LCR meter
Overview
This application will turn your STEMLab into an affordable LCR meter. It is the perfect tool for
educators, students, makers, hobbyists and professionals seeking affordable, highly functional test
and measurement equipment. The Resistor, Capacitors and Inductors are basic components of all
electrical circuits and working on your projects you will definitely need to measure some
components laying around on your working bench. The STEMLab LCR meter will enable you to do
that quickly and accurately just by switching from one application to another. Notice: To use the
LCR meter application an additional extension module is needed. The LCR meter extension module
is available on our web store, http://store.redpitaya.com/. All Red Pitaya applications are web-based
and don’t require the installation of any native software. Users can access them via a browser using
their smartphone, tablet or a PC running any popular operating system (MAC, Linux, Windows,
Android and iOS). The elements on the LCR meter application are arranged logically and offer a
familiar user interface similar to bench LCR meters.
The graphical interface is divided into 6 main areas:
1. Hold/Run button: It is used to start and stop measuring. Log data button: When selected, the
measurements of parameters selected in the “Data options” field are logged in the table
shown in area 6.
2. Data options panel: It is used for selecting the desired parameter for which the measurement
will be displayed on the Main window panel shown on area 4.
3. Measurement option panel: It is used to select a measuring frequency, range mode and
range value. The user can select between the Parallel and Series measuring modes as well as
between the Tolerance, Relative or Normal modes (modes described in the features section)
4. Main display: On this panel the measurements of parameter selected in “Data option” field
are shown. Where the Primary parameter is shown with a larger font and the secondary
parameter with smaller one. This is a very common practice since by reading values from the
display the user can automatically see the most important results.
5. Secondary display: On the secondary display the main settings are shown: current selected
parameters, measuring frequency and range mode. Also the Min, Max and Average value or
Primary parameters are shown.
6. Logging table: Is used to log and export measured data. Logging is started by selecting the
“Log data” button.
7. Option buttons field: I used to manipulate with the table. The “Clear Min/Max” button will
reset the Min and Max value on the Secondary display.
FEATURES
The main features of the LCR meter applications are described below:
MEASURED PRIMARY PARAMETERS: Z, L, C, R
LCR meter application will enable you to measure basic parameters of the passive electrical
components: R – resistance, C – capacitance, L – inductance and Z – impedance.
MEASURED SECONDARY PARAMETERS: P, D, Q, E
Alongside main parameters the secondary parameters are also measured and calculated. These
parameters are common in describing the properties and the quality of the passive components. P –
phase of the impedance (phase between current and voltage on measured component), D –
dissipation factor (often used to quantify the quality of the capacitor), Q – quality factor (often used
to quantify the quality of the inductor), ESR – equivalent series resistance
SELECTABLE FREQUENCIES: 100HZ, 1KHZ, 10KHZ, 100KHZ
LCR meter enables measurements at 4 different frequencies (100Hz, 1kHz, 10kHz, 100kHz). The
user can select desired frequency and the LCR application will use sine signals with the selected
frequency to measure the impedance.
RANGE MODES: AUTO, MANUAL
Since the measured values are unknown, the LCR meter will adjust the measuring range providing
the best accuracy. If the user expects some value in creating ranges, then the Manual mode can be
used.
Measurements modes: Tolerance, Relative, Normal The “Tolerance” and “Relative” buttons
are used for measuring in the Tolerance and Relative mode. When deselected, the LCR meter
measures in the Normal mode.
Tolerance mode: the last value measured before clicking the Tolerance button is saved and
used to calculate the percentage difference between the new value and the saved one.
Relative mode: the last value measured before clicking the Relative button is saved and used
to calculate relative difference between the new value and the saved one. Equivalent
Parameters calculation circuit: Parallel, Series The Parallel and Series measuring modes refer
to using the Series or Parallel equivalent circuit for the parameters (R, C, L...) calculation
from the measured Impedance Z *. LCR meters will only measure Z as the complex value
Z=|Z|e^(jP) where P is the measured phase and |Z| is the impedance amplitude. All other
parameters are calculated from the Series or the Parallel equivalent circuit.
Export of measured data in .csv format
Min, Max, Average measurements
1000 logging points
Specifications
STEMlab 125 - 10
STEMlab 125 - 14
Measured primary parameters
Z, L, C, R
Z, L, C, R
Measured secondary parameters
P, D, Q, E
P, D, Q, E
Selectable frequencies
100Hz, 1kHz, 10kHz, 100kHz
100Hz, 1kHz, 10kHz, 100kHz
Impedance range
1 Ohm-10 MOhm
1 Ohm-10 MOhm
DC bias
0.5 V
0.5 V
Basic accuracy
5,00%
1,00%
Max input voltage
0.5Vpp
0.5Vpp
Input protection
Yes
Yes
Parameter range Z
1 Ohm-10 MOhm
1 Ohm-10 MOhm
Parameter range Rs, Rp
1 Ohm-10 MOhm
1 Ohm-10 MOhm
Parameter range Ls, Lp
100nH-1000 H
100nH-1000 H
Parameter range Cs, Cp
10pF - 100 mF
1pF - 100 mF
Parameter range P
+/- 180 deg
+/- 180 deg
https://redpitaya.com/apps/logic‐analyzer/ 4‐18‐17