Classification of Low-Frequency Transformers

Low-frequency transformers can be classified into interstage coupling transformers, input transformers, and output transformers. These transformers share a similar appearance to power transformers but serve different functions in audio and amplification circuits.

Interstage Coupling Transformer: Used between two amplifier stages, it transmits the output signal while converting impedance to ensure compatibility between stages.

Input Transformer: Found in older semiconductor radios, it couples signals between the audio push stage and power amplifier stage. Input transformers come in single-end and push-pull configurations, depending on the circuit design.

Output Transformer: Placed between the power amplifier's output and the speaker, its role is to match impedance and transmit signals effectively. It can also be single-ended or push-pull, based on the amplifier's design.