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Topic: How did I fry my transistor? (Read 7292 times) previous topic - next topic

ChilliTronix

Some years ago I threw out about half a dozen tea chests full of valves believing I'd never use them again.  Literally just a few weeks later I realised I'd thrown away an absolute gold mine.  They were all in full working condition and over half of them were still in their original packing. :(
I'd give you a slap for that if you lived close by.. I don't so I hope you have suitably chastised yourself! The least you could have done is stick them on ebay!

raschemmel

#16
Dec 27, 2014, 01:17 am Last Edit: Dec 27, 2014, 01:20 am by raschemmel
Quote
It may take a strike of lightening to convince you  
Oh come on. When someone talks about "static discharge" they are not talking about lightning . (which is a plasma discharge in the atmosphere)

If his transistor got hit by lightning I rather doubt he would be around to post on the forum.

Quote
I threw out about half a dozen tea chests full of valves 
Those don't sound like electronic components. How do they apply to the current example ?
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

KenF

Oh come on. When someone talks about "static discharge" they are not talking about lightning . (which is a plasma discharge in the atmosphere)
NO it's a static discharge in the atmosphere that creates plasma.

In my original statement I said it was unlikely to be the original posters problem. Why do you feel the need to pick a fight over this?

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Those don't sound like electronic components.
So are you now criticising me for my slapdash use of the term valve instead of "Thermionic Valves."

Quote
How do they apply to the current example ?
They don't.  I was answering a prior post in this thread.

Sounds like you've forgotten to take your meds again :)

raschemmel

#18
Dec 27, 2014, 01:43 am Last Edit: Dec 27, 2014, 01:54 am by raschemmel
@KenF,

Quote
So are you now criticising me for my slapdash use of the term valve instead of "Thermionic Valves."
Did it occur to you that I might be in the USA where we call them vacuum tubes (and always have) ?
I don't want to continue this discussion but I would like to say that you shouldn't accuse people of trying to
pick a fight because they comment that your association of static discharge with respect to a transistor and lightning is not relevant.



Quote
Sounds like you've forgotten to take your meds again
Really ? Let's keep it civil shall we ?
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

Paul__B

Open base-emitter junction.
Open base tie.  Clearly the emitter tie is functional, as quite likely is the die itself.

It is not unusual for the encapsulation to be less than sturdy, particularly after soldering (LEDs) and an internal weld fails.

In my original statement I said it was unlikely to be the original posters problem. Why do you feel the need to pick a fight over this?
Internet convention?   :smiley-zipper:

raschemmel

#20
Dec 27, 2014, 04:40 am Last Edit: Dec 27, 2014, 04:59 am by raschemmel
Quote
In my original statement I said it was unlikely to be the original posters problem. Why do you feel the need to pick a fight over this?
Yes , but you said static discharge was unlikely, not lightning, which is what prompted my comment about it not being relevant.

@Paul,
You know me well enough to know that I wasn't trying to pick a fight with that comment.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

KenF

Yes , but you said static discharge was unlike, not lightning, which is what prompted my comment about it not being relevant.
I suggested the OPs problem could have been caused by static discharge.  This is STILL more likely than any suggestion you've come up with.

Oh.. Wait..  As per usual you HAVEN'T come up with anything constructive at all.  Instead you're just here picking fights as per your usual form.

Paul__B

Hey, I'm outta here!   :o

(For now, anyway.)

oric_dan

Hey, a tesla member is a colonel and a god member is a corporal, so that should end that argument, lol. I wonder, from an historical perspective, did the concept of common [ie, non-lightning strike] static discharge blowing ckts ever come up prior to the advent of the first [and poorly protected] series of mosfet devices? Would be interesting to know.

OP, if you're not frying at least one transistor a day with "that" kind of setup, you're probably not trying very hard. By far the most likely error with breadboards is operator-error: plugging in something wrong or backwards, and [highly likely] accidentally shorting 2 wires together that shouldn't be shorted together. You likely don't even notice you did it. With an Arduino, the most common screwup is "oops, I plugged 12V into an I/O pin".

raschemmel

#24
Dec 27, 2014, 09:13 am Last Edit: Dec 27, 2014, 09:27 am by raschemmel
Speaking of transistors,  I realize you bent the leads on it to avoid the trouble of addding jumpers but if leave the pins staight and use jumpers you will reducd the chance of cracking a lead on the transistor and it willl last forever. I used to do that to save time but after breaking a couple of leads I started using jumpers instead. I'm not
suggesting that the lead separated from the bond but
just saying that the staighter you keep the leads the longer they last.

20 or 22 guage solid copper insulated hookup wire is cheap and allows you to make exact length
jumpers. You can reuse them a few times and then toss em because their so cheap.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

RogerRowland

if we're being nitpicky, 220 ohms is a tiny bit short since it provides 20.9mA @ 4.6VDC and the LED is rated for 20mA.. ±5% for a carbon film resistor
I think you forgot the voltage drop across the LED in that calculation ....

KenF

Hey, a tesla member is a colonel and a god member is a corporal, so that should end that argument, lol.
And what is a "God Member Faraday Member" then?  :)

Grumpy_Mike

Maybe the OP was wiring up the circuit with the power attached instead of wiring it all up and then applying power.

Tempting though it is never wire up something while the power is connected, it is a good way to blow up transistors.

MarkT

The circuits as drawn can't harm the device, so my take is either:

1) You bought faulty device (eBay is a dumping ground for factory rejects, beware)
2) At some point you miswired the device or shorted something, degrading the device,
  leading to subsequent failure
3) You put a large negative voltage on the base (w.r.t. the emitter) with your finger.
BJT's don't tolerate reverse voltage on the base-emitter junction.  The base-emitter
resistor in the circuit should make that impossible though, and a finger is unlikely to
provide enough current to do damage too.
4) thermal or mechanical strain (use a hot soldering iron for a short time,
avoid bending the leads at the package base)
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

oric_dan

#29
Dec 27, 2014, 06:11 pm Last Edit: Dec 28, 2014, 10:12 pm by oric_dan
I did find this, which seems to make sense.

http://www.radio-electronics.com/info/circuits/esd/electronics-esd.php

"Even ordinary bipolar transistors can be damaged by potentials of around 500V. This is particularly true of the newer transistors which are likely to have much smaller internal geometries to give higher operating frequencies. ...In some areas even passive components are starting to be treated as static sensitive. With the trend to miniaturisation individual electronics components are becoming much smaller. This makes them more sensitive to the effects of damage from ESD."

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