Recently, Easybom (a powerful search engine for the electronic component industry helping you search the electronic components and supplier prices you want in a fast and easy way) is committed to making people learning about electronic components. As a result, it has carried out a series of researches and collected numerous information about the electronic components. The following is an introduction to the audio transformer conducted by Easybom.

Audio transformers, also known as low-frequency transformers, are a kind of transformers that work in the audio range. The operating frequency range is generally from 10 to 20000 Hz. It is often used to change the voltage or the impedance of the load. In radio communications, broadcast television, and automatic control, it is used as a component of voltage amplification, power output, and other circuits.

The audio transformer has a uniform frequency response in the working frequency band, and its core is made of high-permeability materials. The primary and secondary windings are tightly coupled so that almost all the magnetic flux passing through the primary winding is linked with the secondary winding, and the coupling coefficient is close to 1. The lowest frequency of the passband is determined by the inductance of the primary winding, and the highest frequency is determined by the leakage inductance of the transformer.

To ensure that the transformer has enough passband, the original winding inductance should be large, and the leakage inductance should be small. The core’s hysteresis loss and magnetic circuit saturation will cause signal distortion. Properly configuring the load and increasing the load current can reduce the effect of hysteresis loss. Increasing the core section and leaving an air gap can prevent the magnetic circuit from being saturated, which can reduce signal distortion.

Classification

Audio transformers can be divided into 3 categories according to their position in the electronic circuit.

Output transformer: It is connected between the output circuit and the load;

Input transformer: It is connected between the signal source and the input of the amplifier;

Inter-stage transformer: It is connected between the output circuit of the previous stage and the input circuit of the next stage.

Please pay attention to the matching of the front and rear impedance when using it to avoid signal distortion due to reflection. In order to make the load obtain the maximum power, the load impedance should be consistent with the impedance required by the power amplifier stage after the transformation through the impedance of the output transformer, and it should not be too large or too small.

After the audio signal is amplified by the audio transformer, although the voltage can be increased, the power is reduced due to the loss of the transformer. In this way, it cannot drive a larger load. Therefore, audio transformers cannot replace electronic audio signal amplifiers.

Function

The audio transformer can realize voltage transformer conversion like a power transformer, and can also realize audio signal coupling. There are four main functions of audio transformers:

Output transformer: It is used in audio equipment and playback equipment to transform the impedance in the circuit.

Input transformer: The main function is when the sound signal is input, and it plays the role of impedance transformation in the circuit.

Inter-stage transformer: The common inter-stage transformer can harmonize the working units of all levels in the amplifier.

Line-to-line transformers: line-to-line transformers are often used in cable broadcasting equipment. Because there are often many high-power amplifiers on the working unit of cable broadcasting, and the line is long, the long-distance audio transmission will cause audio distortion.

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