Pulsar light sensor

[egomon]

Hello. My Pulsar watch light sensor is not attached and I was wandering is it soldered or with silver epoxy attached to the pcb?

[bruce wegmann]

It was done with conductive silver epoxy...CdS photocells can't tolerate the heat of soldering. Best material I've found is made by MG Chemicals, out of Toronto, Canada. The silver particles (micron-sized) are produced by precipitation out of solution, and provide a more uniform and reliable conductive path. I've even been able to repair broken wire bonds with this.