When such instruments appear useful to other researchers, we undertake to manufacture and supply them in limited quantities at reasonable cost. An image of moving red cells is transmitted by or reflected from a grating and focused onto a pair of photodiodes connected as a differential pair. Net output photocurrent is amplified to produce a sinusoidal voltage having a frequency determined by the red cell velocity, grating constant and overall optical magnification.
Television camera can be screw-mounted to top of sensor head.
Incorporates power supply, signal processing electronics, digital panel meter, audio amplifier and loudspeaker. Optimum results will be obtained with a long focal length, low magnification projection eyepiece. 2x infinity-corrected eyepiece in a Zeiss ACM microscope. Other eyepieces could require some refocusing of the photodiode condenser lenses. The photodiode optics are adjustable.