# Post History

##
**#3: Post edited**

- The relative volumes of cylinders with the same height are proportional to the square of their diameter. Hopefully you can see this is true without further explanation.
- The relative volume of wire on a full spool is therefore
- D<sup>2</sup> - D<sub>empty</sub><sup>2</sup>
- Now take the ratio of the current to the full wire volume using the above formula:
- Fullness = (D<sub>curr</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>) / (D<sub>full</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>)
- Note that D<sub>full</sub> and D<sub>empty</sub> are constants for your purposes. To get remaining length of wire from the fullness fraction only requires another constant. During use, you therefore only need to perform the calculation:
~~ WireLength = (D - K<sub>1</sub>)K<sub>2<sub>~~- You can write K<sub>1</sub> and K<sub>2</sub> on each spool when you receive it full.

- The relative volumes of cylinders with the same height are proportional to the square of their diameter. Hopefully you can see this is true without further explanation.
- The relative volume of wire on a full spool is therefore
- D<sup>2</sup> - D<sub>empty</sub><sup>2</sup>
- Now take the ratio of the current to the full wire volume using the above formula:
- Fullness = (D<sub>curr</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>) / (D<sub>full</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>)
- Note that D<sub>full</sub> and D<sub>empty</sub> are constants for your purposes. To get remaining length of wire from the fullness fraction only requires another constant. During use, you therefore only need to perform the calculation:
- WireLength = (D
**<sup>2</sup>**- K<sub>1</sub>)K<sub>2<sub> - You can write K<sub>1</sub> and K<sub>2</sub> on each spool when you receive it full.

##
**#2: Post edited**

- The relative volumes of cylinders with the same height are proportional to the square of their diameter. Hopefully you can see this is true without further explanation.
- The relative volume of wire on a full spool is therefore
- D<sup>2</sup> - D<sub>empty</sub><sup>2</sup>
- Now take the ratio of the current to the full wire volume using the above formula:
- Fullness = (D<sub>curr</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>) / (D<sub>full</sub><sup>2</sup> - D<sub>empty</sub><sup>2</sup>)

- The relative volume of wire on a full spool is therefore
- D<sup>2</sup> - D<sub>empty</sub><sup>2</sup>
- Now take the ratio of the current to the full wire volume using the above formula:
- Note that D<sub>full</sub> and D<sub>empty</sub> are constants for your purposes. To get remaining length of wire from the fullness fraction only requires another constant. During use, you therefore only need to perform the calculation:
- WireLength = (D - K<sub>1</sub>)K<sub>2<sub>
- You can write K<sub>1</sub> and K<sub>2</sub> on each spool when you receive it full.