Limit control

Claim 2

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a first limit and below a second limit, comprising: first and second summing amplifiers, each having first and second inputs and an output, the first input of said first amplifier being adapted to receive the input signal; means connecting the second inputs of said amplifiers to sources of reference potentials; second and third sources of potential representative of said first and second limits, respectively; means connecting said second source of potential to the first inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the first input of said first amplifier; second unidirectional current conducting means connected between the first input of said second amplifier and the output of said first amplifier; and means responsive to said third source of potential and the output of said second amplifier to apply a signal to the first input of said second amplifier to prevent the output signal from said second amplifier from exceeding said second limit.

Claim 3

The apparatus of claim 1 wherein said first current conducting means comprises a rectifier and a feedback resistor connected in series relationship.

Claim 4

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a preselected limit, comprising: first and second summing amplifiers, each having first and second inputs and an output, the first input of said first amplifier being adapted to receive the input signal; means connecting the second inputs of said amplifiers to sources of reference potentials; a source of second potential representative of said limit; means connecting said source of second potential to the first inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the first input of said first amplifier; and second unidirectional current conducting means connected between the first input of said second amplifier and the output of said first amplifier.

Claim 5

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a preselected limit, comprising: first and second summing amplifiers, each having first and second inputs and an output, the first input of said first amplifier being adapted to receive the input signal; means connecting the second inputs of said amplifiers to sources of reference potentials; a source of second potential representative of said limit; means connecting said source of second potential to the first inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the first input of said first amplifier; and second unidirectional current conducting means connected between the first input of said second amplifier and the output of said first amplifier.

Claim 6

The apparatus of claim 3 wherein said first current conducting means comprises a rectifier and a feedback resistor connected in series relationship.

Claim 7

The apparatus of claim 3 wherein said second current conducting means comprises an input resistor and a rectifier connected in series relationship, and further comprising a feedback resistor connected between the junction between said input resistor and said rectifier and the first input of said first amplifier.

Claim 8

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a first limit and below a second limit, comprising: first and second summing amplifiers, each having an input and an output, the input of said first amplifier being adapted to receive the input signal; first and second sources of reference potential representative of said first and second limits, respectively; means connecting said first source to the inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the input of said first amplifier; an input resistor and a rectifier connected in series relationship between the input of said second amplifier and the output of said first amplifier; a feedback resistor connected between the junction between said input resistor and said rectifier and the input of said first amplifier; and means responsive to said second source and the output of said second amplifier to apply a signal to the input of said second amplifier to prevent the output signal from said second amplifier from exceeding said second limit.

Claim 9

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a first limit and below a second limit, comprising: first and second summing amplifiers, each having an input and an output, the input of said first amplifier being adapted to receive the input signal; first and second sources of reference potential representative of said first and second limits, respectively; means connecting said first source to the inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the input of said first amplifier; an input resistor and a rectifier connected in series relationship between the input of said second amplifier and the output of said first amplifier; a feedback resistor connected between the junction between said input resistor and said rectifier and the input of said first amplifier; and means responsive to said second source and the output of said second amplifier to apply a signal to the input of said second amplifier to prevent the output signal from said second amplifier from exceeding said second limit.

Claim 10

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a first limit and below a second limit, comprising: first and second summing amplifiers, each having an input and an output, the input of said first amplifier being adapted to receive the input signal; a first source of reference potential representative of said first limit; means connecting said first source to the inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the first input of said first amplifier; second unidirectional current conducting means connected between the input of said second amplifier and the output of said first amplifier; a voltage source; a potentiometer having one end terminal connected to said voltage source and the other end terminal connected to the output of said second amplifier, the potential at the contactor of said potentiometer being representative of said second limit; gate means connected to the input of said second amplifier to apply a current thereto when a predetermined control potential is applied to said gate means; and means connecting the contactor of said potentiometer to said gate means to apply a control potentiometer thereto.

Claim 11

Apparatus to establish an output signal which is representative of an input signal when the input signal is above a first limit and below a second limit, comprising: first and second summing amplifiers, each having an input and an output, the input of said first amplifier being adapted to receive the input signal; a first source of reference potential representative of said first limit; means connecting said first source to the inputs of said first and second amplifiers; first unidirectional current conducting means connected between the output and the first input of said first amplifier; second unidirectional current conducting means connected between the input of said second amplifier and the output of said first amplifier; a voltage source; a potentiometer having one end terminal connected to said voltage source and the other end terminal connected to the output of said second amplifier, the potential at the contactor of said potentiometer being representative of said second limit; gate means connected to the input of said second amplifier to apply a current thereto when a predetermined control potential is applied to said gate means; and means connecting the contactor of said potentiometer to said gate means to apply a control potentiometer thereto.

Claim 12

The apparatus of claim 7 wherein said gate means comprises a second voltage source, a transistor having the emitter-collector circuit path thereof connected between said second voltage source and the input of said second amplifier, and wherein said means to apply a control potential is connected to the base of said transistor.