Explain why a variable resistor is used in the circuit instead of a fixed circuit?

enter image source here

1 Answer
Douglas K.
Jan 31, 2018

The designer wanted to be able to use the variable resistor to vary the output voltage to a desired value.

Explanation:

The equation of the output voltage is:

#V_"out" = R_2/(R_1+R_2)V_"in"#

Please observe that, if the input voltage is held constant, then output voltage largely depends on the value of #R_2#.

An application of this may be where the input voltage is unpredictable (within a range) and the user requires an given voltage. The user can use the variable resistor to set the output voltage to the desired value.

Related questions
Impact of this question
1543 views around the world
You can reuse this answer
Creative Commons License