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Which zener diode

Posted: Thu Mar 22, 2018 9:49 pm
by Anton
Hey, ppls. A friend of mine wants to put a pair of relays into his Toyota to switch his high power headlights. Recently the current draw (2x 60w bulbs, so 10a total load) melted the switch inside the indicator stalk, after which no headlights (although thankfully no fire).

I'm thinking a zenier diode would be good, to stop high currents flowing back through the circuit and maybe even into his ECU, but what voltage? Would 15v be ok, or should I go for 17v? I remember reading somewhere that +3v is a good rule of thumb, meaning that a 17 would be more appropriate, but my memory might be shonky. Or shcottky... :brows:

Re: Which zener diode

Posted: Sun Mar 25, 2018 9:02 pm
by Robert.m
I thought wiring the HP lights through a relay would be sufficient to avoid melting anything.

Re: Which zener diode

Posted: Mon Mar 26, 2018 12:29 am
by Anton
It is. I'm not worried about the lights melting anything once the relays are in, I'm worried about the voltage spikes that relays cause when their electromagnetic field collapses.

Re: Which zener diode

Posted: Tue Oct 29, 2019 9:14 pm
by acestu
Hi,

Just get a DC relay and base from city electrical it will allready have a snub diode on it, or if you allready have an AC relay what i normally use is a couple of 1N4001 rectifier diodes in parralel wired across the terminals, make sure the cathodes of the diodes (painted line end) are the same way round and on the posotive terminal, hope this helps

Stuart

Re: Which zener diode

Posted: Wed Oct 30, 2019 12:09 am
by Anton
He bought a pre-wired kit for this about a year and a half ago. Was cheaper than the individual components.

Re: Which zener diode

Posted: Wed Oct 30, 2019 9:15 pm
by acestu
Hi,

I replied to it and then realized how long ago it was

Stuart