AVR Semiconductor, R, L, C, ESR, FRQ, etc. :) TESTER on ATmega microcontrollers
In this section I present to your attention the device - tester of semiconductor elements, meter of capacitance of capacitors and resistance of resistors, in short, a very useful thing :)The description of this measuring device is taken from the article by Marcuse Frejeka and Karl-Heinz Kübbelera posted on their website. This device was developed by them back in 2009 and currently haunts all radio amateurs. The circuit has undergone little changes; to date, the authors and other programmers have released many versions of firmware for microcontrollers (MCUs) of the ATmega8, ATmega48, ATmega168, ATmega328 series (the pinout of all these MCUs is the same, so no changes are needed in the topology of the printed circuit board). I am not a specialist in the field of radio electronics and not a programmer, I am an ordinary self-taught radio amateur, so I will present the information as I perceive it. At first I also thought that this was a Chinese development :) - all sorts of Chinese online stores are simply teeming with kits and ready-made testers, but it turned out that everything is not entirely true.In addition, I found a Czech clone of this tester. I was interested and tried the tester options on (MK) ATmega8 series (two firmware options) and ATmega328. This tester does not measure capacitors with a capacitance of less than 25 pF and inductance of less than 0.01 mH (only the ATmega168 and ATmega328 tester measures inductance and ESR). But as a radio amateur, I am specifically interested in “small” capacitances and inductances, since these are the ones that often have to be selected. In addition, as the authors state, the accuracy of measuring inductance and capacitance is not high - this is true: (In addition, the device on the ATmega328 can measure frequency and voltage, work as a generator, and also work in cyclic measurement mode - without the need to constantly press "TEST" button. As I understand it, this device is the golden mean between expensive specialized industrial measuring instruments and cheap Chinese multimeters, which all markets are littered with, and analog homemade ones. But, as practice shows, one device is not enough. For me, two devices are quite enough: an ATmega8 tester for identifying semiconductor components, measuring the resistance of resistors and the approximate capacitance of capacitors, because it does not measure capacitors with large capacity correctly; R/L/C/ESR tester on PIC16F690, the description of which I posted, for accurately measuring the capacitances of various capacitors, inductors, ESR (EPS) and the dielectric loss tangent of the dielectric of electrolytic capacitors.Of course, I still have several multimeters on my shelf for measuring voltages, currents, circuit continuity, etc., well, where could we go without them :))) - the more devices, the better!
Considering the above, I bring to your attention kit for self-assembly of the tester semiconductor devices on the ATmega8 MK and firmware for the MK in two versions: option No. 1 and option No. 2 . For programming I use the cheapest and most common programmer USBasp which you can buy just anywhere :)... I packed into the archives: Windows drivers for the USBasp programmer, *.hex FLASH firmware file, *.eep EEPROM firmware file, program Kazarma for flashing the MK itself, fuses for setting up the MK and a schematic diagram indicating the necessary modifications for this firmware version.I did not notice any difference in the operation of the device when clocking the MK from an external quartz or from the built-in RC. The difference between the firmware is in the visual display of information on the display (I like both options). In firmware No. 2, the accuracy of measuring the capacitance of capacitors has been increased. The tester accurately determines the numbers and names of the terminals of a transistor, thyristor, diode, etc. It will be very useful not only for a novice radio amateur. Using this tester, it is very convenient to sort semiconductor elements by parameters, for example, select transistors by gain. Those. This is a simple but quite effective tester for quickly checking, sorting and recognizing most semiconductors - transistors, diodes, field-effect transistors, mosfet, double diodes, low-power thyristors, dinistors, etc. The device is convenient for determining the parameters of SMD components; for this purpose, the kit includes corresponding fiberglass scarves with three numbered pads. Allows you to measure the resistance of resistors and the capacitance of capacitors. All of the above is possible for a device based on the ATmega8 microcontroller.On the LCD display we immediately see the pinout, type and parameters, rather than having to go to the Internet for a datasheet, i.e. If you have an unknown SMD element with three legs without markings, then using this device you can determine what it is - a transistor, diode assembly, or others.
Scheme for firmware No. 1:
Scheme for firmware No. 2 (only one resistor was added, because the author programmatically disabled the pull-up resistors in the MK - do not change anything else!):
Device features:
0. With very enviable functionality, the tester is very easy to assemble and does not require scarce parts.
1. Automatic detection of NPN and PNP transistors, N and P channel MOSFETs, diodes, dual diodes, thyristors, triacs, resistors and capacitors.
2. Automatically detects and displays the outputs of the component being tested.
3. Detection and display of the protective diode of transistors.
4. Determination of the gain and forward voltage base-emitter of bipolar transistors.
5. Measurement of gate threshold voltage and gate capacitance of MOS transistors.
6. Measuring forward voltage for simple diodes (LEDs), not for double diodes.
7. Resistor resistance measurement - range from 1 Ohm to 50 MOhm.
8. Measuring the capacitance of capacitors - range from 25 pF to 100 mF.
9. Display of values on a text LCD display (2x16 characters).
10. The duration of testing a part is less than 2 seconds (with the exception of high-capacity capacitors).
11. One button control and automatic power off.
12. Power consumption when switched off< 20 нА
13. Problems in determining powerful thyristors and triacs, due to the fact that the current during measurement is 7 mA, which is less than the holding current of the thyristor.
14. Problems in identifying conventional field-effect transistors, since for most field-effect transistors the drain and source when measured differ little or almost no different, so they may not be recognized; when testing field-effect transistors, the drain and source may be incorrectly designated, but, in principle, The transistor type is shown correctly in any case.
15. The device can be powered from a 9V Krona battery or from a 9-12V DC network adapter. When running on battery power, the display backlight does not turn on. When working from the network adapter, the backlight is on all the time. The power adapter is not included in the package, only a plug for it is included in the package.
VIDEO No. 1 WORK OF SEMICONDUCTOR COMPONENT TESTER
VIDEO No. 2 TESTER WORK (accuracy increased and R/C measurement ranges expanded)
VIDEO No. 3 TESTER WORK (inidea from buyer Andrey from Donetska, go to his channel and you will find a lot of interesting and useful information there)
Indication of tested elements on the device display:
- NPN transistors - on display "NPN"
- PNP transistors - on display "PNP"
- N-channel-enriched MOSFETs - on display "N-E-MOS"
- P-channel-enriched MOSFETs - on display "P-E-MOS"
- N-channel-depletion MOSFETs - on display "N-D-MOS"
- P-channel-depletion MOSFET - on display "P-D-MOS"
- N-channel JFET - on display "N-JFET"
- P-channel JFET - on display "P-JFET"
- Thyristors - on display "Tyrystor"
- Triacs - on the display "Simistor"
- Diodes - on the display "Diode"
- Double-cathode diode assemblies with a common cathode - on display "Double diode CK"
- Double-anode diode assemblies with a common anode - on display "Double diode CA"
- Two diodes connected in series - on display "2 diode series"
- Symmetrical diodes - on the display "Diode symmetric"
- Resistors - "Resistance"
- Capacitors - "Capacitor"
Description of additional measurement parameters:
- h21e - current gain
- (1-2-3) - the order of the connected terminals of the element and, oppositely, their name
- Presence of protection elements - diode - "Diode symbol"
- Forward voltage - Uf mV
- Opening voltage (for MOSFET) - Vt mV
- Gate capacitance (for MOSFET) - C nF
I completely forgot! If you need firmware in another language, you can find it in the appropriate archive. There are also alternative firmwares!
Cost of a printed circuit board with mask and markings: 65 UAH
The cost of a complete set of parts for assembling the tester (including the board, LCD (blue background and white symbols), “flashed” ATmega8 MK with firmware No. 2):330 UAH
Cost of the assembled ATmega8 tester board: 365 UAH
The instructions for the kit with a brief description and list of parts included in the kit can be seen
To order, please contact as shown in the diagram:
The result will be a device whose description can be found :). The archive with firmware No. 3 contains everything that I described above, but with a slight adjustment! The thing is that when programming the programKazarma I “uploaded” the contents of the FLASH and EEPROM files into the MK without any questions, but refused to “upload” the fuses. Maybe my hands are crooked, or maybe something else bothered me. So I went a different route. Downloaded the program AVRDUDESS (it is in the archive), with its help I was able to program FLASH, EEPROM and MK fuses. A screenshot of the fuse settings is in the archive. The instructions for the tester describe absolutely everything in detail! I will only note that this version has an option for auto-calibration of the device.
Good luck to everyone, peace, goodness, 73!
I would like to share a very useful circuit for every radio amateur, found on the Internet and successfully repeated. This is indeed a very useful device, which has many functions and is assembled on the basis of an inexpensive ATmega8 microcontroller. There are a minimum of parts, so if you have a ready-made programmer, it can be assembled in the evening.
This tester accurately determines the numbers and types of terminals of a transistor, thyristor, diode, etc. It will be very useful for both novice radio amateurs and professionals.
It is especially indispensable in cases where there are stocks of transistors with half-erased markings, or if you cannot find a datasheet for some rare Chinese transistor. The diagram is in the figure, click to enlarge or download the archive:
Types of tested radioelements
Element name - Display indication:
NPN transistors - "NPN" on display
- PNP transistors - "PNP" on display
- N-channel-enriched MOSFETs - on display "N-E-MOS"
- P-channel-enriched MOSFETs - on display "P-E-MOS"
- N-channel-depletion MOSFETs - displays "N-D-MOS"
- P-channel-depletion MOSFETs - display "P-D-MOS"
- N-channel JFET - "N-JFET" on display
- P-channel JFET - "P-JFET" on display
- Thyristors - on the display "Tyrystor"
- Triacs - on the "Triak" display
- Diodes - on the display "Diode"
- Double cathode diode assemblies - on the display "Double diode CK"
- Double-anode diode assemblies - on the "Double diode CA" display
- Two diodes connected in series - “2 diode series” on the display
- Symmetrical diodes - on the display "Diode symmetric"
- Resistors - range from 0.5 K to 500K [K]
- Capacitors - range from 0.2nF to 1000uF
Description of additional measurement parameters:
H21e (current gain) - range up to 10000
- (1-2-3) - order of connected terminals of the element
- Presence of protection elements - diode - "Diode symbol"
- Forward voltage - Uf
- Opening voltage (for MOSFET) - Vt
- Gate capacitance (for MOSFET) - C=
The list shows an option for displaying information for English firmware. At the time of writing, Russian firmware appeared, with which everything became much clearer. To program the ATmega8 controller, click here.
The design itself is quite compact - about the size of a pack of cigarettes. Powered by a 9V Krona battery. Current consumption 10-20mA.
To make it easier to connect the parts under test, you need to select a suitable universal connector. Or better yet, several - for different types of radio components.
By the way, many radio amateurs often have problems testing field-effect transistors, including those with an insulated gate. Having this device, you can find out in a couple of seconds its pinout, performance, junction capacitance, and even the presence of a built-in protective diode.
Planar SMD transistors are also difficult to decipher. And many radio components for surface mounting sometimes cannot be even roughly determined - either a diode or something else...
As for conventional resistors, here too the superiority of our tester over conventional ohmmeters included in DT digital multimeters is obvious. Here, automatic switching of the required measurement range is implemented.
This also applies to testing capacitors - picofarads, nanofarads, microfarads. Simply connect the radio component to the device sockets and press the TEST button - all the basic information about the element will immediately be displayed on the screen.
The finished tester can be placed in any small plastic case. The device has been assembled and successfully tested.
Discuss the article TESTER OF SEMICONDUCTOR RADIO ELEMENTS ON A MICROCONTROLLER
AVR-Transistortester construction kit - supplied as a set of parts which includes:
printed circuit board and all parts including resistors and capacitors that are required to assemble a working device. The kit does not include a housing. The device does not require adjustment and is operational immediately after assembly. The processor is installed in the socket. The LED is not displayed on the front panel. It is not an indicator, but is required for the operation of the device. During operation, its glow may not be visible. The display is connected to the main board via a comb with a pitch of 2.54 mm. All documentation necessary for assembling the device (circuit diagram, wiring diagram and list of used components) can be downloaded at the end of the article.
The photo shows the finished assembled device. The second photo shows a set of parts.
A construction kit is a collection of parts. The battery is not included.
Device capabilities.
The tester allows you to determine bipolar transistors, MOSFET and JFET field-effect transistors, diodes (including double series and anti-parallel), thyristors, triacs, resistors, capacitors and some of their parameters. In particular for bipolar transistors:
1. conductivity – NPN or PNP;
2. pinout in format – B=*; C=*; E=*;
3. current gain – hFE;
5. forward base-emitter voltage in millivolts – Uf.
For MOSFET transistors:
1. conductivity (P-channel or N-channel) and channel type (E – enriched, D – depleted) – P-E-MOS, P-D-MOS, or N-E-MOS, N-D-MOS;
2. gate capacity – C;
3. pinout in GDS=*** format;
4. presence of a protective diode – diode symbol;
5. gate-source threshold voltage Uf.
For J-FET transistors:
1. conductivity – N-JFET, or P-JFET;
2. pinout in GDS=*** format.
For diodes (including double diodes):
1. pinout;
2. forward anode-cathode voltage – Uf.
For triacs:
1. type – Triac; 2. pinout in format G=*; A1=*; A2=*.
For thyristors:
1. type – Thyristor;
2. pinout in format – GAK=***.
The result is displayed on a two-line LCD. Testing time less than 2 seconds. (except for large capacitors), the result display time is 10 seconds. One button control, automatic shutdown. Current consumption in the off state is less than 20 nA. Resistance measurement range is from 2 Ohms to 20 MOhms. The accuracy is not very high. Capacitors are rated well from about 0.2nF to 7000μF. Above 4000μF the accuracy deteriorates. Measuring large capacitances can take up to one minute. The tester is not an accurate instrument and does not guarantee 100% reliability of identification and measurements, however, in the vast majority of cases, the measurement result is correct. When measuring power thyristors and triacs, problems may arise if the test current (7 mA) is less holding current.
Documentation
But among the radio components there are also those that are difficult, and sometimes impossible, to check with an ordinary multimeter. These include field-effect transistors (such as MOSFET, so J-FET). Also, a regular multimeter does not always have the function of measuring the capacitance of capacitors, including electrolytic ones. And even if such a function is available, the device, as a rule, does not measure another very important parameter of electrolytic capacitors - equivalent series resistance ( EPS or ESR).
Recently, universal R, C, L and ESR meters have become affordable. Many of them have the ability to test almost all common radio components.
Let's find out what capabilities such a tester has. The photo shows a universal tester for R, C, L and ESR - MTester V2.07(QS2015-T4). Aka LCR T4 Tester. I bought it on Aliexpress. Don’t be surprised that the device does not have a housing; with it it costs much more. option without housing, but with housing.
The radio components tester is assembled on an Atmega328p microcontroller. Also on the printed circuit board there are SMD transistors with markings J6(bipolar S9014), M6(S9015), integrated stabilizer 78L05, TL431 - precision voltage regulator (adjustable zener diode), SMD diodes 1N4148, quartz at 8.042 MHz. and “loose” - planar capacitors and resistors.
The device is powered by a 9V battery (size 6F22). However, if you don’t have one at hand, the device can be powered from a stabilized power supply.
A ZIF panel is installed on the tester's printed circuit board. The numbers 1,2,3,1,1,1,1 are indicated nearby. Additional terminals on the top row of the ZIF panel (those 1,1,1,1) duplicate terminal number 1. This is to make it easier to install parts with spaced pins. By the way, it is worth noting that the bottom row of terminals duplicates terminals 2 and 3. For 2 there are 3 additional terminals, and for 3 there are already 4. You can verify this by examining the layout of printed circuit conductors on the other side of the printed circuit board.
So, what are the capabilities of this tester?
I also advise you to look at the page that talks about the types of field-effect transistors and their designation in the diagram. This will help you understand what the device is showing you.
Let's take our KT817G as an experimental "rabbit". As you can see, the gain of bipolar transistors is measured hFE(aka h21e) and bias voltage B-E (transistor opening) Uf. For silicon bipolar transistors, the bias voltage is in the range of 0.6 ~ 0.7 volts. For our KT817G it was 0.615 volts (615mV).
It also recognizes composite bipolar transistors. But I wouldn’t trust the parameters on the display. Well, really. A composite transistor cannot have a gain hFE = 37. For KT973A, the minimum hFE must be at least 750.
As it turned out, the structure for KT973A (PNP) and KT972A (NPN) is determined correctly. But everything else is measured incorrectly.
It is worth considering that if at least one of the transitions of the transistor is broken, then the tester can identify it as a diode.
The test sample is a 1N4007 diode.
For diodes, the voltage drop across the p-n junction in the open state is indicated Uf. In the technical documentation for diodes it is indicated as V F- Forward Voltage (sometimes V FM). I note that with different forward current through the diode, the value of this parameter also changes.
For a given diode 1N4007: V F=677mV (0.677V). This is a normal value for a low frequency rectifier diode. But for Schottky diodes this value is lower, which is why they are recommended for use in devices with low-voltage autonomous power supply.
In addition, the tester also measures the capacitance of the p-n junction (C=8pF).
The result of checking the KD106A diode. As you can see, its junction capacitance is many times greater than that of the 1N4007 diode. As much as 184 picofarads!
If you install an LED instead of a diode and turn on the test, then during testing it will blink provocatively.
For LEDs, the tester shows the junction capacitance and the minimum voltage at which the LED opens and begins to emit. Specifically for this red LED it was Uf = 1.84V.
As it turns out, the universal tester can also test dual diodes, which can be found in computer power supplies, car amplifier voltage converters, and all kinds of power supplies.
Double diode test MBR20100CT.
The tester shows the voltage drop on each of the diodes Uf = 299mV (in the datasheets it is indicated as V F), as well as the pinout. Do not forget that dual diodes come with both a common anode and a common cathode.
This tester does an excellent job of measuring the resistance of resistors, including variable and trimmers. This is how the device determines a trimmer resistor type 3296 at 1 kOhm. On the display, the variable or trimmer resistor is shown as two resistors, which is not surprising.
You can also check fixed resistors with resistance down to fractions of an ohm. Here's an example. Resistor with a resistance of 0.1 Ohm (R10).
In practice, the function of measuring inductance in coils and chokes is no less in demand. And if large-sized products are marked with parameters, then small-sized and SMD inductors do not have such markings. The device will help in this case too.
The display shows the result of measuring the throttle parameters at 330 μG (0.33 milliHenry).
In addition to the inductance of the inductor (0.3 mH), the tester determined its resistance to direct current - 1 Ohm (1.0Ω).
This tester checks low-power triacs without problems. For example, I checked with them MCR22-8.
But a more powerful thyristor BT151-800R in the TO-220 case the device could not be tested and displayed the following message on the display: "? No, unknown or damaged part" , which loosely translated means “Missing, unknown or damaged part.”
Among other things, the universal tester can measure the voltage of batteries and accumulators.
I was also pleased that this device can test optocouplers. True, such “composite” parts can only be checked in several stages, since they consist of at least two parts isolated from each other.
I'll show you with an example. Here is the internals of the TLP627 optocoupler.
The emitting diode is connected to pins 1 and 2. Let's connect them to the terminals of the device and see what it shows us.
As you can see, the tester determined that a diode was connected to its terminals and displayed the voltage at which it begins to emit Uf = 1.15V. Next, we connect 3 and 4 outputs of the optocoupler to the tester.
This time the tester determined that a regular diode was connected to it. There is nothing surprising. Take a look at the internal structure of the TLP627 optocoupler and you will see that a diode is connected to the emitter and collector terminals of the phototransistor. It bypasses the terminals of the transistor and the tester “sees” only it.
So we checked the serviceability of the TLP627 optocoupler. In a similar way, I was able to test a low-power solid-state relay type K293KP17R.
Now I’ll tell you which parts this tester cannot check.
Powerful thyristors. When testing the BT151-800R thyristor, the device showed on the display a bipolar transistor with zero hFE and Uf values. Another instance of the thyristor was determined to be faulty. Perhaps this is indeed true;
Zener diodes. Defines as a diode. You will not get the main parameters of the zener diode, but you can verify the integrity of the P-N junction. The manufacturer claims correct recognition of zener diodes with a stabilization voltage of less than 4.5V.
When making repairs, I still recommend not to rely on the readings of the device, but to replace the zener diode with a new one, since it happens that the zener diodes are working properly, but the stabilization voltage “walks”;
Any microcircuits, such as integrated stabilizers 78L05, 79L05 and the like. I think explanations are unnecessary;
Dinistors. Actually, this is understandable, since the dinistor opens only at a voltage of several tens of volts, for example, 32V, like the common DB3;
The device also does not recognize ionistors. Apparently due to the long charging time;
Varistors are defined as capacitors;
Unidirectional suppressors are defined as diodes.
A universal tester will not remain idle for any radio amateur, and will save radio mechanics a lot of time and money.
It is worth understanding that when checking faulty semiconductor elements, the device may determine the type of element incorrectly. So, he can define a bipolar transistor with one broken p-n junction as a diode. And a swollen electrolytic capacitor with a huge leak can be recognized as two back-to-back diodes. This has happened. I think there is no need to explain that this indicates the unsuitability of the radio component.
But, it is worth considering the fact that incorrect determination of values also occurs due to poor contact of the part pins in the ZIF panel. Therefore, in some cases it is necessary to reinstall the part into the panel and carry out testing.
I assembled this tester using information from various forums. There are several options for circuits (but not as many as firmware)
The result is a compact, inexpensive device that does not require precise details in the circuit, convenient and functional!
Types of parts tested:
(element name - display indication):
- NPN transistors - "NPN" on display
- PNP transistors - "PNP" on display
- N-channel-enriched MOSFETs - on display "N-E-MOS"
- P-channel-enriched MOSFETs - on display "P-E-MOS"
- N-channel-depletion MOSFETs - display "N-D-MOS"
- P-channel-depletion MOSFETs - display "P-D-MOS"
- N-channel JFET - "N-JFET" on display
- P-channel JFET - "P-JFET" on display
- Thyristors - on the display "Thyristor"
- Triacs - on the display "TRIAC"
- Diodes - on the display "Diode"
- Double-cathode diode assemblies - on the display "Dual diode CA"
- Double-node diode assemblies - on the display "Double diode CC"
- Two diodes connected in series - the display shows "2 diodes in series."
- Symmetrical diodes - on the display "2 counter diodes"
- Resistors - range from 1 Ohm to 10 MOhm [Ohm,KOhm]
- Capacitors - range from 0.2nF to 5000uF
Description of additional measurement parameters:
- H21e (current gain) - range up to 1000
- (1-2-3) - order of connected terminals of the element
- Presence of protection elements - diode - "Diode symbol"
- Forward voltage – Uf
- Opening voltage (for MOSFET) - Vt
- Gate capacitance (for MOSFET) - C=
Fuses for PonyProg
You can also adjust the measurement constants using PonyProgC AndR The cells are marked in the photo.
We change the number in the middle cell of the buffer in increments of + or - 1 (depending on which direction you need to make the edit and by how much, it can be the number 10),
after changing the number in the cell, program the MK, then do a test of the known part, compare before and after.
We repeat the procedure if necessary.
Firmware for ATmega8 and ATmega8А, in the archive (English and Russian EEPROM, correct display in Cyrillic µ
And Omega) Tr-TestNew_11_01_2011.rar
Lay printed circuit board, for 1602V indicator, download the archive here Tester_P-P.rar
By and large, there is no special setup and adjustment of the device; amateurs, of course, can adjust the R and C readings, as it seems this has already been described in detail and there should be no problems either.
So on the author’s website, I looked at what you need to pay attention to when starting up and setting up the device.
My translation is free, but I think the meaning is completely the same.
Troubleshooting
If something starts to show on the display, check the following parameters:
Is the connection to the LCD correct (we check the wiring of the LCD indicator using the datasheet)?
With HD44780 LCD compatible controller?
Check the fuses of the ATMega8 bits, correct (internal 1 MHz oscillator)?
Is EEP flashed? file, read into the EEPROM of the controller?
Perhaps the LCD needs to adjust the contrast voltage. The resistance must be adjusted in any case the LCD is adjusted to obtain good contrast (use a potentiometer if necessary).
If the board is assembled using components of the correct configuration, and the correct order of connection to the probes shows that the component is detected, although it is not connected, or data such as the gain for different connection sequences diverge significantly, look for flux residue on the tracks, poor flux composition or similar soldering components need to be reviewed and cleaned. Between the tracks on the change. The probes should not contain any residual flux component. Flux is usually slightly conductive, causing current to leak through the flux and distort the result.
That's it, these are the global recommendations,
nothing new and nothing special, (the condition of using the nominal values of the parts is observed first of all) you only need to look at installation errors, and I’ll tell you this, it’s not always easy, because it’s easier to find a mistake in others than to admit your mistake (just kidding).... ....
