Solid state scale expanding circuit for electrical indicator devices

A circuit for use with an electrical indicating device to provide a scale-expanding or scale-compressing drive therefor, comprising in combination:

• a. a pair of input terminals adapted to be connected to a source of input voltage which is to be measured and which varies over a predetermined input range,
• b. feeder terminals,
• c. an electrical voltage responsive network branch interposed between one of said input terminals and one of said feeder terminals, said network normally providing, for the entire predetermined range of said input voltage, an incremental voltage contribution to said one feeder terminal in response to incremental input voltage excursions at the input terminals,
• d. a second voltage responsive branch comprising amplifying means including biasing means therefor, said amplifying means being connected with said input terminals and responding to voltages impressed thereon to provide to one of said feeder terminals a voltage contribution having a given characteristic incremental value for incremental voltages over one portion of the predetermined input range and a different characteristic incremental value for incremental voltages over another portion of the predetermined input range whereby a complete voltage excursion between two feeder terminals will manifest zones of different incremental characteristics when an input voltage having an excursion of monotonous incremental characteristic is applied at the input terminals, and
• e. a multi-input summing amplifier connected to said feeder terminals to receive voltage therefrom,
• f. said amplifying means comprising a driving amplifier and a driven amplifier, connected in cascade,
• g. said summing amplifier having a feedback network connected between its output and an input, and
• h. an indicator having a field coil, connected to and receiving voltage from said summing amplifier, said field coil of the indicator constituting part of said feedback network.

Expanded or compressed scale electrical instrumentation comprising, in combination:

• a. a pair of input terminals for connection to a source of incremental input voltage which is to be measured and which can vary over a predetermined range from a preselected low value at the bottom of the range to a preselected high value at the top of the range,
• b. an electrical indicating device including feeder terminals and a feeder-terminal-connected instrument movement with a scale showing voltage values starting with a low value at the bottom of the scale and ending with a higher value at the top of the scale corresponding to full-scale deflection,
• c. an electrical voltage responsive network branch interposed between one of said input terminals and one of the feeder terminals for supplying a voltage to said one feeder terminal which is related to the input voltage from the source being measured,
• d. said network branch normally providing, for the entire predetermined range of said input voltage, an incremental voltage excursion contribution to said one feeder terminal in response to an incremental input voltage excursion at the input terminals starting from the bottom of the input voltage range and ending at the top of the range,
• e. a second branch comprising saturable amplifying means connected with said input terminals, responding to the voltages impressed thereon and providing a driving voltage to one of said feeder terminals, said amplifier means saturating when the input voltage is at some intermediate value between the said selected low and high values of its range,
• f. a negative feedback circuit for said amplifying means,
• g. means biasing said amplifying means to control its response,
• h. said amplifying means supplying to one of said feeder terminals a non-monotonous voltage contribution which, in conjunction with said voltage contribution from the said network branch, effects a full-scale deflection of the instrument movement when the input voltage is at its highest value in said predetermined input range, said non-monotonous voltage contribution having a given incremental characteristic for input voltage excursions over one portion of the predetermined input range, and having a substantially different given incremental characteristics for input voltage excursions over another portion of the predetermined input voltage range whereby the occurrence of a complete, full-range voltage excursion of monotonous characteristic at said input terminals will result in instrument movement deflections defining zones at the instrument movement scale which have substantially different incremental characteristics from each other and which are representative of a scale with expanded or compressed areas.

Expanded or compressed scale electrical instrumentation comprising, in combination:

• a. a pair of input terminals for connection to a source of incremental input voltage which is to be measured and which can vary over a predetermined range from a low value at the bottom of the range to a high value at the top of the range,
• b. an electrical indicating device including feeder terminals and a feeder-terminal-connected instrument movement with scale showing voltage values starting with a low value at the bottom of the scale and ending with a higher value at the top of the scale corresponding to full-scale deflection,
• c. an electrical network branch interposed between one input terminal and one feeder terminal,
• d. said network branch normally providing, for the entire predetermined range of said input voltage, an incremental voltage excursion contribution to said one feeder terminal in response to an incremental input voltage excursion at the input terminals starting from the bottom of the input voltage range and ending at the top of the range, and
• e. a second branch, comprising means connected with said one input terminal and with a feeder terminal, supplying to the latter a non-monotonous voltage contribution which, in conjunction with said voltage contribution from the said network branch, effects a full-scale deflection of the instrument movement when the input voltage is at its highest value in said predetermined input range, said non-monotonous voltage contribution having a given incremental characteristic for input voltage excursions over one portion of the predetermined input range, and having a substantially different given incremental characteristic for input voltage excursions over another portion of the predetermined input voltage range whereby the occurrence of a complete, full-range voltage excursion of monotonous characteristic as said input terminals will result in instrument movement deflections defining zones at the instrument movement scale which have substantially different incremental characteristics from each other and which are representative of a scale with expanded or compressed areas,
• f. said electrical indicating device including a summing amplifier having its input connected to said feeder terminals,
• g. said summing amplifier having a negative feedback circuit,
• h. said instrument movement having a coil constituting part of said negative feedback circuit.

Expanded or compressed scale electrical instrumentation comprising, in combination:

• a. a pair of input terminals for connection to a source of incremental input voltage which is to be measured and which can vary over a predetermined range from a low value at the bottom of the range to a high value at the top of the range,
• b. an electrical indicating device including feeder terminals and a feeder-terminal-connected instrument movement with scale showing voltage values starting with a low value at the bottom of the scale and ending with a higher value at the top of the scale corresponding to full-scale deflection,
• c. an electrical network branch interposed between one input terminal and one feeder terminal,
• d. said network branch normally providing, for the entire predetermined range of said input voltage, an incremental voltage excursion contribution to said one feeder terminal in response to an incremental input voltage excursion at the input terminals starting from the bottom of the input voltage range and ending at the top of the range, and
• e. a second branch, comprising means connected with said one input terminal and with a feeder terminal, supplying to the latter a non-monotonous voltage contribution which, in conjunction with said voltage contribution from the said network branch, effects a full-scale deflection of the instrument movement when the input voltage is at it highest value in said predetermined input range, said non-monotonous voltage contribution having a given incremental characteristic for input voltage excursions over one portion of the predetermined input range, and having a substantially different given incremental characteristic for input voltage excursions over another portion of the predetermined input voltage range whereby the occurrence of a complete, full-range voltage excursion of monotonous characteristic at said input terminals will result in instrument movement deflections defining zones at the instrument movement scale which have substantially different incremental characteristics from each other and which are representative of a scale with expanded or compressed areas,
• f. said voltage responsive network branch including an amplifier having a negative feedback circuit,
• g. said instrument movement having a coil constituting part of said negative feedback circuit.

Expanded or compressed scale electrical instrumentation comprising, in combination:

• a pair of input terminals for connection to a source of incremental input voltage which is to be measured and which can vary over a predetermined range from a low value at the bottom of the range to a high value at the top of the range,
• b. an electrical indicating device including feeder terminals and a feeder-terminal-connected instrument movement with scale showing voltage values starting with a low value at the bottom of the scale and ending with a higher value at the top of the scale corresponding to full-scale deflection,
• c. an electrical network branch interposed between one input terminal and one feeder terminal,
• d. said network branch normally providing, for the entire predetermined range of said input voltage, an incremental voltage excursion contribution to said one feeder terminal in response to an incremental input voltage excursion at the input terminals starting from the bottom of the input voltage range and ending at the top of the range, and
• e. a second branch, comprising means connected with said one input terminal and with a feeder terminal, supplying to the latter a non-monotonous voltage contribution which, in conjunction with said voltage contribution from the said network branch, effects a full-scale deflection of the instrument movement when the input voltage is at its highest value in said predetermined input range, said non-monotonous voltage contribution having a given incremental characteristic for input voltage excursions over one portion of the predetermined input range, and having a substantially different given incremental characteristic for input voltage excursions over another portion of the predetermined input voltage range whereby the occurrence of a complete, full-range voltage excursion of monotonous characteristic at said input terminals will result in instrument movement deflections defining zones at the instrument movement scale which have substantially different incremental characteristics from each other and which are reperesentative of a scale with expanded or compressed areas.
• f. said second branch including an amplifier having a negative feedback circuit,
• g. said instrument movement having a coil constituting part of said negative feedback circuit.