circuit breaker

[newonetoo]

I hope this is a better question then the last one I gave. Can anyone assist in making a 7.5 amp 12v circuit breaker. Doing work on the bike keeps blowing those mini fuses. Which are not cheap.

[Theatronics]

my best guess?  Try about a 32-34ga wire.
Id suggest you build a rig with 2 terminals that you can wrap the wire around and then cover with a shield.  Wire going vapor can be dangerous.

for a few bucks you can buy a circuit breaker.

You can also use a 'shunt' resistor, a RS flipflop and a mosfet.

Run the circuits ground into the drain of the n-channel mosfet.
Connect the drain to the ground.

Set up the shunt resistor so that when the target current is flowing though it you can read about 3-4 volts.  ( 4v / 7.5 amps = 0.53 ohms )

Take the output of that measurement and feed it into the SET input of the flipflop.

When the current gets close to 7.5 amps, the voltages at the flop/flop input will be high enough to cause the f/f to toggle states.  As a result the /Q (not Q) output of the f/f will go low.  When this happens the N-Channel Mosfet will shut off and the circuit will shut off.

-Mike

[ante]

You could use one of these, 6 or 8 A will do:

http://www.elfa.se/elfa-bin/setpage.pl?http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&dok=2013541.htm