Pancake coil wire calc.

[Tim Shoppa]

Not being a mathematical genius myself, can

someone suggest a formula or other way to determine
how many meters of wire of a specific
diameter it would take to wind a single layer
pancake coil of a specific diameter?

a = inner radius of pancake
b = outer radius of pancake
d = diameter of wire

length = pi * (b*b - a*a) / d

 

[Roger Reed]

Not being a mathematical genius myself, can someone suggest a formula
or other way to determine how many meters of wire of a specific
diameter it would take to wind a single layer pancake coil of a
specific diameter?

Roger Reed

 

[John Woodgate]

I read in sci.electronics.design that Roger Reed

Not being a mathematical genius myself, can someone suggest a formula
or other way to determine how many meters of wire of a specific
diameter it would take to wind a single layer pancake coil of a
specific diameter?

Take the average of the outside and inside diameters and multiply by pi.
That gives you the average turn length. The number of turns is found by
taking the difference between the outside and inside diameters and
dividing that by the wire diameter. Total wire length = average turn
length multiplied by number of turns.

Near enough for jazz, anyway.

 

[John Woodgate]

I read in sci.electronics.design that Tim Shoppa

a = inner radius of pancake
b = outer radius of pancake
d = diameter of wire

length = pi * (b*b - a*a) / d

Yes, but I explained why. (;-)

 

[Tim Shoppa]

I read in sci.electronics.design that Tim Shoppa

Yes, but I explained why. (;-)

Well, mine seemed too obvious to explain, but since you asked:

Length = (area of pancake)/(width of wire)

= (area of circle of outer radius - area of circle of inner
radius) / d

= (pi*b*b - pi*a*a) / d

Tim.

 

[Sjouke Burry]

Not being a mathematical genius myself, can someone suggest a formula
or other way to determine how many meters of wire of a specific
diameter it would take to wind a single layer pancake coil of a
specific diameter?

Roger Reed

Mean diameter times number of windings times PI

Burry.