Bipolar Transistors for Audio
 

Many of the power transistors of the late sixties were Germanium - who
remembers the OC35 or the NKT401?

Towers transistor data manual of that time (the copy of which I still
have) had some pages labelled Geranium power transistors - who says
Flower Power didn't exist?



--
Woody

harrogate three at ntlworld dot com

Bipolar Transistors for Audio
 

"David Looser" wrote in message
...
"robert casey" wrote in message
...

But back in the early 70's, table radios made the transision from the
"All American 5ive" tube circuit to a solid state circuit that used a
high voltage bipolar transistor and output transformer for the audio
output.


I'm not sure exactly when this transition was made, but I do know that
it occurred sometime well before the "early 70's", I would say that the
transition occurred in the mid 60's, I know from personal experience
that these radios were already in production by late 66, when they first
went into production I don't know.


I was thinking of the SS radios that were "hot chassis". The audio
output transistor had about 100V B+ on it. Before these, there were some
SS radios that had small power transformers and were essentially portable
circuits inserted inside a table radio cabinet. But it's the hot chassis
high voltage transistors that ran in class A "single ended" I was
thinking of.


That's probably why we never saw them here in the UK. There were the
occasional single-ended transistor output stages in early SS and hybrid
car radios, and some Japanese-made TV sets, but that was about it. A 300V
B+ supply would have been rather too much.


I thought the common bipolar transistor was a "triode". ;)

It's a three-electrode device, so yes, it's a triode. That doesn't mean
it's characteristics are similar to those of a thermionic triode though.



My Chinese friends tell me that the word "transistor" translates into
"crystal triode" in Chinese. :-)


Err..., "transistor" is a contraction of "transfer-resistor", but what it
*is*, is a crystal triode. So if any language group wants it's own word
for the device, rather than just adopt "transistor", then using their own
words for "crystal triode" makes a good deal of sense.

David.



Somewhere around at home, I have an extremely old transistor that is marked
as "Crystal Triode". It is so old that it has a hand written serial number
on it

Keith