The low frequency transformer is used to transmit the signal voltage and signal power, and can also realize the impedance matching between the circuits, and has the isolation effect on the DC power. High frequency transformer and low frequency transformer on the principle of no difference. But due to the high frequency and low frequency. The frequency of different iron core transformer used. Low frequency transformers for general silicon steel sheet with high permeability. The high frequency transformer with high frequency ferrite core.
The low frequency transformer is divided into the interstage coupling transformer, the input transformer and the output transformer, and the shape of the transformer is similar to the power transformer.
The 1. pole coupling transformer interstage coupling transformer is used in the two stage audio amplifier circuit. As a coupling element, the output signal of the pre amplifier circuit is sent to the next level, and the appropriate impedance transformation is carried out.
2., the input transformer is used in the early semiconductor radio. The transformer used between the audio driving stage and the power amplification stage is the input transformer, which plays the role of signal coupling and transmission, also known as the drive transformer.
The input transformer has a single end input and push-pull input. If the circuit is a single ended circuit, the input transformer is also a single ended input transformer. If the driving circuit is a push-pull circuit, the input transformer is also a push-pull input transformer.
The output circuit of the power amplifier of the output transformer of the 3. output transformer is between the output circuit and the speaker, which mainly plays the role of signal transmission and impedance matching.
The output transformer is also divided into two types: single end output transformer and push-pull output transformer.