Pressure Transmitters

Okay, I'm an apprentice Instrument Tech and know how to calibrate Pressure/Flow/Level Transmitters with ease. However, could any of you more experienced colleagues inform me as to how a transmitter recieves the process energy ( pressure ) and turns this into an electrical output?

Do any of you have any simple drawings of the insides and a simple explanation of the electronics/mechanical workings from within a pressure transmitter.

I've searched breifly online and got directed here... Other results were far too technical and in-depth for what I'm wanting to know.

Thanks.