It is divided into an interstage coupling transformer, an input transformer and an output transformer, and the shape is similar to that of a power transformer.
1. Inter-electrode coupling transformer: The interstage coupling transformer is used between two-stage audio amplifier circuits. As a coupling element, the output signal of the preamplifier circuit is transmitted to the next stage, and appropriate impedance transformation is performed.
2. Input Transformer: In the early semiconductor radios, the transformer used between the audio boost stage and the power amplifier stage was an input transformer that acts as a signal coupling and transmission, also known as a push transformer.
The input transformer has a single-ended input and a push-pull input. If the push circuit is a single-ended circuit, the input transformer is also a single-ended input transformer; if the push circuit is a push-pull circuit, the input transformer is also a push-pull input transformer.
3. Output transformer: The output transformer is connected between the output circuit of the power amplifier and the speaker, mainly for signal transmission and impedance matching. The output transformer is also divided into a single-ended output transformer and a push-pull output transformer.
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