The C-995 Optical Chopper is a general purpose optical chopper designed for laboratory use. Equipped with a large five-digit LED readout, the C-995 controller enables digital entry of the desired chopping rate directly from the front panel. Additionally the C-995 is equipped with a bi-directional Rs-232 port that equips the user to set the desired chopping rate to a resolution of .001 Hz and to read the status of the instrument. As the unit is designed with a phase-locked-loop control system, the chopping rate may also be synchronized to a user-supplied external clock ranging from 4 Hz to 5 KHz. The controller is then used to read the frequency of the external clock.
The C-995 chopping head is attached to the controller by means of a 10 foot coiled cord. The precision etched blade is fully enclosed for protection from inadvertent damage. There are two apertures and two blade sections (30 slots and 3 slots) for the high and low frequency ranges respectively. The aperture diameter is 15 mm with a slot width of 4.5 mm (30 slot section) or 15 mm (3 slot section). The small 4.75 inch square outline and 2.5 inch maximum depth permits easy integration into compact optical setups. Dual #8-32 mounting holes permit the apertures to be placed at a height as low as 0.75 inches above an optical bench, or with the included ½ inch rod and stand, as high as 13 inches above the mounting surface.