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Radio Shack power supply

tj107us

Apr 23, 2011
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Apr 23, 2011
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Hey guys I'm working on another project, its a 13.8vdc power supply that has quit working and i need to know how to test a voltage regulator Item # LAS1905B. I have attached a photo of it.


thanks for any help,
Jake
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
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LMGTFY

Measure the input voltage and the output voltage. If the input voltage is more than a couple of volts higher that the regulator's specified output, the output should be within a couple of percent of the rated output voltage.

It should stay that way under load until either the internal current limit is reached, it overheats, or the input voltage sags.

The above text is generic. You will need to read the datasheet for more specific information.
 

tj107us

Apr 23, 2011
48
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Apr 23, 2011
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48
how would i check the voltage, ive tried looking it up but all i can find is how to test a auto/motorcycle type voltage regulator?
 

john monks

Mar 9, 2012
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Mar 9, 2012
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693
Let me take a crack at it. Place anywhere from about 8 volts to 30 volts between pin 1 and the case. Pin 1 should be positive. Take a voltmeter and place it between pin 2 and the case. You should read about 5 volts.
 
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