A note on a parallel-tuned transformer design

An analysis of the parallel-tuned transformer used in radio-frequency amplifiers has been made for a slightly over-coupled case. The resulting design formulas are simple and practical. Two cases are discussed: (a) the so-called matched transformer, with resistance loading on each side; (b) a transformer with loading on one side only, which has the same pass-band and phase characteristics as the matched transformer, but gives 3 db more gain when used as an in terstage. A special arrangement of (a) where the matched transformer design is used with one resistor removed, giving a transformer witha considerably double-humped pass-band characteristic and about 6 dh more gain, is also discussed.