Digital Potentiometer Control Basics - X9C103

Testing out the X9C103 Digital Potentiometer with a function generator.
My batch of 10K pots from eBay measure 100K...
Workbench equipment I regularly use:
946C Solder Hot Plate 200mm x 200mm www.banggood.c...
ANENG AN8008 True RMS Multimeter www.banggood.c...
Minleaf NPS3010W Power Supply www.banggood.c...
FY6900 Dual Channel 60MHZ Signal Generator www.banggood.c...
Siglent SDS1104X-E 100Mhz Digital Oscilloscope 4 Channels Standard decoder
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#ElectronicsCreators

[@vinotec4136]

I love how u explain a tru teacher

[@newburypi]

This project could be referred to as a "grandparents present." Imagine a 10 yo running this through dad's stereo 😁 Looking forward to seeing a practical implementation. How you would use it irl. It seems quite capable of performing on it's own. Background on Halloween? Beatbox? Rhythm backup?

[@felixcat4346]

Clear explaination and interesting, but I'm not the type that wants to go throught the mental gymnastics with a mislabled part to get some use out to this. For now I'll stick with an analogue pot.

[@GadgetReboot]

I am wondering if the cheap eBay parts are cheap because they were mis- labelled much like discounted clothing that has imperfections. One practical use for a digital pot might be having the ability for software to control a current limit for a motor without any hardware Bill of materials change required. I think putting a fixed 11 K resistor in parallel with the 100 K pot will give approximately the equivalent of a 10 K pot. I think I am going to try that.

[@jpcme2002]

I need a 102 because I need to made a 1k electronic pot and all the 2 batchs of 10 units that I bough from 2 different supliers came with 10k, so something is not correct in our evaluation, I though it was only we me but after I saw this video maybe eu are wrong or not seeing the correct prespective... if I bought x9c102s that should have 1K and when measure gives 10k an you with the 103 that should have 10k when measure have 100k... let me see you video until the end...

[@olivierchargy]

Very interesting ! Thanks !

[@goodwill7643]

to store value into memory read datasheet about CS pin. INC pin must be high when you deselecting chip. If you want to save memory life, then deselect pin chip when INC is low.

[@damc7456]

This is a great instructional video for a really useful device, but what I came here looking for is a digital potentiometer that sets its resistance based on a PWM signal. I suspect such a thing exists, just not sure what it's called or how to find it. Any advice would be super helpful. Thanks in advance!

[@GadgetReboot]

I don’t think there is a digital pot with PWM direct control, it’s usually some sort of up/down digital control, or SPI or I2C serial control. So some sort of interface circuit would need to read the PWM duty cycle and translate that to whatever type of control the pot wants so it sounds like some sort of micro controller project. Two general thoughts on that could be a microcontroller can measure the timing of the PWM transitions and determine the duty cycle and then just set the pot when it changes, or put the PWM signal through an RC low pass filter to translate it to an average DC voltage and then read that on the microcontrollers analog input and again convert that into a percentage wiper position and communicate with the digital pot. That all assumes the digital pot will even work in the application like if it is meant to replace a physical pot, usually there’s a maximum operating voltage of 5 V or possibly less I’m not sure

[@damc7456]

@@GadgetReboot Wow! Thank you for the quick reply. I'm wanting to control the variable control side of a SSR-40VA with a PWM signal instead of a manual 500Kohm pot. Maybe I can read the voltage of the signal being sent into and out of the manual pot across its range then just pass the PWM signal across a RC low pass filter that outputs that voltage range to simulate what the output of the manual pot would be.

[@damc7456]

@@GadgetReboot I would just send the PWM signal to a SSR-40DA, but it uses the zero cross trigger method and I'd prefer to use the trimmer control method as illustrated on page 2 of the datasheet linked to below... cdn.sparkfun.com/datasheets/Components/General/SSR40DA.pdf

[@GadgetReboot]

Now that I looked more into the SSR with variable 500K pot control (never worked with SSR before) I see a big can of worms. Here's one thread I stumbled across that summarizes some issues trying to use something other than the 2 watt 500K pot, though it's an old thread so some links/images are broken but the discussion still helps. forum.arduino.cc/t/relay-amperage-output-control-with-pwm/261538/14 Basically, the biggest problem is that 500k 2 watt pot is a heavy duty item, and apparently the mains voltage (peaks over 300v) is present at that control input (probably why it's a high power pot), so trying to add other DC control voltages or devices in place of a high power resistance wouldn't work. I think the pot is part of the mains AC controlling a TRIAC rather than it being an isolated "control input" at low power. So if there's a different variation of the SSR that takes DC control input and can vary the output instead of just on/off, that would be a more hackable starting point. The digital pots in general are really only low current low voltage things, so working up to 5v DC and maybe only max 5 mA current, definitely not something to place across 300+ VAC. They're mostly used for things like adjusting a reference voltage on an op amp where there's really no load current though them, or they can be used to control audio volume on low level signals like line in/out (a few volts peak).

[@damc7456]

@@GadgetReboot That's a great article, kudos for finding it and thanks for sharing. One possible solution is to use the PWM signal to drive a servo that turns the manual pot, but I'm blown away that there's not a more elegant all electronic solution. Seems to me that in our electrified world of billions of people, if I as a hobbyist am trying to solve this challenge, there must have been thousands of engineers who've done the same. Another possible solution is to have a micro controller convert the PWM to a 1-10 number by dropping the second digit of the duty cycle percentage, then use that number to control a transistor array that channels the SSR's control current through 1-10 50K resistors... much like the X9C103 chip in your video above. Also, the pot that ships with the SSR-40VA that I bought off Amazon is 0.25 watt, so not quite as heavy duty. I'm curious to see what voltage I get testing the control input to ground once I get it set up. Main voltage at 240 would certainly rule out all sorts of typical electronic controllers.

[@jpcme2002]

I bouht X9102P for 1kohm and when I measure gives me 10k... we are all wrong or there is a catch?

[@GnuReligion]

Cool. Glad you demonstrated this. Am wondering now if there is a clever way to control it with a rotary encoder sans MCU / function generator.

[@GadgetReboot]

I think I am going to put that on the brainstorm whiteboard as something to think about. I can see the value in using the analogue knob to control the digital pot in some applications for example combining software and analogue override so we can actually do both at the same time. Thanks for the idea!

[@GnuReligion]

Have just finished building a project that drives crystals of arbitrary/unknown value: www.learnabout-electronics.org/Digital/images/clock-7404-xtal.gif With the 1k resistors, as shown, it drives low megahertz crystals. If I put in 1M resistors, it drives my 32khz watch crystals. My thing currently has 3 resistor arrays, all manually jumpered ... now if I had some of those Digital Potentiometers, could probably get an MCU to tell me exactly what resistance drives the crystal at optimal amplitude and stability, and make short work of it.

[@GadgetReboot]

These pots should work for that since they seem to act like true resistors. Some digital pots force you to use VCC or ground or both across the virtual resistor so you’re not as free to use other devices. I have a pile of spare Crystal resonators laying around that I will eventually experiment with. Including using them with inverters. So many projects to get around to ... I was working on something earlier today that wasn’t going well so I decided to destroy some LEDs instead.

[@GadgetReboot]

I think I came up with a way to use the rotary encoder for the digital pot. I sketched it out so I will try it tomorrow and if it works there will be a video forthcoming. If not then let’s pretend I never said anything.

[@kevindogktm]

@@GadgetReboot any update?

[@lamwlgabriel]

I am hacking a machine. It has a potentiometer for the accelerator pedal. It operates at 24volts and the resistance is about 4.7KOhms. Can i use a digital potentiometer to replace the potentiometer to give me remote control

[@GadgetReboot]

I don’t know if they have digital pots that run at higher voltages but the ones I have used can only work with up to 5 V.

[@mdevidograndpacificlumbera1539]

I am also working on a machine- a pallet stacker to be exact: 24v lead acid battery. Did you ever solve your project ??

[@balanagusiddhartha8626]

Hello sir I'm a btech first year student in india. I am learning electronics and I am trying to make my own bluetooth speaker so people ask me y don't ur speaker have buttons to operate the volume so I'm curious to know how this digital potentiometer works and ur videos definately helped me a lot

[@balanagusiddhartha8626]

I just want to know how to connect to the amplifier so that I can control the volume

[@GadgetReboot]

It would depend on the circuit especially being bluetooth if you don't have audio coming in from a wire, normally the pot would go in line with incoming audio like this i.stack.imgur.com/w5C3B.jpg but if you're using some kind of custom chip with all kinds of built in functions, that needs to be analyzed to see what's possible. It wouldn't go on the output of the amplifier heading to the speaker, too much power and it's always done on the low level input side.

[@balanagusiddhartha8626]

@@GadgetReboot thanks a lot sir I'll check that

[@manjurohila4248]

good job thanks many thanks.

[@justinrhodes1138]

Nice fluke! uncle gave me a unworking vintage fluke 88 automobile diagnostics.lcd was was turned the wrong way for pin setup!

[@perceptrongaming4290]

sorry to ask again...but could u please clarify again that,how are u increasing the counter ?

[@GadgetReboot]

The first time I was experimenting with the device I was using square waves from a function generator to make it easy, if I didn’t have that I would either generate pulses from an Arduino or have a pull up resistor to the positive supply and use a switch to ground to manually do it

[@electronic7979]

Useful video

[@ShopperPlug]

3:41 - So an increase or decrease of pule frequency determines the increase or decrease of the digital potentiometer's resistance value?

[@GadgetReboot]

Not the frequency of pulses (how fast they occur) but the number of them received. For each pulse on the increment pin, the wiper moves one step up or down depending how the up/down pin is set

[@ShopperPlug]

@@GadgetReboot Thanks for the clarification. What kind of wattage these digital potentiometer can handle, 1/4 watt?

[@GadgetReboot]

@@ShopperPlug The wiper can handle something up to 4.4 mA with a max voltage of 5v, they're really only intended as non load bearing things like set points on op amps that don't draw anything. So if I use it for a volume or EQ circuit it's likely got an op amp buffering it too.

[@ShopperPlug]

@@GadgetReboot if you ever seen a Triac schematic, it uses a potentiometer, can these digital potentiometer be used as a replacement?

[@goodwill7643]

I would wrtie part label into a subject for search engins and those who as interes in this particular part.

[@GadgetReboot]

Good idea

[@9hstan]

I also ordered the 10k from AliExpress but got the 100k so there must be a large batch of incorrectly labelled 103's....shame...waste of time

[@GadgetReboot]

I wonder why that is happening. It almost makes me want to order some from a reputable distributor just to double check the results but I have not needed to place an order somewhere like that in a long time and it will cost a lot for a minimum order and shipping costs so next time I do, maybe I’ll order some of these as well.

[@MadHatter764]

I couldnt find 103s - just 104s. Regardless of 10k or 100k, it should work for the variable voltage bench supply I am planning to build.

[@peterpisar252]

Súper

[@chuanyeewong9190]

Can control speaker volume

[@acqurius-gx8lr]

between which two terminals resistor is connected

[@GadgetReboot]

Pins 3, 5, 6 contain the potentiometer terminals. www.renesas.com/us/en/www/doc/datasheet/x9c102-103-104-503.pdf

[@pred8rz]

BOM VIDEO