Analog signal comparator

Claim 2

In a motor control circuit for effecting positioning of a motor shaft, analog signal comparator means comprising input means having a first input for receiving a command signal indicative of a desired position for the shaft and a second input for receiving a sense signal indicative of the actual position of the shaft, said input means being responsive to a difference between said command and sense signals to provide a potential difference between first and second outputs thereof of an amplitude and polarity that is indicative of the difference between said command and sense signals, first oscillatable means including a first programmable unijunction transistor and first timing means, said first programmable unijunction transistor having a gate electrode connected to the first output and an anode electrode connected over said first timing means to said second output, said first oscillatable means being enabled whenever the potential difference between said first and second outputs exceeds a predetermined value and is of a first polarity to provide a series of output pulses, second oscillatable means including a second programmable unijunction transistor and a second timing means, said second programmable unijunction transistor having a gate electrode connected to said second output and an anode electrode connected over said second timing means to said first output, said second oscillatable means being enabled whenever the potential difference provided between said first and second outputs exceeds said predetermined value and is of the opposite polarity to provide a series of output pulses, and output means responsive to the series of output pulses provided by said first oscillatable means to control the motor to effect rotation of the motor shaft in one direction, said output means being responsive to the series of output pulses provided by said second oscillatable means to effect rotation of the motor shaft in the opposite direction.

Claim 3

A motor control circuit as set forth in claim 1 wherein said first timing means comprises a first resistor means and a first capacitor means serially connected between said second output and a point of reference potential, said first programmable unijunction transistor means having its anode electrode connected to the junction of said resistor means and said capacitor means, and wherein said second timing means comprises second resistance means and second capacitance means serially connected between said first output and said point of reference potential, said second programmable unijunction transistor means having its anode electrode connected to the junction of said resistance means and said capacitance means, said first capacitance means being enabled to charge to a value sufficient to render said first programmable unijunction transistor means conductive to permit said first capacitance means to discharge over said programmable unijunction transistor means to provide a pulse output whenever the potential difference between said first and second outputs exceeds said predetermined value and is of said first polarity, and said second capacitance means being enabled to charge to a value sufficient to render said second programmable unijunction transistor means conductive to permit said second capacitance means to discharge over said second programmable unijunction transistor means to provide a pulse output whenever the potential difference provided between said first and second outputs exceeds said predetermined value and is of said opposite polarity.

Claim 4

A motor control circuit as set forth in claim 2 wherein said output means includes first switching means responsive to output pulses provided by said first programmable unijunction transistor means to effect rotation of said motor shaft in said one direction, and second switching means responsive to the output pulses provided by said second programmable unijunction transistor means to effect rotation of said motor shaft in the opposite direction.

Claim 5

In a motor control circuit for controlling a motor to effect the positioning of a shaft of the motor to a desired position, an analog signal comparator means comprising differential amplifier means, first means electrically connected to a first input of said differential amplifier means for providing a command signal indicating a desired position for said motor shaft, second means electrically connected to a second input of said differential amplifier means for supplying a sense signal indicative of the actual position of said motor shaft, said differential amplifier means being responsive to a difference in the command and sense signals to provide a potential difference between first and second outputs thereof which is of an amplitude and polarity indicative of the difference between said command and sense signals, first detecting means having a first input connected to said first output of said differential means and a second input connected to said second output of said differential amplifier means, second detecting means having a third input connected to said first output of said differential amplifier means and a fourth input connected to said second output of said differential amplifier means, said first detecting means including first programmable unijunction transistor means and first timing means operable to periodically enable said first programmable unijunction transistor means to provide a series of control pulses whenever the potential difference between said first and second outputs exceeds a predetermined value and is of a first polarity, said second detecting means including second programmable unijunction transistor means and second timing means operable to periodically enable said second programmable unijunction transistor means to provide a series of control pulses, whenever the potential difference between said first and second outputs exceeds said predetermined value and is of the opposite polarity and output means including first switching means controlled by the control pulses provided by said first programmable unijunction transistor means to effect rotation of said motor shaft in one direction and second switching means controlled by the control pulses provided by said second programmable unijunction transistor means to effect rotation of said motor shaft in the opposite direction.

Claim 6

In a motor control circuit for controlling a motor to effect the positioning of a shaft of the motor to a desired position, an analog signal comparator means comprising differential amplifier means, first means electrically connected to a first input of said differential amplifier means for providing a command signal indicating a desired position for said motor shaft, second means electrically connected to a second input of said differential amplifier means for supplying a sense signal indicative of the actual position of said motor shaft, said differential amplifier means being responsive to a difference in the command and sense signals to provide a potential difference between first and second outputs thereof which is of an amplitude and polarity indicative of the difference between said command and sense signals, first detecting means having a first input connected to said first output of said differential means and a second input connected to said second output of said differential amplifier means, second detecting means having a third input connected to said first output of said differential amplifier means and a fourth input connected to said second output of said differential amplifier means, said first detecting means including first programmable unijunction transistor means and first timing means operable to periodically enable said first programmable unijunction transistor means to provide a series of control pulses whenever the potential difference between said first and second outputs exceeds a predetermined value and is of a first polarity, said second detecting means including second programmable unijunction transistor means and second timing means operable to periodically enable said second programmable unijunction transistor means to provide a series of control pulses, whenever the potential difference between said first and second outputs exceeds said predetermined value and is of the opposite polarity and output means including first switching means controlled by the control pulses provided by said first programmable unijunction transistor means to effect rotation of said motor shaft in one direction and second switching means controlled by the control pulses provided by said second programmable unijunction transistor means to effect rotation of said motor shaft in the opposite direction.