CONTROL BOARD

Control of a circuit or piece of equipment by changes in incident light.

A device to prove the physical state of a required condition and to furnish that proof to the primary safety control circuit.

1. Degenerative or regenerative voltage which is fed back to circuits before its originating point; usually applied to a control anode of a tube or other device. 2. Voltage applied to a grid of a tube (or tubes) or electrode of another device to reduce a condition which has been upset by some external cause.

One of the input variables of a control system, such as motor torque or the opening of a valve, which can be varied directly by the operator to maximize some measure of performance of the system.

A circuit that converts the absolute frequency difference between two input signals to a linearly proportional direct-current output voltage that can be used to drive a meter, recorder, oscilloscope, or other device.

A design technique used in linear control theory in which many or all of a system's closed-loop poles are positioned as required, by proper choice of a linear state feedback law; if the system is controllable, all of the closed-loop poles can be arbitrarily positioned by this technique.

1. An instrument used to measure continuously or at intervals a condition that must be kept within prescribed limits, such as radioactivity at some point in a nuclear reactor, a variable quantity in an automatic process control system, the transmissions in a communication channel or bank, or the position of an aircraft in flight. 2. To use meters or special techniques to measure such a condition. 3. A person who watches a monitor.

1. A value of temperature or pressure at which a control circuit closes. 2. An electrical device that allows current to flow through an electric circuit.

In a bipolar or MOS integrated circuit, the generation of photocurrents by ionizing radiation which can provide a trigger signal for a parasitic pnpn circuit and possibly result in permanent damage or operational failure if the circuit remains in this state.

The condition (pressure, flow, temperature, etc.) that a control system is designed to maintain.