Abstract: A photodetector circuit which provides both high sensitivity and fast response time by utilizing a coupling circuit connected to a photodetector to reduce the effective value of the stray capacitances between the electrodes of the photodetector. The coupling circuit causes the AC voltages at all of the electrodes to be substantially equal by utilizing a boot-strap action between the various electrodes.

Abstract: A system which processes menus on which food items have been selected. The menu is encoded to have a plurality of detecting paths, with a first transverse row of preassigned markings in selected areas of the paths. Additionally, there are provided uniform indicated spaces arranged in a subsequent transverse row on the menu. Each indicating space is associated with a respective food item. The user selectively places marks in the indicating spaces indicating desired food items. The system detects the preassigned markings in the first row and in response thereto initializes circuitry to register information identifying the menu, specifically the menu diet and meal. The system then detects the additional markings placed in the indicating spaces, and a recording circuit responds to these additional markings to record a count for each food item selected for that particular identified menu diet. The system then tallies the total count for each food item of all of the different types of menus.