Apparatuur informatie

IET Labs Inc. 1616 Test Set
Fabrikant:
IET Labs Inc.
Model: 1616
Datum: 2001
Categorie: Meetinstrumenten
Groep: Test Set
Beschrijving: Precision Capacitance Bridge
Informatie:
                                    The 1621 Capacitance-Measurement system is designed for the
precise measurement of capacitors and capacitance standards.
In the standards laboratory, its high resolution for
capacitance and conductance make this system well suited for
capacitance standards measurements. Its phase-indicating
error meters facilitate rapid balancing. Convenient in-line
readout maximizes accuracy of manual data recording and BCD
outputs are provided for automatic data processing.

The 1621 system measures either 3-terminal or 2-terminal
capacitors. The transformer-ratio-arm circuitry of the
bridge assures that 3-terminal measurements can be made
accurately, even in the presence of large capacitances to
ground. For instance, a ground capacitance of 1 ;uF produces
an error of only 0.03% in the measurement of 1000-pF
capacitor. This feature makes the assembly very useful for
in situ measurements of ungrounded circuit capacitances.

The 1616 Precision Capacitance Bridge, one of the 3
instruments in that system, may be obtained separately. The
bridge will perform as described herein, if used with an
oscillator and detector equivalent to the CiR 1316 and 1238.
NOTE

This manual describes the 1621 system generally and provides
its operating instructions. This manual also describes in
detail the 1616 bridge only.
A wide range of capacitances can be measured, extending from
the resolution limit of 0.1 aF (10‘7pF) to a maximum of 10
/if, with internal standards, or farther with external
standards. For 3-terminal unknown capacitors, a
pair of coaxial terminals is provided; for 2-terminal
coaxial "unknowns," a single precision connector facilitates
exacting control of fringing effects.

Since an important use of this bridge is the comparison of
capacitance standards, another pair of coaxial terminals is
provided on the bridge to which a 3-terminal reference
standard can be connected and designated EXTERNAL STANDARD.
The other standard is then connected to the selected UNKNOWN
terminals, and the internal standards are used to complete
the balance. If the ratio between the two standards is close
to 0.1, 1., or 10, the accuracy of the measurement is equal
to the accuracy of calibration of the reference standard,
and the precision of comparison is 1 part in 10s (0.01 ppm)
of a 10-pF capacitor (or even better for larger ones).

1.2	DESCRIPTION.	Figure 1-1.

1.2.1	General.

The 1621 Precision Capacitance-Measurement System consists
of the 1616 Precision Capacitance Bridge with the 1316
Oscillator and the 1238 Detector, a complete system for the
precise measurement of capacitance.

Oscillator and detector are mounted above the bridge, in a
pedestal cabinet, as pictured in the front pages (and Figure
1-2); or the three instruments may be rack mounted.
Connecting cables, supplied, go neatly behind the assembly. 

Deze handboeken zijn beschikbaar voor de bovengenoemde apparatuur:

Manueel de Type: Service-en gebruikershandleiding IET-8753-Manual-Page-1-Picture
Pagina 's: 94
Grootte: 20.00 Mbytes (20969728 Bytes)
Taal: Engels
Herziening:
Handleiding-ID/Number:
Datum: 01 januari 2001
Kwaliteit: Gescand document alle leesbaar.
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MD5: 0f18a413ef05df8c38d797519e504826
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Informatie:
CONDENSED OPERATING INSTRUCTIONS . ix
SPECIFICATIONS....................... x

1	INTRODUCTION

1.1	Purpose .......................1-1

1.2	Description.....................1-1

1.2.1	General .................1-1

1.2.2	Bridge Circuit ............1-1

1.2.3	Standards ...............1-2

1.2.4	Oscillator................1-2

1.2.5	Detector ................1-2

1.3	Controls, Indicators, and Connections....................1-3

1.4	Accessories....................1-3

2	INSTALLATION

2.1	General........................2-2

2.2	Dimensions.....................2-3

2.3	Environment....................2-2

2.4	Bench Models ..................2-2

2.4.1	Cabinet Removal .........2-2

2.4.2	Conversion For Rack Mounting ................2-2

2.5	Rack Models ...................2-2

2.5.1	General .................2-3

2.5.2	Installation...............2-3

2.5.3	Conversion To Bench Use .. 2-3

2.6	Power-Line Connection...........2-4

2.7	Line-Voltage Regulation ..........2-4

2.8	System Connections.............2-4

2.8.1	Oscillator, Bridge, and Detector ................2-4

2.8.2	BCD-Capacitance-Output Connector...............2-4

2.8.3	BCD-Conductance-Output Connector...............2-5

2.8.4	Analog Outputs...........2-5

3	OPERATION

3.1	Preliminary Checks ..............3-1

3.2	Functional Self-Checks...........3-1

3.3	Phase Adjustment ...............3-2
Section	Page

3.4	Connection of Unknown Capacitor . 3-3

3.4.1	Three-Terminal Capacitors . 3-3

3.4.2	Two-Terminal Coaxial Capacitors ..............3-3

3.5	Balance and Readout............3-4

3.5.1	Readout Multiplier ........3-4

3.5.2	Initial Settings of Lever Switches................3-5

3.5.3	Balance Procedures.......3-5

3.5.4	Final Balance ............3-6

3.5.5	Readout Correction .......3-7

3.5.6	Units of Measurement.....3-7

3.6	Parameters of The Unknown Capacitor......................3-7

3.6.1	Series Equivalent Parameters..............3-7

3.6.2	Dissipation Factor ........3-8

3.7	Frequency.....................3-8

3.7.1	Setting The Frequency .... 3-8

3.7.2	Monitoring Frequency .....3-8

3.7.3	Locking To a Frequency Reference...............3-10

3.8	Voltage Level ..................3-10

3.9	Accuracy......................3-10

3.9.1	Accuracy Versus Frequency

and Cx .................3-10

3.9.2	Accuracy Versus Temperature.............3-11

3.9.3	Range and Dissipation Factor Limitations
..............3-12

3.9.4	Shunt Capacitance To

Ground .................3-12

3.9.5	Fringing Capacitance......3-13

3.9.6	Conductance Accuracy .... 3-14

3.10	Precision ......................3-15

3.11	External Standards .............3-15

3.11.1	Range Extension To 111 Microfarads..............3-15

3.11.2	Extension of C Resolution .. 3-16

3.11.3	Externally Determined Accuracy/ Comparisons
............3-16
3.11.4	Test-Fixture Compensation . 3-17 3.11. 5 Range
Extensions To 11

Microsiemans ............3-17

3.12	Precise Comparisons ............3-17

3.12.1	Balance Comparisons .....3-17

3.12.2	Direct Substitution ........3-17

3.13	Non-coaxial 2-Terminal Capacitors . 3-17

3.13.1	Unshielded 2-Terminal Capacitors...............3-18

3.13.2	Shielded 2-Terminal Capacitors...............3-18

3.14	Dc Bias........................3-20

3.14.1	Normal Bridge Configuration/ Parallel
Bias..............3-21

3.14.2	Reversed Bridge Configuration/ Series Bias
..............3-21

3.14.3	Dc In The Ratio Transformer/
Demagnetization..........3-22

3.15	Reversed Configuration...........3-22

3.15.1	Explanation ..............3-22

3.15.2	Procedure ...............3-22

4	THEORY

4.1	Introduction ....................4-1

4.2	Properties of Capacitors..........4-1

4.2.1	Basic Components of Capacitance .............4-1

4.2.2	Inductive and Lossy Components .............4-2

4.2.3	Frequency Characteristics .. 4-4

4.3	Basic Bridge Circuitry ............4-5

4.3.1	Elementary Capacitance Bridges .................4-5

4.3.2	Transformer-Ratio Bridges . 4-5

4.4	Circuitry of The 1616 Bridge ......4-7

4.4.1	Excitation................4-7

4.4.2	Circuit For The Unknown ... 4-7

4.4.3	Capacitance Standards .... 4-7

4.4.4	Conductance Standards .... 4-8

4.4.5	External Standards........4-9

4.4.6	Zero Adjust..............4-9

4.5	C-Standards Accuracy...........4-9

4.5.1	Calibration...............4-9

4.5.2	Sealing..................4-10

4.5.3	Thermal Lag .............4-10
Section	Page

4.6	G-Standards Accuracy...........4-9

4.7	Ratio Accuracy .................4-11

4.7.1	Residual Impedances......4-11

4.7.2	Example With 1:1 Ratio ....	4-12

4.7.3	The 10:1 Ratio...........4-13

4.7.4	The 1:100 Ratio..........4-13

4.7.5	C Offset Due To Induction .	4-14

4.7.6	Ground Circuit Impedance .	4-14

5	SERVICE and DIAGRAMS

5.1	GR Field Service................5-1

5.2	Minimum Performance Standards .. 5-1

5.2.1	General.................5-1

5.2.2	Zero Setting, Offsets, and Sensitivity...............5-3

5.2.3	Capacitance Accuracy .... 5-3

5.2.4	Capacitance Ratios .......5-3

5.2.5	Conductance Accuracy .... 5-3

5.2.6	Conductance Multipliers ... 5-4

5.3	Dissassembly...................5-5

5.3.1	Knobs ..................5-5

5.3.2	Cabinet Removal .........5-5

5.3.3	C-Box Removal ..........5-5

5.3.4	The G Box...............5-7

5.4	. Recalibration and Adjustments .... 5-7

5.4.1	Internal Capacitance Standards...............5-8

5.4.2	Conductance Multipliers .. . 5-8

5.4.3	C301/Setting Zero C......5-8

5.4.4	Lever-Switch Stiffness .... 5-8

5.4.5	Maintenance Note On Switches................5-8

5.5	Trouble Analysis ................5-9

5.5.1	Mechanical Damage ......5-9

5.5.2	BCD Circuits.............5-9

5.5.3	Non-Repairable Subassemblies...........5-9

5.5.4	Typical Parameters .......5-9

5.6	Parts Lists and Diagrams.........5-9
IET-8753-Manual-Page-1-Picture


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