zener!

Avalanche 8.7 volts, seems odd, probably associated with a one design or application. (input clamp?). Must be some extant military gear with support contract, keeping the (sub)contractor in business. $140 for a mil-spec part,.. I dunno, haven't kept up on these, but honestly isn't a surprise to me...

=RS

..because.. (for newbies) for mil-spec you're also paying for testing, documentation, and traceability all attached to that part. (Producing the part itself is just a small part!

= RS

Perhaps they have some special alien metal (anti-Lithium?) for 8.7V, but for us civilian 4.3V would be nice.

I need an 8.7 v 2% zener as a clamp, to protect a $300 distributed amp chip rated for 9 volts abs max. Parts are hard to get lately.

I'll go for 5% and pray.

fredag den 15. oktober 2021 kl. 20.01.14 UTC+2 skrev John Larkin:

right on the middle of the page

Series: Military, MIL-PRF-19500/435

They are robbing people like military and semiconductor copy-exact users who can't easily change things.

It's a common thing to do lately.

fredag den 15. oktober 2021 kl. 20.43.17 UTC+2 skrev John Larkin:

also stops other people buying the, I assume, limited number of parts is of the exact type and that has all the paperwork

The JAN (Joint Army Navy) part number is the tell.

Supporting old equipment. Typical lifecycles are 20 to 40 years.

Joe Gwinn

On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in snipped-for-privacy@4ax.com:

There are many ways to do that, simple transistor and trimpot between - and + on base will allow you to select a voltage.

________| | | | c []<---- b | e | | --------|

depends on current etc..

Or maybe some LEDs in series (have that working here in my PIC programmer). Or 2 zeners and / or diodes in series.

In times of 'sjip' shortages BJTs and LEDs etc are cool. It will get worse with power shortages, just ordered a 250 Ah liion 12V battery from Aliexpress, for buffer...

I could have done it with an opamp and such, but this board is cramped for space and the tiny zener is nice. I might need to sink 50 mA or so, through a <1 pF schottky diode to this clamp, to limit the amp output voltage to just over 9.

Ruggedized and space qualified.

Well, maybe. Maybe you're just paying for a different marking.

Plenty of 85'C parts are the same as 125'C parts except for the markings. You really think they make or select different parts?

Why 12v? 8.7v is exactly two Li-Ion batteries in series. A Leaf battery module is 8.7v with center tap, and can sink 66A or 500Whr.

On a sunny day (Fri, 15 Oct 2021 15:44:35 -0700 (PDT)) it happened Ed Lee snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

I am talking about Ah, not Wh! So 12V at 250 Ah makes??? < complicated math here>

Yes I have several small Liion 2 cell, 3 cell, 1 cell in various projects. This is lifepo4, bit more safe cannot go up in flames by itself, The 12V will go into a true sine to 230 V converter. It is also in a water proof housing plus charge control so it can be used in a boat. Bigger ones can power an outboard motor for a while. Experiment.. Can start your car too.

I know, but we are comparing different voltages, so it makes more sense to compare Wh. I don't know how much power John needed, but i doubt more than one 500Wh module.

He is limiting the power source to 8.7v; so, 8.7v battery makes more sense than 12v.

On a sunny day (Fri, 15 Oct 2021 22:39:14 -0700 (PDT)) it happened Ed Lee snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

OK, my fault, I was changing topic, do not want to use my battery as zener! liion will go up to 4.2V per cell! From 3.2 V when low, so way out of his 5 percent range.

There are zero of these in stock. Anywhere.

No WONDER they are so expensive. They are unobtanium !

Cheap - - $3.54/week. Could be low noise, as 8.7 V is in the low noise "valley"; especially for certain manufacturers.

Would about 8.22V 1% do? Low power part as spec is 100uA nominal

500uA max (to 200C). Fudge by adding a diode in series, which can be thermally coupled, time constant maybe 10mSec worst case.

Thanks, R.Baer