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View Full Version : newbish question, what's the "47 ohm 1/2 watt resistor heater" usefull for?

NewJerseyTN
04-17-2007, 08:36 PM
I have in mind a project where I would like to generate some small amounts of fog.· I am wondering if this heater would get warm enough to fog glycol (the stuff in fog juice).· I have a small hand held fog maker that I was going to canabalize but this part might give me more flexability.

Loopy Byteloose
04-17-2007, 10:42 PM
Using Ohms law E=i x r and P = i x e; you will soon begin to determine how much heat you can generate under optimal operation.[clue: 1/2 watt].

Considering the fact that you might be able to handle a 5 watt light bulb with your bare hands, it ain't much heat.

I really have to wonder if this is just a plain old 1/2 resistor and not really a heater that you are playing with.

[another clue: how many watts are in a British Thermal Unit or BTU?]
[yet another clue: how many watts does it take to boil a liter of water?]

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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········

···················· Tropical regards,····· G. Herzog [·黃鶴 ]·in Taiwan

NewJerseyTN
04-17-2007, 10:52 PM
that's a good point Kramer, I hadn't thought of that (about the blub).

Steph Lindsay
04-18-2007, 02:28 AM
Yes, the 47 ohm 1/2 watt resistor heater is just that, a·resistor attached to pluggable leads for use with the Industrial Control parts and text.· There is a picture on the product page:

http://www.parallax.com/detail.asp?product_id=800-00028

In the·text it is·used along with a temperature probe inside a drilled film canister as an incubator, which is cooled by a 12V fan, all connected to a Board of Education and controlled with a BASIC Stamp program.· If you want to read about it, you may download Industrial Control here:

http://www.parallax.com/detail.asp?product_id=27341

BTW, it is being replaced by Process Control, an updated·and·improved version·from the same author.

-Stephanie Lindsay

Editor, Parallax Inc.

Loopy Byteloose
04-18-2007, 11:02 PM
Interesting - a 'micro-heater' application. I now see that this is a safe methodology to in-class presentation.

Since the current at 5 volts works out to roughly 100ma tops, I am quite surprised at the application. But everything is getting smaller these days.

Usually I am testing my circuit construction by touching all the 1/2 resistors to test for heat. If anything is hot, it usually indicates I have done something wrong.

The real beauty of the BasicStamps is that they are inherently much safer to experiment with.

I began to learn electronics at 12 years old with nasty 350volt tube circuits and lots of toxic stuff leaking from electrolytic capacitors. And of cource the T.V. put out 10,000 or more volts.

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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········

···················· Tropical regards,····· G. Herzog [·黃鶴 ]·in Taiwan