Physics 2006 JAMB Past Questions - Question 23: The main purpose of the transformer in an a.c. radio set is to

Correct Answer

C

Explanation

The main purpose of the transformer in an AC (alternating current) radio set is to perform several important functions:

1. Voltage Step-Up/Step-Down: Transformers can be used to step up or step down the voltage of the incoming AC power supply to levels suitable for various components in the radio. For example, they can increase the voltage from the wall outlet to a higher voltage for the radio's vacuum tubes or solid-state components, or they can step down the voltage for the low-voltage components like the filaments of vacuum tubes.

2. Isolation: Transformers provide electrical isolation between different parts of the circuit. This isolation is important for safety and for preventing interference or ground loops. It helps protect the user from potential electrical hazards and prevents unwanted noise or hum in the audio signal.

3. Impedance Matching: Transformers can be used to match the impedance between different components in the radio, such as the antenna and the input stage of the radio receiver. Matching the impedance allows for maximum power transfer and efficient signal reception.

4. Signal Coupling: Transformers can be used for coupling or transferring signals between different stages of the radio circuit. They help transmit the audio signal from the radio's tuner to the amplifier or speaker, for example.

5. Filtration: Some transformers in radio sets may include filters that help remove unwanted noise or interference from the incoming power supply, resulting in cleaner, more stable power for the electronic components.

In summary, transformers in an AC radio set serve several critical functions, including voltage regulation, isolation, impedance matching, signal coupling, and noise filtration, all of which are essential for the proper operation of the radio and the quality of the audio signal it produces.