Short circuit protect power supply

em... i hav another questions about this circuit...
i use lm317 to make 5V fix supply but the current is 2A...
will 2A too big...?
the input voltage is 36V...

Clown of G0d

Do you mean your 5 volt circuit uses 2 amps ?
If so, yes it's too much for the standard LM317 which only supplies 1.5 amps.
Worse, with an input voltage of 36volts the LM317 will probably
fry at 0.5 amp.
A LM317 type regulator supplying 2 amps would dissipate 62 Watts !
You should consider a switched mode regulator.

have any connection to reduce the current...?

Clown of G0d

What do you mean ?

that mean have any suggest to soft this problem...?

Like ExperimenterUK suggested the LM317 is internally current limited to ~750mA for an input-output differential of 30V.
Although the 36v input is not a problem(317 can handle an I-O differential of 40V),the usable current is limited to 0.75A.

Can you tell us your application?

If you need higher current you can consider the low cost switching regulator described in the 317's datasheet (pg19).

Alternatively you can supply a lower Vin in which case currents upto 1.5-2A can be used.

this application is 5v power suppy...
the picture at 1st page...
the purpose is supply power to digital circuit...
lik uP (8051)...
so if current too big will burn the IC or not...?
now i wan decrease the current how can i do...?

See,the 2 amp that the 317 can provide,is the maximum you can draw from it.What is actually being used depends on the circuit you are powering.It's not that the 317 will send full 2 amperes down the throat of a ckt which is meant to draw 100mA.
The ckt will draw whatever it has to...could be 100mA,or 500mA,1A or full 2amps.

get it?

then that mean 2amp for 5v power supply is ok right...?

what is the circuit u want to drive with this supply u are designing anway? because if it is for a simple embedded system, i strongly suggest u first workout the approximate maximum current consumption on the +5V side because the size and price for such a transformer based linear supply would be really large and u would need adequate heatsink around the LM317 regulator.According to my knowledge,most of the non-commercial embedded systems would work nicely well within the 500mA range.
Further , if the input voltage is large,then the effeciency of ur regulator ckt would be greatly reduced. switched regulators would be better for a better conversion efficiency. Use a switched regulator like LM2575-5.0 ( approx 70% efficiency worst case) if current required is less than 1A.