Big crowbar module for <4VDC?

My father had a policy of refusing to service Muntz TV's ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

Of course. TL431 was one of my jelly-bean-parts-of-choice during the mid '70's thru late '80's.

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

I can understand why. I did the same in Germany, there was a brand named "Kuba" where I told neighbors that I won't fix those anymore.

Hey, did you post a few MP3 tunes from your father yet?

With me they still are. When I feel extra generous I might even spring for a TLV431 on regular circuits (not crowbars), but not often.

Why mod it? If you have access to a point within the PS circuitry, just add your own crowbar. Since the existing one is designed for 5V output, odds are that it will never operate and won't interfere with your added circuitry.

Put in whatever SCR it will take to work with the current available. If your load is that valuable, a few dollars more for a beefy part won't break the budget. I'm assuming this isn't for high volume production (in which case, a custom designed PS would be better).

Well, but I want it to work. Ideally at 3.6 volts or so.

Guess I'll have to if nothing commercially available comes up.

"Jim Thompson" skrev i meddelelsen news: snipped-for-privacy@4ax.com...

Communist Chinese actually ;-) .

On a sunny day (Thu, 18 Dec 2008 18:32:11 -0800) it happened Joerg wrote in :

Crowbars are to protect the LOAD, not the supply, and should be at the OUTPUT. In case of a 100K$ load and a 100$ supply, the choice is easy. Shorting before the regulator does not guarantee energy in any caps and or inductors in the circuit does not make it to the load. Simple.

In article , snipped-for-privacy@diespammerdie.jensen.tdcadsl.dk says...>

The difference being that Chi-Comms like business.

I roll my own versions of TL431 now ;-)

...Jim Thompson

Nope. Simple-minded analysis.

...Jim Thompson

But, according to Joerg, $1 for a fuse is too much ;-)

...Jim Thompson

On a sunny day (Fri, 19 Dec 2008 07:53:00 -0700) it happened Jim Thompson wrote in :

Maybe you can address this issue:

'Shorting before the regulator does not guarantee energy in any caps and or inductors in the circuit does not make it to the load.'

versus insulting, you leftist commie ;-)

My view is: Measure temperature where you want to know it, Measure voltage where you want to know it. And limit voltage where you want it limited, not at the power plant LOL.

On a sunny day (Fri, 19 Dec 2008 07:55:41 -0700) it happened Jim Thompson wrote in :

Joerg uses narrower PCB traces as fuse perhaps?

Naaah! YOU be the leftist commie jerk.

...Jim Thompson

On a sunny day (Fri, 19 Dec 2008 08:24:29 -0700) it happened Jim Thompson wrote in :

That begs the question not only about your knowledge of crowbars, but also if you know the difference between left and right.

You can test it here:

Not in this case. In this case there simply is no way to install one without major surgery.

In other cases (med/aero etc.) a fuse is always considered a fire risk. Because it is one. So every fuse will greatly increase a cert effort. So you only place them where they make sense. Between caps and pass devices they often don't.

And the 'working out' has to include the well-known human tendency to cut corners and then lie to cover it up--I'd want to wear a belt and suspenders there. I've seen too many people use fuses wrapped in foil.

Cheers,

Phil Hobbs

Archie Bunker put a penny underneath.