ECE 201 Circuit Theory I 1

Determining Dot Markings

ECE 201 Circuit Theory I 2

Arbitrarily Select One Terminal

• Mark with a dot

ECE 201 Circuit Theory I 3

Assign a Current to the Terminal

ECE 201 Circuit Theory I 4

Apply the Right-Hand Rule

• Determine the direction of magnetic field established by the current

ECE 201 Circuit Theory I 5

Pick one terminal of the second coil

• Assign a current into this terminal

ECE 201 Circuit Theory I 6

Apply the Right-Hand Rule

• Determine the direction of magnetic flux established by this current.

ECE 201 Circuit Theory I 7

Compare the directions of the fluxes

• If the fluxes have the same direction, place a dot at the terminal where the test current enters.

• If the fluxes have different directions, place a dot on the terminal where the test current leaves.

ECE 201 Circuit Theory I 8

Summary

ECE 201 Circuit Theory I 9

Let’s Try Some Examples

ECE 201 Circuit Theory I 10

ECE 201 Circuit Theory I 11

ECE 201 Circuit Theory I 12

ECE 201 Circuit Theory I 13