So I am working on a project where I want a big dumb red button. I got a light-duty industrial illuminated pushbutton from AliExpress (this one, if you want to know: 22mm 3v-6v, non-locking). It looks like it will be fine to use, but I’m confused about the LED. It seems to work regardless of which orientation, and I briefly tried it without a resistor, and that was fine too.
I’d like it to be fairly bright, but as someone who has blown up his share of through-hole diodes in his day, I would rather not mess up this one, since without the diode light it’s sad and dumb, rather than glorious and dumb. :-)
My question is this: is there any standard for these illuminated switches that would make it likely that there is some resistor and diode stuff going on inside the housing, such that this thing is fine to just wire up and use?
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You can test if it has a built-in resistor by measuring current draw - just put a multimeter in series with the LED circuit at different voltages and if the current stays reasonably constnat (doesn’t increase linearly with voltage), theres probably a resistor in there already.
LOL, I took a leap of faith that it was there, and I was right, or else the use case was so light that it hasn’t mattered. That keyboard has been my work daily driver for probably 9 months now, and the LED still works fine.