Audio transformer is a type of transformer specifically used for audio signal transmission and processing. It is mainly used to adjust the level, impedance matching, and isolation of audio signals. It is also known as a low-frequency transformer. The working frequency range generally ranges from 10 to 20000Hz. Commonly used to change voltage or impedance of a load. Used as a component in circuits such as voltage amplification and power output in radio communication, broadcasting and television, and automatic control. The frequency response of the audio transformer is uniform within the working frequency band, and its iron core is stacked with high conductivity magnetic materials. The primary and secondary windings are tightly coupled, so that almost all the magnetic flux passing through the primary winding is linked to the secondary winding, and the coupling coefficient is close to 1. The lowest frequency of the passband is determined by the original winding inductance, and the highest frequency is determined by the transformer leakage inductance. To ensure that the transformer has sufficient passband, the original winding inductance should be large and the leakage inductance should be small. The hysteresis loss and magnetic circuit saturation of the iron core can cause signal distortion. Properly configuring the load and increasing the load current can reduce the impact of hysteresis loss; Increasing the cross-section of the iron core and leaving an air gap can prevent saturation of the magnetic circuit, which can reduce signal distortion.

The audio transformer has the following main functions and characteristics:

1. Level adjustment: The audio transformer can change the signal level by changing the ratio of the turns of the input and output windings. This is very useful for cascading connections between different devices to ensure appropriate level matching during signal transmission.

2. Impedance matching: Audio transformers can provide impedance matching between input and output as needed. They can connect low impedance sound sources to high impedance loads to maximize signal transmission and reduce energy loss.

3. Isolation: Audio transformers can provide electrical isolation, separating the ground wires between input and output, thereby eliminating noise interference and circuit problems caused by the ground loop.

4. Frequency response: Audio transformers are usually designed to maintain the linearity of the frequency response within an acceptable range to ensure that the transmitted audio signal remains intact without distortion or loss.

Audio transformers are widely used in audio equipment and systems, such as amplifiers, mixing stations, recording equipment, audio systems, etc. They play a crucial role in the transmission and processing of audio signals, improving sound quality, reducing noise interference, and achieving mutual communication between different devices