Kepco OPS GROUP IX Operational Power Supplies are a-c source powered devices which can be utilized as d-c high voltage/low current sources or, operationally programmed, as unipolar power amplifiers. Integrated circuits in the OPS "front end" contribute very low offsets and allow accurate tracking of all input signals. The OPS GROUP IX Operational Power Supplies feature sharp crossover between the voltage and current operating modes, ensuring accurate limiting over the full output current range and completely short circuit proof operation. Low output shunt capacitance permits rapid voltage programming in the voltage mode and fast load voltage recovery in the current mode of operation. 1-5 The OPS circuitry, in its simplest form, can be represented by one of the simplified operating diagrams in Section 111 of this manual. A high voltage/low current d-c source is controlled by series pass elements (vacuum tubes), which, in turn, are driven by two high gain wide-band control systems. These control systems consist of two independently programmable channels, operating into a common driver stage. The driver stage is coupled to the series pass tubes via an "exclusive OR" gate, so that only one channel is in control of the OPS output at any time.