a travel - limit circuit having a dc motor for a lens by which the endurance of the motor can be improved while at the same reducing the rebound due to the inertia of the moving body at a travel extremity . the travel - limit circuit has a lens motor that drives , e . g ., zoom lens groups . limits which detect whether the lens group has reached their travel extremities at which mechanical stoppers are provided . the motor driving circuit , which drives the lens motor and the limit switches , activates a short break by short circuiting the pair of input terminals on the lens motor via diodes while cutting current flow from the motor driving circuit for the lens motor upon detection that the lens groups have reached their travel limit .