Abstract: A false bar code inhibitor circuit includes a detector, a signal restore circuit, a comparator, a software controller, and a high impedance clamp circuit. Basically, the detector circuit detects the first transition from either high to low reflectivity or low to high reflectivity. The transition triggers the signal restore circuit which is set for a time constant which is longer than the longest possible time needed to encounter another transition during a valid bar code read. Each time a transition is encountered, the signal restore circuit is triggered. The externally adjustable comparator circuit compares the output from the signal restore circuit against a limit, which can be adjusted by the software controller. The output of the comparator drives a clamp which controls when the bar code digitizer can pass an output. With the software controller, the output of the comparator can be controlled allowing for control over the digitizer output.

Abstract: A flow restricting device is described which includes a conduit with a flow inhibitor therein. A plug stem is placed inside a passage in the inhibitor such that it can slide axially, while the head of the plug, which has a larger cross-sectional area than the passage, remains outside the passage. When the fluid pressure upstream of the flow inhibitor is greater than the fluid pressure downstream thereof, the head of the plug is forced against the face of the inhibitor and flow is restricted. To facilitate resetting of the inhibitor, the head allows a small amount of flow to pass to the downstream side, thereby equalizing the pressure across the device.