On 25/02/2011 04:09, gpcheshire wrote:
> I took apart an old remote control and I am realizing that with only one layer of copper the PCB has manages two layers of electrical connectivity. The layer stackup appears to be
> fr4 -> copper -> solder mask 1 -> solder mask 2 -> black conductive material
>
> My question is what is the black conductive material that forms the membrane button contacts? It also forms short traces running over copper traces and connects to copper pads.
It's carbon.
Leon
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Leon Heller
G1HSM