# Ohm's Law

### From DT Online

##### Description

**Ohm's law** is an extremely useful equation in the field of electrical/electronic engineering because it describes how voltage, current and resistance are interrelated.

##### Features and Applications

If the three symbols for voltage * (V)*, current

*and resistance*

**(I)***are arranged in a triangle as shown, then the various representations of Ohm's Law can easily be seen - i.e.*

**(R)**- Voltage = Current x Resistance
**(V = I x R)** - Current = Voltage / Resistance
**(I = V / R)** - Resistance = Voltage / Current
**(R = V / I)**

A similar triangular graphic may be used to show the various relationships between **electrical power** *(watts)*, electrical current *(amps)* and voltage *(volts)*.

**Note:**
Abbreviations are usually named after the thing you're measuring, not the unit. So resistance is R, not O for ohms (Ω) but voltage is measured in volts, so it's V either way *(the term ‘electromotive force’ and the symbol E are becoming less common, replaced by voltage and V)*