The SmartFan Aurora DC motor speed control is an off-the-shelf solution for analog control of DC motors, fans, and pumps. It accepts analog control signals (0 to 5V, 0 to 10V, 0 to 20 mA, and potentiometer) and adjusts the voltage to the motor from 0% to 100% output voltage. Aurora operates from an AC (12-48V) or DC (10-72V) power source and can control 12-, 24-, or 48-Vdc motors with a current rating up to 6A. Power efficiency is typically greater than 90% and full analog feedback provides closed loop regulation. Price is $76 each/200. Control Resources Inc. Littleton MA. (978) 486-4160.