How do errors in voltage and power relate?

1 Answer
George C.
Feb 26, 2017

I am not sure what you meant to ask, but here's an example that may help...

Explanation:

Suppose you have a circuit with known resistance #R# and apply a voltage #V# to it. The resulting current through the circuit is #I = V/R# and the power dissipated is #VI = V^2/R#.

So the power dissipated is proportional to the square of the voltage.

If you have a #5%# error in measuring the voltage #V#, then what is the error in the calculated power?

Approximately #2xx5% = 10%#

In general, for small values of #epsilon# we have:

#(1+epsilon)^n ~~ 1+n epsilon#

So when raising to the #2#nd power, the error is roughly doubled.

Related questions
See all questions in Combination Capacitor Circuits
Impact of this question
1700 views around the world
You can reuse this answer
Creative Commons License