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     Conductor  is an object or type of material that allows the flow of charge ( electrical  current) in one or more directions. Materials made of metal are common  electrical conductors . A semiconductor is a solid substance that has a conductivity between that of an insulator and that of most metals , either due to the addition of an impurity or because of temperature effects . Devices made of semiconductors, notably silicon , are essential components of most electronic circuits. A Silicon crystal is the purest form of Silicon.  A silicon atom has four valence electrons, and thus it requires another four to complete its outermost shell. This is achieved by sharing one of its valence electrons with each of its four neighboring atoms. Each pair of shared electrons forms a covalent bond. The result is that a crystal of pure or intrinsic silicon has a regular lattice structure, where the atoms are held in their position by the cova...

In last blog we learned about how we can get Relative Gain Array by two stages. If you haven't gone through yet, click below link: Multi-variable System In this blog, we will analyze different conditions for Relative Gain Array. RGA provides a quantitative criterion for for selection of control loops that would lead to minimum interaction among the process. Direct & Indirect Effects of control loop interaction Let us open the loops and detach the controllers from the process. Let us keep u2  constant and introduce step input in u1 . That would yield a static gain and indicate direct effect of input on output. Let us now close only the loop 2 and attach the corresponding controller with the process. Let us now introduce a step input in u1 while maintaining y2 at its desired setpoint through the loop 2 controller. That would yield another open loop gain and indicate direct as well as indirect effect of u1 on output y1 . Let's analyze the following conditions for RGA: D...

What is Multi-variable System? As name suggests, multi-variable means multiple parameters included in system. The control system which have more than one input & more than one output, which is called Multi-variable System .  This kind of system have as many inputs and outputs as needed to control the process. In multi-variable system, the interaction in between variables are very strong. If any disturbance occurred, then response of the system will change. The changes in signal path can be in two way, direct & indirect. Let's learn it with example; Example of Process As above shown, consider the process having two inputs u1, u2 and two outputs y1, y2. Suppose if any kind of change occurred in input u1, it may have two effects. Changes in output y1 ( Direct effect ) via measured value interaction Changes in output y2 ( Indirect effect ) via control loop interaction This process interaction cause potential problems in systems; It will destabilize the closed loop system T...