GB1288792A – – Google Patents
GB1288792A – – Google Patents
Info
Publication number
GB1288792A
GB1288792A
GB1288792DA
GB1288792A
GB 1288792 A
GB1288792 A
GB 1288792A
GB 1288792D A
GB1288792D A
GB 1288792DA
GB 1288792 A
GB1288792 A
GB 1288792A
Authority
GB
United Kingdom
Prior art keywords
frequency
output
converter
bridge
resistance
Prior art date
1968-10-11
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1968-10-11
Filing date
1969-10-10
Publication date
1972-09-13
1969-10-10
Application filed
filed
Critical
1972-09-13
Publication of GB1288792A
publication
Critical
patent/GB1288792A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
H—ELECTRICITY
H03—ELECTRONIC CIRCUITRY
H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
H03M1/00—Analogue/digital conversion; Digital/analogue conversion
G—PHYSICS
G01—MEASURING; TESTING
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
G01R17/10—AC or DC measuring bridges
G01R17/105—AC or DC measuring bridges for measuring impedance or resistance
G—PHYSICS
G01—MEASURING; TESTING
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
H—ELECTRICITY
H03—ELECTRONIC CIRCUITRY
H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
H03M1/00—Analogue/digital conversion; Digital/analogue conversion
H03M1/12—Analogue/digital converters
H03M1/50—Analogue/digital converters with intermediate conversion to time interval
Abstract
1288792 Digital ohmmeter HICKOK ELECTRICAL INSTRUMENT CO 10 Oct 1969 [11 Oct 1968] 49964/69 Heading G1U A digital ohmmeter comprises an automatically adjustable Wheatstone bridge, an amplifier receiving an input which is a function of the difference in voltage across the unknown resistor arm and the balance arm of the bridge and supplying an output to a voltage-frequency converter, a frequencyresistance converter for converting the frequency. to an apparent resistance forming the balance arm of the bridge and a gate circuit opened for a specific time to pass the pulse output of the voltage frequency converter to a digital display. The time period is selected such that the number displayed when the bridge is balanced is the ohmic value of the unknown resistor. The voltage E c across the unknown resistor arm CD and that Ef across the balance arm AB are separately integrated in units 34, 37 and applied to a photo-resistance chopper 35 operated from neon light source 40. The chopper output is combined and applied via a capacitor to the input of high gain amplifier 10 as an AC input having value which is a function of the difference between the signals. The amplifier output is synchronously demodulated 52 by further photo-resistors operated from the light source 40 and the resulting DC signal is applied to the input of a DC to frequency converter 11. The frequency of the pulse output from the converter is halved in the flip-flop Q15, Q16 which supplies an output to control the frequency-resistance converter 12 and to an output gate 14. The frequency resistance converter comprises a capacitor connected across the terminals AB via a charge and discharge transistor switching circuit operating at the frequency of the applied pulse signal. The arrangement represents a balance arm equivalent resistance Rf = 1/cf where C +f are the values of the known capacitor and input pulse frequency respectively. The flip-flop output is also supplied to the gate and at balance of the bridge this frequency is proportional to the value of the unknown resistor Rx. The gate is opened for a chosen period of 100 ms. and during this time the number of pulses passing through the gate to a digital totalizer equals the ohmic value of the resistor Rx. Switching circuits are provided for varying the ratio arm resistors, the bridge supply and the capacitive component of the frequency-resistance converter for each decade range of the instrument.
GB1288792D
1968-10-11
1969-10-10
Expired
GB1288792A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
US76690968A
1968-10-11
1968-10-11
Publications (1)
Publication Number
Publication Date
GB1288792A
true
GB1288792A
(en)
1972-09-13
Family
ID=25077899
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB1288792D
Expired
GB1288792A
(en)
1968-10-11
1969-10-10
Country Status (6)
Country
Link
US
(1)
US3536997A
(en)
BE
(1)
BE740134A
(en)
DE
(1)
DE1951178A1
(en)
FR
(1)
FR2020435A1
(en)
GB
(1)
GB1288792A
(en)
NL
(1)
NL6915352A
(en)
Families Citing this family (12)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
DE2214114C3
(en)
*
1972-03-23
1974-12-05
Philips Patentverwaltung Gmbh, 2000 Hamburg
Circuit arrangement for converting a detuning of a resistor bridge into a proportional frequency change of an RC oscillator
DE2433080C2
(en)
*
1974-07-10
1983-09-29
Philips Patentverwaltung Gmbh, 2000 Hamburg
Circuit arrangement for converting a bridge detuning into a frequency change
US4228394A
(en)
*
1978-11-16
1980-10-14
Beckman Instruments, Inc.
Digital ohmmeter with electrical continuity tester
USRE31606E
(en)
*
1978-11-16
1984-06-19
Beckman Instruments, Inc.
Digital ohmmeter with electrical continuity tester
US4296413A
(en)
*
1979-09-28
1981-10-20
General Electric Company
Resistance-bridge to frequency converter with automatic offset correction
US7762822B2
(en)
*
2005-04-27
2010-07-27
Aehr Test Systems
Apparatus for testing electronic devices
US20070193868A1
(en)
*
2006-02-02
2007-08-23
Delphi Technologies, Inc.
Multiplex signal system for vehicle steering column assembly
US7960979B1
(en)
*
2008-03-28
2011-06-14
Honda Motor Co., Ltd.
Universal resistance testing device for electrical components
WO2010052697A1
(en)
*
2008-11-06
2010-05-14
Vishay Intertechnology, Inc.
Four-terminal resistor with four resistors and adjustable temperature coefficient of resistance
CN104007353B
(en)
*
2013-02-26
2016-12-28
国网山东省电力公司菏泽供电公司
Interface testing circuit
JP6643327B2
(en)
*
2014-09-22
2020-02-12
パンドウィット・コーポレーション
System to check for lack of voltage
US20210364560A1
(en)
*
2020-05-20
2021-11-25
Cirrus Logic International Semiconductor Ltd.
Sense resistor and method for forming same
Family Cites Families (4)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US322825A
(en)
*
1885-07-21
ingham
US2972106A
(en)
*
1958-04-09
1961-02-14
Western Electric Co
Automatic alternating current bridge
US3064193A
(en)
*
1958-10-24
1962-11-13
Standard Oil Co
Digitizing amplifier
US3302106A
(en)
*
1963-05-29
1967-01-31
Beckman Instruments Inc
Resistance measuring apparatus including an automatic balancing bridge
1968
1968-10-11
US
US766909A
patent/US3536997A/en
not_active
Expired – Lifetime
1969
1969-10-10
BE
BE740134D
patent/BE740134A/xx
unknown
1969-10-10
DE
DE19691951178
patent/DE1951178A1/en
active
Pending
1969-10-10
GB
GB1288792D
patent/GB1288792A/en
not_active
Expired
1969-10-10
NL
NL6915352A
patent/NL6915352A/xx
unknown
1969-10-10
FR
FR6934826A
patent/FR2020435A1/fr
not_active
Withdrawn
Also Published As
Publication number
Publication date
BE740134A
(en)
1970-03-16
DE1951178A1
(en)
1970-06-04
NL6915352A
(en)
1970-04-14
US3536997A
(en)
1970-10-27
FR2020435A1
(en)
1970-07-10
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Legal Events
Date
Code
Title
Description
1973-05-09
CSNS
Application of which complete specification have been accepted and published, but patent is not sealed
