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Short circuit

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hrickards

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Hi,

I'm new to electronics and earlier today I attempted to build my own diode logic OR gate. I have two AA batteries in series powering my breadboard, with the conncection between the two AA battery holders taking place in a spare part of the breadboard. I thought I'd build everything correctly, so connected the power. Nothing happened, but I realised I missed the connection between the two diodes and the output. I removed the live and neutral (red and black, I may be getting the names wrong) wires from the power rails of the breadboard and started to get the right size jumper out to add the missing correction. While I was doing this I started to smell burning, and noticed that the two wires I had just removed were touching each other and creating a tiny amount of smoke, creating a short circuit, like the following.
Battery A => Battery A live => Battery B neutral => Battery B => Battery B Live => Battery A Neutral => Battery A

I quickly removed the two touching wires, and disconnected the battery holders. The whole thing must have only been about 10 seconds.

Where the two ends were touching, part of the red plastic has been burned off, partly onto the black plastic.

Is it possible I've harmed anything other than the batteries and battery holders. Is there damage to the batteries (I can replace, but I don't currently have any spare ones so I'd rather not) and/or the battery holders (I've got another 3 just lying around so I can easily replace them)?

Thanks
 
First of all, welcome to the forum.

It is not correct to refer to battery connections as "live" and "neutral", these terms should be used in referring to mains supplies. (There are exceptions but lets keep it simple for now).
Just refer to the positive (+ve) and negative (-ve) when referring to batteries.

Just by coincidence, before logging on the the forum just now I was testing a couple of AA batteries, a short circuit test showed that they could deliver 6amps, that can make thin wires quite warm!.

So what was damaged in your case, probably not much.
The batteries will have lost some of their usefull life but are probably quite servicable for a long time yet.
The wire had its insulation melted, not the end of the world, just trim it off wirh a knife or side-cutters.
The battery holders, are they all melted out of shape? probably not, are the batteries still making good contact? yes they probably are.
So, no problem there then.

Another bit of pedantic terminology, strictly speaking one individual AA "battery" is really a cell, not a battery.
Only when you connect two or more cells together do they form a battery.
But dont worry, everybody uses the term battery for a cell.

Last of all, see my signature line. Appropriate in this case maybe.:)

JimB
 
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