pilot lamp

American  

noun

1. an electric lamp, used in association with a control, which by means of position or color indicates the functioning of the control; an indicator light or a control light.

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pilot lamp British  

noun

1. a small light in an electric circuit or device that lights up when the circuit is closed or when certain conditions prevail

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Etymology

Origin of pilot lamp

First recorded in 1880–85

Example Sentences

This controls, as already described, the circuit of the pilot lamp common to the same group of line lamps.

From Project Gutenberg

Ignoring at first the pilot relay and the pilot lamp, it will be seen that each of the tip-spring anvils of the jacks is connected to a common wire 1 which is grounded.

From Project Gutenberg

The details of the operator's cord circuit and of the pilot lamp and night alarm circuits will be clear from the diagram.

From Project Gutenberg

When it does attract its armature it causes illumination of the pilot lamp in the same way that the line relays cause the illumination of the line lamps.

From Project Gutenberg

This pulls up the line relay and lights the line lamp, the pilot relay also pulling up and lighting the common pilot lamp which is not shown.

From Project Gutenberg