moore at eds.org
Thu Feb 11 21:29:54 PST 2010
On Thu, Feb 11, 2010 at 9:04 PM, Christie Dudley <longobord at gmail.com> wrote:
> Nichrome seems to make sense if we were going to go with electric heat,
> which is probably a good idea for keeping the camera lens defogged/frost
> free. I wouldn't want to use it for much else, and also probably focusing
> on trying to get thermally insulative materials whenever possible. (Which
> means aluminum is right out.)
Well If insulation is enough but for longer flights we might need
> What would the purpose of the 555 chip be, though? I don't think the
> nichrome would work with PWM very well, although I might be mistaken. Then
> you'd have to have a circuit to drive the 555 and...
Yes I was thinking PWM, I see no reason why that would not work. 555
circuits are super simple.
> I understand a thermistor, if well-positioned, could be instrumental in
> controlling the current, but if you have a well-designed circuit to limit
> current flow, wouldn't the thermistor be all you need? What would the
> circuit you have in mind look like?
> Possibly using it in a wheatstone bridge or some other tuned simple circuit
> could be employed to good effect to run the nichrome, don't you think?
I don't really know. The thing about PWM is you could have it
basically 100% if you did not need the heat.
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