Power Supplies 673A full-wave bridge rectifier supplies full-wave recti-
fication without a center tap on the transformer. The
bridge rectifier is not a true single-ended circuit, since it
has no terminal common to both the input and output
circuits.
A full-wave bridge rectifier consists of four rectifier
elements, as shown in Fig. 19-2E. This circuit is the
most familiar and is the type most commonly employed
in the electronics industry.
With the full-wave bridge circuit, the dc output
voltage is equal to 0.9 of the rms value of the ac input
voltage.
Full-wave bridge rectifier circuits may be grounded
by three methods shown in Fig. 19-3A, B, C. Either the
input (ac source) or output (dc load) may be grounded,
but not both simultaneously. If an isolation transformer
is used between the ac source and the input to the recti-
fier, as shown in Fig. 19-3C, both ac and dc sides may
be grounded permanently. A method of grounding a
bridge rectifier is shown in Fig. 19-3D where the center
tap of an isolation transformer is grounded.When designing rectifier circuits, dc load current, dc
load voltage, peak inverse voltage, maximum ambient
temperature, cooling requirements, and overload current
must be analyzed. For example, assume a full-wave
rectifier using silicon rectifiers is to be designed as in
Fig. 19-3D and the dc load voltage Vdc under load is
25 V at 1 A.
Using Table 19-1, determine the current per rectifier
using the equationFigure 19-2. Two one-half wave and two full-wave power
supplies.
A. Half-wave transformerless power supply.B. Half-wave transformer-isolated power supply.C. Output waveform of a half-wave power supply.D. Full-wave center-tapped power supply.E. Full-wave bridge-rectifier power supply.F. Output waveform of a full-wave power supply.VacVacVacVacVdcVdcVdcVdcFigure 19-3. Methods of grounding a power supply.A. Ac grounded.B. Dc grounded.C. Ac and/or dc grounded
using an isolation transformer.D. Full wave center-tapped.