Abstract: A current supply circuit includes a current source producing a first current, a current amplifying circuit for producing a second current having a magnitude a.multidot.I/h.sub.FE from the first current where a is a constant, I is a magnitude of the first current and h.sub.FE is a current transfer ratio of a current supply circuit. The above current supply circuit produces a third current from the second current so that the third current has a magnitude equal to a.multidot.I.

Abstract: A ventilator grill comprises an outer frame made of synthetic resin having an inlet opening and outlet opening, at least one stationary vane extending across an interior of the outer frame, a plurality of through holes provided in each half of the outer frame, arcuate recess provided in an end face of the respective stationary vane, which opposes the inlet opening of the outer frame, and which has a circular arc, and at least one movable vane extending across the stationary vane, which is provided at opposite sides thereof in opposing side walls of the halves of the outer frame with journal shafts received within the through holes for permitting the movable vane to swing about an axis of swing extending through a center of the circular arc of the arcuate recess, and which is provided at one end portion thereof toward the inlet opening of the outer frame with a portion which is in sliding contact with the arcuate recess.