USING REGULAR POTENTIOMETERS ON A BUCK CONVERTER
(This little electronic school project is based on a request from one of my page visitor from Tunisia.)
As we all know, most of the buck converters available come with high precision trimpots to change the output voltage or the current. These trimpots cannot be simply replaced with a regular external potentiometer. A regular potentiometer cannot be precise and would take ages to select a particular low denomination voltage. Let’s say 5.2Volts will be difficult to achieve with a regular potentiometer on a Buck Converter. Yes, you can replace these Trimpots with equivalent value high precision expensive multi-turn potentiometers or you can wire a circuit as shown by me here. It works immaculately.
THE IDEA BEHIND IT
The idea of replacing a Trimpot with a regular potentiometer for a BUCK Coverter is simple. Just note down the value of the Trimpot... 103 (means 10K) or 104 (means 100K)... buy a similar value ordinary potentiometer and an additional 1K potentiometer ... Now connect them as per the circuit given below. 1K potentiomenter will be controlling the lower denomination voltage values, whereas regular voltage value potentiomenter will act as high denomination value controller.
I refrained from using Multi-turn precision potentiometer. The small circuit here can solve your problem of bringing out the potentiometer. All you have to do is use a similar value potentiometer as Trimpot on the Buck Converter and use a small value (1K) potentiometer in series with higher value potentiometer through its central pin as shown in the circuit here. The problem is solved!
For changing higher denomination voltage change use higher value potentiometer (the exact replacement of Trimpot) and to fine-tune the voltage just use 1K pot! It looks and feels cool!
- 1K potentiometer
- 10K Potentiometer
- Buck Converter
Rs.15/- (excluding Buck Converter)