LCR METER

INTRODUCTION;

An LCR meter is used to measure the impedance of a circuit or a device. Now we explain the uses, types,
and some parameters related to LCR meters. The LCR meter also measures D or Q. D stands for the
dissipation factor. It is given by dividing the real part of the impedance by the imaginary part of the
impedance (which is the reactance). Q stands for the quality factor. It is the inverse of D.

LCR Meter Defined

An LCR meter (Inductance (l), Capacitance (C), and Resistance (R)) is an instrument used to measure the
inductance, capacitance, and resistance of a component, sensor or another device that’s operation
depends upon capacitance, inductance or resistance.

Digital LCR meters measure the current (I) flowing through a device under test (DUT), the voltage (V)
across the DUT, and the phase angle between the measured V and I. From these three measurements,
all impedance parameters can then be calculated. A typical LCR meter has four terminal Kelvin
connection to connect to the DUT device under test. The Kelvin connection minimizes errors due to
cabling and connection to the DUT.

Types of LCR Meters

1 .Handheld LCR meters:

As the name suggests, these LCR meters are small in size and can be held in the hand; they are
lightweight and also portable. They have a multiple test frequency, and the data it captures can be
transferred to a PC via a USB port. They are generally used in field operations. They offer an accuracy in
the range of 0.2% to 0.1%. The test frequency of a handheld LCR meter varies from 100 Hz, 120 Hz, 1
kHz, 10 kHz, and 100 kHz.

2 .Benchtop LCR meters:

They are bulky in size. They can be operated on programmable frequencies. They offer an accuracy of
0.01%. They can be controlled via a computer. Test frequencies are above 100kHz.

Working Principle;

We pass an AC voltage through a DUT (Device Under Test). Now the LCR meter is used to measure the
voltage and the current across the DUT. The magnitude of the impedance can be calculated from the
ratio of these two quantities.
Uses of an LCR Meter

A digital LCR meter is used to measure the impedance flowing through a Device Under Test (DUT). It
measures the voltage (V) across it, the current (I) flowing through it, and the phase angle between
current and voltage. Subsequently, we can determine all the impedance parameters from these three
factors.

Thus, an LCR meter measures the following parameters related to a circuit:

 inductance
 capacitance
 resistance
 dissipation factor
 quality factor
 current
 voltage
 phase angle between the current and voltage
 conductance
 susceptance

What is Impedance?

Impedance is the opposition that a circuit offers to the flow of direct or alternating current through it. It
is a vector quantity composed of 2 scalars: resistance and reactance. Reactance is the name given to the
opposition by an electronic component to the flow of alternating current due to capacitance and
inductance
How to use an LCR Meter:

After going through the essential information regarding the LCR meter is vital to know how it functions.
Let us know more about the mechanism of the LCR meter here:

 We already know that LCR is known for measuring a passive component’s capacitance,
inductance, and resistance. It measures the element at a specific voltage or current as well as
frequency. In this device, applying AC voltage at the current test signal is essential to calculate
the component. 

 The application is at a specific frequency. After using the particular frequency to the element,
the current flows through the passive element, and the phase starts to flow. It is the time when
the device measures the difference between the current and the voltage. 

 The LCR meter collects the difference and uses the difference between voltage current and
phase to calculate the inductance resistance and capacitance of the component. 

 The device operates by applying AC voltage on the device under test. After the direct message,
the difference between amplitude and phase of the voltage signal to find out and calculate the
difference between the voltage current and phase. 

1. Measuring Capacitance with LCR Meter:

A capacitor consists of two conductors separated by a dielectric medium, storing electrical energy and
holding an electrostatic charge.

LCR meter is a device that can test capacitors in a circuit and measure the capacitance by applying AC
voltage to the device under test. It also measures the current. It measures the voltage signal in terms of
amplitude and phase.

The current waveform that is present in capacitive impedance leads to a voltage waveform. The current
waveform present in inductor impedance lags behind the voltage waveform. Many lab technicians use
an LCR meter to measure capacitance. 

2. Measuring Inductance with LCR Meter:

Every inductive body has a specific inductance that is an intrinsic property of that body. The inductance
of any conductive body is always the same whether that conductor is energized in the electrical circuit
or is not active. An LCR meter is a great choice when it comes to measuring the inductors of any device.

Let us find out the capacitor and inductor basics here. An inductor is an electrical component. It consists
of a wire wound into one or more loops; the essential elements of every inductor are the same. 

We can determine the inductance of an inductor with two characteristics – its size and the making of the
inductor. The LCR meter subjects the device under test to a set frequency AC voltage.

It measures the current through the device and the voltage. The machine reaches of ratio to find out
voltage and the current flowing through the device, which further algebraically calculates the device’s
impedance.

3. Measuring Resistance using an LCR Meter:

Resistance is the measure of opposition to current flow in an electrical circuit. It is essential to know the
values for each component that make up a complete circuit—identifying the value s essential to ensure
the safe operation of electronic devices.

Resistance is the opposition to the flow of electric current in a circuit. In an electrical circuit, there are
two kinds of resistance: resistors and conductors. The resistance reading taken with an LCR meter may
not be accurate for complex circuits that contain several resistors in series or parallel. 

The device measures the voltage and current flowing through the device under test and the phase angle
between the voltage and current.
The position data conductor in the circuit offers through electric current is found in the machine, known
as resistance. You can enter the resistance value and select the measurement mode. The meter will
display a graph of the resistance versus frequency curve. 

3. Measuring Impedance using an LCR Meter:

LCR meter helps find out the impedance of any passive component. Electrical impedance, also identified
with Z, changes accordingly as per the circuit’s component and on the frequency application in AC.

It is a type of total division that is present in the course following the alternating current. It includes
inductive reactance, resistance, and capacitive reactance. We can use an LCR meter to measure the
impedance of a circuit.

It takes place by placing the meter’s leads across the ends of the component that you want to measure.
The values are then read off on an LCD or LED display.