Overview
Power Supply
This unit has a very basic linear power supply with a 12 VAC input voltage requirement. A 12 VAC wall transformer (120 VAC input) is supplied with each unit. By using the wall transformer the power system provides ground isolation between the input power and the video circuits. The power supply uses a half wave rectifier design to develop the internal positive and negative voltage rails for the active operational amplifiers.
Package
The package for this unit consists of a solid epoxy block. The internal electronics are assembled and tested before the encapsulation process. During the encapsulation the printed circuit board(s) are placed in a five sided box made of RTV mold parts. The cavity is filled with epoxy and the lid (top) of the mold is inserted. The curing process takes 24 hours. This type of package seals the electronics so water and contamination cannot affect the internal electronics. This type of package also provides superior resistance to shock and vibration compared to a metal or plastic box enclosure.