Speed Pot with High and Low Voltage.

Thread Starter

jm14872

Joined Jan 27, 2022
7
Hi i am new to electronics so any help would be much appreaciated. I want to create a speed pot with a high and low voltage setting. but it never as to be adjusted. For instance if I have 17V available. How can i make a speed pot that will out 12v at the very lowest setting. And 17V at is max setting.

Thanks
 

sghioto

Joined Dec 31, 2017
5,380
The schematic: Adding resistor R forms a voltage divider. The value of R depends on the value of the pot and the load connected to the output.
This is the simplest method but may require buffering depending on the load.
1643665396260.png
 

crutschow

Joined Mar 14, 2008
34,285
In sghioto's post #4 circuit, if you use a 1kΩ pot then the current through it would need to be (17V-12V) / 1kΩ = 5mA.
Since that same current goes through the bottom resistor, its value must be 12V / 5mA = 2.4kΩ.
 
Last edited:

panic mode

Joined Oct 10, 2011
2,715
why do you think that what you need is that specific range? if you are looking to replace speed control for existing unit, there is a chance that waveform is not what you think it is. it maybe reading your multimeter displays but perhaps what you observe as different voltage reading is just the average while signal is PWM.
 
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