# Kirchhoff's Voltage Law

Kirchhoff’s Voltage Law: If you travel around any loop in a circuit, the voltages across the elements add up to zero.

## What is the zig-zag symbol?

The $\sum$ symbol is the Greek letter capital Sigma. In mathematical notation it indicates the *summation* operation. It is used to sum up a number of related quantities. The expression

$v_1 + v_2 + v_3 + v_4 + v_5 = 0$

can be written compactly as,

$\displaystyle \sum_{n=1}^{n=5} v_n = 0$

It is understood that the index, $n$, runs from lower limit $n=1$ to upper limit $n=5$, stepping by $1$.

Created by Willy McAllister.