3.6.5. LCR meter

The LCR meter can be used from the console.

Note

The preparation of the environment can be found in this chapter.

root@rp-f0a235:~# lcr
LCR meter version 2.07-494, compiled at Sat Mar 22 06:11:15 2025

Usage:  lcr freq r_shunt [-v]

        freq               Signal frequency used for measurement Hz.
        r_shunt            Shunt resistor value in Ohms [ 10, 100, 1000, 10000, 100000, 1000000 ]. If set to 0, Automatic ranging is used.
        -v                 Verbose mode
                        Automatic ranging demands Extenson module.

Output: Frequency [Hz], |Z| [Ohm], P [deg], Ls [H], Cs [F], Rs [Ohm], Lp [H], Cp [F], Rp [Ohm], Q, D, Xs [H], Gp [S], Bp [S], |Y| [S], -P [deg]

To run the LCR meter, follow these three steps:

1. If not using the LCR meter extension shield. Connect the shunt resistor and the DUT (device under test) as shown in the diagram below.

   

2. Load the standard FPGA image.

   OS version 2.00OS version 1.04 or older

   redpitaya> overlay.sh v0.94
   

3. Launch the console application.

   root@rp-f01c35:~# lcr 100 100000 -v
   Frequency       100 Hz
   Z       5.424000 kOmh
   Phase   1.364216 deg
   L(s)    205.533997 mH
   C(s)    -12.324000 uF
   R(s)    5.422000 kOmh
   L(p)    0.000000 H
   C(p)    0.000000 F
   R(p)    5.425000 kOmh
   Q       0.023815
   D       -41.991112
   X_s     129.141129
   G_p     0.000184
   B_p     0.000000
   |Y|     0.000184
   -P_Y    -1.364216 deg
   

Source code

The Red Pitaya GitHub repository contains the source code for the lcr utility.