3 ms·
> used glass-metal feedthroughs I wonder if this is still the case. I took a WD helium hard drive apart recently and I think I saw just a PCB glued in place fo
by alright2565 2y ago
> used glass-metal feedthroughs
I wonder if this is still the case. I took a WD helium hard drive apart recently and I think I saw just a PCB glued in place for the electrical signals. Probably made from very special materials, but it looked just like usual.
- adrian_b 2y agoGlass-metal feedthroughs have been the standard means of connecting semiconductor devices during the first decade of their existence, when they were packaged in hermetic cases made of either metal or glass. Their main problem is to use pairs of special kinds of glasses and of metal alloys that are matched in their thermal expansion coefficients. After 1960, better passivating methods for the semiconductor chips have been developed, so the hermetic packages have been slowly replaced with plastic packages for most applications. It is likely that the PCB glued in place covers the glass-metal feedthroughs, which have metal pins that are inserted in connectors soldered on the PCB. It is impossible for any case that contains helium to have any part made of plastic in any of its walls. Plastic parts like a PCB can only be attached externally.