US3864631A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic multimeter having a plurality of voltage-to-frequency converters
Assignee: ABB Inc USA
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Filing: 1974-04-16
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Granted: 1975-02-04
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Expires: 1994-04-16
Abstract
Abstract A multimeter suitable for indicating the ampere-squared hours, the volt-squared hours, and the watt-hours in an electrical circuit. Three separate voltage-to-frequency circuits are connected to shared timing and power supply circuits. Electrical signals corresponding to the voltage and current in the monitored electrical circuit are applied by appropriate connections to the voltage-to-frequency circuits through multiplier circuits. One multiplier circuit squares the current, another multiplier circuit squares the voltage, and still another multiplier circuit provides the product of the current and voltage to yield a power indication. Programmable dividing circuits reduce the number of pulses which are counted and displayed by the multimeter and enable the display of measured parameters in exact engineering units. An output is included for applying a digital signal responsive to the indicated quantities to a recorder or computer.
Inventors
- 👤 William E Zitelli
- 👤 Andras I Szabo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:44
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/133; G01R15/00; G01R15/12; G01R15/125; H; H03; H03M; H03M1/00; H03M1/12; H03M1/60
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
259 words
A multimeter for measuring first and second electrical signals, comprising: a timing signal generator; first and second input circuits which respectively transfer the first and second electrical signals; first and second multiplier circuits each having two inputs and an outpUt which is responsive to the product of the signals applied to the inputs, with the inputs of said first and second multiplier circuits being appropriately coupled to the first and second input circuits to provide the desired output products; a first voltage-to-frequency converter connected to the output of said first multiplier circuit and to said timing signal generator, said converter providing output pulses proportional in number to the output from said first multiplier circuit; a first programmable electronic dividing circuit connected to said first voltage-to-frequency converter, said dividing circuit providing one output pulse when the output pulse from said voltage-to-frequency converter occurs a predetermined number of times; first counter and first display means which furnish an indication of the number of output pulses provided by the dividing circuit; a second voltage-to-frequency converter connected to the output of said second multiplier circuit and to said timing signal generator, said converter providing output pulses proportional in number to the output from said second multiplier circuit; a second programmable electronic dividing circuit connected to said second voltage-to-frequency converter, said dividing circuit providing one output pulse when the output pulse from said voltage-to-frequency converter occurs a predetermined number of times; and, second counter and second display means which furnish an indication of the number of output pulses provided by the second dividing circuit.
Claim 2
Dependent Claim
259 words
A multimeter for measuring first and second electrical signals, comprising: a timing signal generator; first and second input circuits which respectively transfer the first and second electrical signals; first and second multiplier circuits each having two inputs and an outpUt which is responsive to the product of the signals applied to the inputs, with the inputs of said first and second multiplier circuits being appropriately coupled to the first and second input circuits to provide the desired output products; a first voltage-to-frequency converter connected to the output of said first multiplier circuit and to said timing signal generator, said converter providing output pulses proportional in number to the output from said first multiplier circuit; a first programmable electronic dividing circuit connected to said first voltage-to-frequency converter, said dividing circuit providing one output pulse when the output pulse from said voltage-to-frequency converter occurs a predetermined number of times; first counter and first display means which furnish an indication of the number of output pulses provided by the dividing circuit; a second voltage-to-frequency converter connected to the output of said second multiplier circuit and to said timing signal generator, said converter providing output pulses proportional in number to the output from said second multiplier circuit; a second programmable electronic dividing circuit connected to said second voltage-to-frequency converter, said dividing circuit providing one output pulse when the output pulse from said voltage-to-frequency converter occurs a predetermined number of times; and, second counter and second display means which furnish an indication of the number of output pulses provided by the second dividing circuit.
Claim 3
Dependent Claim
114 words
The multimeter of claim 1 wherein the first and second voltage-to-frequency converters each include an integrating circuit having a capacitor which is charged by the input signal to the integrating circuit, a discharge circuit connected to said capacitor for discharging said capacitor, a control circuit responsive to the charge on the capacitor, said control circuit activating the discharge circuit to remove charge from the capacitor when the charge is above a predetermined level, said charge being removed in equal amounts by discharge pulses of equal duration, with the number of pulses required to maintain the predetermined level of charge on the capacitor responsive to the amplitude of the input signal to the voltage-to-frequency converter.
Claim 4
Dependent Claim
65 words
The multimeter of claim 1 wherein the first and second programmable dividing circuits each are at least partially programmed by connecting terminals thereof to ''''Hi'''' and ''''Lo'''' state logic terminals by suitable jumpers to apply a binary number to the dividing circuits, with the decimal equivalent of the binary number being equal to the division ratio of at least part of the each dividing circuit.
Claim 5
Dependent Claim
122 words
The multimeter of claim 1 wherein the multimeter includes a third multiplier circuit constructed similar to the first and second multiplier circuits, a third voltage-to-frequency converter constructed similar to the first and second voltage-to-frequency converters, a third dividing circuit constructed similar to the first and second dividing circuits, a third counter and a third display means constructed similar to the first and second counter and display means, with one input of the first and third multiplier circuits connected to the first input circuit, the other input of the first multiplier circuit also connected to the first input circuit, and with both inputs of the second multiplier circuit and the other input of the third multiplier circuit connected to the second input circuit.
Claim 6
Dependent Claim
25 words
The multimeter of claim 1 wherein the multimeter includes means for attaching a recorder to the multimeter to record pulses responsive to the voltage-to-frequency converters.
References Cited (Backward Citations)
US3718860A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |