A variable resistor,called a potentiometer,is shown in Figure. The resistance is varied by moving a wiper arm along a fixed resistance. The resistance from A to C is fixed,but the resistance from B to C varies with the position of the wiper arm from A to C,draw a block diagram of the potentiometer showing the input variable,the output variable,and (inside the block)the gain,which is a constant and is the amount by which the input is multiplied to obtain the output.