The Sherborne Sensors' A200 range of Servo Accelerometers measure vector acceleration with high accuracy using a closed loop force balance torquer mechanism. A pendulous mass develops a torque proportional to the product of its mass unbalance and the applied acceleration. The movement of the mass is detected by a position sensor whose output signal is connected to a servo amplifier. The resulting current is fed into the torque motor which then develops a torque exactly equal to, but directly opposed to the initial torque from the pendulous mass. The mass then stops moving, assuming a position minutely differing from it's initial zero 'g' position. Simultaneously, the current to the torque motor is fed through a stable resistor to provide an output voltage proportional to the applied acceleration. The system is electronically damped by means of a phase advancing network within the integrated servo amplifier. By adjusting the parameters of the servo amplifier and related electronic networks, the operating characteristics of a servo accelerometer can be optimised to suit a particular application.