Complete Electronics Self-Teaching Guide with Projects

Chapter 11

Power Supply Circuits

A power supply is incorporated into many electronic devices. Power supplies convert the 120 volts AC from a wall plug to a DC voltage, providing power for all types of electronic circuits.

Power supply circuits are simple in principle, and those shown in this chapter have been around for many years. Because power supplies incorporate many of the features covered in this book, they make an excellent conclusion to your study of basic electronics.

Diodes are a major component in power supplies. Learning how AC signals are affected by diodes is fundamental to your understanding of how power supplies work. Therefore, this chapter begins with a brief discussion of diodes in AC circuits.

Throughout this chapter, diagrams show how AC signals are affected by diodes and other components in power supply circuits. If you have an oscilloscope, you can breadboard the circuits and observe these waveforms.

When you complete this chapter, you will be able to do the following:

• Describe the function of diodes in AC circuits.
• Identify at least two ways to rectify an AC signal.
• Draw the output waveforms from rectifier and smoothing circuits.
• Calculate the output voltage from a power supply circuit.
• Determine the appropriate component values for a power supply circuit.