goldsilverpro said:Hybrid circuits are simply circuits that are made up of components using a variety of technologies. The term is fairly generic and is used for many different things. They can be such things as small circuit boards containing both analog and digital devices.
The hybrid circuits I have mainly worked with are white alumina substrates with thin or thick film circuitry. They generally have components such as chip capacitors or IC chips. They are usually mounted in a hybrid package as in these links.
http://www.technographmicro.com/thick_film_hybrids.php
http://www.pcmag.com/encyclopedia_term/0,2542,t=hybrid+microcircuit&i=44544,00.asp
The one in the Wiki link above, given by qst42know, is encapsulated.
Thick film circuits are made by silk screening metallic pastes on the alumina substrate and then firing them. Both the substrate and the pastes contain about 4-5% glass frit which melts when fired and holds everything together. The more valuable ones utilize Pt (matte gray colored) or Au (matte yellow) conductor traces.
http://www.emtronhybrids.com/conductors.htm
Often, you will see black thick film Ruthenium oxide resistors (usually square or rectangular) screened over the conductor traces. If you look at these with a loupe, you will usually see a fine line cut into them with a miniature sand blaster or laser. This is used to adjust (trim) the resistance.
We once had 2 drums (very heavy) of reject alumina PGM and Au thick film circuits, not mounted in packages - circuits only, that refined out at $120,000.
Thin film circuits are similar, except the traces are sputtered or evaporated on. The thin film traces are bright and shiny. As a refining item, thin film circuits are far less valuable than thick film circuits.
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