# Digital potentiometer - different voltage

What would be the "correct" way to replace an analogue potentiometer with a microcontroller controlled digitalpotentiometer, when the require voltage is higher than what the chip can support?

In more detail: If I want to replace an analogue potentiometer for a 10 Vdc signal line with a digital potentiometer that only supports up to about 5 Vdc, what is the best way to achieve this ?

Is it a simple 5Vdc digital potentiometer with an opamp before/after to adjust the voltage accordingly ? Or...?

Please be specific - circuit diagrams for achieving this will be appreiciated. Basically, replace a basic manual potentiometer with a digital one, for a different voltage level.

• Are you trying to adjust a voltage, or a resistance? Mar 29, 2019 at 21:58
• I believe it is the voltage. A signal line to control a motor (signal - not in-line) Mar 29, 2019 at 22:01
• Please be specific for what functional purpose do you want to replace the potentiometer. If it is used by the original circuitry to charge-discharge some voltage (like in many 555 circuits) then simple voltage translation (or DAC) won't do the job. Mar 29, 2019 at 23:19

Without knowing more about your circuit: I would use a DAC (Digital to Analog Converter). If you can find a DAC that runs off 10V great, otherwise just use a 5V DAC and put an opamp with a gain of 2 in front of it (or even a 3.3V DAC and a gain of 3).

Your microcontroller will send a serial command to the DAC to set its output voltage.

This is what a non-inverting opamp circuit with a gain of 2 could look like:

simulate this circuit – Schematic created using CircuitLab

• What is the difference between a digital potentiometer and a DAC really ? Both would adjust the voltage according to input signal ? Not really that much into electronics - can you provide some references of how to achieve this ? In particular the opamp circuit ? :) Mar 29, 2019 at 22:09
• A digital potentiometer is a device that takes a digital signal and varies the resistance of its output. A DAC takes a digital signal and outputs a specified voltage. Mar 29, 2019 at 22:10
• So if a motor is controlled by the voltage (signal line adjusted by a manual potentiometer) a DAC would really achieve the same thing? Mar 29, 2019 at 22:14
• Sure. You should see how much current this voltage signal input draws to make sure you can supply it, but yes. Mar 29, 2019 at 22:18
• Very true (and worth mentioning), but without part numbers or schematics, I have to take OP's word at face value. Mar 29, 2019 at 23:32