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Discussion Starter #1 (Edited)
Which Diodes do you use to protect your electronics when using 30/40A relays?

Thinking 1N4001.

Do you use Zener Diodes as well?

How do you like to wire them up?

Do you use them?

Sources:

http://en.wikipedia.org/wiki/Flyback_diode

http://forum.arduino.cc/index.php?topic=59131.0

http://www.electro-tech-online.com/threads/diode-across-a-relay-1n4148-or-1n4001.20794/
"1N4148's have been used for decades across relay coils, and never been a problem."

Tiiiiiggghhtt..
http://honda-tech.com/showthread.php?t=1975159
 

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97 honda coupe
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How to tell if diode built it?

Multimeter will tell with continuity?

Waiting on 9Vs.
continuity checks wont work on diodes because they usually have a 1.6 (for sillicon) or .125 (lowest for schottky diodes) forward voltages. Anything under 1.6 volts will not short the circuit on a sillicon diode. You need a meter able to test diodes.

You can use a zener diode, but they ususally have a much higher forward voltage starting at around 2.4 volts, if that is an issue. Running current through the diode to a light would work to test a diode without a tester.

EDIT: i read up on what your trying to do, you definitly do not want to use a zener diode, the forward voltage is too high and may come on too late to actually help with the electrical discharge. I would stick with either schottky or silicon diodes.
 

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Black/Green Civic HB
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Yeah, no zeners. They are usually used to stabilize voltage in power supplies and such.

1n4001 should work fine ( and the fowar voltage is like 0.7v on these)

To test the forward voltage the best way is to use the diode setting on the multimeter, but a lot of the cheap ones can't test the higher forward voltage diodes
 

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94 Integra
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The diode is just to deal with the massive spike that can happen when the coil de-energizes. I won't go into the boring theory, all that matters is you use at least 1N4001. It is a 1 amp diode that can take a continuous 50 volt spike, or a very short, very high spike. You're dealing with the coil's power rating & spikes, not the load. They are very cheap. 1N4002 & higher just increase the voltage rating.
 

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93 DelSol S, 95 DelSol Si, 01 Odyssey EX, 04 CRV EX
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I generally default to 1n4004 just due to its readily availableness and wide application range.

1n4001 should be find for relays :)

Zener is more specific for RF applications if I'm not mistaken.
 

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Discussion Starter #9
Thanks guys, glad I caught this mod,

Any others you can think of needed to be done when Setting up DIY Relay/Fuse Box?
 

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My civic
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Clamping Diode

Check radio Shack, I picked up 4 on saturday for $4
 

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the artist formerly known as drexelstudent11
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zenier diodes work well for capping voltages, like say... if this was 1999 and you had a turbo honda with a hack fueling system and no EM and needed to keep the ecu from seeing about 0.0 psi on a stock map sensor ;)

(and didn't want to shell out the $60 or whatever that garbage ass missing link cost)
 

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My civic
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I used a 1A diode wired facing backwards IIRC.



I have a video of the spike somewhere in my build thread.
Looks like a clamping diode.
 

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Discussion Starter #15
Gotta love English.

You can call anything whatever you want and always be right with enough arguing.

I've always heard that called a Rectifier Diode.
 

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I think you may be mistaken. A Diode is part of a rectifier, which is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.

Hence why in an alternator, there is a diode rectifier bridge. Its a series of clamping diodes.

But honestly, in todays market you can probably buy either one. Adding to the confusion.

I just used 4 clamping diodes on my yota to run trailer lights from a 6 pin to a 4 pin.
 

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Good thing radio shacks are still around cuz I have to make a trip today to pick up some more diodes, resistors, and heat shrink.
 
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