# difference between............

Discussion in 'General Electronics Discussion' started by krawczuk, Jun 9, 2012.

1. ### krawczuk

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Mar 20, 2011
hi, what is the differance between constant current adjustable and adjustable current limit ?

mark k

2. ### davennModerator

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Sep 5, 2009
hi Mark

well just off the top of my head I would say...

adjustable constant current --- is a power supply that you can adj the current to a required amount, say 1.5 Amps, and it wont vary from that

adjustable current limit --- is a feature of a power supply where you can adj the maximum supplied current to a required limit, say 2 amps, and the current limiting circuit in the power supply wont let the current go over that amount. BUT the current is able to vary anything from 0A to 2A --- therefore it isnt a constant current source.

Dave

3. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,497
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Jan 21, 2010
Let me give you a car analogy.

Constant current is like driving at a constant speed. A current limit is like a speed limit (except more heavily enforced).

We're all used to speed limits. You may not ever travel at the speed limit because of traffic, weather, or personal preference. You have the freedom to travel at any speed up to that limit.

Constant current is like constant speed, but even more so. We never drive with the objective of maintaining a constant speed. Imagine driving along a highway. We might decide to travel at a constant speed (lets say the speed limit), but if there is a traffic jam ahead, we will slow down.

A constant current power supply will always supply that current. It's as if, when finding a traffic jam ahead you just put your foot to the floor and push through it without reducing your speed. In this particular case the constant current power supply will increase the voltage so that it can push harder to maintain the same current.

4. ### BobK

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Jan 5, 2010
Just don't run the constant current supply with no load, it will output infinite voltage

5. ### krawczuk

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Mar 20, 2011
excellent !!!!

hi, thanks for all ya answers !!, exactly what i needed !!!!

mark k