Abstract: A three-mode analog controller for regulating a signal corresponding to a controller variable to produce a controller output, comprises an integrating circuit, a proportional circuit, and a derivative circuit. The integrating circuit includes a reset adjustment for varying a time constant thereof, the proportional circuit includes a gain adjustment for varying the gain thereof and the derivative circuit includes a rate adjustment for adjusting the rate of derivation of the signal. The gain adjustment comprises a photoresistor associated with a source of light which is provided with varying current corresponding to the signal to vary the resistance of the photoresistor and, thus, the gain value. The reset and rate adjustments may also comprise photoresistors with light sources or may be formed of field affect transistors each controlled by a circuit and remotely located potentiometer or variable voltage source.

Abstract: A hybrid analog function generator producing an adjustable time delayed analog output signal varying in predetermined non-linear relationship with an analog input signal wherein the analog input signal is converted to a first digital signal addressing a programmable read only memory which is programmed to produce a second digital signal, corresponding to the predetermined function of the analog input signal, which is converted to a proportional analog output signal and wherein a selected digital number can be added to the first digital signal and wherein the quotient of a first analog input signal divided by a second analog input signal can be converted to the first digital signal and wherein an analog output signal can be generated which is proportional to the second digital signal multiplied by a third analog input signal.