Conrad Hoffman said:
Conrad -- you use this stuff in your long-john's to keep warm in those upstate NY winters? Like hooking up a car-battery to some ni-chrome wire for those Buffalo Bill's games?
I would not "ex ante" assume a value for a gate-stopper resistor in any event. There's an f3 owing to the input capacitance and gate resistance and it makes sense to poke around so that the f3's of the p and n-channel's match up.
Eva's right -- you can use a trace to current sense.
Looks like we're having the first wide spread freeze tonight. I don't resort to heating coils, but prefer the direct connection to the tongue method like John Lithgow (Lord John Warfin) in Buckaroo Bonzai. Direct resistance heating is always more efficient. I like the Manganin, and to a lesser extent, Constantan, because you can solder them without great difficulty. Nichrome (and the modern low tempco precision resistance alloys RO800?) have to be bolted or welded.
crimping to nichrome seems to be the most common connection method commercially next to spot welding. and the spot welded connections eventually fail from metal fatigue compounded by the dissimilarities of the metals and extreme thermal stresses. crimps eventually fail due to oxidation. there's no "perfect" way to connect to nichrome.
unclejed613 said:
Keithley uses crimping in the probes for their nano-voltmeters -- blow on a solder joint and you'll know why.
Don't tell the EPA, but I still have a couple coils of low thermal emf solder. I've never used it, but suspect it's full of cadmium.
My son needed a new darkroom thermometer when he was doing the yearbook in college so he went over to the chem department to borrow one. They gave him all their old mercury thermometers and said "don't tell anyone where they went".
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