I am busy salvaging circuit boards while my mind resets and a new idea for a build takes form. Yesterday I disassembled a circuit board from a Planmeca X-Ray machine (a company from Finland) that dated from the 1990s. Among the salvaged components were a few that looked like this:

 

  

 

I have seen something similar in other equipment that was packaged in brown ceramic but this is the first time I have come across this style. I believe I even knew the name of this type of circuit that was popular about 30 to 40 years ago but the name eludes me at this time.

 

I am curious if any one knows more about them. Were they general electronic parts or were they manufactured for specific applications and OEM only? So far I have not been able to get the internet to cough up anything about them.

 

Thanks

 

John