Voltage is the electrical "pressure" that pushes current through a circuit. It ranges from millivolts in biological signals to kilovolts in power lines.
What Is Voltage?
Voltage = energy per unit charge. 1 V = 1 J/C. Using the water analogy: voltage is pressure, current is flow, resistance is pipe size.
Common Voltage Levels
AA battery: 1.5 V. USB: 5 V. Car battery: 12.6 V. Wall outlet: 120 V (US) / 230 V (EU). Power lines: 100–765 kV.
Conversions
- 1 kV = 1,000 V
- 1 V = 1,000 mV
- 1 mV = 1,000 µV
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Convert between all electric voltage units instantly.
Frequently Asked Questions
What is the difference between 120V and 230V?
120V is North American; 230V is European. Both deliver the same power, but 230V uses less current, allowing thinner wires.