Transistor markings

[ALFRED]

hi all. Working on vintage dynavox phono, with stereo amp. The 2n2429 & 2n2431 transistors have red dots...does this indicate base,collector, or emitter? Thanks Al

 

[Martaine2005]

Farb = colour. So I would guess 'collector'? I am probably way off though. Sorry.

Martin

 

[ALFRED]

Here are some pics. I don't have schematic

 

[ALFRED]

Thanks Martin. It makes sense!

 

[davenn]

I

Farb = colour. So I would guess 'collector'? I am probably way off though. Sorry.

Martin

I had a feeling it was always the emitter that was the one marked

 

[Martaine2005]

I



I had a feeling it was always the emitter that was the one marked

I did say I could be wrong Dave!

 

[davenn]

Just trying to remember back to my 1970's electronics work and all those old transistors
till more years ago than I care to remember
pretty sure its the emitter that's marked


D

 

[Martaine2005]

I am reading this now (cheers Dave) I normally only read on Sundays!!.

What a great read it is though...
Seems that they were coloured for hearing aid use first? The whole thing, not dots.
Ya know Dave, I just thought.... Can you edit out every word 'transistor' from this thread?
If not, you know what will happen..

Martin

 

[Martaine2005]

Just found something else which may be useful..

"Other than the usual red dot to denote the collector lead". Found 3/4 down page here.
Getting closer!!

Martin

 

[davenn]

gosh seeing the old devices on that page brought back many memories
thanks for the find

 

[Martaine2005]

Haha, Dave, It's my first time seeing them! Ouch!!

Martin

 

[davenn]

what age range are u in, Martin ?

 

[Martaine2005]

That's a difficult question to answer!
If you ask my family.....About 12!
If you look at my birth certificate it says 48! (Nov) just gone..

I believe my family

 

[davenn]

hahahaha

well ya know the ol saying ... " act your age and not your shoe size !! " hahaha

but then there's rarely any fun acting my age
I turned 56 last july


D

 

[duke37]

The first transistors I used were red spot (audio) and white spot (a bit faster). These were surplus transistors which did not fully comply with the spec. The spot was by the collector and they were emitter/base/collector.

 

[Martaine2005]

So... Trevor.....
Was the spot defining a leg? or just a spot?

Martin

 

[duke37]

I don't have spots on a leg, just on my body.

 

[Martaine2005]

@davenn had big rashes on his legs a few months back!
Is he the Collector or Emitter?

Martin

 

[davenn]

@davenn had big rashes on his legs a few months back!
Is he the Collector or Emitter?

Martin

 

[Martaine2005]

Sorry Dave, as you can see, just acting my age!!