Cutting off a diode's pin?

[samwhiteUK]

Hi all,

I was wondering, if I find out that the diode I have bought is case negative, which ATM I believe it is, can I cut off the negative pin, or at least shorten it, in order to bnetter fit my host, and use the case pin as the negative pin? Is that what case negative means? Or does it mean that I should short the pin to negative myself?

My understanding is that a case-isolated diode can have the case pin shorted to either positve or negative, and then connect that to the host in case it is difficult to connect the corresponding pin on the driver to the host. Is this correct?

If this is the case, then working on the same logic, if a diode is case-negative, I can either attach the negative of the diode to the driver and connect the driver to the host, OR I can connect the positive of the driver to the positive pin of the doide, and connect the case of the diode to the host, as this is also negative. Am I correct?

Thanks for the help,
Sam

 

[Things]

Depends on your driver. You'll find there are 2 different types, highside and lowside drivers. If it's a highside driver, then you can use the diode case as negative to the host straight to the battery, then driver between the battery and positive pin.

However, if it's a lowside driver, you'll need to somehow get the driver between the negative of the battery and the diode, which can be an issue with case negative or positive diodes.

 

[samwhiteUK]

LM317 driver, so I'm assuming it's highside

 

[Things]

Correct, so yes, you can just cut off the negative diode pin and use the case as ground. But I'd doublecheck first that it is actually case negative, just check for continuity between case and the negative pin. A lot more difficult to get the pin back on if not

 

[samwhiteUK]

That's great, exactly what I was looking for! It's my first build, the diode cost ~$10, so not extremely expensive, but I obviously dont want to waste money, no matter how much/little!

 

[The Lightning Stalker]

I have seen a freakish case where the diode was not making any contact with the case whatsoever.
Pretty rare though it does happen. Pressing out partially and back in fixes this.