Electronic tachometer

Claim 2

An electronic tachometer comprising, in combination, first means for demanding current at a rate proportional to RPM being measured; feedback amplifier means having said first means as the input thereto and having an output, and having a feedback path from its output to its input including load means for passing the current demanded by said first means; measuring means having at least two successive indicating ranges for the RPM being measured, said measuring means being driven by the output of said feedback amplifier means; said feedback path having a first portion in series with said load means for accommodating only one range of said measuring means, and a second portion adapted to be connected to said first branch for accommodating the next successive range of said measuring means; and control means connected across said load means for abruptly connecting said second portion to said first portion in response to a signal generated by said load means corresponding to the end of said one range of the measuring means.

Claim 3

The electronic tachometer defined in claim 1 wherein said first means comrises a capacitor and means for transferring current to said capacitor at a rate proportional to the RPM being measured.

Claim 4

The electronic tachometer as defined in claim 2 wherein said control means comprises a field effect transistor for connecting said second portion to said first portion, and trigger means having an output for gating said field effect transistor.

Claim 5

The electronic tachometer as defined in claim 3 wherein said first and second portions are connected in parallel by said field effect transistor, each portion comprising a feedback resistor.

Claim 6

The electronic tachometer as defined in claim 4 including an indicating lamp for each of said ranges of the measuring means, and interlock means connected to the output of said trigger means for controlling said lamps in accord with the range being measured.

Claim 7

An electronic tachometer comprising, in combination: means for producing a pulse output whose frequency is proportional to rotational speed being measured; capacitive charge transfer means for demanding current in proportion to the frequency of said pulse output; a feedback amplifier having said charge transfer means as its input and having an output including measuring means having at least two successive indicating ranges for the RPM being measured, and said amplifier having a feedback path for supplying the current demanded by said charge transfer means and including load resistor means through which the demanded current passes; and control means connected across said load resistor means for sharply reducing the resistance of said feedback path in response to predetermined voltage drop across said load resistor means whereby abruptly to decrease the output of said amplifier to switch range on said measuring means.

Claim 8

An electronic tachometer comprising, in combination: means for producing a pulse output whose frequency is proportional to rotational speed being measured; capacitive charge transfer means for demanding current in proportion to the frequency of said pulse output; a feedback amplifier having said charge transfer means as its input and having an output including measuring means having at least two successive indicating ranges for the RPM being measured, and said amplifier having a feedback path for supplying the current demanded by said charge transfer means and including load resistor means through which the demanded current passes; and control means connected across said load resistor means for sharply reducing the resistance of said feedback path in response to predetermined voltage drop across said load resistor means whereby abruptly to decrease the output of said amplifier to switch range on said measuring means.

Claim 9

The electronic tachometer as defined in claim 6 wherein said control means includes a field effect transistor and trigger means for gating said field effect transistor.

Claim 10

The electronic tachometer as defined in claim 7 wherein said feedback path includes first and second resistance branches connected in parallel by said field effect transistor.

Claim 11

The electronic tachometer as defined in claim 8 including an indicating lamp for each of said ranges of the measuring means, and interlock means for controlling said lamps in accord with the range being measured.

Claim 12

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means comprising a dual diode pump for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for sharply reducing the feedback resistance comprising switch means for inserting a resistor in parallel with a portion of said feedback path and trigger means responsive to current flowing through another portion of said feedback path for actuating said switch means.

Claim 13

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means comprising a dual diode pump for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for sharply reducing the feedback resistance comprising switch means for inserting a resistor in parallel with a portion of said feedback path and trigger means responsive to current flowing through another portion of said feedback path for actuating said switch means.

Claim 14

The system as defined in claim 10 wherein said scales are provided with individual illuminating lamps and said trigger means controls operation of said lamps selectively to illuminate the scale under consideration.

Claim 15

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for sharply reducing the feedback resistance comprising switch means for inserting a resistor in parallel with a portion of said feedback path and trigger means responsive to current flowing through another portion of said feedback path for actuating said switch means.

Claim 16

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for sharply reducing the feedback resistance comprising switch means for inserting a resistor in parallel with a portion of said feedback path and trigger means responsive to current flowing through another portion of said feedback path for actuating said switch means.

Claim 17

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for providing a d.c. signal comprising a dual diode pump having two pairs of complemental transistors, biasing means, said transistors of each pair having their emitter-collector paths in series and the emitter-collector paths of the two pairs being connected in parallel across said biasing means, means for applying said pulse output to the base electrodes of one pair of said transistors, the emitter-collector paths of said one pair being arranged to cause one transistor of such pair to conduct while the other is cut off during each pulse output and vice versa for interpulse periods, a first capacitor connected through the emitter-collector path of said one transistor to said biasing means when said one transistor conducts, means connecting the base electrodes of the other pair of trAnsistors to said biasing means when said one transistor conducts, the emitter-collector paths of said other pair being arranged to cause one transistor of said other pair to conduct while the other is cut off when said one transistor of said one pair conducts and vice versa when the other transistor of said one pair conducts, a second capacitor adapted to be charged through the other transistor of said other pair, and an output capacitor connected respectively to said first capacitor and said second capacitor through the emitter-collector paths of the other transistor of said one pair and the one transistor of said other pair whereby to have the charges of said first and second capacitors transferred thereto.

Claim 18

An electronic tachometer system, comprising in combination: means for producing a pulse output whose frequency is proportional to the speed of a device being measured; means for providing a d.c. signal proportional to the frequency of said pulses; an amplifier having said signal as an input thereto and having an output including an indicating instrument provided with a plurality of indicating scales thereon and an indicator for successively sweeping said scales, the sweep movement being substantially identical for each of the scales; said amplifier having a feedback resistance path for determining the output level of the amplifier; and means for sharply reducing the resistance of said feedback path in response to a predetermined output of the amplifier whereby the indicator will move from the high end of one scale to the lower end of another scale thereof; said means for providing a d.c. signal comprising a dual diode pump having two pairs of complemental transistors, biasing means, said transistors of each pair having their emitter-collector paths in series and the emitter-collector paths of the two pairs being connected in parallel across said biasing means, means for applying said pulse output to the base electrodes of one pair of said transistors, the emitter-collector paths of said one pair being arranged to cause one transistor of such pair to conduct while the other is cut off during each pulse output and vice versa for interpulse periods, a first capacitor connected through the emitter-collector path of said one transistor to said biasing means when said one transistor conducts, means connecting the base electrodes of the other pair of trAnsistors to said biasing means when said one transistor conducts, the emitter-collector paths of said other pair being arranged to cause one transistor of said other pair to conduct while the other is cut off when said one transistor of said one pair conducts and vice versa when the other transistor of said one pair conducts, a second capacitor adapted to be charged through the other transistor of said other pair, and an output capacitor connected respectively to said first capacitor and said second capacitor through the emitter-collector paths of the other transistor of said one pair and the one transistor of said other pair whereby to have the charges of said first and second capacitors transferred thereto.

Claim 19

The system as defined in claim 13 wherein the first mentioned means comprises an amplifier having an output, and a plurality of diodes connected between said output and the input of the amplifier.