IS205AOCAG1A

About the IS205AOCAG1A

The IS205AOCAG1A is a board component manufactured by GE for the Mark VI system.  The Mark VI, which was one of the final Speedtronic systems released by GE, is a gas/steam turbine management program.  It is built around a central control module that is responsible for most of the protection, control, and monitoring within the system.

The IS205AOCAG1A functions as an Octal Analog Comparator.  Comparators perform the basic task of comparing voltages, usually by accepting analog signals as an input and producing a binary signal as the output.  Comparators are often trimmed in such a way to provide superior switching times. However, this is often at the expense of the board’s frequency-response correction.  Comparators tend to use internal hysteresis to impede oscillation at output.

It is important to note the very small size of the IS205AOCAG1A component; this board is only a few inches long.    The board is populated by components on both surfaces. This includes twenty-six resistors (located on both sides of the board,) eight diodes (located on one side,) five capacitors (located on one side,) two integrated circuits, and one backplane connector.  The backplane connector straddles two sides of the board, with pins alternating from side-to-side. Both integrated circuits are marked LM239A. These are quad voltage comparators with low input biasing current and offset current, and a wide single supply voltage range. The board is drilled in one corner and is marked with codes like 0902, TTM-RR-4, 94V-0, 6BA01, and A0CA. Manufacturer publications like datasheets and manuals will give the user more information on the board’s use, specifications, and installation location.