A device that increases or decreases the voltage of alternating current is a
The Correct Answer and Explanation is:
The correct answer is transformer.
A transformer is an electrical device that is used to either increase (step-up) or decrease (step-down) the voltage in an alternating current (AC) electrical circuit. It works on the principle of electromagnetic induction, which allows it to transfer electrical energy between two or more circuits. Transformers consist of two main components: the primary coil (or winding) and the secondary coil (or winding). These coils are wound around a core made of a magnetic material, typically iron.
Here’s how a transformer works:
- Principle of Electromagnetic Induction: When an alternating current flows through the primary coil, it creates a changing magnetic field around the coil. This magnetic field induces a voltage in the secondary coil due to Faraday’s Law of Induction. The induced voltage depends on the number of turns (or windings) in the secondary coil relative to the primary coil.
- Voltage Change:
- Step-up Transformer: If the secondary coil has more turns than the primary coil, the voltage in the secondary coil will be higher than the primary voltage. This is known as a step-up transformer.
- Step-down Transformer: Conversely, if the secondary coil has fewer turns than the primary coil, the voltage in the secondary coil will be lower than the primary voltage. This is known as a step-down transformer.
- Equation: The relationship between the primary and secondary voltage is given by the following equation:
[
\frac{V_s}{V_p} = \frac{N_s}{N_p}
]
Where:
- ( V_s ) is the secondary voltage
- ( V_p ) is the primary voltage
- ( N_s ) is the number of turns in the secondary coil
- ( N_p ) is the number of turns in the primary coil.
- Applications: Transformers are used in a wide range of applications. For example, in power distribution systems, step-up transformers are used at power plants to increase the voltage for efficient transmission over long distances. Step-down transformers are then used at substations to reduce the voltage to safe levels for residential and commercial use.
In summary, a transformer plays a crucial role in efficiently managing and distributing electrical power by adjusting the voltage levels as needed.