US3714570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring the effective value of electrical waveforms
Assignee: Individual
•
Filing: 1970-04-09
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Granted: 1973-01-30
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Expires: 1990-04-09
Abstract
Abstract Devices for measuring the effective value of an input waveform are disclosed which employ one or more amplifiers and a feedback path for supplying a feedback signal to the input of the detector which has a value such that the average output value of the waveform from the measuring circuit is substantially equal to the effective value of the input waveform. The output waveform is coupled to a conventional average measuring device, such as a meter, to obtain a measurement of the RMS (root-mean-square) or the effective value of the input waveform. The measuring apparatus of one of the disclosed embodiments is a single stage differential amplifier which has its non-inverting input terminal coupled to its output terminal through a resistor and a capacitor in series. Two other disclosed embodiments include two-stage circuits each of which has a pair of operational amplifiers which are coupled so that the second amplifier stage supplies an output signal of one polarity through an RC feedback path to the inverting input terminal of the first stage of amplification. A series combination of a resistor and a capacitor which is coupled between the resistor of the feedback path and the inverting input of the output amplifier stage is disclosed in one of the two-stage embodiments.
Inventors
- 👤 J Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:13
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
98 words
A measuring apparatus for providing an output signal at its output terminal having an average value approximately equal to the effective value of the input signal applied at its input terminal, the apparatus comprising: a. an amplifier/rectifier means connected between the input and the output of said apparatus for simultaneously amplifying and rectifying said input signal, said rectified/amplified output including an average dc component and Fourier ac components; and b. a series resistance and capacitance regenerative feedback means for regeneratively applying the Fourier ac components only of said output terminal to said input terminal of said amplifier/rectifier means.
Claim 2
Dependent Claim
98 words
A measuring apparatus for providing an output signal at its output terminal having an average value approximately equal to the effective value of the input signal applied at its input terminal, the apparatus comprising: a. an amplifier/rectifier means connected between the input and the output of said apparatus for simultaneously amplifying and rectifying said input signal, said rectified/amplified output including an average dc component and Fourier ac components; and b. a series resistance and capacitance regenerative feedback means for regeneratively applying the Fourier ac components only of said output terminal to said input terminal of said amplifier/rectifier means.
Claim 3
Dependent Claim
98 words
A measuring apparatus for providing an output signal at its output terminal having an average value approximately equal to the effective value of the input signal applied at its input terminal, the apparatus comprising: a. an amplifier/rectifier means connected between the input and the output of said apparatus for simultaneously amplifying and rectifying said input signal, said rectified/amplified output including an average dc component and Fourier ac components; and b. a series resistance and capacitance regenerative feedback means for regeneratively applying the Fourier ac components only of said output terminal to said input terminal of said amplifier/rectifier means.
Claim 4
Dependent Claim
98 words
A measuring apparatus for providing an output signal at its output terminal having an average value approximately equal to the effective value of the input signal applied at its input terminal, the apparatus comprising: a. an amplifier/rectifier means connected between the input and the output of said apparatus for simultaneously amplifying and rectifying said input signal, said rectified/amplified output including an average dc component and Fourier ac components; and b. a series resistance and capacitance regenerative feedback means for regeneratively applying the Fourier ac components only of said output terminal to said input terminal of said amplifier/rectifier means.
Claim 5
Dependent Claim
18 words
An apparatus according to claim 1 wherein said amplifier/rectifier means full wave rectifies the signal at its input.
Claim 6
Dependent Claim
20 words
An apparatus according to claim 2 wherein an average reading meter is connected at said output of said measuring apparatus.
Claim 7
Dependent Claim
95 words
An apparatus to claim 2 wherein said amplifier/rectifier comprises: a. a first differential amplifier having two series connected resistor-diode pairs each series resistor-diode pair connecting the output of said first amplifier to the inverting input of said amplifier, said diodes being oppositely polarized and having said input signal applied to one of the inputs of said first amplifier; and b. a second differential amplifier having each of its inputs resistively connected to the intermediate node of a different one of said resistor-diode pairs, the output of said second amplifier being the output of said apparatus.
Claim 8
Dependent Claim
33 words
An apparatus according to claim 4 wherein a second series connected resistor and capacitor is connected between the intermediate node of said feedback means and the inverting input of said second differential amplifier.
Claim 9
Dependent Claim
43 words
An apparatus according to claim 4 wherein a full wave rectifier is interposed between said input terminal of said apparatus and the input of said first differential amplifier, said full wave rectifier being polarized for adding said input signal and said feedback signal.
Claim 10
Dependent Claim
33 words
An apparatus according to claim 6 wherein a second series connected resistor and capacitor is connected between the intermediate node of said feedback means and the inverting input of said second differential amplifier.
Claim 11
Dependent Claim
33 words
An apparatus according to claim 7 wherein the input signal is applied to the inverting input of said amplifier and wherein the noniNverting input of said first amplifier is resistively connected to ground.
References Cited (Backward Citations)
US2861182A
Cited
US3159787A
Cited
US3226633A
Cited
US3345562A
Cited
US3432764A
Cited
US3553566A
Cited
US3555432A
Cited
US3564389A
Cited
US3564387A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |