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Current rating of power supply

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shiv

New Member
Hi
i use 5V,10mA supply. For some special cases, 30mA current rating is required and i can use only one 5V,10mA supply. How can 30mA be accomodated with 5V,10mA power supply?

Thanks
Shiva
 

stevez

Active Member
The short answer is that it can't.

Your 10 ma supply may be grossly under-rated and/or the 30 ma requirement is an overstatement. Without a lot more information about the supply and load it's tough to comment.
 

Gene

New Member
steve is right. I would re-build it into a 30ma supply which would be strong enough to handle either application.
 

stevez

Active Member
Worth mentioning is that a power supply (like anything else) is only as strong as it's weakest link. Sometimes careful examination of the components will reveal an opportunity to get more out of something - but only sometimes.

Sometimes we get by in connecting a 30 ma load to a 10 ma supply because the 30 ma represents a peak that is seldom reached and the 10 ma is a continuous rating. Sometimes we can make the 10 ma supply work by not pushing whatever it is so hard. An example might be a 300 watt amplifier that we might want to run on a power supply that falls short of requirements - we might simply limit how far up we turn the volume as a way of managing the inadequate supply.

Transformers are one of several components that can be stretched, so to speak. I know that a transformer designed for continuous commercial service can be used at levels twice it's design if used in intermittent amateur service. It really doesn't put out any more - it's just that we've put it to work in a situation that is less demanding.

Wire is another one of those where how much current it can carry depends on a number of things. A 12 ga wire in a conduit is rated at less current than one in open air - presuming of course that voltage drop isn't the issue.

Sometimes the answer is "try it and see" but this applies only if the result of failure is acceptable - not a fire, injury, death, costly, etc.

So the short answer is still "no" but I've offered a little more.
 
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