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Microcontroladores: Capacímetro Autorrango

tags331 smd resistor

A tool that no workbench can lack is

. Most of the instruments we find on the market are very expensive. In addition, we are

, In the best case. The instrument we are showing you today can measure equipment ranging from a few picofarads to a few farads. Its advantage is that it uses a

And no selection keys are needed. Find out the status

This will no longer be the privilege of only certain professionals. This article details all the step-by-step construction methods, would you miss it? only one

And a popular timer

You can use a capacitance meter in an afternoon's work. Its simple structure, ease of use, and most importantly, the accuracy of using common components will surprise you. You can see the 555 timer from the circuit

The most popular are products manufactured by Harris, Texas Instruments, Philips, Intersil and Thomson. The integrated circuit is basically the same as the ordinary NE555, the only difference is the manufacturing technology used. Benefits of using this type

It's him

(60uA) has been added to

(2%) and very low current requirements (20pA) for activation inputs (such as THRESHOLD, TRIGGER and RESET).

The instrument operation we provide you with today is based on 7555 operation

. To measure the capacitor, the microcontroller is responsible for managing the input


Correctly, once the multivibrator is triggered, it takes time

Still very high (

). As shown below,

(This is the capacitor under test) and Ra. Briefly reviewing the working mode of the monostable multivibrator, we can recall that

Will be loaded by

, Try to reach a load voltage equal to the power supply voltage of the circuit. In fact, this will never happen because the transistor connected to IC pin 7 will cause C to discharge when it reaches 2/3 of C.


In order to obtain the desired performance, the PIC will set a low state on pin 4, thereby

To the timer. Then it will shoot (

) Maintain the monostable state by making a very short transition from the high state to the low state, then returning and maintaining the high state until the next multivibrator trips. During the falling edge of the trigger pulse, 7555 will activate its count by changing the state of the counter.

Internal IC, can be charged

It is forced to GND potential by releasing the internal transistor. While shooting

, The internal transistor (pin 7) releases the capacitor (unknown value in our case) from a potential equal to GND and allows the component to be charged through the resistor

In our circuit, it will be the one selected for each range and will be determined by

. Choose a job to determine which "branch"

Will be responsible for charging the capacitor, PIC will be responsible for charging, it will depend on the result obtained as an output

The development of multivibrators. In other words: PIC starts a time accumulator, if it exceeds a certain number of counts, PIC will know that it is not a small capacitor (Farad peak scale), and will automatically switch to consume current through this capacitor. Represented as a resistor branch of nanofarad. If the output of the multivibrator remains high and the second counter in the microcontroller program also overflows, the PIC will automatically switch to the third range to charge the capacitor faster, which will obviously be in the microfarad Within range. Depending on the program executed, the overflow will occur in 9,999 units, and in order to facilitate the reading of the obtained results, the scale will be expressed as 1 to 999 picofarads, then 1.00 to 9.9 nanofarads, and 10 to 10 picofarads. 99 nano farads, repeat this display mode on micron and millifarad rulers.

The PIC continuously drives the multivibrator and "reads" the duration of the output pulse when the OUTPUT state changes.





It's T).

This version of the circuit and its architecture is inspired by the very popular circuit released not long ago. In this case, what we have to do is to make full use of its outstanding characteristics and simplify the circuit into easy-to-understand, practical and useful components. In this way, we can see

This will be done by

, Multivibrator and

. As far as the fountain is concerned, due to the limited space in the selected cabinet and easy construction, we decided to adopt a split installation. (We use cabinets made of aluminum profiles obtained in the scrapyard).

see more

You can view the voting history in your profile

Very good Mario, I like it very much, I have thought of doing similar things, including coil gauges. One question is, is it cheaper to use the PIC internal comparator to make a relaxation oscillator?

Hello there!

I can't tell you if it can be done, but I think it can.

The problem (I think) will be that you will not be able to control the oscillator, and it will not be able to operate continuously under control. With 555, you can shoot at any time to achieve accurate timing. Otherwise, you should "catch" the beginning of the pulse to start the measurement.

Here, this moment can be managed at will.

Best wishes!

Ok, ok, I would like to know if you can use precision 555, what happened, I have bought everything, but 7555 is not available anywhere... I am from Venezuela

#7 Hello, Mario, I have carefully followed your project, and sincere congratulations to you, I successfully built the ESR meter

Now I plan to assemble a capacitive capacitance meter. Although I have just started using pic microcontrollers, I have many questions about this. One of them is: 16×2 LCD modules must also be programmed in advance? I cannot see that the LCD terminals in the picture are displayed very clearly, that is, I did not clearly identify all of its terminals. . Thank you for your help, because I hope to install this excellent tool on the workbench, if possible, great. Thank you for your cooperation. ..Goodbye.

#1 Greetings are what I have been looking for

This will be the reason why you can pass the material list to me. When adding an image, the name will be lost and cannot be read, and the same will happen to the schematic

Very good, very useful, can't you put the code in C or basic pictures? This will be quite convincing.

Excellent Mario, very good article.

If one day you plan to publish something about the oscilloscope, I will read it very enthusiastically.

So far, there are no plans, but I would love to write an article discussing how to use low resources to make an elemental spectrum analyzer. Maybe I will soon. This is a video I made with the analyzer.

Don't stop visiting us.


Good morning Mario:

I found this article great. This measuring device is very useful. The fact is that I do need it. I also tell you that I have never seen this 7555 before. I have always used the traditional 555, but I will look for it and Learn more.

I want to ask if you can upload the .bas file to use with Proton, or you can provide yourself some code guidelines to continue working wisely and then follow the programming, programming and programming knowledge. At least on the LCD monitor, we handled it well, which will be the logic of the measurement.

Thank you very much not to forget the fans of microcontrollers, we have missed these wonderful articles. I also tell you that because I can't find the STCN75 sensor, I have slowed down the I2C-processed thermometer project. Until today, I could not find a TMP100 sensor with the same characteristics with a bus. On-site I2C, although the size is small, the specific surface resistance is small, hehehe, when I buy it, I can hardly see it, I will do it, and I will tell you how it works.

Greetings from Colombia

Hello Yesbond!

You must order it as "555 CMOS version", or also known as 7555. It is an updated version of the traditional 555 (and CMOS).

Regarding TMP100, I want to use it, but I don't have enough time. I think by following the instructions in the STCN75 article, you will have no problem.

Have you asked me about mariogsacco (at gmailpuntocom)

Thank you very much for your trust, I will definitely write to you, although as you have taught, this will be the last choice.


To be clear, now is a question: why do they always use Pics and never use Motorola or FreeScale series products? Simple and inexpensive products such as jk1 will definitely suit hair.


Hello Victor

The answer is... because I don’t know how to use others

I think it is possible through what you said or some economic Atmel, but my world ended in PIC friends.

Very very good, I congratulate you, this is the best I have seen on the Internet, I will do this without a doubt, but what is its maximum measurement range? So, what is the largest capacitor you can measure?

Hi Leo!

I have a "can" of 90,000 microfarads (90 millifarads) and I usually take measurements. It took a long time (or longer), but he took the measurement without problems. That is my biggest exercise.

Hello there,

superior. And source code?


Wow! Great, it's much better than I thought, very good, and there is no doubt that I will arm it with great desire. Thank you so much capooooooooooo!!!!!!!

The only thing I need to do is to build an impedance meter (z) and a high range inductance meter (h) in the coil.

If you work together for us, that would be great.

superior! ! !

Theory of operation, surprisingly can be inferred to other things ^ _ ^

Mario, as always, ranks 10th in your project app, here we are looking for your notes, although working hours are a bit late, I always spend a few minutes to understand what is new... Congratulations . . . A Mexican from Arequipa, Peru.

Very good Mario! Bamboo

Ok, ok, it seems great to me,,, today I bought everything together, but in Venezuela I encountered a big problem, I can’t get 7555 or any equivalent product... Only 555 precision, I want to know whether it is effective or whether the program code needs to be modified... Thank you very much for your answer

Hello, cheotrix!

A great way to call me in the previous article... :))

It must be precision 555. This feature appears in this article because it is a feature we use, but you can place the obtained feature. The requirement is the accuracy of obtaining correct readings over the entire measurement range.

In any case, even if you use generic code, you don’t need to change anything in the code. A special algorithm must be created for each situation, which is practically impossible.

Thank you very much for your answers, and thank you for your compliments... Then, I will assemble the capacitive capacitance meter... I hope there is no problem with my LCD monitor, thank you very much, and I will know of any other designs you post

Regards Mario. I am from Venezuela and I tell you that I have assembled but the measurement results are not satisfactory. The meter spends a long time in demo messages and calibration (it's fast in the video), and the reading can't even get close to the actual level (can't be adjusted). I do not know what I did wrong. I am using all the components and the same table you indicated in the assembly. I told cheotrix in Venezuela that 7555 is in log Caracas form, but now they are on vacation. Thanks for everything.

Hi Will!

What you told me is really strange. The speed of my video is normal, so your situation should be the same.

Let's review:

Are you using 20Mhz crystals?

Are you using 16F628A that can run at this speed?

Is the power supply voltage correct at 5 volts?

Does the potentiometer rotate multiple times as shown in the picture?

Do you use the HEX file at the end of the text?

Have you confused the position of the potentiometer on the board?

Is the pin of transistor T1 in the correct position?

If all these are properly controlled and correct, we will look for other alternatives, friends. Don't worry, the circuit works very well. There may be some small errors, it has now disappeared, but we will find out.

Greetings and congratulations!

Hi Mario, I tell you I still have problems. Follow the delay in the demo:

25 seconds before the speech

55 s during demonstration

20 s for zero adjustment and 5 s for the first reading. I supply 5V to the circuit from the PC power supply. The crystal is 20 Mhz and the image is 16F628A (this is the only crystal), and I am recording it with Winpic800. When saving the Pic, can you tell me the configuration parameters. I put a C = 47 uF, the maximum reading I can read is 5 uF. Thank you

Do me a favor, I have completed the assembly of the circuit, I need to pass it to the PCB, but everything is fine from there, I haven't encountered any problems, but I want to know how it works (the program of the picture ), because it is fun, it urges me to help me a lot in school

Thanks in advance for your help

Regards Mario. solved the problem. It works well and has a little flexibility for extremely low values, but it works very well. Thank you

Hello, Mario, excellent article, I am a huge fan of NeoTeo, which makes me a very professional page, they know what they are talking about, and when I enter, I can’t stop reading the excellent articles they published Articles, especially if you are fascinated by me, I have read almost every one.

Regarding this article, I have only one question: the fact is that the location of these components on the PCB is not very clear. Wouldn't you find components with traces and tops on the PCB to know exactly where they are going? Thanks, greetings from Mexico

How useful is your article, but I doubt I have anything to tell me, but what should I do if the voltage is 4.2 to 3.5 volts? Tell me YAAAAAAAAAAAAAAAAA or when.

Hi Mario, you can activate or deactivate the PIC's PWM module by configuring the pins as outputs/inputs (previous frequency and initial configuration), you have a comparator and a frequency generator, you can save 555 Greetings

Hi, Mario.... I congratulate you.. This is an outstanding contribution, I will set myself the task of building it.. Hope it will be useful to me, thank you

I built it and it works 100%!

your good friend! Your article is very good. I haven't assembled the circuit yet, but will interact with it later. I am new to PIC and I am learning to program... If you can publish the file in .BASS to see how the picture works and the commands used, I would appreciate it. Thanks in advance.

Mario tells me what to do, where is the bill of materials, how do I know how the part works on the schematic PCB, am I missing something?

Or you just need to follow the schematic and put it in the program

And I have to do PCB and everything else?

I want to get an impression first. On which website can I get an impression?

This is where I live may become difficult.

Great project.

But, is there any list or package in which we can see the relationship of all components, or do we only need to display the image to understand everything?

How do you request a list of components and their position in the circuit above.

Thank you

Hello, my user name is invalid because I need to measure surface capacitors, so I am very interested in your project. I am on the breadboard for the time being. It works well, but I burned Bakura (I’m in Eagle Created a circuit in ), when I tried it, I encountered several problems, the first problem is that it can only work using 4 Mhz or 10 Mhz crystals or the second thing that works from there is that it measured It’s nanometers and micrometers, not peaks. It always sends me a 1nF signal on the screen, but when I touch it, it doesn’t send me a 0pF signal. Sometimes it changes and gives unstable values. Another thing is that I know that the zero value still needs to be adjusted and passed, because you have to touch the resistor to enter the measurement, and finally it stays still or freezes after measuring the microfarad. I need your help, my email is

Thank you

Congratulations, Mario. As always, you can embroider! I have installed the breadboard, although it took me some time, because in the end I misplaced the T1 A1015, and I have verified that it works. I measured 15 picofarads to 400 millifaras. It works perfectly!

For the final assembly, I will use a printing plate made due to the type of printing plate you printed. But I found that there are two electrolytic capacitors in the board photos of the components. In this picture, I also see two, but if one of them is outside the board (along with the regulator), we will only have the other 10 microfarads for the printed circuit board. So, in the photo, what is the foreground of PIC 16F628 and the second electrolytic capacitor that appeared before?

thanks for all you have done. You are a genius

I already have a circuit board with assembled and soldered components. After corresponding rectification and resolution, I finally managed to make it work, although not completely.

For Pico and Nano Farads, it works perfectly. Trace and millifaraday are not.

I even set the 220 ohm potentiometer P4 to zero, and even reduced the associated resistance R6 from 100 ohms to 27 ohms, which is at least 50% higher than my actual capacity (I have tested it with many capacitors.

Can anyone give me some ideas about failure?

Thank you very much foreros!

I have assembled it and it works well. Thank you very much, Mario. I will follow your other montage montages. This is one of my favorite devices.

Thanks again and greetings to all members.


Congratulations to Mario for making such an outstanding contribution. I have done it and it worked very well. Likewise, I congratulate those who dared to put it together and those who have not yet completed it, and then cheer up because it is very useful for work in the electronics field. wish everyone

Well, Mario, first of all, I have been a follower of your project for a long time, and I found an extension of knowledge and working tools in it.

Let me tell you that in the past few days, I have started searching for the 7555 camouflage heart of this project. This is the moment I couldn't find after nearly 2 weeks of searching. This is why I dare not write to ask what possible alternatives exist.

Similarly, I want to know if anyone in Colombia has completed the assembly and where can I get the parts?

thank you very much

Hello, my friend Sebastian (Sebastian) I am also you in Colombia. You can get generic or original components through sigma and get a good appreciation. You can search for Colombian sigma electronics in Google, enter the page, and find the components in it The catalog and warehouse address of the company's sales can also be-

Hello how are you!

If someone has already used the same PCB as proposed by Mario for assembly, you can contact me in the following ways

; I have installed it, but it does not work for me. Someone from the community is helping me, I made a video to show him how it works,

So you can understand the problems he is currently experiencing.

Thank you for your valuable help!

Thank you Mario, I will test how it works, I am a novice, but we will try our best to complete it.

Hello, I would like to know if anyone can send me a list of the components needed to assemble the capacitor. I am new to electronics and do not understand all the components of the schematic.

Thank you.

A few days ago, I completed the assembly of a picture recorder that worked well!

Hello, sorry, what is the highest measuring range of this capacitance meter? Because I have one, it is indeed very accurate. But its maximum range is 20 millifarads. Now I have a big problem. I have a device that uses a set of capacitors, each of which is 70 millifaras.. I know they can be connected in series, but I have to connect four in series Know if its condition is good.. 1 / c = (1 / c1) + (1 / c2) + (1 / c3) + (1 / c4), the number is because if I put two, it will be 35, And it will still happen. . If anyone knows how to improve the ranking, please help me.. Thank you, good day..

Hi Mario, I want to know if it is possible to check the capacity of a capacitor with this capacitance meter without having to take it out of the circuit.

thank you very much.

I want to know the list of materials and more specific installation methods, I am a beginner, thank you

Mr. Marco Antonio’s cordial and extensive greetings, congratulations to 1001 for such a beautiful project. The fact is, I’m a beginner, and I want to ask you if you are very modest, or if anyone guides the components on the plate, Congratulations to Neoteo and all the outstanding people who accompanied us through these places. Thank you in advance.

Greetings to all forums: For AUTO RANGE TRAINER, my question is

I made the PCB like in the picture, but it doesn’t work. I don’t know why

Because the IC is LM555, I cannot get 7555, and there is no signal on pin (3)

555, DIPLEY worked for me, because its results are as follows: Digital Capacimeter / Neo Teo / Adj-

Zero C = 0pF, there may be some modifications in the circuit, maybe

Problem I have no signal on LM555.

thank you very much for your help.

My mail: Carloscordov@hotmail.com

From Ambato ECUADOR.

Hello, I want to ask you a question. The capacitor started well and it welcomed me, but then got stuck in the zero setting and didn't jump to C=0. What could be the problem?

PS: The page is very good, thank you very much for your project.

Where can I download the picture consulting software

Please check how many millimeters you have made

I want to know the size of printing it out and using the flat plate method to make the PCB

Hello, don’t you provide us with assembly drawings and component lists for mortals? Thank you very much salu2

I want to know the source code of the ASM capacitance analyzer. Just look at how it is done and make some personal modifications.

I think these items are the best, I want to know how to record pic 16f628a, or if it melts, because everything else is easy to get, so congratulations on such an excellent project

I’m no stranger to this, and I really want to apply the knowledge gained to people like you who took the time to provide us with such a good tool. Congratulations to Mario for his excellent work

Okay, I have a question about the capacitive capacitance meter. Which email can I clarify or send my doubt to....... I will be very grateful.

Hello, this project is very good, I put it together, but there is a problem, the display I get is 16×1, and because the first 8 frames are displayed in contrast but no text is displayed, it seems that this hexadecimal cannot be used system. Thank you

Very good capacitance meter mario.

You can compare and research asm.

Thank you..

Hi Mario, if you can, I will leave you an email and pass the .asm to me,

Thank you..

Out of all due respect, I have seen this circuit and the people who always try to do it don't work, it's not because you keep something in the circuit so that it doesn't work.

Thank you, if so, it is because you better designed the pressure of the kit and solved the problem.

I already have a 16×2 display. The problem now is that it gives people a welcome, but it has been adjusted to zero, and it will not happen from then on.

Hello, I would like to ask you how to solve this problem, this does not start from zero adjustment, thank you, regards

Hello, sorry, but I don’t know what ASM is, I don’t know what I am doing because it starts up and insists on adjusting zero, it hasn’t happened since then, I have tried another picture, but no attempt, There is no problem with the hex file on the page? . Cheers

The capacitance meter did not work, I did all the tests, but it remained in the zeroing state, and nothing happened from there, the simulation of the deformed protein gave a hexadecimal failure???????????? ?????????, if someone does and he is gone, can you help me? Thank you.

Can someone pass me the list of materials and PCB? thank you for your help

Finally gone, the diode has a bad soldier, thank you very much...

Everything is on the page, which is good

OláMario...eu so so do Brasil. Simulei or circuit is not Proteus, it works very well and the physical structure also works.

You want to view the source code of the program to find the exact details of the two Pifarahs. Can't you send emails?

Very tossing.

Hi Mario, I am a novice in the forum, I want to know if it is possible to enter the same program as in Figure 16f84a. If it is not possible to enter, can you pass me .hex so that it will work in 16f84a? I hope you can, because it is difficult to get 16f624a from where I come from, I have checked the datasheet, even though I don’t know if it is possible to just input the file uploaded to my pic 16f84a to work properly because I see it brings I don’t have an analog input function, I hope you will reply as soon as possible

Thanks for greetings from Campeche, Mexico =)

If you want to send me the code, I would be very grateful, I have pic c ccs, I want to change it for my pic 16f84a, or send me a .hex file, but for my 16f84a, I hope you don’t have to modify the header file =) Regards

of course

Hi, I’m Marcelo from Buenos Aires, Argentina. This article is very good and I am very impressed. I will do my best to put it together. Thank you very much. This is my first visit to this page.

And where do you get the pic .HEX file?

The project is very good, I gave it a 10, which made it difficult for me to figure out the location of these components, but once I tried it, it was really great, I need to put it in the cabinet and do some testing, but this Great.

Hi Mario, thank you very much for sharing this excellent capacitor project with us, I have assembled it and it works well. My only problem is the measurement of low-capacity capacitors (less than 100pF), which gives me lower values ​​than actual capacitors.

If there are not too many questions to ask, can you post annotated .asm and hex with a low battery indicator? Or encourage people with picture programming knowledge to do so.


I have done this excellent project, it is perfect for me, congratulations

The tester is very efficient, because it can test all capacitors, I congratulate you, and thank you for your contribution and your guidance, and hope you can introduce more test equipment.

thank you very much

Hello in the entire community of the neoteo forum, I am a newbie to this forum, and I would like to extend my sincerest greetings to everyone who composes this forum.

I have been working on this digital capacitance meter project, and I like it very much, so I decided to install it immediately, but since I am a novice, I don't know how to download the diagram and the necessary conditions to build it.

Can someone help me solve the problem of downloading the schematic diagram and programming code of the picture?

I thank everyone in advance for your help.

Sincere regards

#84 Hello, take a look at the image of the circuit, right-click, you will see a pop-up menu where you can select SAVE IMAGE AS or something similar, and then select the location to save, and it has been saved on the PC On the PC, I saved it but when printing, they did not give me the size of the component.

Then use the free ICPROG program to open it from the cap.hex file, and use the serial programmer to load it into the picture. I have any questions about my email:

Hello friends, I am very grateful for this project and its very useful .hex file for me. The most incredible thing is the automatic calibration. I really congratulate you. Although my size is large, I redesigned it. PCB, but the important thing for me is the function. thank you very much

Hi Carlos, thank you for your answer, so I have already done it, what I will do is to redesign the circuit with deformation or eagle, which are the best two simulators so far.

Kind regards from Seville to Carlos and the entire forum community

Very good, I think the parts list is missing, but it is great because I have never used a capacitor, but with this capacitor, I already have one

I will make it, and I will no longer worry about the quality of the capacitor. Greetings from Mexico.

This project is great! Congratulations! If you can attach the source code in ASM, BASIC or CCS, that would be great!

Hello there! ! ! Can you share project code? Read and understand the functions of PIC. thank you very much! ! !

I found that the tester is very easy to assemble and very good. I just want to use the prototype to make the board. Thank you and congratulations

I congratulate you Mario for a good project, if you provide the source code, that would be great.

General query, what are blue square components, do they have three pins soldered to the board and one output? They are next to ceramic capacitors and some resistors. How do you know, what is its function?

Thank you very much from already

good afternoon! The image of the schematic circuit is missing. Does anyone have it? ? ?

Thank you for your great contribution!


Compile the component list of the tester.

Regards pita_123

Okay, please forgive me, but what about the microprocessor program? Because I don't know what programming is like. thanks for your help. Thank you.

I made a capacitor and it worked fine except for one problem. In the welcome message, the "i" in the capacitor is displayed as a small "o". With different microcontrollers and displays, the same thing will happen. Are there errors in the microcontroller code? Does anyone else have this problem? Too bad, Mario did not release the code for verification.

The data collector says that the precision timer is assembled with the ordinary NE555P and can run perfectly on all scales. The stability and measurement accuracy of the device are incredible. Thank you Mario, your contribution is very good.

Good afternoon, what is the value of resistor R5. I hope to get a reply soon, thank you very much..

Good afternoon, Mario, thank you very much for sharing this great project, I want to know if you can share the file in order to print the pcb, because when I try to print the image like this, its size exceeds my electronics Email address:

, I really need your help. Given the current status of COVID-19, it is very difficult to acquire a factory.

Good afternoon, the capacitance meter is very good, but where is the microprogram? I didn't see it. Another question is how to change this design to place pic16f877.

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