# DIY Audio & Video

## Inductor Designer / Calculator Help

Use the Inductor Designer.

When winding your own coils, make sure you use special Magnet (electric motor) wire. Also, you will need to wrap the wire around some type of cylinder. When you are done making the coil, remove this cylinder, and keep the coil together using nylon wire. You can also use wire ties, tape or use a hot glue gun. If you leave in the cylinder that you wrapped the wire around, it will affect the inductance of the coil. You should also stabilize the coil by dipping the coil in a wire varnish like Glyptol. If you need to connect different segments of the magnet wire together to make the coil, simply scrape off the enamel insulation and solder the different segments together. You do not need to reinsulate the connection. Just make sure that two solder segments do not contact each other.

Da = Average Turn Diameter in inches

Cl = Coil Length in inches

T = Number of Turns

These calculations do not take into consideration the thickness of the wire insulation. Magnet wire uses enamel insulation which is very thin so it wont make much of a difference. Still, after winding the coil test it with a meter. Then make any necessary changes (adding or removing turns) to get the desired inductance. Use the following table for wire thickness and to determine the DCR of the coil.

Wire Gauge
(AWG)
Wire Size
(inch)
DC Wire Resistance
(Ohms per 1000 ft @ 25 deg C)
Length per Pound
(Feet)
80.1285.640520.01
90.1144.807725.23
100.10191.01831.82
110.09071.28440.12
120.08081.61950.59
130.07202.04263.80
140.06412.57580.44
150.05713.247101.4
160.05084.094127.9
170.04535.163161.3
180.04036.510203.4
190.03598.210256.5
200.032010.35323.4
210.028513.05407.8
220.025316.46514.2
230.022620.76648.4
240.020126.17817.7