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catman

How often does this happen....or am I just cursed?

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Just now, andyr said:

 

I'm well aware of all you said, Peter - that's why I asked "is there a similar device for opamps?"  :hmm:

 

Andy

 

No there isn’t, 

 

the best thing to do before plugging it in is to ensure with a multimeter that no DC is present at the output before you go plugging it in to anything else.   Then if you have a scope and a generator you can work out the gain.  Usually inverted Opamps gain is usually RF/Rin.   Non inverted gain is 1+ Rf/Rin.   

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1 hour ago, catman said:

G'day mate, well you are perfectly right but in my general sense of trustfulness, I honestly didn't think that a brand new op amp would be faulty, but obviously I was wrong!  Regards, Felix.

Correct, there are no CMOS in an NE5534. It’s all BJTs see PDF in my above post.

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27 minutes ago, iant said:

Felix,do you use an antistatic wrist strap?

It's easy enough to kill an opamp with the odd stray "zap".

As a Telstra tech we had it drummed into us "use antistatic precautions" especially when handling CMOS boards.

I cringe when I see the local Jaycar staff handling semis without any consideration for antistatic measures.If it doesn't kill the device straight away it may well shorten it's lifespan long term.

Before you go around recommending anti static straps or any thing anti static,  never trust them!   Meter it out on a MM and you’ll be surprised that even some are not what they seem to be....  Never use an anti static strap or anything suggesting that’s it is anti static until you have meter it out, test the anti static claims 1st before you go trusting it. some are BS even from places like E14 or RS or Digikey. 

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8 minutes ago, Addicted to music said:

Before you go around recommending anti static straps or any thing anti static,  never trust them!   Meter it out on a MM and you’ll be surprised that even some are not what they seem to be....  Never use an anti static strap or anything suggesting that’s it is anti static until you have meter it out, test the anti static claims 1st before you go trusting it. some are BS even from places like E14 or RS or Digikey. 

Radio Parts  actually sells a Wrist Strap Checker.Recommended resistance for a properly functional wrist strap is 750Kohm-9Mohm.

 Low ~750kΩ; Good 750kΩ~9MΩ; High 9MΩ~

Edited by iant

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17 minutes ago, iant said:

Radio Parts  actually sells a Wrist Strap Checker.Recommended resistance for a properly functional wrist strap is 750Kohm-9Mohm.

 Low ~750kΩ; Good 750kΩ~9MΩ; High 9MΩ~

If me, I’d be still metering it out to ensure that they do what they are intended to do....like I said never trust them.

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After building PC's for years, I very quickly learned about ESD early on, walk out of a few stores after seeing CPU's and RAM sticks and other hardware handled incorrectly.


Edit: wasn't going to buy something for it only to fail after 1 week, 1 month or 1 year down the track due to incorrect handling in the store.

Edited by Muon N'

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22 minutes ago, Addicted to music said:

If me, I’d be still metering it out to ensure that they do what they are intended to do....like I said never trust them.

Fair enough and I've just listed the recommended values,anything up to 9Mohm.

Edited by iant

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7 minutes ago, iant said:

Fair enough and I've just listed the recommended values.Not sure what your problem is?

The problem is obvious,  they don’t measure what they say they do, some I have tested to be full open even with a MM that has a 20M range....  just be careful when you use them, take my approach and never trust them especially with your own gear not so much on the stuff at work but that’s where I discover that a lot of these antistatic straps work was providing do not work as claim. I actually discharge myself with ground b4 I go handling pcb..  I don’t even take the pcb out of that antistatic wrap, I place the package so it’s grounded too before I pull the pcb out b4 installation...  

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3 minutes ago, Addicted to music said:

  I don’t even take the pcb out of that antistatic wrap, I place the package so it’s grounded too before I pull the pcb out b4 installation...  

Yep that's good policy.I always work with a properly grounded antistatic mat on the workbench as an extra ESD precaution.

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I always ground myself first also, and handle PCB's by edges, avoiding connectors, IC's and tracks completely.

I don't use a strap which means I have to take extra care at all times. I have been known to wear surgical gloves in some situations.

gloves.jpg.495e94b5e5e656e0d42027f097e27511.jpg

 

Can worry some if they walk in on me at the wrong time :D

 

Edit: Always tempting to say "Oh! I have been expecting you!"

Edited by Muon N'

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