Electro-Optical Products Corp.

Low Frequency Optical Modulators-Shutters-Choppers

The Low cost VARIABLE FREQUENCY Shutters/Choppers Models CH-50, CH-60 and CH-61 consist of a blade (vane) mounted on a motor with a limited rotation angle. The position of the blade follows the direction of the current in the motor winding. Current in one direction sets the shutter to the open position and current in the other direction sets the shutter to the close position. Alternating the current cause the blade to open and close the chopper at a frequency range from DC to 12 Hz for the CH-50, or from DC to 50 Hz for the CH-60 and CH-61. This method of chopping is jitter free. High reliability and long life is achieved by eliminating the use of a brush type motor or gear heads. The device can be used at the same time as a shutter that is controlled by the direction of the current.