6 ms·
Measuring Feline Capacitance
- stolio 12y agoOr, say a cat's roughly a sphere of radius 10cm, capacitance of an isolated sphere is C=4(pi)(epsilon_0)(radius) = radius/k_e = .1/(9x10^9) = 11 pF Ballpark. YCCMV.
- ChuckMcM 12y agoI am not a cat fan, or a squirrel fan. I do know from observing squirrels crossing power lines that their dielectric constant is significantly lower than that of air, but I've never figured out how to determine it strictly from observation without actually doing an empirical measurement.
- monkeymagic 12y agoSquirrels act as inductors in DC circuits. Only once though. There's a high current surge that drops to zero as they turn rapidly into a carbon resistor!
- walshemj 12y agoa bit like the NED Noise Emitting Diode - makes a lound noise once
- monkeymagic 12y agoHaving sat there, as a teenager, with a whole bag of 1N4148s and a mains test block, can confirm :)
- kabdib 12y agoWe had a number of network outages at Apple due to squirrels inserting themselves in the NOC's power lines. Note to self: Don't design any circuits that incorporate these animals. Squirrels make terrible fuses.
- monkeymagic 12y agoSo true. We had a different problem. They chewed through the fibre cables between our offices to get the fiberglass sheath for their nests. Eventually they ran Ethernet underground because they'd have broken it again in a couple of weeks.
- kabdib 12y agoWhereupon: Moles :-)
- walshemj 12y agoI imagine getting the kitty to hold still while you attach the clips from your ESR meter might be the tricky part
- omegaham 12y agoI laughed at one of the answers mentioning this: "Connect one end of cap to ground - one end of cap to cat. .... ( How 'to cat' is achieved is left as an exercise for the reader.)"
- tonteldoos 12y agoI imagine this experiment may not have a high level of repeatability.
- amelius 12y agoNext question: how much energy can it store, until the capacitance breaks down?
- gweinberg 12y agoI don;t think there's a well-defined answer. The "capacitance of a cat" is actually the capacitance of the cat and some other condictor. For purposes of calculating the cat's capacitance you can treat the other plate as a grounded sphere at infinity. It doesn't really matter., you'd get pretty much the same answer with a grounded sphere a few feet away. But for figuring out how much energy you can store before you get an arc, it's all about how far away the second conductor is.
- pvaldes 12y agoI'm feeling the desire to build a cat scratcher with multimeter right now... maybe with some nice bulb leds aligned forming the meow! word. muahahah... is alive!!!
- anotherevan 12y agoThis reminds me of a throw-away comment a lecturer made once while discussing the maintenance of telecommunications equipment. He dryly observed that, “Burning technicians don’t smell very nice.”
- kjs3 12y agoDo we have to assume a spherical cat?