[SML] Source 4 Power and LED Cabling

[Dan Sheehan]

Very rough estimate, cold (room temperature) R of a tungsten filament
is about 1/10 the R at full rated power.

Thus a 600W lamp draws 5A at 120V, the hot R is 24 ohms,
cold R is someplace near 2.4 ohms.

Inrush current can start near 50A, very quickly drops off.
Most common circuit breakers are designed to handle this.

Charging capacitors in a power supply,
or starting a heavily-loaded electric motor,
are different ballgames.

Nichrome resistance heaters (toaster, hair dryer, baseboard heater)
have maybe 90% of hot R when cold...
but their "hot" isn't white-hot like a lamp (at least not for long !)

Small children's resistance to compliance with parental instruction
varys with instantaneous food content.


-- 
...Dan Sheehan
Fixer of things that break
Saddleback,Maine must NOT become a Lost Ski Area
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