# Potentiometer In Parallel

Discussion in 'The Projects Forum' started by ilnar, Jun 18, 2012.

1. ### ilnar Thread Starter New Member

May 8, 2012
16
0
here is my potentiometer and it's wiper is connected in parallel with 12k resistor.
my wiper also serves as an output . so... how do i order this circuit to output 2.1 volts?

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2. ### wayneh Expert

Sep 9, 2010
15,207
5,557
You need to separate the wiper from ground, and extract whatever voltage you want from the wiper.

3. ### DickCappels Moderator

Aug 21, 2008
5,064
1,549
Get the right value for the pot and you will have 2.1 volts when at 80%. The rest is left as an exercise.

4. ### wayneh Expert

Sep 9, 2010
15,207
5,557
shortbus likes this.
5. ### cork_ie Active Member

Oct 8, 2011
400
66
R= total pot resistance and assuming it is a linear potentiometer

2.1 Volt is dropped across 20% of your pot,
2.9 Volt across 12K & 80% of your pot in parallel.

[0.2R= 2.1/I ] & [ 1/ (1/.8R + 1/12000)] = 2.9/I =>

10.5/R = I = [2.9 x (1/.8R +1/12000)] = [2.9/.8R + 2.9/1200]

= 3.625/R + 2.9/12000 =>

6.875/R = 2.9/12000 =>

R= (12000x 6.875)/2.9 = 28.448K

Theoretical Pot size to get 2.1V at the wiper as in your drawing is 28.448K
In practice you are unlikely to get one outside a standard value

ilnar likes this.
6. ### ilnar Thread Starter New Member

May 8, 2012
16
0
you are the GOD of Pots )) thank you very much.