Active resistors for reduction of transient power grid noise. An active resistance added in parallel to the operating circuit blocks of a semiconductor device. This resistance increases the damping ratio of the power grid, which in turn decreases the number and the magnitude of oscillations and/or noise resulting from step disturbances of the power supply current. The active resistance can implemented by a transistor connected to a bias voltage. Alternatively, the active resistance can be implemented by a drive transistor with a gain stage, or two active resistors where one responds to overshoots in the current flow and the second active resistor responds to droops in the current flow.