rationale between two stage lamps?

Question

Why do you have to turn the little black switch twice for some lamps? What are the intermediary "clicks" for?

Answer 1

You have a 3 way lamp. One click you get is the real off the next click actually would turn the light on to a low setting (say 50 W) if you had a 3 way bulb installed. The next click would turn on the middle setting (100 W). Then the next click would turn on both filaments for 150 W. Thats why with a regular bulb you get off off on on.

The three way bulb has the center post contact like you are familiar with on the screw shell of a regular bulb, but outside of that center contact there is a ring contact. The ring is for the low 50 W setting and the center contact is for the 100 W setting. Both turned on give you 150 W.

Hope this helps, Merry Christmas!

Answer 2

There are lightbulbs (or were, I haven't seen them in quite a while) that were 3 different wattages. The first click was 15-20 watts, the second was30-45 watts and the last was around 100 watts.
If you don't put a 3 way bulb in the lamp, it clicks through until it turns on.
Annoying isn't it, I don't even know if they even make those bulbs anymore. Everyone uses the enery efficient ones.