[larry.said]

Hello All!

Haven't posted in a long time, but it's great to be back with so many audio enthusiasts.

The reason I'm writing today is because I'm concerned about handling semiconductors, specifically transistors. I had bad experiences with my PPAv2 which, I believe, can be linked to the mishandling (or mis-soldering if thats a word) of transistors. I am currently building a beta22 and would like to clear up this matter before I destroy such a worth amp

Are transistors sensitive to static? Can I handle transistors with my bare hands or do I need to use pliers? Is it okay just to touch the semiconductive material (black cover) ?

Thank you in advance!

 

[cobaltmute]

I can't answer for certain, but my local shop just packs transistors in plastic bags. I've always ended up with problems from them. I've always ended up replacing them with ones from Digikey, who tends to pack them in antistatic bags.

I haven't taken any precautions in soldering them in (just take them out of the bag and go), but if you were concerned about static, you could wear something like this:
Desco Grounding Wrist Strap

 

[larry.said]

Instead of the wristband, could i just touch the return ground of my AC outlet (as safe as that may sound)

 

[DKJones96]

If the transistors are in an anti-static bag you don't have to worry about them even if you are carrying a static charge.

I don't think I've ever killed a transistor with static but all my transistors from Mouser come in some sort of anti-static bag.

 

[Uncle Erik]

Yes, static can kill transistors.

You'll want to wear a grounding strap when handling them or, at the very least, discharge yourself before handling them.

An ESD-safe soldering iron is a good choice, too. And be sure to leave your chips in their anti-static bags (do not use ordinary plastic bags or bubble wrap) until you're ready to use them.

And people say tubes are delicate....

 

[Nick 214]

Agreed all the way around on the anti-static baggies, Newegg ships basically everything in them, they have a purple-ish tint to them.

Also, does anyone here use an anti-static mat?

NK

 

[jnewman]

Just a note - the antistatic bracelet by itself doesn't really do anything. You've got to connect it to ground.

 

[tomb]

Transistors are pretty robust. I have not found them to be overly-sensitive to static. Vendors ship them to me all the time in non-static bags and I've never had one go bad - that includes extensive handling with un-grounded fingers, etc.

You mentioned soldering - most will be destroyed instantly if you solder them in backwards. Power transistors can usually withstand a bit of backwards-soldering if you get to them before they burn, but it may not be worth the trouble to save them.

You also mentioned the B22 - MOSFETs are an entirely different matter. The MOSFET itself contains a capacitive charge capability. For that reason, they are super-sensitive to static. When bought in bulk, they're often packaged in tubes like opamps - it keeps the leads separated and ensures that they don't touch one another. In fact, most should not be sold without testing, first - they are that prone to static damage. Handle them very carefully with respect to static.

 

[amb]

JFETs can also be ESD-sensitive, but not as much as MOSFETs. BJTs are the least static prone. Passive parts are usually not ESD-sensitive. I've never killed any parts just "handling" them normally, and I never bothered with wriststraps and such. But then I don't do something like holding bare parts out of their anti-static bags and walk around on rubber-soled shoes and static-prone carpeting...

Just keep the parts in their packaging until you're ready to solder them, and don't overheat them. If you're paranoid, touching something that's grounded helps (such as an exposed metal surface of your AC-powered computer case), but if you have to get up and walk a distance to do that, then it probably isn't worth the bother.

 

[larry.said]

So, in conclusion...keep transistors in anti-static bags until ready to be soldered.

When soldering it is OK to touch the transistor to place it on the board.
But it is also possible to ground yourself before doing so...

 

[linuxworks]

sit down, touch something metal and grounded to discharge yourself

then touch all the parts you want. go nuts; have a ball. they won't get ruined.

just avoid moving around (one rule). if you do, de-zap yourself and you're good to go.

I often have a pc computer near me. that has metal going to ground. I touch the metal case, then I'm 'good to go' after that. that's really all the esd training you need

 

[larry.said]

thanks linux, i like that.

 

[m1abrams]

My work lamp is a metal lamp with a 3 prong outlet. The lamp is properly grounded so by turning on my lamp I ground myself

.

So if no computer case nearby to touch check other AC items, if they have a metal case chances are that case is grounded. So lick before touching anything

As AMB said if you have to move out of your seat to do this ground procedure then it is pointless because you will build up a charge in the process.

 

[Nemo de Monet]

Also, don't let your cat(s) play with your semiconductors, not least because you'll never find the parts again afterwords.

Cats: adorable, lovable, co-dependent walking static death bombs of the electronic apocalypse.

 

[ShinyFalcon]

Touch bare metal (shiny or dull silver)! The backside of your computer case should suffice. Touching the outside of a metal case doesn't guarantee a connection to ground, because of the paint, anodizing, etc.