Output calculator program

Bazukaz · 16th December 2005, 10:47 PM

Hi,

My new Output transformer calculation program can be found at
http://bazukaz.puslapiai.lt/

It would be great if somebody could test if it works correctly.

Regards ,
Lukas

Capaciti · 17th December 2005, 12:22 AM

Hi bazukaz,

is that calculator meant for stepup transformers for ESL ?

If yes, there seems to be no dependency on magnetic permeability of the core alloy. For frequency transformers the permeability impacts the lowest frequency to be transformed, since the primary inductance is a result of coil diamter, length of magnetic field and permeability.

I guess your calculator is based on standard transformer calculation.

capaciti

Bazukaz · 17th December 2005, 12:58 AM

Hi,
It is for stepup transformers.
I used formulas for standard tube amplifier output trannies as described at
http://www.valveheart.com/theory/transformer.html

Surprisingly , there is no permeability included in these formulas.
I think formulas are used for standard steel cores.

However , i think that i will have to include permeability in program as well , if i find full formulas.

Bazukaz · 21st December 2005, 12:10 AM

Also , what do you think about air-core transformers ?
I think they should work okay for higher frequencies , say 300-500 hz and above.

Capaciti · 21st December 2005, 07:07 AM

Hi Bazukaz,

air core is best because there is no saturation of the magnetic field.

But you need a lot of windings to achieve appropriate inductance of the primary winding. Even for 300 Hz you still need about 3mH, which might require about 300 windings for a small diameter coil. Now you will need 30000 for 1:100 secondary. This will be a llarge secondary winding suffering from bad coupling and, more critical, from a significant capacity.

capaciti

Bazukaz · 21st December 2005, 05:30 PM

Yes , i know this problem of large capacity.
I imagine core-less transformer as an inductor.
Number of primary turns can be greatly decreased by making diameter bigger.However , this does not affect total wire length by much ,
and capacitance would still be large.Separating transformer into sections would decrease capacitance, but greatly increase leakage inductance , wouldn't it ?

16th December 2005, 10:47 PM	#1
Bazukaz diyAudio Member Join Date: Nov 2005 Location: Vilnius	Output calculator program Hi, My new Output transformer calculation program can be found at http://bazukaz.puslapiai.lt/ It would be great if somebody could test if it works correctly. Regards , Lukas

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17th December 2005, 12:22 AM	#2
Capaciti diyAudio Member Join Date: Nov 2005 Location: Southern Germany	Hi bazukaz, is that calculator meant for stepup transformers for ESL ? If yes, there seems to be no dependency on magnetic permeability of the core alloy. For frequency transformers the permeability impacts the lowest frequency to be transformed, since the primary inductance is a result of coil diamter, length of magnetic field and permeability. I guess your calculator is based on standard transformer calculation. capaciti

17th December 2005, 12:58 AM	#3
Bazukaz diyAudio Member Join Date: Nov 2005 Location: Vilnius	Hi, It is for stepup transformers. I used formulas for standard tube amplifier output trannies as described at http://www.valveheart.com/theory/transformer.html Surprisingly , there is no permeability included in these formulas. I think formulas are used for standard steel cores. However , i think that i will have to include permeability in program as well , if i find full formulas.

21st December 2005, 12:10 AM	#4
Bazukaz diyAudio Member Join Date: Nov 2005 Location: Vilnius	Also , what do you think about air-core transformers ? I think they should work okay for higher frequencies , say 300-500 hz and above.

21st December 2005, 07:07 AM	#5
Capaciti diyAudio Member Join Date: Nov 2005 Location: Southern Germany	Hi Bazukaz, air core is best because there is no saturation of the magnetic field. But you need a lot of windings to achieve appropriate inductance of the primary winding. Even for 300 Hz you still need about 3mH, which might require about 300 windings for a small diameter coil. Now you will need 30000 for 1:100 secondary. This will be a llarge secondary winding suffering from bad coupling and, more critical, from a significant capacity. capaciti

21st December 2005, 05:30 PM	#6
Bazukaz diyAudio Member Join Date: Nov 2005 Location: Vilnius	Yes , i know this problem of large capacity. I imagine core-less transformer as an inductor. Number of primary turns can be greatly decreased by making diameter bigger.However , this does not affect total wire length by much , and capacitance would still be large.Separating transformer into sections would decrease capacitance, but greatly increase leakage inductance , wouldn't it ?