Q. Explain Block diagram of the system?

The block diagram is a pictorial representation of the equations of the system. Each block represents a mathematical operation, and the blocks are interconnected to satisfy the governing equations of the system. The block diagram thus provides a chart of the procedure to be followed in combining the simultaneous equations, from which useful information can often be obtained without finding a complete analytical solution. The block-diagram technique has been highly developed in connection with studies of feedback control systems, often leading to programming a problem for solution on an analog computer.

The simple configuration shown in Figure is actually the basic building block of a complex block diagram. The arrows on the diagram imply that the block diagram has a unilateral property; in other words, a signal can pass only in the direction of the arrows. A box is the symbol for multiplication; the input quantity is multiplied by the function in the box to obtain the output. With circles indicating summing points (in an algebraic sense), and with boxes or blocks denotingmultiplication, any linearmathematical expression can be represented by block-diagram notation, as in Figure for an elementary feedback control system. The expression for the output quantity with negative feedback is given by

The transfer function M of the closed-loop system is then given by

The block diagrams of complex feedback control systems usually contain several feedback loops, which might have to be simplified in order to evaluate an overall transfer function for the system.