Off topic electrical question about diodes.

[SER240Z]

If I remember correctly when everyone was talking about the switch to an internally regulated alternator somebody mentioned that the diode prevents power from traveling back through the wire?

Are there different sizes or ratings? What would be best for automotive light wiring?

Thanks in advance.

Scott

[montoya_fan01]

One of the former members of classiczcars (bambikiller240), has an article about the change to IR alt which includes the info your asking about. It used to be in the Tech forum, but he pulled it, and now offers it directly to interested people. I'd suggest contacting him by PM for a copy of the instructions.

[Arne]

I've got a copy of bambikiller's info, and while it addresses the alternator swap well, it doesn't go into detail about diodes for other purposes.

But I'd say that the same diode I used for my alternator swap should work fine for lighting mods as well. It is an NTE part #NTE506, the generic number is 1N5062.

[montoya_fan01]

i didn 't realize he was asking about diodes for other purposes. I thought he meant "light duty" wiring.

can't imagine why one would need or want a diode in wiring for lighting purposes.

[Arne]

Oh, I can. A 240Z for example, has 6 bulbs in use as brake lights (3 per side). If I wish to wire one of the left ones for use as a rear fog light (as is common and required in Europe), a diode would allow me to manually switch on one bulb without lighting any of the others. Many other uses can be imagined too, regarding better ways to enhance the visibility of the car without adding lots of extra wiring and relays.

[montoya_fan01]

I don't think all 6 are used as brake lights (at least they aren't on my 240Z), and considering how bright they are, and considering the lense it/they will shine through, one (or even all 6) won't do much as a fog lamp.

your imagination is far more fanciful than mine!

[SER240Z]

Thanks for the responses, but am i correct then that it will keep the current going one way only or am I still misinformed?

Thanks Again,

Scott

[Arne]

A diode allows current to flow in one direction only.

[a7dz]

Think of a diode as an electronic check valve.

[Arne]

I don't think all 6 are used as brake lights (at least they aren't on my 240Z), and considering how bright they are, and considering the lense it/they will shine through, one (or even all 6) won't do much as a fog lamp.

I happened to re-open this thread, and I now know a bit more about the brake lights on the 240Zs. On the series 1 cars (like mine), all six bulbs in the red sections are used as brake lights. In the later 240Zs, the inner bulb on the top is only used as a tail light. So most 240Zs only have 4 bulb brake lights. That is what confused the issue, I'm sure.

And as for their use as a fog lamp, for the most part that is exactly what the rear fog lamps in Europe are - a brighter tail light that can be switched on in inclement weather to enhance the visibility of your car to people following you.