- on Power Supplies
- Published in issue 10/2001 on page 0
Three-legged voltage regulators are known as handy and straightforward components. There are, nevertheless, still a number of interesting facts to report. As always, practice is never quite the same as theory.Since their introduction, the three-legged voltage regulators have quickly displaced their discretely built counterparts. And with good reason, why be difficult when one component will suffice? They are available for practically any desired output voltage and the performance of the famous 78xx-series is usually more than adequate for most applications. In addition, hardly anything can go wrong, because it comes with a robust thermal and overload protection circuit built in.The only demand that the threelegged creature makes, is that the unregulated DC input voltage is at least 3 V higher than the output voltage. Otherwise the regulator circuit cannot do its job properly.