The article here says type 43 NiZn ferrite's resistive impedance exceeds it's reactance at about 2MHz <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> but I think that's a misprint, looks more like 15MHz: <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> The data-sheet is here: <https://www.fair-rite.com/43-material-data-sheet/> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH common-mode choke for about 3 MHz, the calculator says about 30 turns should give me that but I'm unclear if this is an appropriate material
Type 43 material for common-mode choke
Started by ●September 24, 2020
Reply by ●September 25, 20202020-09-25
On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <user@example.net> wrote:>The article here says type 43 NiZn ferrite's resistive impedance exceeds >it's reactance at about 2MHz > ><https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> > >but I think that's a misprint, looks more like 15MHz: > ><https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> > >The data-sheet is here: > ><https://www.fair-rite.com/43-material-data-sheet/> > >I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH >common-mode choke for about 3 MHz, the calculator says about 30 turns >should give me that but I'm unclear if this is an appropriate materialThat's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. You'd only need 16 turns x2 to get a 2x100uH common mode choke. It's the right material for the application. RL
Reply by ●September 25, 20202020-09-25
On 9/24/2020 11:17 PM, legg wrote:> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <user@example.net> wrote: > >> The article here says type 43 NiZn ferrite's resistive impedance exceeds >> it's reactance at about 2MHz >> >> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> >> >> but I think that's a misprint, looks more like 15MHz: >> >> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> >> >> The data-sheet is here: >> >> <https://www.fair-rite.com/43-material-data-sheet/> >> >> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH >> common-mode choke for about 3 MHz, the calculator says about 30 turns >> should give me that but I'm unclear if this is an appropriate material > > That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. > > You'd only need 16 turns x2 to get a 2x100uH common mode choke. > > It's the right material for the application. > > RL >Yes you're right, 16, thank you. Nice
Reply by ●September 25, 20202020-09-25
legg wrote:> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <user@example.net> wrote: > >> The article here says type 43 NiZn ferrite's resistive impedance exceeds >> it's reactance at about 2MHz >> >> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> >> >> but I think that's a misprint, looks more like 15MHz: >> >> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> >> >> The data-sheet is here: >> >> <https://www.fair-rite.com/43-material-data-sheet/> >> >> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH >> common-mode choke for about 3 MHz, the calculator says about 30 turns >> should give me that but I'm unclear if this is an appropriate material > > That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5.375nH/n^2> > You'd only need 16 turns x2 to get a 2x100uH common mode choke. > > It's the right material for the application.Yes. Jeroen Belleman
Reply by ●September 26, 20202020-09-26
On Fri, 25 Sep 2020 09:31:40 +0200, Jeroen Belleman <jeroen@nospam.please> wrote:>legg wrote: >> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <user@example.net> wrote: >> >>> The article here says type 43 NiZn ferrite's resistive impedance exceeds >>> it's reactance at about 2MHz >>> >>> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> >>> >>> but I think that's a misprint, looks more like 15MHz: >>> >>> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> >>> >>> The data-sheet is here: >>> >>> <https://www.fair-rite.com/43-material-data-sheet/> >>> >>> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH >>> common-mode choke for about 3 MHz, the calculator says about 30 turns >>> should give me that but I'm unclear if this is an appropriate material >> >> That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. > >375nH/n^2 > >> >> You'd only need 16 turns x2 to get a 2x100uH common mode choke. >> >> It's the right material for the application. > >Yes. > >Jeroen BellemanToo many turns can eventually give diminishing returns due to too much intra-winding capacitance.
Reply by ●September 26, 20202020-09-26
On Saturday, September 26, 2020 at 3:20:43 PM UTC+10, boB wrote:> On Fri, 25 Sep 2020 09:31:40 +0200, Jeroen Belleman > <jer...@nospam.please> wrote: > > >legg wrote: > >> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <us...@example.net> wrote: > >> > >>> The article here says type 43 NiZn ferrite's resistive impedance exceeds > >>> it's reactance at about 2MHz > >>> > >>> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> > >>> > >>> but I think that's a misprint, looks more like 15MHz: > >>> > >>> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> > >>> > >>> The data-sheet is here: > >>> > >>> <https://www.fair-rite.com/43-material-data-sheet/> > >>> > >>> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH > >>> common-mode choke for about 3 MHz, the calculator says about 30 turns > >>> should give me that but I'm unclear if this is an appropriate material > >> > >> That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. > > > >375nH/n^2 > > > >> > >> You'd only need 16 turns x2 to get a 2x100uH common mode choke. > >> > >> It's the right material for the application. > > > >Yes. > > Too many turns can eventually give diminishing returns due to too much > intra-winding capacitance.You can work that out. Sixteen turns on a toroid sounds like a single layer winding, where the parallel capacitance tend to be around 1pF, which would make the coil parallel resonant at about 8MHz (very roughly). As soon as you start stacking up layers of windings, life gets more difficult and you have to starting thinking about partitioning the winding into successive multilayer chunks, where there isn't a lot of voltage difference within any one chunk. -- Bill Sloman, Sydney
Reply by ●September 26, 20202020-09-26
On 26/09/2020 06:36, Bill Sloman wrote:> On Saturday, September 26, 2020 at 3:20:43 PM UTC+10, boB wrote: >> On Fri, 25 Sep 2020 09:31:40 +0200, Jeroen Belleman >> <jer...@nospam.please> wrote: >> >>> legg wrote: >>>> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <us...@example.net> wrote: >>>> >>>>> The article here says type 43 NiZn ferrite's resistive impedance exceeds >>>>> it's reactance at about 2MHz >>>>> >>>>> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> >>>>> >>>>> but I think that's a misprint, looks more like 15MHz: >>>>> >>>>> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> >>>>> >>>>> The data-sheet is here: >>>>> >>>>> <https://www.fair-rite.com/43-material-data-sheet/> >>>>> >>>>> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH >>>>> common-mode choke for about 3 MHz, the calculator says about 30 turns >>>>> should give me that but I'm unclear if this is an appropriate material >>>> >>>> That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. >>> >>> 375nH/n^2 >>> >>>> >>>> You'd only need 16 turns x2 to get a 2x100uH common mode choke. >>>> >>>> It's the right material for the application. >>> >>> Yes. >> >> Too many turns can eventually give diminishing returns due to too much >> intra-winding capacitance. > > You can work that out. Sixteen turns on a toroid sounds like a single layer winding, where the parallel capacitance tend to be around 1pF, which would make the coil parallel resonant at about 8MHz (very roughly).Very roughly indeed, an octave out - I make 1pF 100uH resonant at 16MHz> > As soon as you start stacking up layers of windings, life gets more difficult and you have to starting thinking about partitioning the winding into successive multilayer chunks, where there isn't a lot of voltage difference within any one chunk. >piglet
Reply by ●September 26, 20202020-09-26
Piglet wrote:> Very roughly indeed, an octave out - I make 1pF 100uH resonant at 16MHzI would say an octave is good enough for a SWAG. Even a decade would pass in most of the cases. Best regards, Piotr
Reply by ●September 26, 20202020-09-26
On 26/09/2020 09:12, Piotr Wyderski wrote:> Piglet wrote: > >> Very roughly indeed, an octave out - I make 1pF 100uH resonant at 16MHz > > I would say an octave is good enough for a SWAG. Even a decade would > pass in most of the cases. > > Best regards, PiotrYou are right when some information is missing but in this case all the data was available to calculate better. piglet
Reply by ●September 26, 20202020-09-26
On Saturday, September 26, 2020 at 6:00:29 PM UTC+10, piglet wrote:> On 26/09/2020 06:36, Bill Sloman wrote: > > On Saturday, September 26, 2020 at 3:20:43 PM UTC+10, boB wrote: > >> On Fri, 25 Sep 2020 09:31:40 +0200, Jeroen Belleman > >> <jer...@nospam.please> wrote: > >> > >>> legg wrote: > >>>> On Thu, 24 Sep 2020 21:36:53 -0400, bitrex <us...@example.net> wrote: > >>>> > >>>>> The article here says type 43 NiZn ferrite's resistive impedance exceeds > >>>>> it's reactance at about 2MHz > >>>>> > >>>>> <https://www.nutsvolts.com/magazine/article/July2015_HamWorkbench#:~:text=Type%2043%20is%20one%20such,video%20cables%20use%20this%20mix.> > >>>>> > >>>>> but I think that's a misprint, looks more like 15MHz: > >>>>> > >>>>> <https://www.nutsvolts.com/uploads/wygwam/NV_0715_Silver_Figure01.jpg> > >>>>> > >>>>> The data-sheet is here: > >>>>> > >>>>> <https://www.fair-rite.com/43-material-data-sheet/> > >>>>> > >>>>> I have a bunch of FT37-43s ferrite toroids on hand and I need a 100uH > >>>>> common-mode choke for about 3 MHz, the calculator says about 30 turns > >>>>> should give me that but I'm unclear if this is an appropriate material > >>>> > >>>> That's a 5943000201 in the Fair-Rite catalog. Al = 375nH/n^0.5. > >>> > >>> 375nH/n^2 > >>> > >>>> > >>>> You'd only need 16 turns x2 to get a 2x100uH common mode choke. > >>>> > >>>> It's the right material for the application. > >>> > >>> Yes. > >> > >> Too many turns can eventually give diminishing returns due to too much > >> intra-winding capacitance. > > > > You can work that out. Sixteen turns on a toroid sounds like a single layer winding, where the parallel capacitance tend to be around 1pF, which would make the coil parallel resonant at about 8MHz (very roughly). > > Very roughly indeed, an octave out - I make 1pF 100uH resonant at 16MHzOops. I wasn't reading carefully enough. I got quite the wrong inductance, and seem to have plugged in the wrong capacitance too. Repeating the calculation gives me 15.9MHz - which certainly isn't worth reporting as anything different from 16MHz. A common mode choke is going to use a bifilar winding, which is to say a length of twisted pair, which has a very well-defined interwinding capacitance, which I'm no longer game to try to work out. Thanks for the correction .> > As soon as you start stacking up layers of windings, life gets more difficult and you have to starting thinking about partitioning the winding into successive multi-layer chunks, where there isn't a lot of voltage difference within any one chunk.-- Bill Sloman, Sydney
