Keithley 7077, Instruction Manual

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ii
3 Applications
3.1 Introduction.......................................................................................................................................................... 3-1
3.2 Thick film resistor network testing...................................................................................................................... 3-1
3.2.1 Four-terminal ohms measurements............................................................................................................ 3-1
3.2.2 Voltage divider checks .............................................................................................................................. 3-3
3.3 Transistor testing ................................................................................................................................................. 3-3
3.3.1 Current gain checks ................................................................................................................................... 3-6
3.3.2 I
E
and V
BE
measurements ......................................................................................................................... 3-7
4 Service Information
4.1 Introduction.......................................................................................................................................................... 4-1
4.2 Handling and cleaning precautions...................................................................................................................... 4-1
4.3 Card installation and removal .............................................................................................................................. 4-1
4.4 Performance verification ..................................................................................................................................... 4-4
4.4.1 Environmental conditions .......................................................................................................................... 4-4
4.4.2 Recommended equipment ......................................................................................................................... 4-4
4.4.3 Path resistance tests ................................................................................................................................... 4-5
4.4.4 Offset current tests ..................................................................................................................................... 4-6
4.4.5 Path isolation tests ..................................................................................................................................... 4-8
4.4.6 Differential and common model isolation tests ....................................................................................... 4-10
4.5 Principles of operation ....................................................................................................................................... 4-12
4.5.1 Card identification ................................................................................................................................... 4-12
4.5.2 Switching circuitry................................................................................................................................... 4-12
4.5.3 Power up safeguard.................................................................................................................................. 4-13
4.6 Special handling of static-sensitive devices ...................................................................................................... 4-13
4.7 Troubleshooting ................................................................................................................................................. 4-13
4.7.1 Recommended equipment ....................................................................................................................... 4-13
4.7.2 Troubleshooting procedure ...................................................................................................................... 4-13
5 Replaceable Parts
5.1 Introduction.......................................................................................................................................................... 5-1
5.2 Parts list ............................................................................................................................................................... 5-1
5.3 Ordering information ........................................................................................................................................... 5-1
5.4 Factory service..................................................................................................................................................... 5-1
5.5 Component layout and schematic diagram.......................................................................................................... 5-1