What is LCR Meter – an overview!
LCR Meters are used to measure parameters of basic passive electronics components viz Resistor, Capacitor, and Inductor. LCR meters are available as desktop meters and handheld meters. Handheld meters are basically used for portability, use in the field and also by hobbyists to have a low-cost alternative with limited accuracy. The basic functions provided by an LCR meter are – Measurement Mode, Frequency of Measurement, Type of component (Inductor, Capacitor or Resistor). Most of the meters provide auto detection for component type and measurement frequency.
Mainly we are interested in the following parameters of passive components – 1. Inductance, 2.Capacitance, 3. Resistance / DC Resistance, 4.Quality Factor, 5.Dissipation Factor, 6.Series equivalent Resistance and 7. Parallel Equivalent resistance.
Quality factor (Q) & Dissipation Factor (D) basically indicates the purity of the component i.e. it indicates how close is the component to its ideal behavior. Q is the ratio of power stored in the component to the energy dissipated by the component. D is reciprocal of Quality Factor. Generally, Q is measured for Inductor and D is measured for Capacitor.
Most of the LCR meters offer two modes for measurement Series Mode and Parallel Mode. Different modes are required as all the real world components have a parasitic component in series & in parallel, along with its own value. Series mode treats the component under test as an equivalent series circuit whereas parallel mode treats the component as a parallel equivalent circuit. If the impedance of the component under test is high then its equivalent series resistance is negligible and hence parallel mode is used. Alternately if the impedance is less, its parallel component is negligible and the series mode is to be used.
In other words, small value Inductors & large value capacitor should be measured in Series Mode and large value Inductor & small value capacitor should be measured by selecting Parallel Mode. Generally, the component manufacturer provides details about mode and frequency to be used for measurement in the datasheet of the component.
Additional details to be checked while selecting an LCR meter are the range of test frequencies provided and test signal level. DC bias (Voltage /Current) is required to check component under conditions of actual use of the component in the circuit.
Peak Atlas LCR45 – LCR and Impedance Meter
LCR45 (by Peak) is a very compact, handy, light weight and easy to use instrument that fits easily in your palm. It operates on +9V battery. It can be used to measure Inductance, Capacitance, Resistance and Impedance of the component and sensor. It also displays Impedance and Admittance in complex number format and in the magnitude & phase angle format. In Auto Mode LCR45 can be used to detect the type of component automatically and also will select the appropriate frequency of measurement for a better result. In Manual Mode, you can select measurement frequency as per the component under test. LCR45 gives continuous reading making it suitable for alignment operations and also the reading can be put in hold mode for individual component measurement. LCR45 is provided with gold plated clips for minimum contact resistance resulting in more accurate measurement.
LCR45 has fairly good measurement range and accuracy. You can measure capacitance in the range of 0.5pF~10000uF at a resolution of 0.2pF and with an accuracy of +/-1.5%+/-0.6pF. For an inductor, the allowed range is 1uH ~ 10H at a resolution of 0.2uH and with an accuracy of +/-1.5%+/-0.6uH. For a resistor, the specified range is 0Ω ~ 2MΩ at a resolution of 0.1Ω and with an accuracy of +/-1%+/-0.6Ω. LCR45 provides a good range of test frequencies viz – DC, 1kHz, 15kHz and 200kHz. The operating temperature range is very tight: 10°C~40°C LCR45 is a good option if you need to measure impedance or basic parameters of Inductor and Capacitor. It is also suitable for applications where there is a need to align/adjust capacitance/Inductance/resistance.
DE-5000 Handheld LCR Meter.
DE-5000 is a highly accurate handheld LCR meter. It can be used to measure – Inductance, Capacitance, Resistance, Quality Factor (Q), Dissipation Factor (D), Phase Angle, Equivalent Series and Equivalent Parallel resistance. It comes with a set of useful accessories – 1.Test Leads, 2.Tweezers for SMD components and 3.Guard Line. However, the length of wires given for Test Leads is very short. The user can start working instantly using AUTO LCR mode to measure without setting any parameter. DE-5000 has a very good feature which helps to sort a batch of components by specifying tolerance range. A wide range of tolerances is possible to be specified. DE- 5000 provides measurements in series or parallel mode and at various frequencies 100Hz, 120Hz, 1kHz, 10kHz, and 100kHz. It has an indication for the low battery which alerts the user on time and also has backlight function to have clear reading even in low light or darkness. Overall DE-5000 is a good alternative at an affordable cost for testing the quality of passive components.
Extech 380193 Passive Component LCR Meter
Extech 380193 supports the measurement of Inductance, Capacitance, Quality Factor and Dissipation Factor. It allows measurement in Series and Parallel mode, however, the frequency of measurement is limited to 120Hz and 1kHz. This meter can be used for sorting components by specifying the acceptable range. For improving accuracy and reducing the error it provides a facility for calibration. The short and open calibration facility removes stray components added by the measuring system. Extech 380193 allows display of the average, minimum and maximum value for a set of measurements and also provides the RS232 interface for sending measurement data to a spreadsheet on PC. This helps to make an easier analysis of measurements. It supports dual display – displays secondary parameter (D, Q etc) along with primary parameter (Capacitance, Inductance etc). It has the backlight feature for better readability of measurement.
The battery required for this meter is non-standard, however, the battery is provided with the meter as a standard accessory. Test leads are also included as standard accessories. The meter also has a built-in fixture for leaded components. Extech 380193 is a highly accurate LCR meter with good features at a moderate cost.
Smart Tweezers ST5-S Professional LCR Meter/ESR Meter
ST5-S is specifically suitable for chip components. It can measure Inductance, Capacitance, Resistance, Impedance and ESR in Automatic (range and component selection) or Manual mode. ST5-S can measure with 0.2 % accuracy. It has a nice OLED display and gold plated Tweezer leads. The display can be rotated to make it suitable for use by right hand or by the left hand. It operates on an inbuilt Li-Ion battery, and for charging the battery adaptor is provided with the instrument. It is also possible to charge the battery using USB port. ST5-S is a good option for SMD component measurement but it comes with a high price tag.
B&K Precision 879B LCR Meter
879B can be used to measure Inductance, Capacitance, Resistance, Q, D, Phase Angle and ESR. The basic accuracy provided by this meter is 0.5% with 40000 counts for primary parameters and 10000 counts for the secondary parameter. Like all other LCR meters, series and parallel mode of measurement are provided. It has nice features for analysis of measurement which includes min/max and average display, USB interface to log measurement data and provides hold function for easy reading. For the convenience of reading in the dark, a backlight option is provided. B&K 879B LCR Meter can also be used for sorting components by specifying the tolerance.
It provides multi-options for test frequency – 100Hz, 120Hz, 1kHz and 10kHz with a test signal level of 0.6Vrms. It operates with 9V battery and provision is given for using a DC adaptor also. When operated using battery, a Low Battery indication is provided to remind the user to replace the battery on time. The accessories include – a Battery, a Mini USB cable, Test Leads and an Adaptor. B&K Precision 879B provides rich features with good accuracy for a handheld meter and the product comes with a moderate price tag.
Agilent U1731C Handheld LCR Meter
Agilent U1731C can be used for the measurement of Inductance, Capacitance, Resistance, Impedance, D, Q, ESR and Phase Angle. Both Parallel and Series modes are provided for measurement. You can select one of the following frequencies as the test frequency – 100Hz, 120Hz & 1kHz. For all measurement, Auto Range selection is possible for starting quick measurement. For better results, you can select measurement range manually. The LCR Meter can be used for sorting components by specifying the tolerance from the standard value. U1731C provides the display of Min/Max/Average reading and also the user can freeze/hold the display.A backlight is provided for the LCD display to support reading in dark conditions.
U1731C runs on a 9V battery which is provided along with standard accessories. The meter provides an indication for Low Battery to help the user replacing the battery in time. An external 12V adaptor can also be used in place of the battery. For analysis of measured data, U1731C has an IR port. However, it needs a special cable to connect to the USB port of the computer. U1731C is a good option in Handheld meters with a high price tag. It comes with rich features and the only issue be the ng limited range of test frequency.