How Does a Transformer Lower Voltage for Devices Like Computers?

Question:

How does a transformer work to lower the RMS voltage to about 12 volts for devices like computers?

Answer:

A transformer used in devices like computers is responsible for lowering the RMS voltage to around 12 volts. It operates through electromagnetic induction, where a primary coil carries the input voltage and induces a corresponding voltage in a secondary coil with a different number of turns.

The transformer used in this scenario operates based on the principles of electromagnetic induction. It consists of two coils, the primary coil and the secondary coil, wound around a common magnetic core. The primary coil is connected to the input voltage, while the secondary coil is connected to the device requiring a lower voltage.

When the input voltage is applied to the primary coil, it creates an alternating current that produces a changing magnetic field around the coil. This changing magnetic field induces a voltage in the secondary coil due to mutual induction. The magnitude of the induced voltage depends on the ratio of the number of turns in the primary coil to the number of turns in the secondary coil.

To lower the voltage, the secondary coil typically has fewer turns than the primary coil. This difference in the number of turns allows for a voltage reduction in the secondary coil. The ratio of the input voltage to the output voltage is directly proportional to the ratio of the number of turns in the primary coil to the number of turns in the secondary coil.

By adjusting the number of turns in the primary and secondary coils, the transformer can step down the RMS voltage from the input to a desired lower voltage suitable for the device being powered, such as 12 volts in the case of a computer.