LCR meter basics and types
This page covers LCR meter basics and types.It covers how does LCR meter work. It mentions LCR meter advantages and manufacturers or vendors.
As we know L stands for inductance, C stands for Capacitance and R stands for resistance. The device which measures these parameters is known as LCR meter.
Digital LCR meter type measures I(through DUT) and V (across DUT) and phase angle between measured I and V. From these measured parameters useful impedance parameters are calculated.
There are two types of LCR meter viz. benchtop and handheld.
Benchtop are developed for bench applications and hence are kept at fixed location without much of
movement. Handheld are developed for portable applications and hence can be moved around for
test and measurement purpose.
Handheld LCR meters are lightweight and are battery powered. It usually will have USB port to transfer data tothe PC/Laptop. It provides measurement of inductance and AC resistance. It will usually have measurement accuracy between 0.1% to 0.2%.
Benchtop LCR meter will have additional features compare to handheld type such as programmable frequency setting. It will have very higher measuement accuracy of about 0.01%. It provides advanced measurement capabilities such as DC bias current and voltage, sweep etc. This type of LCR meter is used for AC calibration of L, C and R. Typically measurements is performed at frequencies such as 100Hz, 120Hz, 1kHz and 10kHz.
LCR meters are also categorized into analog and digital type based on display formats. Analog type are cheaper compare to digital type as they are made of basic discrete components. Digital type are costlier but are more accurate compare to analog counterpart.
How does LCR meter work
Before we move to understand how does LCR meter work, let us understand concept of impedance first. As shown in the figure, impedance consists of two parts viz. resistance (i.e. real) and reactance(i.e. imaginary). Zs represents series impedance which is combination of resistance(Rs) and reactance(Xs).
Impedance can be expressed with magnitude |Z| and phase angle θ
When θ>0 the reactance is inductive and
when θ<0 the reactance is capacitive.
There are two reactance types viz. inductive reactance (XL) and
capacitive reactance (XC). They can be expressed as follows:
XL = 2*π * f * L
XC = 1/ (2* π * f * C)
Impedance can be measured either in series or in parallel mode.
Impedance in parallel mode can be expressed as reciprocal of admittance(Y).
Here , Z=1/Y,
Y = G + j*B, where G = Conductance and B = Susceptance
There are various techniques for the measurement of impedance.
The most common method is nulling type bridge as shown in the figure-1 above.
When there is no current flow through detector(D), value of unknown impedance can be expressed as follows:
Zx = (Z1/Z2)*Z3
Different applications use different combinations of L, C and R as elements of the bridge.
LCR meter Advantages
Following are the advantages of LCR meter:
• User friendly to operate.
• It measures passive components with minimal of errors.
• This instruments are very easy in calibration.
• There are many companies which manufactures the LCR meter and hence more features and options are available for user to purchase.
LCR meter manufacturers or vendors
Following are the best LCR meter manufacturers or vendors:
1. Keysight technologies
2. Meco Instruments P.Ltd (www.mecoinst.com)
3. IET Labs, Inc. (www.ietlabs.com)
4. Scientific Mes-Technik Pvt. Ltd. INDIA
5. Extech Instruments
6. InnovateUs Inc.
7. Stanford Research Systems, Inc.
8. Sigma Instruments
Test and Measurement Equipments
Test and Measurement Equipments BER Testing equipments Agilent T & M Solutions Anritsu T & M Solutions Rohde & Schwarz T & M solutions wireless channel emulator Vector signal generator Vector signal analyzer Power Analyzer Equipments Protocol Analyzer