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...
zener!
Started by ●October 15, 2021
Reply by ●October 15, 20212021-10-15
Reply by ●October 15, 20212021-10-15
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
Reply by ●October 15, 20212021-10-15
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
Reply by ●October 15, 20212021-10-15
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
Reply by ●October 15, 20212021-10-15
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.
Reply by ●October 16, 20212021-10-16
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.
Reply by ●October 16, 20212021-10-16
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.
Reply by ●October 16, 20212021-10-16
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.
Reply by ●October 16, 20212021-10-16
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 paperworkThere are zero of these in stock. Anywhere. No WONDER they are so expensive. They are unobtanium !
Reply by ●October 16, 20212021-10-16
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
