The first step is to set up the system so that the BEMF compensation is zero, which is done by setting the registers that control the slope of the BEMF compensation to zero. This keeps the applied voltage constant over the operating range. On the scope, one channel is set to show the current and the second channel to show the applied voltage. With no back EMF compensation, the variation of current as the speed increases will be seen. If trigger of the scope is set at the start of a movement, it will display the applied voltage and phase current as the motor accelerates. It will be seen that if the applied voltage remains constant, the current decreases with speed. Since the torque is directly proportional to the current, the torque would be significantly reduced in this operating mode.