Full-Wave Center-Tap Rectifiers

Author: J.B. Hoag

Several circuit diagrams of a full-wave center-tap rectifier are shown in Fig. 11 C, together with the wave form of the direct-pulsating current which flows through the load R.

Fig. 11 C. Full-wave center-tap rectifiers

When the upper end of the transformer secondary in (a) is +, the upper tube conducts, and on the next half-cycle, when the lower end is +, the lower tube conducts. It will be noted that during each half-cycle, the current flows through R in the same direction. Thus both halves of the supply voltage are used. Since only one-half of the transformer secondary is used at one time, the total secondary voltage must be twice that required with a half-wave rectifier.

The inverse-peak-voltage on the non-conducting tube, which it must be built to withstand, is equal to 1.41 times the total r.m.s. secondary voltage (minus the voltage drop in the conducting tube, which is usually small).

The ripple frequency is twice that of the supply line; 120 for a 60-cycle line.