Wondering if a computer driver can potentially be damaged by incandescent test light in rush current? A 200mA incandescent test light can have maybe 800mA or more cold start in rush current. Isn't that somewhat of a concern when using a test light to test computer driver outputs (as discussed on page 12 in Section 3 of book)?
Potentially? I'm no engineer, but I believe it's a non-issue because the in-rush period is so brief that the driver never has a chance to build up significant heat from the extra current.
For example, most fuel pumps and blower motors easily exceed the rating of their fuses when first energized. But the fuses don't pop because they never get hot enough to burn.
What the driver controls would be important, too. An O2 heater? They draw over 1A when cold anyway. An EVAP solenoid? Probably 500mA or so, so briefly seeing 800mA is no biggie.
Nearly all drivers on an ECU drive some type of electromagnetic induction device ie. solenoid coil or motor, the extra initial in-rush on this type of device is much much greater than any kind of tungsten light bulb.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
I'm still not sure about this. Everything I read says that the inductance of a DC coil (combined with it's resistance) actually limits the in rush current of a DC solenoid (creating more of a soft start type current flow). And aren't most automotive motors controlled thru relays? So it would seem like most PCU output driver transistors maybe aren't really exposed to large current spikes (like that of a tungsten filament) in normal operation?
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