could anybody offer me a current limited circuit?

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the current is limited between 400mA and 700mA,thanks!
 

Hi...

Ok, lets clarify ur Qs. If u mean a current source then u can use a current mirror using 2 transistors. If ur asking for a kind of protection circuit, there are many automatic so-called fuses available.
 

Check this circuit:

Here you have a PNP transistor, that has 0,7V between emiter and base.
D1 is a diode, that could be a LED diode, with 1,7V diode tension.

Then, the value of current in collector-emiter from circuit, will be:

Ice = (Vdiode - Vbe) / Rlimit

So, for 500mA => Rlimit = (1.7-0.7) / 0.5 A = 1/0.5 = 2ohm.

The current in Rload will be always 500mA, and regulated!!!

Chose a transistor that supports more than 1A in collector-emiter, for not burning.

Hope it helps.
Good luck
 

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