SYSTEM which provides the necessary controlling torque.In the zero position of the pointer, the control weight HANGS vertically downward and therefore provides no controlling torque.Under the action of deflecting torque, the pointer moves from zero position (from left to right), and the control weight moves in the OPPOSITE direction.Due to gravity, the control weight would tend to come to the original position (i.e. vertical) and thus provides an opposing or controlling torque.The pointer comes to rest at a position where the controlling torque is equal to the deflecting torque.Initially at the zero position of pointer controlling torque is zero. If the pointer deflects the weight position also changes. The system deflects through an angle θ, the control weight tries to restore the pointer back to the zero position.\({T_C} = W\;sin\;\theta \TIMES L\)\({T_C} = K\;sin\;\theta \)Where K = gravity constant.\({T_C} \propto \;sin\;\theta .\)Here the controlling torque is directly proportional to sin θ.Advantages:It is slightly cheaper in manufacturing costs than spring control.It is UNAFFECTED by temperature variations.It is not subjected to fatigue.The controlling torque can be changed easily. Disadvantages:The instrument has to be kept in a vertical position.The control weight increases the weight of the moving system.Gravity-controlled instruments have a non-uniform scale.