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Topic: query on the ams1117 regulator (Read 505 times) previous topic - next topic

knuckles

hi i bough a cheapo breadboard power supply off the bay which supplies 3.3 vand 5 v.
now when i ramp up the volts the 3.3v is mostly constant off the 3.3 v reg.(can be 9v supplied)
but when i ramp up the v on the 5 v reg its never 5v but can be 7v or more ,so is my 5v reg faulty ?
should it only give 5v no matter how much i feed it ?in which case i need to replace it .
within reason of course of the regs data sheet parameters ..

Erdin

#1
Feb 20, 2013, 07:23 pm Last Edit: Feb 20, 2013, 07:39 pm by Erdin Reason: 1
The 5V should be 5V, just as the 3.3V is 3.3V.

Perhaps you can measure the pins of the voltage regulator with a multimeter.
Are you sure you are testing the right pins? Some pins are the input voltage.
You should report it as broken.

CrossRoads

"is my 5v reg faulty"
Possibly.
Are you running it with no load? Try adding 1K resistor for 5mA load, see if it does the same.
Do you have any input & output capactitors on it?  You may need those as well.  Check the datasheet on the part.
http://www.advanced-monolithic.com/pdf/ds1117.pdf
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

knuckles

no load , i may as well replace the reg as theyre very cheap but my wallwart has adjustable v out so can control it ,thanx

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