Ohm's Law

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.

If the three symbols for voltage (V), current (I) and resistance (R) are arranged in a triangle as shown, then the various representations of Ohm's Law can easily be seen - i.e.

• 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).

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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)

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