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<title>Power supplies for battery chargers</title>
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<p><b>Power supplies for battery chargers</b><br>
When selecting an unregulated DC wall transformer (power adapter), for example
to power a battery charger, keep in mind that the output voltage can be much
higher than the rated voltage shown on the label. Make sure you don't exceed
the maximum input voltage of the device being powered. Adding a voltage regulator
to the circuit is one way to prevent this:</p>
<img src="charger_reg.gif" width="500" height="250">
<p><b>Voltage regulator circuit</b>. IC number 78XX. The last two digits represent
output voltage. Example, a 7815 is a 15V regulator.</p>
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<p><img src="fut_charger.gif" width="478" height="313"></p>
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