| [ Total Views: 423 | Total Replies: 6 | Thread Id: 40135 ] |
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 seagull
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| posted on June 5th, 2005 at 01:16 AM |
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why have a relay fitted with resistor ?
does it stop back feed ?
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General_Failure
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| posted on June 5th, 2005 at 02:46 AM |
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Depends on where the resistor is and what it's used for. Can you give us a diagram?
Taking a totally uninformed guess, it may be to stop the source of the switching current being pulled to ground..or it could be an open collec....oh.
VW, not electronics. Sorry. Diagram please :P
Anyway, you usually use a capacitor to help with damping spikes and smoothing off abrupt terminations of power. Resistors provide balance to the force
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bus914
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| posted on June 5th, 2005 at 10:07 AM |
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Some times they put a multi mega ohm resistor across the relay coil, because it, as coils do, generates a spark when its field collapses. this
resistor grounds the spark, while not allowing any significant current flow under normal operating conditions.
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BajaChris
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| posted on June 5th, 2005 at 12:06 PM |
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Are you sure it's not a diode?
I was taught to use diodes for spike suppresion, though I can't think of any reason you would need to use this on a vw
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General_Failure
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| posted on June 6th, 2005 at 09:50 PM |
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I tend to use capacitors. They soak up all the surging electrons. That's on the main current, not the switching current. Put a cap across the
switching pins and it may be a while before your relay turns off.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
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BajaChris
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| posted on June 7th, 2005 at 12:31 PM |
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It's just occured to me that it could be there to prevent radio interference from the switching contacts.
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Purple Martin
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| posted on June 7th, 2005 at 02:27 PM |
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| Quote: | Originally
posted by BajaChris
It's just occured to me that it could be there to prevent radio interference from the switching contacts.
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That would be by damping sparks, wouldn't it? If so, makes sense to me.
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