When is a diode not a diode....

CoggesRailway

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I am setting up two batteries two discharge in paralell. However I need to have a diode in order to prevent any risk of one discharging to the other. I just want a diode (one way valve in my speak) with a given amp rating. Nothing more than that. But every jolly diode at maplin is to clever for it's own good. Again terminolgy is confounding me. any ideas, links?
 

Gizzy

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A couple of bog standard 1N 4004 diodes will do the job.

High current rating and sufficient for a couple of 12 V batteries....
 

Neil Robinson

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Re:When is a diode not a diode....

CoggesRailway said:
Thanks chaps. Gizzy http://www.maplin.co.uk/1a-silicon-rectifiers-46385 is this the job?
Could you look at the specifications tab and tell me if that will be OK for 3a running.

In short no, the clue is in the description; 1A diode. For 3amps you need a 1N54xx or similar type.
I'll look at Maplin's site and edit this post with their details shortly.

Edit, go for Maplins' code QL84F, the 1N5404.
If you local shop's out of stock of these then the 1N5406, 1N5408 or 1N5402 would be fine.
 

Rod Fearnley

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Re:When is a diode not a diode....

When I wanted to do that, it was recommended that I use a Shotkey Diode. I bought them at Maplins. But, I never did get around to using them.
 

CoggesRailway

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Re:When is a diode not a diode....

Many thanks especially neil for the maplin code. The 1a was what i was worrying about!
 

beavercreek

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Re:When is a diode not a diode....

Hi Ian
The IN5404 diodes are what I use for my shuttle line. My current shuttle can take 8amps so the diodes that I had for the LGB shuttle (1 amp) were not 'beefy' enough so I substituted with the IN5404 and all is well.
 

Neil Robinson

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Re:When is a diode not a diode....

beavercreek said:
The IN5404 diodes are what I use for my shuttle line. My current shuttle can take 8amps so the diodes that I had for the LGB shuttle (1 amp) were not 'beefy' enough so I substituted with the IN5404 and all is well.
The 1N5404 diodes are rated at 3A. The shuttle only uses the diode for a short time at the end of each trip so it can exceed the maximum continuous rated current somewhat in this application.
For new installations or any future replacement I suggest you consider at least the six amp rated P600D or P600J versions.
 

beavercreek

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Re:When is a diode not a diode....

Hi Neil
My needs for loco with lights and smoke etc. were about 3 amps so I replaced the LGB shuttle (and a subsequent Aristocraft one...max 1.5amp) with an 8 amp one from Fleabay and swapped the diodes for the IN5404s as I was not expecting to go above the 3 amps. But as you say it might be prudent to go up to the P600 series as you never know............