Rear light

[Shoogle]

I have a Smart LED rear light. Occasionally I have to open it to clean the switch contacts. The button you press to turn it on and off contacts directly onto the circuit board but it's made of rubber. How does that work?

[Brucey]

usually the rubber is loaded up with carbon so that it conducts a tiny amount of electricity, which is enough to trigger the switching circuit. It is the same kind of approach that is used in calculators and remote controls for TVs etc.

cheers

[Shoogle]

Thanks, Brucey.