The toroidal transformer used in the loudspeaker is determined by the characteristics of the audio power amplifier. It is not necessary to use a toroidal transformer for speakers, but it is most suitable.
Different from other equipment, the power consumption of electrical equipment is basically fixed, and the power consumption of audio power amplifier not only changes rapidly, but also can reach 10000%. Such a great change requires that the transformer must have strong instantaneous overload capability and fast response speed. Otherwise, it is easy to form noise, the sound is not enough and the sound quality is not good. Because of the large capacity of the ring transformer with the same volume, the direct coupling almost has zero delay response, which conforms to the characteristics of the speaker power supply point;
Characteristics of toroidal transformer
The core of toroidal transformer is made of high-quality cold-rolled silicon steel sheet (generally less than 0.35mm in thickness) by seamless rolling, and its core performance is better than that of traditional laminated core. The coils of the toroidal transformer are evenly wound on the iron core, and the direction of magnetic lines generated by the coils almost coincides with the magnetic circuit of the iron core. Compared with the laminated type, the excitation energy and core loss will be reduced by 25%, which brings the following advantages.
1) iron core has high electrical efficiency, no air gap and stacking coefficient up to 95%?
Above the ring transformer, the magnetic permeability of the core can be 1.5 ~ 1.8t (laminated core can only be 1.2 ~ 1.4t), the electric efficiency is as high as 95%, and the no-load current is only 10% of laminated core.
2) The annular transformer is small in overall size and light in weight, which can be reduced by half compared with the laminated transformer. As long as the cross-sectional area of the core is kept equal, the aspect ratio of the core can be easily changed and the overall size can be designed to meet the requirements.
3) The magnetic interference is small. The core of the toroidal transformer has no air gap, and the windings are evenly wound on the toroidal core, so the magnetic leakage and electromagnetic radiation are small, and it can be used in high-sensitivity electronic equipment without additional shielding, such as low-level amplifiers and medical equipment.
4) Low vibration and noise. There is no air gap in the iron core to reduce the induced vibration noise of the iron core, and the winding is evenly and tightly wrapped around the annular iron core, effectively reducing the "buzzing" sound caused by magnetostrictive.
5) Low operating temperature Because the iron loss can reach 1. 1W/kg, the iron loss is very small, and the temperature rise of the iron core is low, so the temperature rise of the transformer is low.
6) Easy-to-install ring transformer, with only one installation screw in the center, is particularly easy to install and disassemble quickly in electronic equipment.