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BS170 EOL
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Hi Jim A specific part number going end of life is not necessarily a cause for concern, there are quite a number of different BS170s with various variations; the particular part concerned in this post has bent leads on cut tape, and isn't the one we use in QRP Labs kits anyway. So this kind of post is worth checking up on, but normally, as in this case, isn't a concern. Other variants even available?at Digikey, have 172,849 available for example,?BS170-D26Z.? There are certain parts like BS170 which can never go away, because they are used in just too many places for too many different things... 73 Hans G0UPL On Mon, Jul 10, 2023 at 5:05?PM jim conrad <conr2286@...> wrote: Hans etc al, |
¿ªÔÆÌåÓýAnd for those of us who can remember the dreaded
unity-gain-compensated 741 op amp from over 50 years ago, note
that TI still offer it as a current part: Even more worryingly, the 723 regulator is still current. The 748 op amp is only current as a military specification part, though! Some components do have a very long life, for all sorts of reasons¡ 73, Robin, G8DQX (and now recovering from a fit of nostalgia) On 10/07/2023 15:55, Hans Summers
wrote:
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My favorite thing about the 2N2222 - easy to remember over decades. On Tue, Jul 11, 2023 at 7:14 AM ajparent1/kb1gmx <kb1gmx@...> wrote: My favorite is the 2n706 and 2n2222, Those were deveeloped and sold back in 1961 |
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More nostalgia! As a kid I saved my 'chores' earnings to purchase devices like 1N34, 2N107, 2N170 and the venerable CK722. I remember feeling kind of down when the integrated circuit was developed. I felt that it would suck the life out of my future designer experience and turn me into a low skill user of canned pre designed P/N's. Little did I realize at the time how liberating IC devices actually were and how they would transform virtually every aspect of our lives from how we entertain ourselves, to how we do medicine, to how we wage war. I went on to become a chip designer back in the days of 5 micron NMOS. How far things have come! One of my dearest possessions is an autographed wafer of TI cellphone chips signed to me by Dr. Jack Kilby,? TI's inventor of the integrated circuit and Nobel Laureate. I will treasure it as long as I live. JZ KJ4A? On Tue, Jul 11, 2023, 1:48 PM Tony Scaminaci <tonyscam@...> wrote:
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John, I must be younger than you¡ I started chip design with 3 micron CMOS back in ¡®86. ? FPGA¡¯s are taking over the world today and even amateur radio as evidenced by the ongoing M17 project. It¡¯s great to be in this field and experience the rapidly growing use of these devices as they replace most, if not all, discrete logic in numerous systems. On Tue, Jul 11, 2023 at 1:47 PM John Z <jdzbrozek@...> wrote:
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Tony, Back in my day CMOS was a speculative thing. Folks wondered about the balance between process complexity and device functionality. We all know now how that turned out. CMOS complexity won handily! On Tue, Jul 11, 2023, 3:13 PM Tony Scaminaci <tonyscam@...> wrote:
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On Tue, Jul 11, 2023 at 01:14 PM, ajparent1/kb1gmx wrote:
In the industry everyone know the 2n2222 as the roach as itRoaches that don't die..hmm lets make a list for some fun. 2N2222 BS170 741's 555's BC108's IRF510's and similar. RF power trannies are a bit fickle though. MRF series and some old 5-10w chicken band stuff etc. RF PA devices appear to follow the trend of whatever has been used in the professional user world. But that stuff has fades quite a bit. No one cares? about QRO VHF /UHF land mobile stuff for example because cell phones have replaced the RF services. No taxi / police / courier rigs needed so the devices that could be used a few Mhz either side for ham service eventually die :-( 10-20w chicken band stuff is dead, so those parts adopted for ham usage have gone too. Dual gate mosfets, almost dead now thanks to SDR, not good. The only decent RF PA parts come from Mitsubishi, and how? long will they last. The overriding thing about have an *RF* part is that they are designed to have a constant input / output impedance across their freq range, as well as a constant Gate bias voltage. Something a crappy IRF device and others simply cannot offer since they vary too much. Non RF parts can be good, not disputing that, but real RF parts are still superior. At least with something like an RD06HHF1 you can guarantee 6 watts into ANY load forever, have a constant input / output RF impedance, use the same Gate bias voltage in production, and with reasonable heatsinking and a good load push them to 15-20w with 100% duty cycle for years, just like a broadcast TX. (Same for other RD series stuff). Or RD16's. 16 watts guaranteed to any load 100% duty cycle, just a different input / output Z and a slightly higher input drive required for max output. (Use a 1:9 un-un in the output instead of a 1:4 to bring the lower output Z to 50R) Bullet, manual ATU proof and idiot proof. Shove about 2.5 volts on the GATE and make a Class A amp, perfect. Standing current about 50ma, does everything you want, works perfect even on AM with about 400mw of drive. -- - 73 de Andy - |
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John, I went through the nostalgia cycles, also starting with the 1N34 and CK-722.
One weekend my other EE roomate in school decided we should build a digital clock using nothing but nand gates "7400" with eventual output to an LED array showing th time in BCD format.? I wish I could remember the chip count, but it was a fairly large number. Mark |
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Bravo, Mark! An excellent project to remind us of the way things were. BTW, if you find yourself in Santa Clara County, California, the Computer Museum there is a fabulous trip through the Wayback Machine. The last time I was there a full size and functioning replica of the Babbage Difference Engine was on display, along with a dazzling array of calculating, computing, input and display devices from every era and of every technology you might think of. Amazing stuff. JZ On Tue, Jul 11, 2023, 9:29 PM Mark <venchant@...> wrote: John, I went through the nostalgia cycles, also starting with the 1N34 and CK-722. |
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?CK722???? WOW!??
What a flash back (op here 1941, ham 1956, retired 1997) couple days ago saw an add for CK 722s in Popular Electronics while? lQQking for.... ???? "Thunderbolts and Whistlers ...... Don Gleason " ???????? Page 39 in the Dec 1957 issue (35 cents) Whistlers ... Still an interest for me today In fact I am tooling up for the two solar eclips re? ...hamSCI.org... Check out my QRZ page Some of that hardware date back to 1988 except for current QRPLabs? GPSDO kits and 'stuff' :>) 72 73 74 John N3AAZ FM19 on DELMARVA Peninsula |
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The Apollo Guidance Computer was built out of nothing but triple input NOR gates. I can't even imagine how that might be done.
Big thumbs up on the Computer History Museum in Mountain View, CA. See the IBM 1401. See how data processing worked when the card sorter was the primary tool. Try to comprehend qui-binary data. My favorite bit was the missile tracking console. It has a built-in ash tray, because, come on, you can't expect someone to sit there for eight hours watching for incoming missiles without a smoke. |
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This thread has gotten somewhat off topic but the mention of the Computer Museum prompted me to add my comment. My wife and I had gone to the Museum about 8-10 year ago. I had been a developer from about the mid-seventies - during the transition from mainframe to smaller machines. As we were walking through the museum I kept pointing to a machine and saying 'I worked on that - and that - and that' - machines from CDC, Burroughs, DEC. Made me feel old even then - machines that I'd worked on now in a museum!? Also reminded me that the computing world was not always dominated by 8/16/32/64 bit machines - wonderful architectures with 60 bit words, or 36 bit words with usable settable variable bit sizes!
John, KI3J |
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There are some great posts here, even if they have nothing to do with the original premise! Continuing this friendly nostalgia hijack, I will relate a story from my college days. This one is especially for the several Nixie tube fans that I know to be here on the forum. At our Engineering College in 1970 there was a Wang Calculator laboratory. A central processing unit supported about two dozen work stations that consisted of a multi digit Nixie display and an enhanced numpad. We did everything from basic 4-function calculation to numerical solutions of non-linear or otherwise complicated equations there. Yes, it was a pain. This (and slide rules) was how we did engineering math back in the days before the HP and TI scientific calculators. There was always a wait list to get on to a Wang Calculator head. Even at 2AM on a Sunday morning, when the brightest lights in the room were orange Nixie numerals, getting a seat was difficult. When first the HP and soon thereafter the lower cost TI scientific calculators arrived, demand for the Wang lab evaporated. So many other important student purchases were delayed, deferred, or forgotten so that one of these magic devices could be afforded. It was a sea change, an end of an era and the beginning of a new one, and we were relieved. JZ On Thu, Jul 13, 2023, 9:11 AM Andy <andy.mm0fmf@...> wrote: On 13/07/2023 02:43, pgramsey via wrote: |
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When I was teaching statistics at Creighton (early 1970's), I needed a calculator that had a square root function. Texas Instruments had the SR-10 (??) which had a square root key, reciprocal, and x-squared function. That's it...no other functions. Educators got a 50% discount, so mine only cost me $175.00!! I was at a conference recently where they were giving away credit-card sized calculators with more functionality for free! Jack, W8TEE
On Thursday, July 13, 2023 at 02:11:24 PM EDT, John Z <jdzbrozek@...> wrote:
There are some great posts here, even if they have nothing to do with the original premise! Continuing this friendly nostalgia hijack, I will relate a story from my college days. This one is especially for the several Nixie tube fans that I know to be here on the forum. At our Engineering College in 1970 there was a Wang Calculator laboratory. A central processing unit supported about two dozen work stations that consisted of a multi digit Nixie display and an enhanced numpad. We did everything from basic 4-function calculation to numerical solutions of non-linear or otherwise complicated equations there. Yes, it was a pain. This (and slide rules) was how we did engineering math back in the days before the HP and TI scientific calculators. There was always a wait list to get on to a Wang Calculator head. Even at 2AM on a Sunday morning, when the brightest lights in the room were orange Nixie numerals, getting a seat was difficult. When first the HP and soon thereafter the lower cost TI scientific calculators arrived, demand for the Wang lab evaporated. So many other important student purchases were delayed, deferred, or forgotten so that one of these magic devices could be afforded. It was a sea change, an end of an era and the beginning of a new one, and we were relieved. JZ On Thu, Jul 13, 2023, 9:11 AM Andy <andy.mm0fmf@...> wrote: On 13/07/2023 02:43, pgramsey via wrote: |
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On 13/07/2023 19:11, John Z wrote:
This (and slide rules) was how we did engineering math back in the days before the HP and TI scientific calculators.I still have my TI59 programmable calculator from 1979. This was the poor man's HP65. It didn't have as good a keyboard but was half the price. It had both ROM modules you could install as well magnetic cards for saving programs and data. It came with a standard library in ROM and offered Statistics, Real Estate, Surveying, Navigation, Aviation, Leisure, Securities Analysis, Business Decisions, Math Utilities, Electrical Engineering, Agriculture and an RPN Simulator. Started writing my 1st software on it which led to a 40 year career in Electronics and deeply embedded software. Much more fun solving astronomy algorithms than doing school homework! Mine still works apart from the card reader. Cleaning didn't help. Probably the capstan roller is dented from lack of use and possibly the rubber has hardened or gone all gooey. No surprise as it's 44 years old now. Andy |
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Jack, Andy Fabulous recollections! Thanks! JZ On Thu, Jul 13, 2023, 2:36 PM Andy <andy.mm0fmf@...> wrote: On 13/07/2023 19:11, John Z wrote: |
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I was brought up on HP9820 "desk top" calculators with plug in ROMs and? a cassette drive! We even had them manifested as Meteorological equipment as it attracted less attention from Customs at airports Best HP for me was the HP67 it had a card reader and thermal printer, mind you my HP11 serves me well for day to day stuff cheers Geoff GI0GDP
On Thursday, 13 July 2023 at 19:36:48 BST, Andy <andy.mm0fmf@...> wrote:
On 13/07/2023 19:11, John Z wrote: > > This (and slide rules) was how we did engineering math back in the days > before the HP and TI scientific calculators. I still have my TI59 programmable calculator from 1979. This was the poor man's HP65. It didn't have as good a keyboard but was half the price. It had both ROM modules you could install as well magnetic cards for saving programs and data. It came with a standard library in ROM and offered Statistics, Real Estate, Surveying, Navigation, Aviation, Leisure, Securities Analysis, Business Decisions, Math Utilities, Electrical Engineering, Agriculture and an RPN Simulator. Started writing my 1st software on it which led to a 40 year career in Electronics and deeply embedded software. Much more fun solving astronomy algorithms than doing school homework! Mine still works apart from the card reader. Cleaning didn't help. Probably the capstan roller is dented from lack of use and possibly the rubber has hardened or gone all gooey. No surprise as it's 44 years old now. Andy |
Mark K9TR
jjpurdum
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