Something interesting found in an old databook

Jan 20, 2018 6 Replies

I stopped by a local electronics-surplus store yesterday (Weird Stuff Warehouse in Sunnyvale). Out in front they had a rack full of VHS tapes, cassettes, and other stuff with a "FREE" sign on it. There were a couple of boxes of databooks of various sorts as well. I dug through and found two I decided to take home - Motorola, and National Semiconductor "Small Signal" transistor/diode manuals from a couple of decades ago. Most of the parts involved are now unobtanium as new-stock in through-hole packaging, of course, but there are still enough SMT versions and old-stock around to make these books interesting reading.



Looking through one, I saw something that I found rather surprising.



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Am I missing something here, or is this as odd as it seems?


What do you think is odd about it ?

The emitter has to be connected to the base. It is not.

Ok, I see it now. Been a long time ago that I really looked close at what was drawn inside the circle of the devices.

Pretty odd for silicon, for sure. Germanium transistors commonly had negative betas (alpha > 1) so weird circuits like that were around back in the day.

(My 1994 edition Motorola small-signal databook has the figure corrected.)

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com

Yes it's a mistake. Correctly shown here though:

Brian Gregory (in England).

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