Indicator tubes for transistor logic machines.

5.0 was a standard value in an earlier system, in the early 1930s. Three other things to consider with your quiz resistor: Was the first band twice as thick as the others? If so, it was wirewound, and can be thought of as being one standard size bigger for power dissipation. Was the body color a light tan, rather than standard brown? If so, it was insulated. This part of the standard died quickly, as the method of making resistors out of solid chunks of carbon with no insulation on the outer skin went away. And very unlikely with a 20 percent resistor (no tolerance band), was there one more band, in the fifth position? This was used for some time by the military to signify all sorts of things, like reliability, stability, and so forth. Univac fell in love with the fifth band. -- Will