Pages: [1]   Go Down
Author Topic: query on the ams1117 regulator  (Read 485 times)
0 Members and 1 Guest are viewing this topic.
LONDON UK
Offline Offline
Full Member
***
Karma: 0
Posts: 163
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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 ..
Logged

Offline Offline
Edison Member
*
Karma: 58
Posts: 2078
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
« Last Edit: February 20, 2013, 01:39:47 pm by Erdin » Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 545
Posts: 27353
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

"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
Logged

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.

LONDON UK
Offline Offline
Full Member
***
Karma: 0
Posts: 163
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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
Logged

Pages: [1]   Go Up
Jump to: