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An introduction to the LC1020E from FNIRSI
What is the LC1020E?
This device is a portable LCR meter designed to measure the parameters of passive electronic components. The device primarily (1st display) measures resistance in ohms, capacitance in farads or inductance in henrys. Secondarily (2nd display), you can measure other parameters of the component:
- The impedance X.
- The dissipation factor D.
- The quality factor Q.
- The phase angle Φ.
- The equivalent series resistance ESR.
The measurement principle utilises sinusoidal voltages. You can set both the amplitude and the frequency of the measurement voltage. Furthermore, you can apply a small offset to the signal, ensuring that the measurement signal lies entirely above the zero axis and allowing you to measure electrolytic capacitors with the correct polarity.
As an added feature, the LC1020E is equipped with a sorting function. This allows you to quickly check which components from a batch meet your specified accuracy requirements. After each measurement, the meter indicates whether the measured value falls within the specified range. The display shows a 'PASS/FAIL' indication. A red LED flashes when ‘FAIL’ is indicated, and you can set an audible alarm.
The component to be measured can be connected to the LC1020E using either the two-wire or four-wire method. A Kelvin probe is supplied for the latter function. A calibration function is included, allowing you to compensate for the parasitic characteristics of the measuring cables or probes.
The LC1020E can operate fully automatically, but if desired, you can also manually set the device to a specific measurement parameter and a desired range. The accuracy of the LC1020E depends on the type of component, the frequency and the measurement range, and varies from ±0.3 % to ±5.0 % in the extreme ranges.
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| Measuring an electrolytic capacitor with the Kelvin probe. (© AMAZON) |
The main features of the LC1020E
- Measures the characteristics of resistors, capacitors and inductors.
- Two 4½ digits displays for both the primary and secondary measured values.
- Calculates the values for series or parallel equivalent circuits.
- Signal frequency from 100 Hz to 100 kHz.
- Maximum measurement voltage of the measurement signal is 0.6 V.
- Minimum measurement voltage of 0.1 V allows measurements to be taken in circuits.
- Offset voltage of 0.5 V.
- HOLD function.
- Three measurement speeds.
- Gold-plated Kelvin probe included.
- Semi-automatic sorting function.
- Automatic calibration with probe open or closed.
- Powered by a 3.7 V ~ 3,000 mAh battery.
- USB-C connector for charging cable.
The manufacturer of the LC1020E
The LC1020E is marketed by the Chinese company FNIRSI, a firm that is making a name for itself and rapidly bringing fairly innovative and reasonably priced electronic measuring equipment to the market. ‘Shenzhen FNIRSI Technology Co., Ltd.’ was founded in 2016 and has since developed an extensive portfolio comprising handheld oscilloscopes, digital multimeters, signal generators, transistor testers, digital current clamps and USB fast-charging testers. A distinctive feature of FNIRSI measuring instruments is that they often combine various measuring functions in a single device. In addition, FNIRSI has developed a number of cordless soldering irons and also manufactures radiation detectors, wall detectors and laser distance metres. At its head office, around 180 engineers are engaged in research and product development.
Suppliers and price
Like all FNIRSI products, the LC1020E is very popular. The device is offered by dozens of suppliers on all the well-known international sales platforms, such as AliExpress, Amazon and Banggood.
On Banggood, it costs € 55.87, whilst on AliExpress it costs € 57.69. If you want the device delivered very quickly, you can also order it from the Elektor Store, although you’ll have to pay € 69.95 for it there.
The packaging of the LC1020E
The LC1020E is supplied in a cardboard box with attractive printing, measuring 20.5 cm by 14.0 cm by 8.0 cm. The LCR meter is housed in a sturdy cardboard inner packaging that fits comfortably inside the box, ensuring that any damage during transport is limited to the outer box and the meter remains undamaged.
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| The packaging of the LC1020E. (© AMAZON) |
What’s included with the LC1020E
In addition to the meter itself, the box contains:
- A USB-C to USB-A cable for charging the battery.
- A Kelvin test lead approximately 70 cm long.
- The two standard test probes supplied with every Chinese multimeter.
- A shorting plate, useful for calibrating the meter.
- A comprehensive user manual.
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| What’s included with the LC1020. (© 2026 Jos Verstraten) |
The appearance of the LC1020E
In the photograph below, we have combined the three main views of the LC1020E. The front panel features the 58 mm by 43 mm display and fourteen push-buttons for operating the meter. Below this control panel, you will see three slots into which you can click the Kelvin probe connector. At the very bottom are three standard 4 mm female banana sockets, which are useful if you wish to measure components on a printed circuit board and cannot use the Kelvin probe. To the left of the display is a red LED which lights up when a component is rejected whilst using the sorting function.
On the right-hand side, under a small cover, is the USB-C connector for plugging in the charging cable. Above this connector, you will find a small hole. If the software in the meter crashes completely, you can reset the meter’s hardware by inserting a paperclip into this hole. On the back, you will see the fold-out stand, which allows you to position the meter in an easy-to-read position.
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| Three views of the LC1020. (© 2026 Jos Verstraten) |
The Kelvin probe
The Kelvin probe is not a masterpiece of precision engineering, but it suffices for non-intensive use. However, the cable is thick and rather stiff, causing the meter to occasionally tip over when connecting a component to the two crocodile clips. The connector you plug into the meter consists of nothing more than a small double-sided printed circuit board with three gold-plated copper strips on either side. You plug this connector into the three slots on the meter and then push the connector to the right. The connector then remains securely in place in the meter.
A cheap but well-thought-out solution! More expensive LCR meters use four BNC connectors for this purpose. That is obviously much more reliable in the long run, but the solution chosen by FNIRSI seems good enough to us for non-intensive hobby use. GW Instek and UNI-T also use a similar probe with their LCR meters.
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| The included Kelvin probe. (© 2026 Jos Verstraten) |
The manual
The manual is a thick 48-page document, bilingual in Chinese and English. However, not all functions of the LC1020E are clearly described in it. For example, the sorting function is called 'Data Logging Function', which creates false expectations. In fact, nothing is logged at all; only the number of approved and rejected parts from a batch is displayed on the screen.
We have included the English section of this manual in our own cloud on Google Drive. You can download it here:
The specifications of the LC1020E
According to the manufacturer, the LC1020E meets the specifications below:
- Display: 2.8-inch TFT LCD screen
- Number of digits: 2 x 4½ digits
- Measuring signal: sine wave, 0.1 V ~ 0.3 V ~ 0.6 V
- Measuring frequency: 100 Hz ~ 120 Hz ~ 1 kHz ~ 10 kHz ~ 100 kHz
- Offset voltage: 0.5 V
- Primary parameters: AUTO ~ R ~ C ~ L ~ Z
- Secondary parameters: X ~ D ~ Q ~ θ ~ ESR
- Measurement range: 100 H ~ 100 mF ~ 10 MΩ
- Equivalent schemes: AUTO ~ serial ~ parallel
- Measuring speed: 1/s ~ 2/s ~ 4/s
- Calibration function: Open and short-circuit circuit
- Sorting function: Calculation of the percentage error
- Registration function: Records successful and failed measurements
- Terminal configuration: three-terminal, five-terminal
- Output impedance: 100 Ω
- Interface: USB-C (virtual serial port)
- Power supply: 3.7 V ~ 3,000 mAh battery
- Automatic shutdown: Yes
- HOLD function: Yes
- Dimensions: 18.2 cm x 8.8 cm x 3.8 cm
- Weight: 292 g
The accuracy of the LC1020E
FNIRSI announces the LC1020A as a 'High-Precision LCR Meter' and advertises an accuracy of ±0.3 %. However, that accuracy applies only to a limited number of measurement ranges. For extreme measurement ranges, the accuracy can even drop to ±5 %. Fortunately, the manual provides a detailed overview of the accuracies for each measurement range.
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| Overview of specified accuracies. (© FNIRSI) |
A protective case for the LC1020E
This LCR meter is apparently so popular that the Chinese company ZOPRORE has developed a special protective case for it. The meter and the single test probes fit inside this box, see the photo below. This box costs € 10.49 and can be ordered via:
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| A protective case for the LC1020E. (© AliExpress) |
The electronics in the LC1020E
The operating principle
Measuring capacitances and inductances is not as simple as it seems. It will be clear that you must measure with AC. After all, for DC, a capacitor has an infinitely high resistance and an inductor is a short circuit. But therein lies the difficulty: with AC, the parasitic properties of the measurement setup come into play. Measuring cables have a certain unknown capacitance and self-inductance. To eliminate these parasitic properties, the same technique is used in all modern LCR meters. A sinusoidal voltage is applied to the component to be measured via two connections. The voltage across the component is then fed back to the meter via two other connections.
This is a modified form of the Kelvin bridge, also known as the Thomson bridge. William Thomson was later promoted to Lord Kelvin, so both names refer to the same person. With this bridge, powered by AC voltage, you can take measurements without the parasitic properties of the measuring cables and probe interfering with the measurement. This is because the measuring voltage and the signal to be measured are supplied and drawn off at exactly the same location, as close as possible to the component.
The basic principle of this measurement method is illustrated in the figure below. A very small sinusoidal voltage is generated in the measuring device. This is applied to the passive component to be measured via one of the four shielded cables, either superimposed on a DC voltage (BIAS) or not. This voltage is measured as close as possible to the component via a second shielded cable. The other two shielded cables are connected to the other terminal of the component. This point is virtually connected to ground. The current flowing through the component also flows through the resistor R ref of the measuring device. M1 and M2 are not ordinary voltmeters, but circuits that measure not only the magnitude but also the phase of the applied voltage. From these two measurements, the processor in the meter can derive a great many properties of the measured component, such as the value, the impedance X, the ESR, the phase shift θ, and the quality factor Q.
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| The principle of Kelvin measurement technology. (© 2026 Jos Verstraten) |
The electronics in the LC1020E
After removing six screws, you can separate the two parts of the housing to get a clear view of the main circuit board containing all the electronics. On the left, you see a small auxiliary circuit board, mounted on the main board, which connects both the Kelvin probe and the three 4 mm female banana plug sockets to the electronics on the main board.
The model number of the central processor has been laser-removed. However, all other chips can be identified:
- 1 x GH444G:
We found no information about this on the internet. - 5 x RS822:
The RS822 is a rail-to-rail CMOS op-amp from the manufacturer Runic Technology. - 1 x RS8752:
The RS8752 is a dual high-speed rail-to-rail op-amp from the manufacturer Runic Technology. - 2 x MS8606:
This is a dual rail-to-rail op-amp from Hangzhou Ruimeng Technology. It is a functional one-to-one replacement for the very well-known AD8606 from Analog Devices. - 1 x TC4056A:
The TC4056A is a very popular lithium-ion battery charger chip, functionally identical to and interchangeable with the TP4056. - 1 x LB33:
The code LB33 is the print code for a 3.3 V low-drop linear voltage regulator.
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| The electronics in the LC1020E. (© 2026 Jos Verstraten) |
Working with the LC1020E
Startup
After pressing the large, square button with the familiar 'START' icon, a FNIRSI startup screen briefly appears, and you immediately enter the mode in which you can measure resistors, capacitors and inductors. The display is shown in the figure below. In this example, an inductor L is connected to the meter, and the quality factor Q has been selected as the secondary measurement.
On the bottom line of the display, you can see the settings for the frequency (FREQ), the magnitude of the measurement signal (AMP), the offset (BIAS) and the measurement function (RANGE). It couldn't be clearer!
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| The measurement function with which the LC1020E starts up. (© 2026 Jos Verstraten) |
You can adjust these settings if desired using the 'FREQ', 'LEVEL', 'OFFSET' and 'RANGE' push buttons. It would have been slightly clearer if the programmers had replaced the 'AMP' and 'BIAS' indications on the display with 'LEVEL' and 'OFFSET', just like on the push buttons.
You can optionally change the measured values of both displays using the 'AUTO/R/C/L/Z' and 'X/D/Q/Φ/ESR' buttons .
There is nothing more to explain about measuring components with the LC1020E! Any hobbyist electronics enthusiast can get started with the device straight away!
The 'SETTING' menu
In this menu, you can configure some settings. You enter this menu by pressing the 'OK' button for a few seconds. You can exit this menu in the same way.
- Sorting:
In this option, you set the criteria for sorting components, read more. - Language:
Sets the user interface language to Chinese or English. - Brightness:
Adjusting the brightness of the display. - Volume:
Adjusting the strength of the sound the meter makes. - Off Time:
Select the time after which the LC1020E switches itself off. You select 5, 15, or 30 minutes or 'NO'. - Calibration:
With this option, you start the automatic calibration, read on. - System:
In this window, you can read the software version and restore the factory settings.
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| The options of the 'SETTING' menu. (© 2026 Jos Verstraten) |
You select one of the options using the '▼' and '▲' keys and set the desired value using the '◄' and '►' keys. For options marked with the '➡' symbol, you must press 'OK' to activate the option.
The calibration option
After selecting this option, the screen below will appear on the display. You must now connect the Kelvin probe to the device and short-circuit the two alligator clips. After pressing 'OK', the first part of the calibration routine will be executed. After a beep, press the '►' key, open the short circuit, and execute the second part of the routine after pressing 'OK'. After a second beep, the calibration with open circuit is also completed, and you can exit the calibration option by pressing and holding the 'OK' key.
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The start of the calibration routine. (© FNIRSI) |
Working with the sorting function
Setting the sorting conditions
You start by selecting the 'Sorting' option in the 'SETTING' menu. In the window below, you set the desired value for the component (Norm) and the maximum tolerance (Tol) you still accept. With 'Volume' and 'LED', you can indicate whether or not you want visual and auditory alarms if a component falls outside the sorting conditions. You exit this window by pressing the 'OK' key twice for longer than one second.
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| Setting the sorting conditions. (© 2026 Jos Verstraten) |
To the sorting function display
Connect the first resistor to be sorted to the meter. Then press and hold the 'HOLD' button for more than one second. The sorting function data will appear on the display, see the figure below.
- 1ST:
The value of the measured resistance. - NOM:
The set value of the sorting condition. - TOL:
The percentage deviation between the measured resistance and the sorting value. - NG:
This resistor is not approved! - CNT:
The number of approved (green) and rejected (red) resistors.
You can now connect resistors from the batch to the LC1020E one after another. The software recognizes each new measurement by the transition from infinite resistance to finite resistance and automatically adjusts the values in 'CNT'.
You exit the sorting function by pressing the 'HOLD' button again for longer than one second. In this example, a resistor is selected. You can, of course, also work with capacitors or inductors.
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| The sorting function display. (© 2026 Jos Verstraten) |
Testing the FNIRSI LC1020E
Test conditions
The tests were performed after a half-hour warm-up period and a full calibration of the meter. A Fluke 8842A was used as comparison meters for the resistance measurements, and an EastTester ET4401 for the other measurements. Both meters use Kelvin probes.
Testing the measurement voltage
We measure the open-loop voltage with our oscilloscope at a setting of 100 kHz and 0.6 V. That looks perfect; see the oscillogram below.
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| The measured voltage at 100 kHz and 0.6 V. (© 2026 Jos Verstraten) |
Measuring film resistors with a tolerance of ±0.01 %
We purchased a set of Visay resistors with a tolerance of ±0.01 % from DigiKey to test the accuracy of resistance meters. We measure these with the LC1020E and our Fluke 8842A. You can see the measurement results in the table below. It is clear: FNIRSI is not exaggerating when they claim the LC1020E measures accurately. Now we just have to wait and see if we can conclude the same for capacitors and inductors!
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Measuring film resistors. (© 2026 Jos Verstraten) |
But first... some wire-wound resistors
Meters with Kelvin probes are ideal for measuring small resistances. After all, you are not bothered by the resistance of the test leads, as this is not included in the measurement. Unfortunately, we do not have high-precision wire-wound resistors, so we rely on our Fluke as a reference. The table below shows that the FNIRSI performs excellently even at these low resistance values.
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| Measuring wire-wound resistors. (© 2026 Jos Verstraten) |
Measuring high-precision capacitors
Thanks to a set of high-precision capacitors with a tolerance of ±1 % and a few standard capacitors with tolerances of only ±0.1 % and ±0.05 %, we can accurately map the performance of the LC1020E when measuring such components. As a reference meter, we use the EastTester ET4401 with an accuracy of ±0.2 % for non-electrolytic capacitors. We measure with both meters using a 0.6 V signal at a frequency of 1 kHz, as recommended in the manual. The results are summarized in a table. As you can see, these components are also measured quite accurately.
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| Measuring high-precision capacitors. (© 2026 Jos Verstraten) |
Measuring electrolytic capacitors
Since we do not have high-precision electrolytic capacitors, we can only compare the measurement results of the LC1020E with those of the EastTester ET4401. We immediately record the results of the measurement of the ESR, the equivalent series resistance. This is an important property of electrolytic capacitors, especially when they are used in switched-mode power supplies. We measure at 0.3 V and 120 Hz. The results are summarized in the table below; both devices broadly agree on the values of the capacitance and the ESR.
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| Measuring electrolytic capacitors. (© 2026 Jos Verstraten) |
Measuring coils
Unfortunately, we do not have high-precision coils in stock. Therefore, we cannot perform an accuracy test, but can only provide a comparison between the measurements with the LC1020E and our EastTester ET4401. After all, both meters are specified with approximately identical accuracies. We measure at 0.6 V and 1 kHz. The results are summarized in the table below. Here too, the measurement results run surprisingly parallel, from which we deduce that the LC1020E also reliably measures inductances.
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| Measuring coils. (© 2026 Jos Verstraten) |
Finally: measuring a small power transformer
Because we want to test an inductance higher than 10 mH, we finally bring out a small power transformer. We measure the primary and secondary inductances and resistances with both meters, naturally at 100 Hz.
SECONDARY:
LC1020E: 146.91 mH and 35.710 Ω
ET4401: 150.34 mH and 36.252 Ω
PRIMARY:
LC1020E: 15.09 H and 3.8658 kΩ
ET4401: 15.107 H and 3.8874 kΩ
Both meters agree on these measurements as well.
Our opinion on the FNIRSI LC1020E
If you take another look at the various tables, you will agree with us that the LC1020E is a wonderful meter with which you can measure resistors, capacitors, and inductors quite accurately in an inexpensive way. In fact, very inexpensive: you can purchase the LC1020E for about sixty euros, while our ET4401, with comparable accuracies, is still available for € 204.69 via AliExpress.
The only point of criticism is the construction of the Kelvin measuring cable. It could have been a bit thinner and more flexible! Naturally, we cannot predict whether the connector with the six contacts on a piece of double-sided PCB will continue to function reliably in the long term.
For every electronics hobbyist looking to acquire something that allows them to reliably measure the properties of passive components from time to time, we consider the LC1020E to be highly recommended.
LC1020E LCR-meter from FNIRSI
