Voltage is electrical push
Voltage is the difference in electric potential between two points. It gives charge a reason to move. Higher voltage can push charge through more resistance or move more energy for each unit of charge.
Current is moving charge
Current tells how much charge passes a point each second. It is measured in amperes. A larger current means more charge is moving through the path.
Resistance limits current
Resistance is opposition to current. Materials, wire size, temperature, and component design can increase or decrease resistance.
| Quantity | Unit | What it tells you |
|---|---|---|
| Voltage | Volt | How much electrical push exists |
| Current | Ampere | How much charge is moving |
| Resistance | Ohm | How strongly the path limits current |
| Power | Watt | How fast energy is being used or delivered |
| Energy | Joule or watt hour | Total amount of work done over time |
Ohms law
Ohms law connects voltage, current, and resistance for many simple components. If resistance stays the same and voltage rises, current rises. If voltage stays the same and resistance rises, current falls.
Voltage is push, current is flow, resistance is opposition, and power is how fast useful or unwanted energy conversion happens.
Power and energy
Power measures the rate of energy transfer. A device using more watts is converting electrical energy faster. Energy is power over time, which is why electrical bills often use kilowatt hours.
| Device type | Electrical action | Main output |
|---|---|---|
| Lamp | Current through a light source | Light and heat |
| Heater | Current through resistance | Heat |
| Motor | Current and magnetic fields | Motion |
| Speaker | Changing current in a coil | Sound |
| Computer | Controlled tiny currents | Information processing |
Why high voltage can be useful
Power grids use high voltage for transmission because it allows the same power to move with lower current. Lower current reduces heating losses in long wires.
Do not treat voltage alone as the only danger. Current through the body, path through the body, duration, environment, and source capability all matter. Avoid contact with unknown electrical systems.
Frequently asked questions
Yes. A battery can have voltage even when nothing is connected. Current flows only when there is a closed path.
Continue from quantities to full circuit behavior.