Soldering a transistor: is it possible to blow it?

[MathGeek]

Is it possible to damage a regular transistor (plastic TO 92) by soldering with 55W iron? Somehow, my circuit is not working, and I was wondering if this could be a problem.

How about diodes, 1/4W resistors, and electrolyte caps?

 

[Nigel Goodwin]

Is it possible to damage a regular transistor (plastic TO 92) by soldering with 55W iron? Somehow, my circuit is not working, and I was wondering if this could be a problem.

How about diodes, 1/4W resistors, and electrolyte caps?

Yes you can! - soldering should be as short as possible, but modern silicon transistors can take a considerable amount of heat - soldering shouldn't take more than a second per joint (if that?).

 

[MathGeek]

Stupid me...

No wonder my JDM prog does not work anymore....

Oh, well, everyone is a beginner at first.

 

[JimB]

Yes it is possible to damage transistors, diodes and integrated circuits during soldering, but resisitors and capacitors are much less susceptible.

Many years ago (1960s), when transistors were the new thing, the advice was to use a heat shunt on the legs of the transistor when soldering it. This kept the heat from conducting up the wire and into the transistor. Imagine my horror when I saw a "wave soldering machine" for the first time. The components where inserted into the circuit board and it was passed across a bath of molten solder. I just could not equate this to the advice I had previously seen in various hobby magazines.

Back to your problem.
If your transistor is dead, consider the following:
Is the soldering iron properly earthed? If not the leakage current from the heating element is enough to kill the transistor.
Could you be generating static electricity in your working area? Consider the carpet first. You can generate thousands of volts of static charge just walking on the carpet. You may not feel it, but it will kill your transistors very easily.

JimB

 

[Someone Electro]

Static killing bipolar transistors ? That never hapend to me.CMOS stuff is highly sesitive to static but bipolar transistors are much more imune agenst this.

I once tryed how imune an LED is.So i fierd an piezo acros the LED a cuple of times and it worked normaly whith absolutly no signs of damege.

 

[Pyroandrew]

I've never heard of static damage to bipolar stuff!
Heat is a very easy way to bugger up anything. There are many view on soldering techniques, some say use lots of heat sinks, some say hot tip less time, others say cooler tip more time. I suggest looking at the recomendations of the manufacturer. In the datasheet there is almost always info on soldering tip temperatures and time you can expose it to that much heat etc.

 

[Someone Electro]

I remove the iron as fast at the solder melts.

 

[Exo]

How long did you solder the part?
I sometimes solder parts for over 15 seconds to get them out of multi-layer pcb's (parts tend to be realy realy stuck on those) and they always still work...

A normal error in your circuit is far more likely, unless you really cooked the part for a full minute or so :lol:

Also, a 55W iron is overkill, use something less powerfull

 

[Nigel Goodwin]

Also, a 55W iron is overkill, use something less powerfull

Unless it's temperature controlled?.

 

[MathGeek]

my JDM programmer worked at first on a breadboard.

Being successful, I tried to actually put together the JDM programmer, but after soldering it did not work.

So pissed, I did the exactly same thing again on the breadboard. I replaced all the parts except the caps. No, JDM does not work.

This JDM programmer previously caused many problems with my computer and I think I will just buy ICD2.

By the way, does ICD2 need an external power supply? I, on ebay, looked for ICD2, and the listing says DC adapter is not included, and I was wondering if this should concern me.