Wie baue ich eine Kurzschlusssicherung?

Was spricht den gegen die klassischen Sicherungen?Da gäbe es z.B. 
Schmelzsicherungen wie sie Millionenfach im Einsatz sind.Haben sogut wie 
keinen Leitungswiderstand und sind von Flink bis Träge für verschiedene 
Ströme erhältlich.Wer in seiner Schaltung die Sicherung nicht mehr 
wechseln will/kann könnte alternativ eine Polyswitch.Die würde sich nach 
dem Abschalten des Stromes regenerieren und ohne Austausch des 
physischen Bauelements auskommen.

Funktionsweise:

Kurzschluss führt zu einem hohen Strom der die Schmelzsicherung stark 
erwärmt.Das führt zum durchbrennen des dünnen Drähtchens in der 
Sicherung.Damit ist die Leitung unterbrochen und der Kurschluss 
beseitigt.

Hi,

schau mal hier:
http://tuxgraphics.org/electronics

Da sind drei Artikel "A digital DC powersupply".
Vieleicht findest Du da ja ein paar Anregungen.

CU Frank

Hallo Hein hier,
Entschuldige das ich auf englich weiter gehe...mein Deutch ist 
grausam...

First of all you should look for a schematic for a constant current 
(source) not for an electronic fuse.
A fuse blows...it interrupts your supply when its maximum current is 
exeeded.
Maybe that is what you want, but it's much better to use a constant 
current circuit that allows YOU to adjust the max. current YOU allow to 
flow into your experiment or load.
For a supply, the latter is what you need I think.
There are an abondance of powersupply (regulator) chips that can do this 
for you. From heart I recall the L200... try and google >>L200 .pdf<<

I don't now your level of expertise, but allow me to warn you to take 
good care with the heat dissapation with linear voltage and current 
regulators.
What comes out of the transformer but goes NOT into your load has to go 
somewhere, and heat it is. That's why power supplies are often fitted 
with large heat sinks.
If you considder building a switchmode power supply with constant 
current regulation whilst not finding your electronic fuse on the net, 
than youre in bigger trouble than can to help you with.
So linear it is... big heatsink and happy hunting on 
www.circuitcellar.com

bey, tjuss
Hein
PS1: the magazine elektor has released several electronic fuses.
PS2: Multi fuses (polyfuses)as mentioned by Ronny are only to be used 
for short circuit currents, where currents rise to a multiple of the 
nominal current. they  are often to slow on 110-150% overload 
conditions. Besides that you have to consider the (umgebungs wärme) for 
they may kick in a lot to soon when operated in e.g. 60 degrees C or not 
at all below freezing.
The cheapest autoresettable fuse would be a multi fuse well selected and 
than thermally connected to the voltage regulating (pass) transistor. 
That way the pass transistor pre-heats the multi fuse... very cheap... 
but slow on resetting.

Da wahr noch was....
Look for regulators with a build in and very nifty "current fold back" 
mechanism. This kicks in when a short current or overload condition 
occurs and lowers the output voltage to minimun yet does not heat up 
during the overload, yet it recovers automatically when the short 
circuit is removed.
"Texas instruments, Linear circuits-voltage regulators and supervisors", 
explains it all.

tjuss,
Hein