Combinator light?

[BillH]

There appears to be a tiny light on the output of decider and arithmetic combinators. Presumably it's supposed to light up when a signal is output, but that doesn't always seem to be the case. I've set up a simple AND gate in my game to control light oil cracking -- one decider combinator is set to output signal A if "rocket fuel > 99", and the other one outputs signal B if "petroleum < light oil". The outputs of these two are connected to an arithmetic combinator outputting a red signal on "A*B", which is connected to my pump. In operation, as petroleum goes above and below the light oil value, the lights on the B combinator and the arithmetic combinator go on and off. The A signal combinator stays on (while I'm not preparing a rocket, that is), and though I see that it's outputting a signal, the output light doesn't come on. Is this intended?

[ssilk]

Pic please. With this description alone nobody can follow.

[XKnight]

Combinator blinks each time when its input value is changed.

[ssilk]

Ah, I didn't know it. I also wondered... now it makes all sense...