How does a step-up transformer increase voltage?
1 Answer
A step-up transformer is a device used to increase the voltage of an alternating current (AC) while decreasing the current proportionally. It operates on the principle of electromagnetic induction, which is governed by Faraday's law of electromagnetic induction.
Here's how a step-up transformer works to increase voltage:
Primary Coil (Input Coil): The primary coil is the coil of wire connected to the input voltage source. When AC voltage is applied to the primary coil, it creates an alternating magnetic field around the coil.
Secondary Coil (Output Coil): The secondary coil is wound around the same core as the primary coil but has a different number of turns of wire. The number of turns in the secondary coil is typically greater than the number of turns in the primary coil. This difference in the number of turns is what enables the voltage to be increased.
Electromagnetic Induction: When the AC voltage in the primary coil changes direction, it causes the magnetic field around the primary coil to also change direction. This changing magnetic field induces a voltage in the secondary coil due to Faraday's law of electromagnetic induction. The voltage induced in the secondary coil is proportional to the rate of change of the magnetic field and the number of turns in the coil.
Voltage Transformation: Since the secondary coil has more turns than the primary coil, the voltage induced in the secondary coil will be higher than the voltage applied to the primary coil. This is because the changing magnetic field affects a larger number of turns in the secondary coil, resulting in a higher induced voltage.
Current and Power Relationship: According to the law of conservation of energy, the power (product of voltage and current) remains approximately constant in an ideal transformer (neglecting losses due to resistance and other factors). Therefore, as the voltage increases in the secondary coil, the current must decrease proportionally to keep the power constant.
In summary, a step-up transformer increases voltage while decreasing current by utilizing electromagnetic induction. The primary coil's changing magnetic field induces a higher voltage in the secondary coil due to the difference in the number of turns between the two coils. This transformation allows for efficient transmission of power over long distances with reduced energy losses, as lower current reduces resistive losses in transmission lines.
Here's how a step-up transformer works to increase voltage:
Primary Coil (Input Coil): The primary coil is the coil of wire connected to the input voltage source. When AC voltage is applied to the primary coil, it creates an alternating magnetic field around the coil.
Secondary Coil (Output Coil): The secondary coil is wound around the same core as the primary coil but has a different number of turns of wire. The number of turns in the secondary coil is typically greater than the number of turns in the primary coil. This difference in the number of turns is what enables the voltage to be increased.
Electromagnetic Induction: When the AC voltage in the primary coil changes direction, it causes the magnetic field around the primary coil to also change direction. This changing magnetic field induces a voltage in the secondary coil due to Faraday's law of electromagnetic induction. The voltage induced in the secondary coil is proportional to the rate of change of the magnetic field and the number of turns in the coil.
Voltage Transformation: Since the secondary coil has more turns than the primary coil, the voltage induced in the secondary coil will be higher than the voltage applied to the primary coil. This is because the changing magnetic field affects a larger number of turns in the secondary coil, resulting in a higher induced voltage.
Current and Power Relationship: According to the law of conservation of energy, the power (product of voltage and current) remains approximately constant in an ideal transformer (neglecting losses due to resistance and other factors). Therefore, as the voltage increases in the secondary coil, the current must decrease proportionally to keep the power constant.
In summary, a step-up transformer increases voltage while decreasing current by utilizing electromagnetic induction. The primary coil's changing magnetic field induces a higher voltage in the secondary coil due to the difference in the number of turns between the two coils. This transformation allows for efficient transmission of power over long distances with reduced energy losses, as lower current reduces resistive losses in transmission lines.