Electrical Potential Emf

Overview

Engineering reference data for Electrical Potential Emf in electrical engineering.

Key Formulas

Ohm's Law

$V = IR$

Voltage = Current × Resistance.

Power

$P = VI = I^2R = V^2/R$

Electrical power.

Energy

$E = Pt$

Energy = Power × Time.

Variables

Symbol	Description	Unit
$V$	Voltage	V
$I$	Current	A
$R$	Resistance	Ω
$P$	Power	W

Key Definitions

• Potential Difference: The change in electrical potential between two points in an electric circuit, measured in volts (V).
• Electromotive Force (e.m.f.): The potential difference provided by a source of electrical energy (such as a generator or battery) that drives current through a circuit. It is also measured in volts.

Voltage Relationships

The unit "volt" (V) can be derived from fundamental SI units, providing key relationships for engineering calculations:

$1\ \text{V} = 1\ \frac{\text{W}}{\text{A}} = 1\ \frac{\text{J}}{\text{C}}$

This shows that:

• Voltage (V) equals Power (P) in watts divided by Current (I) in amperes ($V = \frac{P}{I}$).
• Voltage (V) also equals Energy (E) in joules divided by Charge (Q) in coulombs ($V = \frac{E}{Q}$).

References

• Original Source