Amplifier Transformers

The major problem of amplifier transformer design is obtaining proper output when the transformer is operated in conjunction with the apparatus for which it is intended. Several factors external to the transformer affect its performance, namely, (1) impedance of the source; (2) linearity of this impedance; (3) impedance of the load; and (4) frequency.

The simplest method of dealing with amplifier transformers is an adaptation of the so-called equivalent network which has long been used for power transformers. The transformer that connects the source to its load in Fig. 103 (a) may be represented more fully by the diagram of Fig. 107(a).

Fig. 107. (a) Transformer equivalent circuit; (b) low-frequency equivalent circuit; (c) simplified low-frequency circuit; (d) high-frequency equivalent circuit; (e) simplified high-frequency circuit.