High Current Power Supply 12v, with zener on base

[jacquesl]

Yea, that crowbar circuit will work fine, I cant seem to locate that link, can you please supply me with it in a post, I've seem one with a zener and transistor once but cant remember where


EDIT: i finaly founded it

its called "Active Power Zener"

http://sound.westhost.com/appnotes/an007.htm

[AndrewT]

no, that is a negative version of your positive regulator.
It is a zener with a bit of muscle behind it.

It is called a "crowbar"
When it triggers it shorts the top to bottom of the triac.
That blows the fuse in the supply line, hopefully before anything is damaged.

[jacquesl]

Originally posted by AndrewT
no, that is a negative version of your positive regulator.
It is a zener with a bit of muscle behind it.

It is called a "crowbar"
When it triggers it shorts the top to bottom of the triac.
That blows the fuse in the supply line, hopefully before anything is damaged.

No man, this device filter out all the voltages above the zener and short circuit it, and maybe that will be able to blow the fuse, I don’t want to use a triac, maybe I cant make it like with if the voltage get to high it flips a relay and disconnects the 28v DC from the rest of the system, this function can be useful for my UPS I’m busy building, I want a under power and over power disconnecter

[ifrythings]

The one you posted is a shunt regulator, if you go with that it will "double" regulate your line, theres still no protection and you have to heat sink the other transistor. A crowbar disables the supply in the event of overvoltage.

Check this site out: http://www.kbt-dc-supplies.com/crowbar.php