Holmarc's optical chopper is a highly stable device through out the frequency range. The basic system consists of a control unit, a rotating head and a set of four chopper discs. A DC motor drives the rotating head in closed loop control. Chopping discs are replaceable at user end with ease. A heavy base to which the rotating assembly is fixed provides stability during operation . Optical axis height is approximately 100 mm. The required disc depending on the frequency can be fixed to the rotating head. This system can provide wide range of frequencies (10Hz - 3.7kHz.) A wide selection of additional discs and accessories are available to extend the frequency range and to satisfy individual requirements. Frequency is displayed directly on the digital display of the control unit. The easy-to-interchange blades are made of corrosion protected material for durability.