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Who Has Used Resistors as Fuses

- The only place where I've seen this done in a production device was on a Newport panel meter. It was a 10 ohm 1/10 watt carbon composition resistor. Never saw one blow, but from the aftereffects, it was pretty violent. Apparently, it worked. I've never done it myself, since I've never blown more than one or two fuses in all the things I've built, and at a buck or two each, it was no big deal. In this vein, I'd like to add that from painful experience I distrust polyswitches and all their relatives. They're slow, have a limited life, can fail destructively or in an irritating half-on manner, and have a narrow range of application. It's an interesting idea, but they are by no means to be considered a general replacement for fuses. This was one of those all too rare instances where I was able to learn from others' mistakes, rather than my own.

Reply to
Palinurus
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I don't know much about polyswitches. I think it only works as fast as it's temperature rate of rise. A chunk of polyswitch material doesn't instantly heat up.. D from BC

Reply to
D from BC

Unfortunately your confident assertion that carbon resistors always blow open circuit is the dream. Enjoy it while it lasts.

-- Bill Sloman, Nijmegen

Reply to
bill.sloman

On a sunny day (Wed, 27 Jun 2007 10:16:07 -0700) it happened snipped-for-privacy@ieee.org wrote in :

Your reading disability is such that you missed out on a whole lot of conditions, perhaps you were sleep reading. RINGGGGGGGGGGGGGGGGGGGGGGGGGGGG

Reply to
Jan Panteltje

conditions,

Dream on. Reality has a tendency to ignore engineer-imposed conditions.

-- Bill Sloman, Nijmegen

Reply to
bill.sloman

On a sunny day (Thu, 28 Jun 2007 05:01:46 -0700) it happened snipped-for-privacy@ieee.org wrote in :

conditions,

Dear Bill, I do not want to get into a fight about this. Of course you are 100% right that reality may ignore your conditions. But I realized only late last nigh, - just before falling asleep - the greatness of the event you witnessed 30 years ago. It hit me (like a ton of bricks) that you witnessed the 'body temperature carbon superconductor'. Now that is good for a free ticket to a northern country to receive the Nobel.

May I humbly suggest you cross-post your carbon experience to sci.physics, as many people there are desperately looking for just such a thing, and will be more then happy to nominate you, or even claim they were first. Some other great names of observers come to light : Pons & Fleischman for example, who also observed Nobel stuff and are still working very hard to reproduce it.

What will you do with all that prize money?

Reply to
Jan Panteltje

conditions,

After three remarkably skeptical postings from you, this comes as a surprise.

My reading must be disabled - I though you were referring to conditions that you had specified.

greatness

carbon superconductor'.

There was a voltage drop, and some heat dissipation so it wasn't superconductivity. Like I said, the current seems to have concentrated itself into a narrow channel, in which the carbon was very hot, with a correspondingly low (but non-zero) resistance.

more then happy

Since the target audience could expected to read my account more carefully than you have, they would immediately detect that the event did not involve superconductivity.

example,

When I was a post-doc in Southampton, from 1971 to 1973, I met Fleischman - he was professor of electrochemistry there at that time. I can't remember a thing about him ... I don't think it would be all that hard to reproduce the effect that I saw. I've got Colin hunter's address somewhere, and he could probably tell me how he managed to set up the hot channel in the carbon film - he'd got one of the apprentices to spend a couple days working out out how to initiate the channelling reliably before he went to trouble of dragging the engineers around to see the hot channel in action.

I'll save worrying about that until there is a chance that I might win it.

-- Bill Sloman, Nijmegen

Reply to
bill.sloman

conditions,

greatness

carbon superconductor'.

more then happy

example,

A ten megohm resistor makes an ideal fuse as you will never have to replace it.

--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com

Please visit my GURU\'s LAIR web site at http://www.tinaja.com
Reply to
Don Lancaster

Unless your equipment happens to be somewhere close to a lightning strike. Given a sufficiently high voltage difference across the resistor, it is possible to destroy even a 10M part.

Let me tell you about 100kV scanning electron microscopes and Nijmegen University's system for making very high transient magnetic fields ...

-- Bill Sloman, Nijmegen

Reply to
bill.sloman

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