Time responsive variable voltage power supply

DETAILED DESCRIPTION What is claimed is: 1.
A variable voltage power supply comprising: (a) an input adapted to be connected to an alternating voltage source; (b) an output; (c) latching switch means having a terminal connected to said input, another terminal connected to said output, and a control terminal adapted to have applied to it a switching signal for latching said switch means into a closed condition to permit current flow between said input and said output during a sub-cycle of said alternating voltage, said switch means switching to an open condition to prevent further current flow therethrough in response to completion of said sub-cycle of said alternating voltage; and (d) control means for latching said switch means into a closed condition during each said sub-cycle of said alternating voltage, said control means including: (1) means for generating a voltage level setting signal; (2) first counting means having an incrementing input and a decrementing input responsive to a first source of periodic electrical signals, said first counting means including means for storing a count representative of the last selected output voltage level during the last on output state of said power supply; (3) second counting means responsive to a second source of periodic electrical signals, said second counting means having a reset input responsive to the zero crossings of said alternating voltage; (4) comparing means for comparing the counts in said first and second counting means, respectively, said comparing means providing when the compared counts are equal said switching signal to said control terminal causing said switch means to latch into a closed condition and permitting current flow between said input and said output; and (5) timing means responsive to said voltage level setting signal for: a.
inhibiting a change in output state of said power supply when the duration of said voltage level setting signal is less than a first predetermined period of time; b.
effecting a change in output state of said power supply when the duration of said voltage level setting signal is greater than said first predetermined period of time and less than a second predetermined period of time; and c