5 volts versus 5.4 volts

Discussion in 'General Electronics Chat' started by aac9876, May 3, 2010.

  1. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    I have a cell phone amp that only came with a 5.4 volt 900 ma car power source.
    Its a Wilson. Do you think a 5 volt 1000 ma wall wart will be good enough.??? its the Sleek
    cell phone cradle amplifier....please elaborate.
     
  2. BMorse

    Senior Member

    Sep 26, 2009
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    If the wall wart was not designed for the phone, I would be careful in connecting it to the phone,the power output and the current supplied seems adequate, BUT the polarity of the adapter may not be correct, some manufacturers will be completely opposite of others. What type of connector does the wall wart have (i.e. is it a barrel type connector with a hole in the center, etc.)?

    B. Morse
     
  3. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    I should have said..its a USB power supply type.. if they are both pos tip polarity.
    what do you say??
     
  4. BMorse

    Senior Member

    Sep 26, 2009
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    Then the power connections should match pin to pin.... should work, the only difference is less than 1/2 a volt from the original adapter and the new one, plenty of current... can you post some pictures of the connections on both devices?

    B. Morse
     
  5. eblc1388

    Senior Member

    Nov 28, 2008
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    Yes, but if and only if it is a regulated one, with the word "regulated" printed on the wall wart body. Or you have confirmed the actual output voltage using a voltmeter.

    If you cannot see the word "regulated", then it is properly not suitable as the output voltage of the wall wart can be as high as 9V without load.
     
  6. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    are those 5 dollar Belkin 5 volt/1 amp USB wall warts regulated...????
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
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    If it doesn't say
    OUTPUT 5v REGULATED
    then no. (99.9% of the time)

    Do you have a meter? If you check the voltage with a meter, and it is a few volts over the rating, then it is not regulated.
     
  8. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    I got ya, but the cheap cigarette USB 5.4 v wouldnt be regulated either .????
     
  9. kingdano

    Member

    Apr 14, 2010
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    i have to chime in here.

    i do a lot of R&D development, and often use wall warts to power my PCBs

    i have found that it is nearly impossible to tell which wall warts are regulated by reading the case, and often snip off the connector and SAFELY measure the voltage with a DMM to check.

    once you do this it is very obvious - if you are within 10% or so of the rated output - the supply is regulated.
     
  10. BMorse

    Senior Member

    Sep 26, 2009
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    If it has a USB connector on it to fit the phone I would say 99.9% that it is regulated, most devices that plug in to a USB have either a built in regulator or they depend on the regulated 5 volts from the PC, so I am pretty certain the wall wart is regulated if the op was correct in stating it has a USB connector on it.

    My .02

    B. Morse
     
  11. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    i meant that the cheap looking dc power 12v adaptor that came with it, that says its 5.4 v it looks too cheap for accuracy.. but now I see the instructions say the power req. is 5 volts. thats all it says.
    Its an amp too, thats all, so a little extra or less isnt gonna hurt it ..??it will just make a little less or more of a signal...right..
     
  12. BMorse

    Senior Member

    Sep 26, 2009
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    Should work just fine..... (Keep your fingers crossed:D)...

    But if you still have doubts, you can contact the manufacturer of the phone for support, and just find out for sure, or else, plug it in and see what happens, but do this on your own accord, as long as you take full responsibility for whatever the outcome.

    B. Morse
     
  13. aac9876

    Thread Starter Active Member

    Dec 9, 2006
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    it didnt blow up someone from Wilson would know for sure
     
  14. retched

    AAC Fanatic!

    Dec 5, 2009
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    Most circuit components have a 10 to 20% leeway.

    Even though a resistor says 100 ohm, It can be anywhere from 90 to 110 ohms.

    Same with capacitors. but even larger variance. 100uF cap can be 80 or 120uF standard.

    So a less than 10% voltage fluctuation isnt usually harmful.

    Think about the US house voltage. You will see it listed on breakers, motors, hairdryers, tvs, gfci outlets, switches, etc. from 110v to 125v. The thing is, it can change from outlet to outlet, room to room, and house to house.
     
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