We present the original design of an LC meter from our colleague R2-D2. Next, a word from the author of the diagram: In amateur radio, especially during repairs, it is necessary to have on hand a device for measuring capacitance and inductance - the so-called lc meter. Today, for repetition, you can find many diagrams of similar devices on the Internet, some complex and some not so complex. But I decided to create my own version of the device. Almost all circuits of LC meters using microcontrollers presented on the Internet look the same. The idea is to calculate the value of unknown components using the formula for the dependence of frequency on capacitance and inductance. To simplify my design, I decided to use the internal comparator of the microcontroller as a generator. The LCD from the phone is used to display information Nokia 3310 or something similar with a controller PCD8544 and resolution 84x48, for example Nokia 5110.

Lc meter circuit on a microcontroller

Setup and features

The heart of the device is the microcontroller PIC18F2520. For stable operation of the generator, it is better to use non-polar or tantalum capacitors as C3 and C4. You can use any relay that matches the voltage (3-5 volts), but preferably with the minimum possible contact resistance in the closed position. For sound, a buzzer without a built-in generator, or a regular piezoelectric element, is used.

At the first start assembled device, the program automatically starts the display contrast adjustment mode. Use the 2/4 buttons to set an acceptable contrast and press the OK button (3). After completing these steps, the device should be turned off and on again. For some customization of the meter’s operation, there is a section in the menu “ Setup" In the submenu " Capacitor", you must indicate the exact value of the calibration capacitor used (C_cal) in pF. The accuracy of the specified value directly affects the accuracy of the measurement. You can monitor the operation of the generator itself using a frequency meter at control point “B”, but it is better to use the already built-in frequency control system in the submenu “ Oscillator».

By selecting L1 and C1, it is necessary to achieve stable frequency readings in the region of 500-800 kHz. A high frequency has a positive effect on the measurement accuracy; at the same time, as the frequency increases, the stability of the generator may deteriorate. The frequency and stability of the generator, as I said above, can be conveniently monitored in the menu section “ Oscillator" If you have an external calibrated frequency meter, you can calibrate the LC meter's frequency meter. To do this, you need to connect an external frequency meter to the control point “B” and use the +/- buttons in the “ Oscillator» select the constant “K” so that the readings of both frequency meters coincide. For correct operation system for displaying the battery status, you need to configure a resistive divider built on resistors R9, R10, then install jumper S1 and write the values ​​in the fields of the “Battery” section.

Setting procedure

• - Measure the supply voltage of the microcontroller (pins 19 - 20). This is the reference voltage “V.ref”
• - Measure the voltage up to the resistive divider = U1
• - Measure the supply voltage after the divider = U2
• - Calculate the coefficient. division “С.div” = U1/U2
• - Enter the received numbers into the appropriate sections of the menu, saving them by pressing the “OK” button.

Also enter the voltage “V.max” - the maximum voltage of the battery (all segments of the displayed battery are filled) and, accordingly, “V.min” - the minimum voltage of the battery (all segments of the battery are extinguished, the device signals the necessary change or charge of the battery). The supply voltage values ​​for displaying intermediate segments on the battery icon will be calculated automatically after entering information about “V.max” and “V.min”.

The use of a stabilizer to power the circuit is mandatory, since the reference voltage must be stable and not change when the battery is discharged.

Working with the device

The lc meter menu also contains sections Light, Sound, Memory. In the section Light It is possible to enable or disable LCD backlight. Chapter Sound, to turn sound on/off. In the section Memory you can see the results of the last 10 measurements, and also (for beginners) see the result obtained in different units measurements. The purpose of the buttons is described by the icons located at the bottom of the screen.

• (F) - “Function” go to the Setup menu
• (M) - “Memory” saving measurement results in memory
• (☼ ) - “Light” on/off backlight
• (C) - “Calibration” calibration

The main screen contains a conditional measurement error scale, which must be monitored and, if necessary, calibrated in a timely manner.

Capacitance measurement

1. Switch the device to capacitance measurement mode. Perform calibration. Make sure that the measurement error is within acceptable limits. In case of large deviations, repeat the calibration.

2. Connect the capacitor to be measured to the terminals. The measurement result will appear on the screen. To save the result in memory, press (M).

Inductance measurement

1. Switch the device to inductance measurement mode. Close the terminals. Perform calibration. Make sure that the measurement error is within acceptable limits. In case of large deviations, repeat the calibration.

2. Connect the measured inductance to the terminals. The measurement result will appear on the screen. To save the result in memory, press (M).

Video of the meter working

The body was used by a Chinese tester who died heroically while repairing a TV.

All files - controller firmware, boards in Lay and so on can be found on the forum. Material provided - Savva. Author of the scheme R2-D2.

Discuss the article LC METER

I am sure that this project is not new, but it is my own development and I want this project to be well-known and useful.

Scheme LC meter on ATmega8 quite simple. The oscillator is classic and is based on an LM311 operational amplifier. The main goal that I pursued when creating this LC meter was to make it inexpensive and accessible for every radio amateur to assemble.

Schematic diagram of a capacitance and induction meter

LC Meter Features:

• Measuring capacitance of capacitors: 1pF - 0.3 µF.
• Coil inductance measurement: 1μH-0.5mH.
• Information output on LCD indicator 1×6 or 2×16 characters depending on the selected software

For this device I developed software, allowing you to use the indicator that the radio amateur has at his disposal, either a 1x16 character LCD display or 2x 16 characters.

Tests from both displays gave excellent results. When using a 2x16 character display, the top line displays the measurement mode (Cap – capacitance, Ind –) and the generator frequency, and the bottom line displays the measurement result. The 1x16 character display shows the measurement result on the left, and the generator operating frequency on the right.

However, in order to fit the measured value and frequency onto one line of characters, I reduced the display resolution. This does not affect the accuracy of the measurement in any way, only purely visually.

As with other well-known options that are based on the same universal circuit, I added a calibration button to the LC meter. Calibration is carried out using a 1000pF reference capacitor with a deviation of 1%.

When you press the calibration button, the following is displayed:

The measurements taken with this meter are surprisingly accurate, and the accuracy largely depends on the accuracy of the standard capacitor that is inserted into the circuit when you press the calibration button. The device calibration method simply involves measuring the capacitance of a reference capacitor and automatic recording its values ​​are stored in the microcontroller memory.

If you don't know the exact value, you can calibrate the meter by changing the measurement values ​​step by step until you get the most accurate capacitor value. For such calibration there are two buttons, please note that in the diagram they are designated as “UP” and “DOWN”. By pressing them you can adjust the capacitance of the calibration capacitor. Then given value automatically recorded in memory.

Before each capacitance measurement, the previous readings must be reset. Reset to zero occurs when “CAL” is pressed.

To reset in inductive mode, you must first short-circuit the input pins and then press “CAL”.

The entire installation is designed taking into account the free availability of radio components and in order to achieve a compact device. The size of the board does not exceed the size of the LCD display. I used both discrete and surface mount components. Relay with operating voltage 5V. Quartz resonator - 8MHz.

Stepan Mironov.

ESR+LCF v3 meter.

It has long been no secret that half of the failures in modern household appliances connected to electrolytic capacitors.
Swollen capacitors are immediately visible, but there are also those that look quite normal. All faulty capacitors have a loss of capacity and an increased ESR value, or only an increased ESR value (the capacity is normal or higher than normal).
Calculating them is not so easy; you have to unsolder them, if several capacitors are connected in parallel, or if any shunt elements are connected in parallel to the capacitor being measured, check them and solder them back into working order. Many capacitors are glued to the board, located in hard-to-reach places and dismantling/installing them takes a lot of time. Even when heated, a faulty capacitor can temporarily restore its functionality.
Therefore, radio mechanics, and not only them, dream of having a device for checking the serviceability of electrolytic capacitors, in-circuit, without desoldering them.
I want to disappoint you, it’s 100% impossible. It is not possible to correctly measure capacitance and ESR, but it is possible to check the serviceability of an electrolytic capacitor without soldering, in many cases using an increased ESR value.
Faulty capacitors with increased ESR and normal capacity are common, but those with normal ESR and loss of capacity are not.
A decrease in capacitance from the nominal value by 20% is not considered a defect, this is normal even for new capacitors, therefore, for the initial defectiveness of an electrolytic capacitor, it is enough to measure the ESR. In-circuit capacitance readings, for information only and depending on the shunt elements in the circuit, may be significantly overestimated or may not be measured.

An indicative table of acceptable ESR values ​​is given below:

Several versions of the ESR meter have been developed.
The ESR+LCF v3 meter (third version) was developed taking into account maximum capabilities for in-circuit measurements. In addition to the main ESR measurement (on the display Rx>x.xxx), there is additional function for in-circuit ESR calculation, called "aESR" by the analyzer (display a x.xx).
The analyzer detects nonlinear areas when charging the measured capacitor (a working capacitor is charged linearly). Next, the estimated deviation is calculated mathematically and added to the ESR value.
When measuring a working capacitor, “aESR” and “ESR” are close in value. The display additionally shows the value “aESR”.
This function does not have a prototype, so at the time of preparing the main documentation, there was very little experience in using it.

On at the moment, there are many positive reviews from different people with recommendations for its use.
This mode does not give a hundred percent result, but with knowledge of circuit design and accumulated experience, the effectiveness of this mode is great.
The result of an in-circuit measurement depends on the shunting effect of the circuit elements.
Semiconductor elements (transistors, diodes) do not affect the measurement result.
The greatest influence is exerted by low-resistance resistors, inductors, as well as other capacitors connected to the circuits of the measured capacitor.
In places where the shunting effect on the capacitor being tested is not great, the faulty capacitor can be easily measured in normal mode"ESR", and in places where the shunting influence is large, a faulty capacitor (without desoldering) can only be calculated using an "analyzer - aESR".

It should be remembered that when making in-circuit measurements of healthy electrolytic capacitors, the "aESR" readings in most cases are slightly higher than the "ESR" readings. This is normal, since multiple connections to the capacitor being measured introduce error.

The most difficult places to measure are circuits with simultaneous shunting of many elements of different types.

In the diagram above, the faulty capacitor C2+1ohm is shunted by C1+L1+C3+R2.

When measuring such a capacitor, the ESR value is normal, but the analyzer shows “0.18” - this is exceeding the norm.

Unfortunately, it is not always possible to determine the serviceability of an electrolytic capacitor within the circuit.
For example: in motherboards it will not work to power the processor, the shunting there is too large. A radio mechanic, as a rule, repairs equipment of the same type, and over time he gains experience, and he already knows exactly where and how electrolytic capacitors are diagnosed.

So, what can my meter do?

ESR+LCF v3 meter - measures

Additional features:

In ESR mode you can measure constant resistances 0.001 - 100 Ohm, measuring the resistance of circuits with inductance or capacitance is impossible (since the measurement is carried out in pulse mode and the measured resistance is shunted). To correctly measure such resistances, you must press the “+” button (in this case, the measurement is carried out at DC 10mA). In this mode, the range of measured resistances is 0.001 - 20 Ohm.
- In ESR mode, when the “L/C_F/P” button is pressed, the in-circuit analyzer function is turned on ( detailed description see below).
- In frequency meter mode, when the “Lx/Cx_Px” button is pressed, the “pulse counter” function is activated (continuous counting of pulses arriving at the “Fx” input). The counter is reset using the “+” button.
- Low battery indication.
- Automatic shutdown- about 4 minutes (in ESR mode - 2 minutes). After the idle time has expired, the inscription “StBy” lights up and within 10 seconds, you can press any button and work will continue in the same mode.

In modern technology, electrolytic capacitors are often bypassed with inductance less than 1 μH and ceramic capacitors. In normal mode here, the meter is not able to detect a faulty electrolytic capacitor without desoldering. For these purposes, an in-circuit analyzer function has been added.
The analyzer detects nonlinear areas when charging the measured capacitor (a working capacitor is charged linearly). Next, the expected deviation is calculated mathematically and added to the value ESR(Rx) = aESR(a). The display also shows the aESR (a) value. Most effective this function when measuring capacitances above 300 µF. To enable this function, you must press the “L/C_F/P” button.

Schematic diagram.

“The heart of the meter is the PIC16F886-I/SS microcontroller. This meter can also operate PIC16F876, PIC16F877 microcontrollers without changing the firmware.

Construction and details.

LCD indicator based on the HD44780 controller, 2 lines of 16 characters.
Controller - PIC16F886-I/SS.
Transistors BC807 - any P-N-P, similar in parameters.
Op-amp TL082 - any of this series (TL082CP, AC, etc.). It is possible to use the MC34072 op amp. The use of other op-amps (with different speeds) is not recommended.
Field effect transistor P45N02 - 06N03, P3055LD, etc., fits almost any computer motherboard.
Choke L101 - 100 µH + -5%. You can make it yourself or use a ready-made one. The diameter of the winding wire must be at least 0.2mm.
S101 - 430-650pF with low TKE, K31-11-2-G - can be found in the KOS of domestic 4-5 generation TVs (KVP circuit).
S102, S104 4-10uF SMD - can be found in any old computer motherboard Pentium-3 near the processor, as well as in the boxed Pentium-2 processor.
BF998 - can be found in VCRs, TVs and VCRs GRUNDIK.
SW1 (size 7*7mm) - pay attention to the pinout, there are two types. Wiring printed circuit board corresponds to Fig. 2.

The printed circuit board is made of single-sided fiberglass.

At the same time, the printed circuit board serves as the base for the housing. 21mm wide fiberglass strips are soldered around the perimeter of the board.

The covers are made of black plastic.

There are control buttons on top, and in front there are three TULIP type sockets for a removable probe. For the “R/ESR” mode - a higher quality socket.

Probe design:

A metal tulip-type plug was used as a probe. A needle is soldered to the central pin.

From the available material, a brass rod with a diameter of 3 mm can be used to make a needle. After some time, the needle oxidizes and to restore reliable contact, it is enough to wipe the tip with fine sandpaper.

Below in the archive there are all the necessary files and materials for assembling and configuring this meter.

Good luck to everyone and all the best!

miron63.

Archive ESR+LCF v3 meter.

I somehow made myself this extremely useful and irreplaceable device, due to the urgent need to measure capacitance and inductance. It has surprisingly very good measurement accuracy and the circuit is quite simple, the basic component of which is the PIC16F628A microcontroller.

Scheme:

As you can see, the main components of the circuit are PIC16F628A, a character-synthesizing display (3 types of display 16x01 16x02 08x02 can be used), a linear stabilizer LM7805, a 4 MHz quartz resonator, a 5V relay in a DIP package, a two-section switch (for switching measurement modes L or C ).

Firmware for microcontroller:

PCB:

PCB file in sprint layout format:

The original board is wired for a relay in a DIP package.

I didn’t have such a thing and I used what I had, an old compact relay that was just the right size. I used tantalum scoop capacitors as tantalum capacitors. I used the measurement mode switch, power switch and calibration button, taken from old Soviet oscilloscopes.

Test leads:

Should be as short as possible.

During assembly and setup, I followed these instructions:

Assemble the board, install 7 jumpers. First install jumpers under the PIC and under the relay and two jumpers next to the pins for the display.

Use tantalum capacitors (in the generator) - 2 pcs.
10uF.
The two 1000pF capacitors should be polyester or better (approx. tolerance no more than 1%).

It is recommended to use a backlit display (note that the limiting resistor 50-100 Ohm is not indicated on pins 15, 16 in the diagram).
Install the board into the case. The connection between the board and the display can be soldered at your request, or made using a connector. Make the wires around the L/C switch as short and rigid as possible (to reduce interference and to properly compensate for measurements, especially for the grounded end L).

Quartz should be used at 4.000MHz, 4.1, 4.3, etc. cannot be used.

Testing and calibration:

1. Check the installation of parts on the board.
2. Check the settings of all jumpers on the board.
3. Check that the PIC, diodes and 7805 are installed correctly.
4. Don’t forget to flash the PIC before installing it in the LC meter.
5. Turn on the power carefully. If possible, use a regulated power supply for the first time. Measure current as voltage increases. The current should be no more than 20mA. The sample consumed a current of 8mA. If nothing is visible on the display, turn the variable contrast adjustment resistor. The display should read " Calibrating", then C=0.0pF (or C= +/- 10pF).
6. Wait a few minutes (“warm-up”), then press the “zero” (Reset) button to recalibrate. The display should read C=0.0pF.
7. Connect the "calibration" capacitor. On the LC meter display you will see the readings (with +/- 10% error).
8. To increase the capacitance readings, close jumper “4”, see the picture below (approx. 7 PIC leg). To decrease the capacitance readings, close jumper “3” (approx. 6 PIC leg) see the picture below. When the capacitance value matches the “calibration” value, remove the jumper. The PIC will remember the calibration. You can repeat the calibration many times (up to 10,000,000).
9. If there are problems with measurements, you can use jumpers “1” and “2” to check the frequency of the generator. Connect jumper “2” (approx. 8 PIC pin) and check the frequency “F1” of the generator. Should be 00050000 +/- 10%. If the readings are too high (near 00065535), the device goes into “overflow” mode and displays the “overflow” error. If the reading is too low (below 00040000), you will lose measurement accuracy. Connect jumper "1" (approx. 9 PIC pin) to check frequency calibration "F2". It should be about 71% +/- 5% of “F1” which you got by connecting jumper “2”.
10. To get the most accurate readings, you can adjust L until you get F1 around 00060000. It is preferable to set “L” = 82 µH on a 100 µH circuit (you may not buy 82 µH;)).
11. If the display shows 00000000 for F1 or F2, check the wiring near the L/C switch - this means the generator is not running.
12. The inductance calibration function is automatically calibrated when capacitance calibration occurs. (approx. calibration occurs at the moment the relay is activated when L and C in the device are closed).

Testjumpers

1. F2 check
2. F1 check
3. Decrease C
4. Increase C

How to take measurements:

Capacitance measurement mode:

1. Move the measurement mode selection switch to position “C”
2. Press the “Zero” button
3. The message “Setting! .tunngu.” wait until “C = 0.00pF” appears

Inductance measurement mode:

1. Turn on the device and wait until it boots
2. Move the measurement mode selection switch to the “L” position
3. We close the measuring wires
4. Press the “Zero” button
5. The message “Setting! .tunngu." wait until “L = 0.00uH” appears

Well, that’s it, leave your questions and comments in the comments under the article.

The device is designed to measure low resistance, inductance, capacitance and ESR of capacitors. Functionally, the circuit can be divided into 8 main modules:
- L/C generator
- Block of stable current sources (50mA/5mA/0.5mA)
- Block responsible for discharging the capacitor under test
- Voltage amplifier block
- Information display unit (Nokia LCD 3310)
- Control buttons
- Microcontroller PIC18F2520
- Switch (for switching components under test)

I don’t see any point in describing the principle of operation of an LC generator and, accordingly, the principle of measuring inductance and capacitance (1p - 1 uF) in detail. This is described in detail in the descriptions of similar devices, of which there are a lot on the Internet. I will note only some of the features that were used in this scheme and calculation algorithm. To measure inductance and capacitance, different pairs of probes are used... this approach made it possible to increase the accuracy of the measurement by organizing constant, automatic, partial calibration. Those. The frequency drift of the LC generator does not have such a significant impact on the measurement accuracy as it previously did. Also, a new approach to calculations made it possible to get rid of the influence of the interturn capacitance of the measured inductance on the measurement result (it is taken into account during calibration).

Measuring the capacitance of electrolytic capacitors is organized according to the classical method - charging the capacitor with a stable current source to a certain voltage level (0.2v) with parallel calculation of the charging time. This is implemented in the circuit. way. The connected capacitor under test is pre-discharged (Q1), after which a stable voltage is applied to it and the timer is turned on. When the voltage reaches 0.2v. The internal comparator is triggered and the timer time is recorded. Next, the capacitance of the capacitor is calculated. To reduce the measurement time, you can select in the menu the maximum limit for measuring the capacitance of the capacitor under test (100/300/600 thousand microfarads).

Measuring the ESR (ESR) of a capacitor and measuring small resistances is carried out as follows. principle. A short voltage pulse generated by a stable current source is applied to the capacitor under test. This causes a voltage surge, the magnitude of which is proportional to Capacitor ESR. Two op-amps connected in series increase this signal to the required level. Next, the microcontroller connected to the op-amp output registers the pulse peak and performs analog-to-digital conversion for further calculation of the voltage value. Knowing the value of the pulse current and voltage, the ESR is calculated.

When measuring ESR small containers (<10uF) происходит незначительное завышение показаний измерителя. Не смотря на то, что длительность импульса всего 1-2uS этого достаточно для того, чтобы конденсатор успел немного зарядиться, тем самым слегка завысив значение измеряемого напряжения.

Some design features that should be taken into account when repeating. It is better to replace the trimming resistors in the stable current source block (2. I_source) with constant ones, after selecting their approximate value during the setup process (described below).

It is recommended to use multi-turn trimmers R3 and R8 in the amplifier block (4. Amp). This will allow you to fine-tune the coefficient. gain, the value of which determines the accuracy of the device (especially critical for
ESR).

Instead of two MCP601 op-amps, you can use one MCP602.
The relay in the switching unit (8. Switch) must be used bistable with two windings designed for a voltage of 5v.

Capacitors C2 and C5 are tantalum or non-polar “ceramics”. Throttle L1 is a dumbbell type. It’s even better if this “dumbbell” is in a ferrite “glass”.

The "S1 optional" block is a control unit for supplying voltage to the LC generator. Optionally, it is possible to turn off the generator in the “electrolyte” measurement mode to reduce the power consumption of the circuit. Block S1 can be omitted by simply connecting the LC generator to the power supply.

To avoid failure of the microcontroller, the Jmp jumper should be installed only after adjusting the voltage at point “B” with the resistor “R_Vbat” (described below).

The circuit lacks a frequency counter module (prescaler and buffer), although the frequency counter itself is implemented in software. The measured frequency (with the “correct” amplitude) should be applied to pin 6 of MK (F). It is necessary to understand that for the operation of the capacitance and inductance meter modes, a signal from the output of the LC generator must be supplied to input 6 MK. For this purpose, the diagram shows a switch. One of the possible schematic solutions for the frequency meter module (prescaler/buffer, switching) is still under development. If necessary, switching can be organized using ordinary switches, and one of the many circuits available on the Internet can be used as input circuit diagrams (divider/buffer).

Setting up and working with the device.

When you turn on the device for the first time, you should reset all settings to default settings. To do this, press button 3 and turn on the power of the device. In the future, this operation can be performed from the “Function” menu, section “Reset”. After resetting, it is advisable to turn the device off and on. By default, after resetting the settings, the contrast value “Contrast” is set to 200. This value can be changed in the settings menu or you can turn the device off/on by holding button 4 down. In this case, after turning on the device will immediately go to the contrast adjustment menu. Next, use button 4 to increase the contrast, and use button 3 to decrease it.

Setting up stable current sources.

The accuracy of measurement is significantly influenced by the accuracy of setting up stable current sources. To configure, you need to go to the “Function” menu and then select the “I_50” section with the “OK” button. Then connect a milliammeter to the C/ESR measurement terminals. The milliammeter will show the future pulse current value for ESR measurement. Using a trimming resistor (R3), it is necessary to set this current as close as possible to the value of 50mA. After this, remember the readings and turn off the milliammeter. Next, using the +/- buttons, set in the device menu the value previously reflected on the milliammeter with an accuracy of tenths and save it by pressing the OK button. The same procedure must be performed for current sources of 5 and 0.5mA... sections "I_5" and "I_05", adjusting the current with the corresponding string resistors, while the measured value must be entered in the device menu with
accurate to hundredths/thousands.

It is important to remember that switching between sections must be done with the milliammeter turned off. In the future, it is recommended to replace the trimming resistors with constant ones and repeat the setup procedure.

Setting up the op-amp.

The op-amp tuning process comes down to adjusting the K gain of each op-amp to the value specified in the Ampl and Amp2 sections. To do this, select the ESR/C/R measurement mode and further:

1. Connect an electrolyte with a known capacity to the terminals (it is better to take a capacitor with a small capacity of 10-50uF) and using the construction resistor R3 and the value of the Amp1 variable (~6.0) in the setup menu, achieve the corresponding readings on the device screen.
2. Then connect a known resistance to the terminals (preferably 1 - 10 Ohms) and using the construction resistor R8 and the Amp2 variable (~6.0) in the setup menu, achieve the corresponding readings on the device screen.

The accuracy of readings when measuring resistance will be affected by the accuracy of setting the current value for current sources
0.00 -1.00 Om - section "I_50"
1.00 -10.0 Om - section "I_5"
10.0 -100 Om - section "I_05"

Setting up the LC generator.

Setting up an LC generator comes down to selecting inductance L1 and capacitor C1 so that the generator frequency, which can be controlled using the “Oscillator” mode, is in the range of 900 kHz. C2 and C5 must be tantalum or non-polar "ceramics". The calibration capacitor can be anything in the range of 500-1200 pF. The main thing is that it is a capacitor with a minimum TKE and with a capacitance value known to you. It is very good if it is possible to pre-measure its real capacity using some calibrated meter. The value of the total capacity C_cal and C3 must be entered in the "6.Ccal" section. C3 does not need to be installed (....saw it in one similar solution as a possible option for reducing the overall TKE).

Battery charge indicator.

Setting the charge indicator is reduced to setting the voltage at point “B” to approximately 1/3 of the battery voltage. To do this, you need to measure the battery voltage at point “A” (with the device turned on) U1. Then connect a voltmeter to point “B” and, by adjusting the resistor “R_Vbat”, achieve the readings of the voltmeter U2 equal to approximately 1/3 of U1. Next, calculate the division coefficient K_div = U1/U2 and write the values ​​in the menu in the corresponding settings sections. Also specify in the settings the voltage value of a fully charged battery “V_bat” and the minimum battery voltage level at which the device will signal the need to replace/charge the battery.

Also, to increase the accuracy of the ADC, it is advisable to specify in the menu the exact supply voltage of the microcontroller V_ref (default is 5v) by measuring it with the device turned on at the V_ref point.

ESR/C/R measurement (C 0.1 - 600,000 uF)

To measure you need:

2. Switch the device using the "Mode" button (hereinafter M) to ESR/C/R mode

(C)

It should be noted that the speed of measurement is affected by the capacitance of the capacitor being measured. The maximum measuring limit can be selected in the “Function” menu (C_max) (indicated in thousand microfarads)

Calibration in ESR/C/R mode.

Calibration serves to compensate for the influence of the length of terminal wires, etc. on the result of measuring internal resistance. To carry out calibration, while in ESR/C/R mode, press the “Calibration” button (hereinafter C). When the “Close probes” menu appears, you must close the probes of the device before the countdown on the screen ends. After completing the calibration process, information about the settings will be automatically saved in the device’s non-volatile memory, which will eliminate the need for further calibration each time the device is turned on.

Measurement C (C< 1uF)

To measure you need:
1. Turn on the device (terminals for connecting the measuring component are free)
2. Switch the device using the "M" button to C-meter mode
3. If necessary, perform calibration (described below)
4. Connect the component to be measured to the terminals
5. The device screen will display the measurement result.

Calibration in C mode

Calibration serves to compensate for the influence of the length of terminal wires, etc. on the result of measuring the capacitance of the capacitor. To carry out calibration, you must be in mode C (the connection terminals of the measuring component are open, the capacitor being measured is disconnected) and press the “C” button.

L measurement

To measure you need:
1. Turn on the device (terminals for connecting the measuring component are free)
2. Switch the device using the "M" button to L-meter mode
3. If necessary, perform calibration (described below)
4. Connect the component to be measured to the terminals
5. The device screen will display the measurement result.
6. When measuring inductance (especially small values), to obtain higher measurement accuracy, you can perform calibration during the measurement process (without turning off the measured inductance) by pressing the “C” button. In this case, the device will perform calibration and the screen will display the value of the connected inductance as close as possible to the real one.

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Calibration in L mode

Calibration serves to compensate for the influence of the length of terminal wires, etc. on the inductance measurement result. There are two types of calibration - “deep” for calculating the inductance of the probes and “normal” for correcting generator drift. Normal calibration is performed by pressing the “C” button in L-meter mode. Calibration can be performed with the measured inductance connected to the probes of the device.

To perform a “deep” calibration, press the “C” button and hold it pressed until the inscription “Close probes and take away hand” appears (close the probes and take away your hands), then close the measuring probes until the end of the countdown on the device screen, remove your hands and wait for the calibration process to complete. After calibration, open the probes. Deep calibration may not be carried out constantly because... after performing a “deep” calibration, the inductance values ​​of the connection probes are stored in the non-volatile memory of the microprocessor.

Dimension F

To measure frequency you need:
1. Turn on the device
2. Switch the device using the "M" button to F-meter mode
3. Select the operating mode (with or without prescaler) using the “/” button
4. Apply the measured frequency to input “F” (6th pin of the MK).

You can change the division coefficient of the applied prescaler using the “K” button. After setting the coefficient and saving the “OK button”, the value will be saved in the non-volatile memory of the device. The device circuit does not contain frequency counter modules (prescaler and buffer).

Beep"Reminder"

If measurements are not taken for more than ~1 minute, the device begins to emit an intermittent sound signal. Subsequently, the signal is repeated every ~20 seconds. The “reminder” sound signal will not turn on if the device is set to “Silent” mode.