Keithley 6512 Instruction Manual page 10

3.6.1 Bus error .................................................................................................................................................. 3-24
3.6.2 Number error ........................................................................................................................................... 3-24
3.6.3 Trigger overrun error ............................................................................................................................... 3-24
3.7 Bus data transmission times .............................................................................................................................. 3-24
4 Applications
4.1 Introduction ......................................................................................................................................................... 4-1
4.2 Low-level leakage current measurements ........................................................................................................... 4-1
4.3 Diode characterization ........................................................................................................................................ 4-3
4.4 Capacitor leakage measurements ........................................................................................................................ 4-4
4.5 Capacitance measurement ................................................................................................................................... 4-5
4.6 Insulation resistance measurements .................................................................................................................... 4-5
4.6.1 Unguarded resistance measurements ........................................................................................................ 4-5
4.6.2 Guarded resistance measurements ............................................................................................................ 4-6
4.6.3 V/I resistance measurements with external voltage source ....................................................................... 4-6
4.7 High-impedance voltmeter .................................................................................................................................. 4-9
4.8 Voltage coefficients of high-megohm resistors .................................................................................................. 4-9
4.9 Static charge detection ...................................................................................................................................... 4-11
5 Performance Verification
5.1 Introduction ......................................................................................................................................................... 5-1
5.2 Environmental conditions ................................................................................................................................... 5-1
5.3 Initial conditions ................................................................................................................................................. 5-1
5.4 Recommended test equipment ............................................................................................................................ 5-1
5.5 Verification procedures ....................................................................................................................................... 5-2
5.5.1 Input current verification .......................................................................................................................... 5-2
5.5.2 Amps verification ...................................................................................................................................... 5-2
5.5.3 Coulombs verification ............................................................................................................................... 5-3
5.5.4 Volts verification ....................................................................................................................................... 5-3
5.5.5 Ohms verification ...................................................................................................................................... 5-4
5.5.6 Input impedance verification .................................................................................................................... 5-6
6 Theory of Operation
6.1 Introduction ......................................................................................................................................................... 6-1
6.2 Overall functional description ............................................................................................................................. 6-1
6.3 Input preamplifier ............................................................................................................................................... 6-2
6.3.1 Input stage ................................................................................................................................................. 6-3
6.3.2 Gain stage .................................................................................................................................................. 6-4
6.3.3 Output stage .............................................................................................................................................. 6-4
6.3.4 Ohms voltage source ................................................................................................................................. 6-5
6.3.5 Zero check ................................................................................................................................................. 6-5
6.4 Additional signal conditioning ............................................................................................................................ 6-6
6.4.1 Ranging amplifier ..................................................................................................................................... 6-6
6.4.2 Multiplexer and buffer amplifier ............................................................................................................... 6-6
6.4.3 -2V reference source ................................................................................................................................. 6-7
6.5 A/D converter ...................................................................................................................................................... 6-7
6.6 Digital circuitry ................................................................................................................................................... 6-9
6.6.1 Microcomputer .......................................................................................................................................... 6-9
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