Re: Quattro Digest V2 #451

[rsco@lubrizol.com (Robert S. Cohen)]

>From: Scott=John=Mockry%Mktg%TM@banyan2.BV.TEK.COM
>
-snip-

>55/65W. Even with the stock bulbs I still was replacing the bulbs every
>12-18 months.
>
>Most bulbs burn out when they are first turned on (cold) due to low bulb
>resistance and the
>fact that the inrush current is something like 5-10 times the normal
>operating current. I have
>measured this using a current probe and an oscilloscope. This is also true
>for most household
>light bulbs.
>
>Previously I had gone several years without replacing any bulbs. I
>theorized that the shorter
>bulb life was caused by 1. (lousy bulb manufacturer) or 2. The relays I
>added had lowered the
>voltage source resistance enough that the inrush current was being
>increased. Eventually
> this burned out  the bulb sooner than when I had the stock wiring with
>all of the added resistance
>from the fuse box through the headlamp switch and out to the lights.

>Scott M.

Use a solid state relay. They are commonly available at electronics supply
houses (not Radio Shack). At least some of these (fairly) inexpensive and
(very) reliable devices are zero-voltage switching; meaning that when the
thing turns 'ON' the voltage at its output is zero, then quickly ramps up
to its input voltage. No voltage means no current and no attendant current
'inrush'.

Good Luck,
Rob

_____________________________________________________________________________
Robert S. Cohen         rsco@lubrizol.com       Lubrizol Corp.,
NewMedia Inc.           ^^^ preferred ^^^       29400 Lakeland Blvd  MS 228,
Cleveland, OH                 -or-              Wickliffe OH, 44092
                        rsc2@po.cwru.edu        voice 216.943.1200 x 2012
____________________________________________________________________________
_