Forums

zener!

Started by John Larkin October 15, 2021
On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin
<jlarkin@highland_atwork_technology.com> wrote in
<9mijmglv4q0sqcjvlh87u0u8sob51tjnh6@4ax.com>:

>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.
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...
On Fri, 15 Oct 2021 19:57:43 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin ><jlarkin@highland_atwork_technology.com> wrote in ><9mijmglv4q0sqcjvlh87u0u8sob51tjnh6@4ax.com>: > >>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. > >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. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
On Friday, October 15, 2021 at 2:01:14 PM UTC-4, John Larkin wrote:
> https://www.digikey.com/en/products/detail/microchip-technology/JANS1N4102DUR-1-TR/13995295 > > Somebody must buy them.
https://www.microsemi.com/existing-parts/parts/17155 Ruggedized and space qualified.
> > -- > > If a man will begin with certainties, he shall end with doubts, > but if he will be content to begin with doubts he shall end in certainties. > Francis Bacon
On 15/10/2021 19:24, Rich S wrote:
> >> 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!
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? -- Cheers Clive 0
On Friday, October 15, 2021 at 1:02:28 PM UTC-7, Jan Panteltje wrote:
> On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin > <jlarkin@highland_atwork_technology.com> wrote in > <9mijmglv4q0sqcjvl...@4ax.com>: > >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. > 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...
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
<edward.ming.lee@gmail.com> wrote in
<a9490547-a634-4174-8a59-ad24d50fe2b1n@googlegroups.com>:

>On Friday, October 15, 2021 at 1:02:28 PM UTC-7, Jan Panteltje wrote: >> On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin >> <jlarkin@highland_atwork_technology.com> wrote in >> <9mijmglv4q0sqcjvl...@4ax.com>: >> >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. >> 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... > >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.
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.
On Friday, October 15, 2021 at 10:30:22 PM UTC-7, Jan Panteltje wrote:
> On a sunny day (Fri, 15 Oct 2021 15:44:35 -0700 (PDT)) it happened Ed Lee > <edward....@gmail.com> wrote in > <a9490547-a634-4174...@googlegroups.com>: > >On Friday, October 15, 2021 at 1:02:28 PM UTC-7, Jan Panteltje wrote: > >> On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin > >> <jlarkin@highland_atwork_technology.com> wrote in > >> <9mijmglv4q0sqcjvl...@4ax.com>: > >> >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. > >> 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... > > > >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. > I am talking about Ah, not Wh!
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.
> 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.
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
<edward.ming.lee@gmail.com> wrote in
<80ff42d4-b0c1-45f4-92fd-9acb2c0a84bdn@googlegroups.com>:

>On Friday, October 15, 2021 at 10:30:22 PM UTC-7, Jan Panteltje wrote: >> On a sunny day (Fri, 15 Oct 2021 15:44:35 -0700 (PDT)) it happened Ed Lee >> <edward....@gmail.com> wrote in >> <a9490547-a634-4174...@googlegroups.com>: >> >On Friday, October 15, 2021 at 1:02:28 PM UTC-7, Jan Panteltje wrote: >> >> On a sunny day (Fri, 15 Oct 2021 11:41:25 -0700) it happened John Larkin >> >> <jlarkin@highland_atwork_technology.com> wrote in >> >> <9mijmglv4q0sqcjvl...@4ax.com>: >> >> >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. >> >> 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... >> > >> >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. >> I am talking about Ah, not Wh! > >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. > >> 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. > >He is limiting the power source to 8.7v; so, 8.7v battery makes more sense than 12v.
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.
On Fri, 15 Oct 2021 11:50:54 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>fredag den 15. oktober 2021 kl. 20.43.17 UTC+2 skrev John Larkin: >> On Fri, 15 Oct 2021 11:24:12 -0700 (PDT), Rich S >> <richsuli...@gmail.com> wrote: >> >> > >> >> 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 >> They are robbing people like military and semiconductor copy-exact >> users who can't easily change things. > >also stops other people buying the, I assume, limited number of parts >is of the exact type and that has all the paperwork
There are zero of these in stock. Anywhere. No WONDER they are so expensive. They are unobtanium !
John Larkin wrote:
> https://www.digikey.com/en/products/detail/microchip-technology/JANS1N4102DUR-1-TR/13995295 > > Somebody must buy them. >
Cheap - - $3.54/week. Could be low noise, as 8.7 V is in the low noise "valley"; especially for certain manufacturers. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus