Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com .
I bought some T-37's and T-50's. The problem is... they're not color coded,
and not identified by mix. So I have mystery toroids T-37-?? and T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

Thanks for all assistance.

Jim Shrum - KC9FFX

Look at the tables in the ARRL Handbook, in 2003 it was in Chapter 24, for
tables with the info you need to calculate the inductance on a given core
with a certain number of windings. You need to solve for AL obviously since
you want to find your core.

Uwe

in article , J Shrum at
wrote on 4/21/04 18:55:

Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com .
I bought some T-37's and T-50's. The problem is... they're not color coded,
and not identified by mix. So I have mystery toroids T-37-?? and T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

Thanks for all assistance.

Jim Shrum - KC9FFX

Look at the tables in the ARRL Handbook, in 2003 it was in Chapter 24, for
tables with the info you need to calculate the inductance on a given core
with a certain number of windings. You need to solve for AL obviously since
you want to find your core.

Uwe

in article , J Shrum at
wrote on 4/21/04 18:55:

Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com .
I bought some T-37's and T-50's. The problem is... they're not color coded,
and not identified by mix. So I have mystery toroids T-37-?? and T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

Thanks for all assistance.

Jim Shrum - KC9FFX

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

The equation goes;

Turns = 100SQR(uH/Al) where Al is the inductance in uH per 100 turns)

and

15 = 100SQR(150/Al)

and (0.15)^2 = 150/Al

and

150/0.0225 = Al = 6666.

You have ferrite not powdered iron.

For Ferrite, it's just the conversion

Turns = 1000SQR (mH/Al) where Al = mH/1000 turns

15 = 1000SQR(.15/Al)

and
0.15/0.00225 =66 which looks like, (for T50 core) material 61

W4ZCB

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

The equation goes;

Turns = 100SQR(uH/Al) where Al is the inductance in uH per 100 turns)

and

15 = 100SQR(150/Al)

and (0.15)^2 = 150/Al

and

150/0.0225 = Al = 6666.

You have ferrite not powdered iron.

For Ferrite, it's just the conversion

Turns = 1000SQR (mH/Al) where Al = mH/1000 turns

15 = 1000SQR(.15/Al)

and
0.15/0.00225 =66 which looks like, (for T50 core) material 61

W4ZCB

and
0.15/0.00225 =66 which looks like, (for T50 core) material 61

And the T37 core, at 2200, looks like 75 material, look out for it's bulk
resistivity which is pretty low.

W4ZCB

and
0.15/0.00225 =66 which looks like, (for T50 core) material 61

And the T37 core, at 2200, looks like 75 material, look out for it's bulk
resistivity which is pretty low.

W4ZCB

"J Shrum" wrote in message
news
Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com
..
I bought some T-37's and T-50's. The problem is... they're not color
coded,
and not identified by mix. So I have mystery toroids T-37-?? and
T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH

Al = 150uH * square(1/15) = 667


T-37 9turns 30awg = ~180uH

Al = 180uH * square(1/9) = 2200


See if these Al values look realistic. Even if not, this is the value of
inductance of one turn for the core which some manufacturers used as Al many
years ago when I worked with the devices. The inductance ratio varies as the
square of the turns ratio.

John

"J Shrum" wrote in message
news
Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com
..
I bought some T-37's and T-50's. The problem is... they're not color
coded,
and not identified by mix. So I have mystery toroids T-37-?? and
T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH

Al = 150uH * square(1/15) = 667


T-37 9turns 30awg = ~180uH

Al = 180uH * square(1/9) = 2200


See if these Al values look realistic. Even if not, this is the value of
inductance of one turn for the core which some manufacturers used as Al many
years ago when I worked with the devices. The inductance ratio varies as the
square of the turns ratio.

John

Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com .
I bought some T-37's and T-50's. The problem is... they're not color coded,
and not identified by mix. So I have mystery toroids T-37-?? and T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

Start at http://www.amidoncorp.com/aai_productselection.htm

Follow the "Iron Powder Cores" and "Ferrite cores" links.

The formulas, and the specific inductance index A(L) values for
various toroid formulas, are on those pages.

It's important to note that the A(L) values are stated in different
units for the two toroid types. For iron-powder cores, it's given as
"microhenries for 100 turns", while for ferrite cores it's
"millihenries for 1000 turns".

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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