Hawkins Electrical Guide v. 06 (of 10) / Questions, Answers, & Illustrations, A progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications

by N. Hawkins

Ans. The negative electrode resistance.

Ques. What must be done before any current can pass?

Ans. The negative electrode resistance must be overcome.

When once started the current will continue to flow, meeting with practically no resistance as long as the current is uninterrupted.

Ques. What will happen if the current be interrupted even for the smallest instant of time?

Ans. The negative electrode resistance will re-establish itself, and stop the operation of the bulb.

Ques. How is the negative electrode resistance overcome?

Ans. The bulb is tilted or shaken so that the space between the mercury electrodes is bridged by the mercury.

Ques. What happens when the bulb is tilted?

Ans. Current then passes between the two mercury electrodes from the starting transformer and the little stream of mercury which bridges the space between the electrodes breaks with a spark as the bulb is returned to its vertical position.