Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electrical Leakage from Cars?

  1. Mar 10, 2006 #1
    This is going back a ways, but we used to have a car (I think it was the '89 Camry) that seemed to affect our streetlights. The lights often seemed to go on or wink out as we passed under them.

    Was this one of those you-wouldn't-see-it-if-you-weren't-there things, where it only seems to be related to your presence because you were present to observe something that's always occurring anyway, or can a car actually affect a somewhat unstable electrical system like some cheap streetlights?
     
  2. jcsd
  3. Mar 10, 2006 #2

    Cliff_J

    User Avatar
    Science Advisor

    The ignition system in gasoline cars pulses a very high voltage down the spark plug wires to allow the electricity to jump the gap at the end of the spark plug.

    If the spark plug wires are not properly designed and shielded (or old age has caused them to breakdown), they can cause all types of interference with electromagnetic devices like TVs or radios. If the street lights had a circuit on them to determine when to turn on/off, its possible the circuit (or a sensor) wasn't shielded and when presented with the interference it behaved oddly.

    Its typically blocked by the metal body of the car, and if you look at older Corvettes (all had plastic bodies) they had an additional metal cover over the ignition distributor to help shield this noise.
     
  4. Mar 10, 2006 #3

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

    Well I've seen this before. It's not the electrical noise of the car that causes the lamps to go off. It's your headlight shining on or reflecting to the street lights daylight sensor. If you notice, you can see the photoelectric sensors that are usually mounted above the lamps.
     
  5. Mar 10, 2006 #4

    WFO

    User Avatar

    Precisely!
     
  6. Mar 10, 2006 #5

    Cliff_J

    User Avatar
    Science Advisor

    Didn't Einstein have something to say about keeping problems simple? :smile:

    I would have thought it logical to mount an ambient light sensor outside of the range of headlights for that reason, but then again maintenace would be more difficult and maybe the car in question had headlights that were misadjusted?
     
  7. Mar 15, 2006 #6
    Well, the headlights were perfectly normal, I think, but that sounds like the answer. Duh! Although I don't see it happening now with our other cars, it could just be a different kind of headlight that doesn't trip the light sensor.

    I still think the electrical leakage idea is cooler, though. :)
     
  8. Mar 15, 2006 #7

    DaveC426913

    User Avatar
    Gold Member

    I am crushed. Disillusioned.

    I have been sure for many, many years now that I am the God of streetlamps, and they have been bowing to me.

    Now I'm finding out it's not just me?
     
  9. Mar 16, 2006 #8

    WFO

    User Avatar


    Actually it IS you. The above was just to placate Gnophos. :biggrin:
     
  10. Mar 16, 2006 #9

    DaveC426913

    User Avatar
    Gold Member

    : relieved :
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Electrical Leakage from Cars?
  1. Electric cars (Replies: 11)

Loading...