Power supplies

Chapter Power supplies

Teach Yourself Electricity and Electronics Third Edition Book
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Summary of Contents

Teach Yourself Electricity and Electronics Third Edition Book

  • 21CHAPTERPower suppliesMOST ELECTRONIC EQUIPMENT NEEDS DIRECT CURRENT (DC) TO WORK. BATTER-ies produce dc, but there is a limit to how much energy and how much voltage a bat-tery can provide. The same is true of solar panels.The electricity from the utility company is alternating current (ac) with a fre-quency of 60 Hz. In your house, most wall outlets carry an effective voltage of 117 V;some have 234 V. The energy from a wall outlet is practically unlimited, but it must beconverted from ac to dc, and tailored to just the right voltage, to be suitable for elec-tronic equipment.Parts of a power supplyA power supply provides the proper voltage and current for electronic apparatus.Most power supplies consist of several stages, always in the same order (Fig. 21-1).38321-1Block diagram of a power supply. Sometimes a regulator is not needed.First, the ac encounters a transformer that steps the voltage either down or up, depending on the exact needs of the electronic circuits.Copyright © 2002, 1997, 1993 by The McGraw-Hill Companies. Click here for terms of use.