# Single Layer Coil Design ChartMarch 1955 Popular Electronics

 March 1955 Popular Electronics Table of Contents Wax nostalgic about and learn from the history of early electronics. See articles from Popular Electronics, published October 1954 - April 1985. All copyrights are hereby acknowledged. articles from Popular Electronics.

Single layer coil design charts (aka nomographs) are a dime a dozen on the Internet. Here is RF Cafe's 0.083¢ contribution. A couple examples of usage are included. You're welcome.

Single Layer Coil Design Chart

This chart can be used to find inductance of a coil when dimensions and number of turns are known, or to find specifications to give a desired Inductance. Draw a line between either T and L or d and l/d, whichever are both known. Draw a second line between remaining known quantity and point of intersection of first line and unmarked vertical line. Extend second line to scale for unknown quantity and read answer.

EXAMPLE A: We have a coil 5" in diameter, 19 turns, 37 turns per inch, and wish to find the inductance. l = 19/37= .52"; l/d = .52/5 = .104. Draw a line between d=5 and l/d = .104. Draw a second line from T = 37 through the intersection point to the L scale. Read the answer, 100 microhenries.

EXAMPLE B: We require the number of turns of a coil 5" in diameter, wound 37 turns per inch, to give 100 microhenries. Draw a line between T = 37 and L = 100. Draw a second line from d = 5, through the intersection point, to the l/d scale, and read l/d = .104. Then l = 5 x .104 = .52 Inches. The number of turns is .52 x 37 = 19, approximately.

Single Layer Coil Design Chart

Posted April 16, 2013