Abstract: A transducer for converting position displacement into a digital output signal correlated to the current placement state. An opaque vane is operably movable transversely in a radiation path between a radiation source and two juxtaposed radiation sensitive diodes. Discrete signals, emitted by each of the diodes in relation to the amount of their respective surface areas exposed to radiation, are converted by logic and a dual slope integrating analog-to-digital converter to a useful digital output signal. In one embodiment, both diodes are subject to having exposed radiation interrupted by the vane. Logic supplies the difference of the diode signals to the converter as its measured input while a sum signal is supplied thereto as its reference input. The ratio of input signals is then emitted by the converter as an output signal indicative of the current placement state.

Abstract: Pressure regulator system and apparatus for producing a controlled output pressure corresponding to a pre-programmed BCD set point command. Measured values of output fluid pressure emitted from the regulator is applied in BCD signal form to electronic logic in which the measured signal is compared with the signal of the set point. In response to a determined differential between signals, output pressure is changed in a series of repetitive but rate variable differential reduction steps until set point pressure is achieved. In each step a D. C. motor under control of a logic actuated servo-system operates a force balanced air system to adjust a primary control pressure which in turn operatively resets the output pressure of the regulator.