Electronic control for automatic developability system

Claim 1

A process monitoring circuit for generating a periodically reversible bias across electrodes under normal process conditions and for developing constant low intensity field under abnormal conditions comprising: a comparator for generating a first signal in response to normal process conditions and a second signal in response to an abnormal condition, a pair of electronic gates, each gate having first and second inputs and an output, the output of the comparator being coupled to said first gate inputs, oscillator switching means for providing two pulse trains, each train characterized by first and second voltage levels, said trains displaced in phase by 180°, said trains being coupled to said second gate inputs, the gates providing, in response to said first signal from the comparator, two pulse trains of a character similar to those received from the oscillator switching means, and, in response to said second signal, a constant level signal, and switching means coupled intermediate the gates and the electrodes and responsive to the pulse train output of the gates to periodically apply reversible biases to the electrodes, and responsive to the constant level gate output to apply constant equal biases to each electrode.