4 ms·

Stick some steel wool across a 9v battery and you'll get what I mean. It's the current, not the voltage. Video for you: http://www.youtube.com/watch?v=MWuJokR

• bigiain 13y ago
  Yeah but - these are powered by CR2032s - typical capacity is around 200 milli Amp Hours, and they're usually rated at a maximum continuous current of 1mA with 10mA "pulse" capacity. That's a continuous 0.003W or pulses of 0.03W. It's probably not _impossible_ to start a fire with a pair of CR2032s, but you're going to have to set it up that way on purpose – the chance of "accidentally" creating enough heat to set non-intensionally-incendiary materials alight is low enough to be ignored. (Note, I carry a pair of these cells around in my pocket - an LED light attached to my keyring. These cheapo lights rely on the internal resistance in the battery to current limit the LED, with a white LED across a pair of cells, the battery's own resistance is enough to keep the current down under the "let the smoke out" limit of the LED - it might be more than 20mA, but it can't be heaps more.)
  • csmuk 13y ago
    They are powered by that here. The inevitable chain will be either the battery will go flat in minutes or there will be brown outs which are inevitable if you have LEDs and non MSP430 grade CPUs hanging off it. The result of this will be inevitably, judging by usual projects I've seen, either stick a PP3 in with a regulator or even worse chuck a cheap LiPoly on it. Then you're in trouble/on fire.