Complete Electronics Self-Teaching Guide with Projects

Level DC (Smoothing Pulsating DC)

14 A basic power supply circuit can be divided into four sections, as shown in Figure 11.31.

Figure 11.31

Questions

A. If you use a center-tap transformer in a power supply, how many diodes would you need to produce a full-wave rectified output? _____

B. Will the power supply circuit shown in Figure 11.31 result in full- or half-wave rectification? _____

C. What type of output will the rectifier section of the power supply circuit shown in Figure 11.31 produce? _____

Answers

A. Two

B. Half-wave

C. Pulsating DC

15 The function of the smoothing section of a power supply circuit is to take the pulsating DC (PDC) and convert it to a “pure” DC with as little AC “ripple” as possible. The smoothed DC voltage, shown in the illustration on the right in Figure 11.32, is then applied to the load.

Figure 11.32

The load (which is “driven” by the power supply) can be a simple lamp or a complex electronic circuit. Whatever load you use, it requires a certain voltage across its terminals and draws a current. Therefore, the load has a resistance.

Usually, the voltage and current required by the load (and, hence, its resistance) are known, and you must design the power supply to provide that voltage and current.

To simplify the circuit diagrams, ...