Home >> Collecting >> Antiques

How to Identify Antique Resistors

The value of an antique resistor is not marked on the resistor, instead it's color coded on the outside. The body is one color, the end another color and a spot or band in the center is another color. You put the colors together to determine the resistors ohmic (measurement of the resistance to electricity) value. Some of the newer antique resistors have circles in the center, with standard commercial resistor having four bands and the military having five bands. The colorful glass resistors are used to repair old radios.

Things You'll Need

Pencil
Paper

Instructions

- 1
  Write down the colors on the antique resistor. The primary colors are black. brown, red, orange, yellow, green, blue, violet, gray and white.
- 2
  Use this chart to figure the resistance value in ohms. The black represents 0, brown-1 the red-2, the orange-3, yellow-4, green-5, blue-6, violet-7, gray-8 and white represents 9.
- 3
  Figure the numbers by looking at the color of the resistor. If the resistor body is red, the first number will be 2. If the ends are orange the second number is 3.
- 4
  Compute the number of zeros by the color of the dot in the middle. The number of zeros are equal to the number a color represents. If the dot is blue and blue represents 6, there are 6 zeros after the first two digits.
- 5
  Computed resistance in ohms for the resistor with a red body, orange ends and a blue dot in the middle is 23,000,000.

Antiques