0 0 votes Despite the presence of negative feedback, control systems still have problems of instability because the components used have nonlinearities. dynamic equations of the subsystems are not known exactly. mathematical analysis involves approximations. system has large negative phase angle at high frequencies. Control Systems gate2005-ec control-systems feedback-systems stability + – admin 647 views answer comment Share Follow Add Sync Questions Print 0 reply Please log in or register to add a comment.