Automatic guidance systems comprising accelerometers, gyroscopicall stabilized platforms and computers; gunfire control systems comprising radar receivers, transmitters, radar antennas, and computers; aircraft flight control systems and components thereof; distance meters; altimeters; computers; gyroscopes; magnetic recorders; digital computers; electromechanical servo systems; automatic electromechanical machine tool control systems; potentiometers; and power supplies, magnetic amplifiers, magnetic modulators and electronic amplifiers specially adapted for use with radar equipment, computers, gunfire control systems and aircraft flight control systems