SIGMA : Jurnal Sains Dan Teknologi, Vol. 11, No. 2, Juli 2008 (Rak 7-N : Sains Dan Teknologi) ABSTRAK : This paper discusses optimal control of continuous-time systems, especially continuous-time Linear Quadratic Regulator (LQR). The LQR will be implemented to determine the optimal feedback control of a scalar system. The result of scalar system simulation showed that as the coefficient of state in performance index increases, the state is forced to zero at the expense of an increase in control energy.