русский
Deutsch
Français
Portugues
Español
العربية
lingua italiana
日本語
한국어
Türk dili
Audio transformer, also known as "audio transformer". An iron core coil type transformer operating in the audio frequency range. In radio equipment, it is used as a coupling element between audio circuits to increase voltage or achieve impedance matching. Generally, a material with high magnetic permeability is used as the core, and the primary and secondary coils are often wound in layers and segments to obtain good frequency response characteristics. Next, I will tell you the difference between the audio transformer winding method and the power transformer in detail.
Winding method of audio transformer
Through the principle of audio transformers, we know that the most important factors affecting the quality of audio transformers are the amount of leakage inductance, inductance and distributed capacitance. The lowest frequency of the passband is determined by the inductance of the original winding, and the highest frequency is determined by the leakage inductance of the transformer. To ensure that the audio transformer has enough passband, the primary winding inductance should be large and the leakage inductance should be small. Therefore, in order to wind an audio transformer with better quality and performance, the most important problem is to reduce the leakage inductance of the audio transformer and increase the inductance.
In view of the above problems, the most important thing for winding audio transformers is the iron core of the transformer. The quality of the iron core directly determines the inductance and leakage inductance of the transformer. We should try to use silicon steel sheets with higher magnetic flux density as the iron core. The purpose of using pure copper wire is to increase the inductance and reduce the leakage inductance as much as possible under the limited number of turns (which is beneficial to reduce the distributed capacitance).
At the same time, in order to achieve better results, it is best to fully encapsulate epoxy resin inside the audio transformer. After the toroidal transformer is filled with glue, the coil vibration caused by the alternating current can be effectively reduced, the noise of the transformer can be reduced, and the noise caused by the audio power amplifier transformer can be reduced. The requirements are very strict, so the toroidal transformers used in audio power amplifiers are mostly potting.
Difference between audio transformer and power transformer
Audio transformers are often used to transform voltage or transform the impedance of a load. It is used as a component of circuits such as voltage amplification and power output in radio communication, radio and television, and automatic control. The frequency response of the audio transformer is uniform in the working frequency band. The core is made of high-permeability materials. The primary and secondary windings are closely coupled, so that the magnetic flux passing through the primary winding is almost all linked with the secondary winding, and the coupling coefficient is close to 1. The lowest frequency of the passband is determined by the primary winding inductance, and the highest frequency is determined by the transformer leakage inductance. To ensure that the transformer has enough passband, the primary winding inductance should be large and the leakage inductance should be small. The hysteresis loss of the iron core and the saturation of the magnetic circuit can cause signal distortion. Properly configuring the load and increasing the load current can reduce the influence of hysteresis loss; increasing the section of the iron core and leaving an air gap can prevent the magnetic circuit from being saturated, which can reduce the distortion of the signal.
The low-frequency transformer is used to transmit signal voltage and signal power, and can also achieve impedance matching between circuits, which has an isolation effect on direct current. It is mostly used as a power transformer for voltage conversion.
Audio transformers are still different from ordinary power transformers. Because the input impedance and output impedance of the audio transformer and the power transformer are different, the functions of the power transformer are power transfer, voltage conversion and isolation. The audio transformer is a transformer working in the audio range, called a low-frequency transformer, which is often used to transform voltage or transform the impedance of the load.
Winding method of audio transformer
Through the principle of audio transformers, we know that the most important factors affecting the quality of audio transformers are the amount of leakage inductance, inductance and distributed capacitance. The lowest frequency of the passband is determined by the inductance of the original winding, and the highest frequency is determined by the leakage inductance of the transformer. To ensure that the audio transformer has enough passband, the primary winding inductance should be large and the leakage inductance should be small. Therefore, in order to wind an audio transformer with better quality and performance, the most important problem is to reduce the leakage inductance of the audio transformer and increase the inductance.
In view of the above problems, the most important thing for winding audio transformers is the iron core of the transformer. The quality of the iron core directly determines the inductance and leakage inductance of the transformer. We should try to use silicon steel sheets with higher magnetic flux density as the iron core. The purpose of using pure copper wire is to increase the inductance and reduce the leakage inductance as much as possible under the limited number of turns (which is beneficial to reduce the distributed capacitance).
At the same time, in order to achieve better results, it is best to fully encapsulate epoxy resin inside the audio transformer. After the toroidal transformer is filled with glue, the coil vibration caused by the alternating current can be effectively reduced, the noise of the transformer can be reduced, and the noise caused by the audio power amplifier transformer can be reduced. The requirements are very strict, so the toroidal transformers used in audio power amplifiers are mostly potting.
Difference between audio transformer and power transformer
Audio transformers are often used to transform voltage or transform the impedance of a load. It is used as a component of circuits such as voltage amplification and power output in radio communication, radio and television, and automatic control. The frequency response of the audio transformer is uniform in the working frequency band. The core is made of high-permeability materials. The primary and secondary windings are closely coupled, so that the magnetic flux passing through the primary winding is almost all linked with the secondary winding, and the coupling coefficient is close to 1. The lowest frequency of the passband is determined by the primary winding inductance, and the highest frequency is determined by the transformer leakage inductance. To ensure that the transformer has enough passband, the primary winding inductance should be large and the leakage inductance should be small. The hysteresis loss of the iron core and the saturation of the magnetic circuit can cause signal distortion. Properly configuring the load and increasing the load current can reduce the influence of hysteresis loss; increasing the section of the iron core and leaving an air gap can prevent the magnetic circuit from being saturated, which can reduce the distortion of the signal.
The low-frequency transformer is used to transmit signal voltage and signal power, and can also achieve impedance matching between circuits, which has an isolation effect on direct current. It is mostly used as a power transformer for voltage conversion.
Audio transformers are still different from ordinary power transformers. Because the input impedance and output impedance of the audio transformer and the power transformer are different, the functions of the power transformer are power transfer, voltage conversion and isolation. The audio transformer is a transformer working in the audio range, called a low-frequency transformer, which is often used to transform voltage or transform the impedance of the load.
