Sequentially addressable display apparatus with means for reversing direction of transfer

Claim 1

A circuit for controlling the energization of a multi-element load such that energy is applied to predetermined elements of said multi-elements of said load in a predetermined sequence, said circuit comprising a plurality of stages, each stage being substantially identical and comprising: a. a load element including a gaseous discharge tube, with the tube having first and second terminals operatively associated therewith, said first terminal being coupled to a point of substantially fixed potential, said discharge tube having a certain ignition potential and a relatively lower sustaining potential; b. a triac switching device for each of said load elements; c. conductive means individually coupling each of said second electrode terminals of each of said discharge tubes to thereby couple each of said gaseous discharge tubes in series with one of said triac switching devices across an electrical current supply such that when one of said triac switching devices is triggered, current flows through that certain one of the load elements coupled thereto; d. a triggering network for generating triggering pulses for each of said triac switching devices in said stages and in a predetermined sequence, each of said triggering networks comprising: 1. the gaseous discharge tube of said load element being of the type which fires when the potential thereacross exceeds said ignition potential and which is extinguished when the potential thereacross falls below said sustaining potential; 2. means connecting said first terminal of said discharge tube to a point of fixed potential; 3. input and output circuit means each including a unidirectional current conducting device individually connecting said second terminal of said discharge tube to a certain individual pulse source, each pulse source having pulse outputs with first and second amplitude values; and 4. a capacitor coupled between said output circuit means of one stage and the input circuit means of an adjacent stage, the arrangement being such that when a first pulse with a certain first amplitude is applied to said output circuit means current flows to charge said capaciTor and when a second pulse with a certain second amplitude is coincidentally applied to said input circuit means the potential across said discharge tube falls below said sustaining potential.