The problem of mechanical switches not working wellsparkle wrote:One more consideration is the quality of the switch contacts themselves, a separate issue from bounce.mikerd wrote:...I still occassionally get a phantom dim output light. But it is sufficiently different from an 'on' that I can explain it to my students...
Yet, the same contacts may clean up, and work well for a while thereafter, if subjected to a low voltage load of tens to hundreds of milliamps, the so-called wetting current (or sealing current) you can look up in Wikipedia and elsewhere.
in low voltage low energy "digital" or "logic" circuits is
an old problem, dating back at least a few decades.
The solution adopted by many switch companies is to
construct wiping contacts that provide self-cleaning
without the need for deliberate contact arcing.
I think the OP has several issues with their design
beyond mechanical switch selection.
Here's a couple of references for anyone interested
in wiping action and switch de-bounce.