Hermetic feedthroughs have been commercially available for a while now and are often associated with use within industries such as electronics, automotive, and even aerospace and defense applications. Yet, while they grow popular because of the resiliency and electrical integrity that they impart to certain elements, you may still be left to wonder about the details behind this important vessel component.
Before you examine what hermetic feedthroughs are, however, it is important to be familiar with the basics.
What is a feedthrough?
In between two circuit boards (or an enclosure) stands a connector known as a feedthrough. This kind of connector is capable of acting as an electrical conductor for certain environmental barriers or enclosures. Depending on the kind, a feedthrough can transmit low current or low voltage electrical signals (instrumentation feedthroughs) or high current or high voltage ones (power feedthroughs).
What makes a feedthrough hermetic?
A hermetic feedthrough is an electrical conductor that is armed with a hermetic sealing. This kind of connector is completely sealed and made to be airtight.
Hermetic sealing of feedthroughs is done to protect the feedthrough from harsh environments and other forms of extreme and damaging conditions that may surround it. Things like oxygen, moisture, and humidity are kept out as they would otherwise cause the sealed electric components to malfunction once they seep in.
The hermetic sealing used for hermetic feedthroughs can also vary in constitution and function. For example, some are made out of epoxy resins (epoxy hermetic seals) which are effective for sealing off some gases and even certain types of fluids.
On the other hand, some are those that utilize glass-to-metal hermetic sealing technology (such as the ones used in vacuum tubes). They can withstand higher pressure and higher temperature (as opposed to epoxy hermetic seals that operate on lower temperature ranges.