram.

ZRLC hardware

The following diagram shows an improved version of the hardware we will be using:

Improved schematic

How the circuit is used to measure ZRLC is described at http://www.sillanumsoft.org/ZRLC.htm.

However, I have made some of the improvements that he suggested and corrected an error on the schematic he included. My circuit works mostly the same as he described. The TL082 operational amplifier has a FET (short for Field Effect Transistor) input, which gives it a very high input impedance. This is important because as the author says, the input and output impedances of the sound card adversely...