This component can control tons of circuits! Digital Potentiometer Guide! EB#51

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In this episode of electronics basics we will be having a look at digital potentiometers. You can use them to control any circuit digitally by replacing their mechanical potentiometers with them. But there can be pitfalls when trying to simply replacing the potentiometer. That is why I will tell you all about digital potentiometers which includes how to control them, what kind of current and voltage they can handle and how to properly use them. Let’s get started!

Thanks to Altium for sponsoring this video.

2011 Lookalike by Bartlebeats

0:00 Where Digital Potentiometers can be used!
1:39 Intro
2:14 X9C103 Overview
4:22 Digital Potentiometer Functional Principle
5:43 X9C103 Practical Test
6:42 Voltage Converter Digital Pot Problem
8:39 High Voltage Digital Pot solves the problem
9:49 Final Test & Verdict

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Comment (353)

  1. This was the video I was looking for! Thanks for doing all the research. I always wanted to control the brightness of a led with an arduino but never was able to, because I didn't knew how to use a digital potentiometer. Now I can finish my project🎉

  2. I used a dual digital pot to replace the joystick input on a wheelchair controller. Was a great way to get a digital interface, while keeping the wheelchair's insanely good control systems.

  3. Really a good video that I have ever seen great Scott you are the best youtuber I ever I watch your video almost 3 year . Really you are a good engineer . And I always appreciate to make this type of videos projects and other thing as.
    And and this pwm digital are best for degitily controling features

  4. Honestly never knew these existed, now I do. Thanks!! But I don't understand how the one IC destroyed itself when given 25V? You destroyed it….. lol (joking……)

  5. A few years ago i took apart a radio that had an electronically controlled volume potentiometer (if i'm not mistaken, i think it was volume). This was a radio from the 90's. Their solution to this problem? The potentiometer had a dc motor stuck to its back, if the radio deemed the volume too low, it just turned its own knob with the motor to crank the volume. Beautifully simple and complex at the same time.

  6. How fast can these be switched? If I want to generate 1ms voltage pulses on a boost converter (dropping 8vdc from a normal output of 40vdc) can I use this to signal the boost microcontroller? Or is it better to use a pair of fixed resistors and switch one in/out with a FET?

  7. couldn't you just use something like a DAC where you have a bunch of resistors with the 1st one having a very low resitance, then the next one being double that, and so on. Then use a bunch of switches to either bypass or go through each resitor giving you a wide range of resitance with plenty of accuracy.

  8. I remember reading it's not that easy to use a digital pot for audio applications, at least not as a direct replacement for a mechanical pot. The reason is you get pops on the audio every time you adjust it up/down and it requires some complications to the circuit so it only adjusts at zero-crossing….would be great to see a project like this though 🙂

  9. Very nice. Thank you for showing actually using one of these little guys. I've looked at them, but never had the need to try one. (Plus I like SPI and made my own bit-banging code in assembler for PIC–much faster that way.)
    A question that occurs to me: if a higher voltage needs to be handled, why not put the DP between the base and emitter of an NPN transistor and vary between just off to turn-on needed? It would be less than 0.7V and take only a little bit of math to calculate. Or do the same thing using an open collector Opto Coupler instead of the transistor.

  10. If somebody needs ever higher voltages, look up motor-driven potentiometers. They are also used in some audio equipment as a very fun way to control sound volume.

  11. I have to LOL at this. I literally bought a X9C103S for this exact purpose of replacing the POT on a boost converter. Except I have been too lazy to get it done. Have the POT working with an Arduino but thats about it. My idea was more to use it on the CC pot of a CC/CV converter to make a DIY MPPT solar converter to charge a 29V (7S) lithium system. From testing it seems the voltage on the CC POT is not very high so V would not be an issue as it was on the CV POT. Anyway great video as always!

  12. Danke schön für das Video. Sowas wie den MCP41HV hab ich gesucht. Damit kann man vllt schön analoge Synths nachträglich digitalisieren bzw midifizieren 😉 Wenns das ganze noch in 10 bit gäbe … 😀

  13. This is soo cool. I'm definitely trying this.

    Since the first time i learned about digital potentiometers i haven't given much thought to it till now. Cool video ideas loading.

  14. One important question:
    Is the Output Stage galvanically isolated from the interface side?
    And if, what are terms in the datasheet to look for?
    This is a problem, that restrained me from using them in the past…

  15. I hadn't really thought about digital potentiometers, so this was a good topic for me!

    Now add a mechanical potentiometer to your microcontroller's ADC, then use that value to set the resistance value on the digital potentiometer, so you still have the feel of the rotary switch! 😛😛

  16. Interesting. I am currently building a project that includes replacing a mechanical pot with an electronic control, but intend to use a PWM signal from the controller. My intent is to replace the potentiometer with a transistor using a small pair of smoothing capacitors to cut ripple and a bleed resistor to keep a good response rate. I realize this will take some tuning and increase the parts count but it should be both less expensive and less time consuming. Would need more filtering for an audio application but I am controlling current through various circuits of a LED array. The mechanical potentiometer would always be roughly in the middle of the 10k potentiometer's sweep so I'm not worried about transistor voltage drop.

    Anybody see a problem with my approach?

  17. Nice video, as always. One interesting application I used a digital pot for was to control an analog filter before an ADC. In this way it is possible to change the low pass frequency depending on the sampling rate.

  18. If you put a comparator (opamp) between the feedback voltage and the PWM chip, then you can work with 5V or so.
    Then put the Digital Potentiometer with another 10k resistor to form voltage divider, and add that to the other opamp input.
    So the Boost Convertor's 0-25V becomes 0-5V, and you can adjust the other voltage divider it's being compared against.
    As the PWM FB pin expects something like 1.2V before it triggers, you need a 3rd voltage divider on the Opamp output.

  19. 05:10 – Resolution could be increased by a factor of 100 by utilizing 3 potentiometers. The third would be connected between both wipers of P1 and P2. The total resolution could be calculated with a simple formula. Total Resolution = init.resolution power 2.

  20. Didn’t know this thing exists. I once have thought of connecting a motor shaft to a mechanical potentiometer to have it controlled digitally lol. I have considered using light dependent resistors as well

  21. Yours channel is very informative, always learn something new. The best thing is, its not overly complicated, any useful topics only, and not too much kidy like simple arduino code to control PWM, it goes down to the basic electronics concepts, without focusing too much on online code.

  22. I knew I had to watch this the moment I saw a QSKJ boost converter board in the thumbnail. I adapted one to take the 18VDC nominal from my Ryobi battery packs and boost it to 20V to run my Thinkpad. Since I was able to order two for like a dollar more than one would have cost me, I have a spare and I've been thinking of all the different stuff I can do with it. Doing things digitally is a lot more interesting than analog, I have to admit.

  23. Is there a initialization time to worry about between cold power up and setting the tap value from memory? It seems to me that also by defaults first it would start with high Z on the tap, and after an instant it would turn into the selected tap value. I guess that there must be some circuits sensitive to this high-Z or whatever is while powered off

  24. Sir.. Your video are great as same as Your Name….
    Coming back to my point digital potentiometer has its own uses but just to increase or decrease voltage from a boost or buck convert digitally can't we use a mosfet driver circuit because here also we have to mess up with arduino code and a jungle of wires…

  25. Since I am a mechanical engineer, I do not know much …..but isn't it possible to use PWM instead of Digital Potentiometer for high power application? Essentially the demand of Potentiometer is to get varying voltage divider to compare with reference voltage (in boost/buck converter application). PWM might be a good alternative to get similar results……unless I am misunderstanding the reason why PWM should not be used instead of Potentiometer. Please someone guide me why PWM is OK or not OK to be used instead of Potentiometer.

  26. I need to control an AC power dimmer that has a 500kΩ potentiometer. But the X9C digital pots max out at 100kΩ.

    I could string five 100kΩ in series and program the microcontroller to sequentially activate them in a coordinated fashion. I will get some really good resolution but a lot of wiring and space usage. Any other component or methodology to do this cleaner?

  27. How many steps does this digital pot have?

    I was thinking to use it in a synthesizer project.
    So i can store presets.

    It would be a bit lame… If you hear the steps of the potentiometer in the sound.

    Kind regards,

  28. I can see that the current has to be super-low or it will burn the ic.
    I was thinking of using a digital pot for a li-on battery charger but the current there has to be between 200-500 mA, at least.

  29. Perfect.. this is what I was looking for. I will use this digital potentiometer with regular buck converter boards to make my own low-cost Arduino-controlled smart MPPT solar charge controller. Thank you for the video.


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