Protecting ICs

[Rafa]

Hi everyone:
I would like to know if thers any way of protecting ICs on the LXH2 marshall simulator, I have burned some TL084 so its becoming expensive.
Last night a TL084 actually burned up smoke was from it, I pluged it the other way round, the V+/- were inverted.
Thankssss
Rafa
Sorry for my english

[Seljer]

Using sockets saves them from any harm you may do when soldering
other than that you just have to make sure everything is connected right and connected in the right direction. The circuit having polarity protection (the thing with the diode) will possibly save you from a power supply thats got the wrong polarity, but you have to make sure that all your ICs are inserted correctly yourself 

[Gilles C]

First, the only way to make sure you don't make this kind of mistake again is to identify the sockets and the ICs with a small white dot for the pin #1 of the IC.

You can use this kind of correction pen for that

http://www.walgreens.com/store/product.jsp?CATID=100421&navAction=jump&navCount=1&id=prod17744

I did that a couple of times both for myself and for a circuit I gave to a friend that wanted to swap the IC sometimes. It is also useful for me when I cut a 14 or 16 pins IC socket to make a smaller socket for an 8 pin IC or a 3 or 4 pin socket for a transistor.

Gilles

[Rafa]

Hi:
I Knewit was the other way round I did it to see what happend
Rafa

[Rafa]

I dont recomennd it
I thoguht that it was the same as inverting polarity, because that the only that changes when you turn it 180º is the V+/-, anyaway thanks a lot Ill have to install taht diode

[R.G.]

I Knewit was the other way round I did it to see what happend

Almost every known IC will do the same thing when you reverse the power supply. The parts of the IC inside are insulated from the substrate and each other by reverse-diode diffusions. Turning the power supply around converts the entire IC into one massive forward biased diode, so the current that comes through is not limited by the IC, and unless some miracle happens, the IC is burned out within a fraction of a second. Only the tough ones last long enough to smoke first, then die.

Putting an IC in backwards instantly converts it into a Darkness Emitting Diode, also known as a DED.

[Rafa]

Thanks RG so probaly al the Ic are damaged, because the only 2 diodes in the circuit are for clipping I think.
Rafa

[Seljer]

R.G. is talking about the actual insides of the IC (you may have seen some schematics if you've ever gone and looked up the datasheet for an opamp), theres an entire circuit within that black chip