The terms voltage , current , resistance , and power are fundamental concepts in electricity and electronics . They are linked by Ohm's law and the law of conservation of energy. Here are the definitions and differences between these terms:
1. Voltage:
- Symbol : VV (or UU)
- Unit : Volt (V)
- Definition : Voltage is the difference in electrical potential between two points in an electrical circuit. It is the "force" that pushes electrons through a wire or other conductor.
- Comparison : You can compare voltage to water pressure in a pipe. The greater the voltage, the greater the "pressure" that drives the electrons.
- Formula : Voltage is equal to the amount of energy per unit charge available to move. It can also be expressed as: V=I×RV = I \times R Where II is the current (in amps) and RR is the resistance (in ohms).
2. Current:
- Symbol : II
- Unit : Ampere (A)
- Definition : Current is the amount of electric charge flowing through a conductor per second. It is often thought of as the movement of electrons through a circuit.
- Comparison : Current can be compared to the amount of water flowing through a pipe per second.
- Formula : Current can be calculated by dividing the voltage by the resistance, like this: I=VRI = \frac{V}{R} Where VV is the voltage and RR is the resistance.
3. Resistance:
- Symbol : RR
- Unit : Ohm (Ω)
- Definition : Resistance is the property of a material to impede current flow. It determines how much current is inhibited when a voltage is applied. The higher the resistance, the less current can flow through the material at a given voltage.
- Comparison : You can compare resistance to the thickness of a water pipe . A narrower pipe offers more resistance to the flow of water, just as a thin wire offers more resistance to the flow of electrons.
- Formula : Resistance is often expressed as: R=VIR = \frac{V}{I} Where VV is the voltage and II is the current.
4. Power:
- Symbol : PP
- Unit : Watt (W)
- Definition : Power is the amount of energy consumed or supplied per second by an electrical device. It is measured in watts and indicates the amount of work performed by the electric current.
- Comparison : Power can be compared to the rate at which water flows from a faucet. The greater the flow (amount of water) and the pressure (voltage), the greater the power to do work, such as turning a motor or heating an appliance.
- Formula : Power is calculated as the product of voltage and current: P=V×IP = V \times I Where VV is the voltage and II is the current. This can also be expressed as: P=I2×R or P=V2RP = I^2 \times R \quad \text{of} \quad P = \frac{V^2}{R} depending on which values are known.
Summary of the differences:
|
Characteristic |
Definition |
Unit |
Relation |
|
Tension |
Difference in electrical potential between two points. |
Volt (V) |
V=I×RV = I \times R (Voltage equals current times resistance) |
|
Current |
Amount of electric charge moving per second. |
Ampere (A) |
I=VRI = \frac{V}{R} (Current is equal to voltage divided by resistance) |
|
Resistance |
The property of a material to impede current flow. |
Ohm (Ω) |
R=VIR = \frac{V}{I} (Resistance is equal to voltage divided by current) |
|
Assets |
Amount of energy consumed or supplied per unit of time. |
Watt (W) |
P=V×IP = V \times I (Power is the product of voltage and current) |
Relationships between the concepts:
- Ohm's law ( V=I×RV = I \times R ) links voltage, current, and resistance.
- The power is determined by the formula P=V×IP = V \times I, which means that power increases with higher voltage or higher current.
Understanding these four concepts and how they relate to each other will give you a better understanding of how electrical systems work.