Electronics > Beginners

Jellybean hobbyist general purpose transistors..

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Zero999:

--- Quote from: Vtile on October 14, 2017, 10:38:43 am ---How disturbing it is that VHF means very high frequenzy in a 30 MHz to 300 MHz range while every dog collar today transmit in Gigahertz range Wifi. Anyone else annoyed.  >:D ^-^

--- End quote ---
The designations LF, MF, HF, VHF, UHF etc. came about when electronics were much slower, than they are today.

Vtile:

--- Quote from: Hero999 on October 14, 2017, 07:30:23 pm ---
--- Quote from: Vtile on October 14, 2017, 10:38:43 am ---How disturbing it is that VHF means very high frequenzy in a 30 MHz to 300 MHz range while every dog collar today transmit in Gigahertz range Wifi. Anyone else annoyed.  >:D ^-^

--- End quote ---
The designations LF, MF, HF, VHF, UHF etc. came about when electronics were much slower, than they are today.

--- End quote ---
Yep, when the silicon were still used for rectifier casings and not rectifying material.  ::)

David Hess:

--- Quote from: Vtile on October 14, 2017, 07:12:42 pm ---Anyone seen sot-23 to to-39 canning machine cheaply on chinese evilbays???  :D
--- End quote ---

That would be nice; there is a much larger variety now in small signal surface mount than leaded components.  There are SOT-23 to leaded adapters but I have not seen any that I like.

floobydust:
Whatever happened to transistor technology improving?

I found TIP30's in my junkbox date code 1973. hFE measured 5. Tossed them in the garbage.
40+ years later, TIP30 still available and same specs. fT 3MHz, hFE 15-40, 30W.

Planar, perforated emitter, epitaxial, mesa, alloy junction etc. I thought improvements occurred over the past few decades.
I don't see why antique part numbers are still around.

edit - added some silicon crystal configs

T3sl4co1l:
TIP30 is another one of those ancient parts, tied to ancient specs.  I don't know if TIPxx is JEDEC registered (they're originally Texas Instruments Plastic transistors), but they're widely available and genericized.

You might get one that overperforms, or you might get one that's shite.

I would be surprised to see a modern (since 80s) part perform as poorly as the originals, for the same reason I suggested regarding 2N3055 and such: the old diffusion lines are long since scrapped.  Compatible parts are made on newer processes, but not benefiting from modern designs, so they still suck, like in hFE linearity and switching performance.

You're more than welcome to buy new-designed parts, but, surprise surprise, they're more expensive.....

Tim

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