#1740

[@p_mouse8676]

Just the fact that you were able to still buy any electronic devices in a physical store is already mind blowing to me

[@M0UAW_IO83]

Zetex made some damn fine parts, they were a UK company until Diodes Inc took them over. Used to be Ferranti, then Plessey, then Zetex and now Diodes Inc. I did some IT work for them at their UK foundry in Chadderton, never did manage to cadge any samples out of them though.

[@SkyhawkSteve]

I used to buy Zetex transistors and some little LED drivers back in the Zetex era. The transistors typically had high gain, low Vsat, etc. The little ZXSC310 was a LED boost driver that would operate down to 0.8v, which was very handy for some of my home projects. Cool parts, and kinda sad to see them absorbed into a larger company. Of course, this is the normal pattern in the semiconductor industry.

[@quesoestbonne]

Definitely Zetex, recognised the part number and datasheet style instantly. This family of parts is designed for things like switching power supplies and power switching in general, easily driven from low power source with the high hFE. This transistor family is a development of the Ferranti ZTX devices. The odd first digits are all PNP (e.g. 5xx, 7xx), and even (6xx, 8xx etc) are NPN. (Zetex name came from there with the staff buyout of the discrete devices plant when Ferranti broke up after the Ferranti International purchase of ISC late '80's) Still have a plentiful supply of some of those transistors, a few reels and tapes in a cupboard

[@Pixelwaster]

Fun fact, you can easily mount these to TO-220 left overs. Clean off the resin and blown die, solder at the bottom edge. The reader is encouraged to engineer their own solution to the missing leaes. New THP out of SMD.

[@ats89117]

It looks like a nice part for a lot of PNP applications and it's in-stock everywhere for 16 to 35 cents apiece. The SOT-89 is a great package for copper core boards.

[@GRPZ66]

Good info on using the datasheet and the gotcha's in there. Thanks

[@AnalogDude_]

Wow, a part that almost can solder it self to the pcb.

[@bigjd2k]

Or desolder itself!

[@R2AUK]

fT is the frequency where a common-emitter amplifier has a gain of 1. I think they measured the gain at 50 Mhz and approximated minimum fT. 2N3904 has fT around 300 Mhz which means it can be used as a decent HF amplifier at 30 MHz or so. A transistor with fT of 500-600 MHz would be even better in this application but usually they are somewhat more expensive. fT = 100 Mhz basically tells us that this is not a good transistor for RF applications, it's an AF one.

[@bob_mosavo]

Thanks 👍

[@blahblahblahblah2933]

Low Vce(sat) BJT's are nice when you are in situations where you don't have the Vcc to drive a MOSFET efficiently, (more applicable with NPNs though).

[@Mr.Leeroy]

Sure you gave it a bit more thermal mass, but also glued over considerable amount of required heatsinking area as well as severely limited thermal resistivity with a tip of a tab barely touching heatsink via tin mostly. Pretty sure they intended good substrate to copper contact in the middle (or at least lower half of) area and probably thermal vias in case of FR4 PCB

[@bigjd2k]

NXP used to make beefy little bipolars too

[@VEC7ORlt]

Its a really nice demo that shows how all the lines converge at at single point indicating Early voltage.

[@TheElectronicDilettante]

Here’s an fyi is you’re interested. I came across an upcoming tech auction in the Silicon Valley area. It’s listed on a site called HiBid and takes place from January 16-19. I did a cursory glance at the listing and there’s a lot of cool kit like VNAs and Spectrum Analyzers. Purchasing can be done online but this particular sale doesn’t offer shipping. I’d be all over it otherwise.

[@IMSAIGuy]

stuff is pretty vintage

[@bob_mosavo]

@@IMSAIGuy Your curve tracer is pretty vintage 😉

[@ChrisSmith-tc4df]

as the temperature zooms past 120C 🤣

[@edbeckerich3737]

Man I like that part, and I miss BGMicro...

[@herbertsusmann986]

What is the manufacturer of that part? Someone mentioned Zetex/Diodes Inc. in another comment. Is that correct?

[@ats89117]

Wow, I'd be pissed if I bought some transistors for a project labeled as NPN and they turned out to be PNP, but being very cynical, I would have checked them prior to making the purchase...

[@IMSAIGuy]

it was $1 bag full of parts

[@AnalogDude_]

1$, that's amazing, but you never know when they are useful. :) @@IMSAIGuy

[@stamasd8500]

Then please don't buy from Chinese sites. What you get will be a complete surprise from what you ordered. Once I ordered some depletion MOSFETs and received NPNs. :)

[@ats89117]

@@stamasd8500 Newark has pretty good periodic specials and if you are ordering parts for a job and are over $150 they pick up shipping, so I get most of my cheap stuff from them as well.

[@bartonstano9327]

IMSAI Guy what store do you get these grab bags from?

[@IMSAIGuy]

kzbin.info/www/bejne/jYTNoKKaaNtqiqssi=xSA_ZsHjOw8LyhQu

[@joejane9977]

npn to pnp mark that bag