a very common type of analog light meter for photography, where a photodiode (or a photoresistor or a phototransistor) controls a needle whose position on a dial depends on the amount of light received.
The light meter user controls a second needle via a diaphragm wheel and/or an exposure time wheel.
When the two needles match, the exposure will be OK for the scene being metered - under all the caveats exposed in light metering.
Match needle meters used to be very common both in cameras and as stand alone meters. Nowadays the digital meter is prevalent.
It is not clear to me if, in the particular problem of light metering, an analog indication may not be the better (if more expensive) alternative.
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