![\"\"](\"https:\/\/www.paleotechnologist.net\/wp-content\/uploads\/2011\/10\/scorched.jpg\" "\\"Breadboard")
<\/a>High current = high temperatures = bad. (Click for larger.)<\/p><\/div>\n
This kind of failure, though, demonstrates a valid diagnostic technique (albeit one taken to destructive extremes in this case): All else being equal, a conductor will become warmer when carrying more current. For example, it’s evident from the above picture what the high-current path was — through the first and fourth relays, which make up one half of an H-bridge setup. For some reason, the final part of the path — the short green wire at the upper left — didn’t get cooked, although it was carrying just as much current as the rest of the circuit. A different formulation of plastic, perhaps…?<\/p>\n
Given an IR thermometer, this resistive heating effect (hopefully with less extreme temperatures) can be used to determine which chips are dissipating more power than others in a circuit. It can also sometimes be used to determine which device is causing a short — without risking burning your fingertips. Simple IR thermometers are available for around $20US<\/a>; I picked one up a while back and keep finding new uses for it.<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Burnt plastic is one of Nature’s ways of telling you “DON’T DO THAT!” Continue reading