Edge lit displays represent another class of electronic numeral display that came into wide use during the narrow time in human history when electronics had advanced enough to cause electrical number displays to be desperately needed despite the fact that solid state LEDs had not yet been invented. Edge lit displays consist of a stack of glass plates with numbers etched or dimpled into their faces. These plates are enclosed in a frame and lit from above or below by an array of incandescent lamps. Edge lit display are bright and easily visible and have a rather distinctive appearance, but as with other stacked-digit displays, the numbers located in the rear of the digit stack are obscured by other digit outlines and can be rather hard to read.
The edge lit display example shown here, manufactured by NLS, is a fairly typical example of edge lit display appearance. NLS popularized the use of edge lit number displays in it's line of first generation digital voltmeters, which used electromagnetic uniselectors to measure and display a voltage measurement on a rack of edge lit displays. In modern times, edge lit display have become popular for their use in vintage clock and electronics projects where incandescent bulbs can be easily replaced with LEDs
Special thanks to John Taylor, of Taylor Electronics Services, for donating this unusual part.
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