Triad chassis mount power transformers provide maximum performance when integrated into full wave center tap or bridge type circuits with silicon or selenium rectifiers. The secondary voltages are selected by primary taps. The secondaries of the Series F-90 transformers may be connected to provide a wide variety of output voltages. The Series F-90 transformers are designed for use with silicon diode rectifiers to supply the DC voltages for transistors in their various applications. They are intended for use with full wave center tap or bridge rectifiers, but may be used with voltage doubler circuits at one-half of the rated current.