Text preview for : LowCurrentHiResistance_EHandbook.pdf part of Keithley LowCurrentHiResistance EHandbook Keithley LowCurrentHiResistance_EHandbook.pdf
Back to : LowCurrentHiResistance_EH | Home
begin
A g r e At e r m e A s u r e o f c o n f i d e n c e
Introduction 2 Low Current Measurements 2 Measurement Circuit 2 Leakage Currents and Guarding 3 Noise and Source Resistance 3 Zero Drift 4 Generated
Currents 4 Overload Protection 6 AC Interference and Damping 6 Using a Coulombmeter to Measure Low Current 7 High Resistance Measurements 8 Constant-
Voltage Method 8 Constant-Current Method 8 Guarding 9 Settling Time 10 Low-I Application 11 High-R Application 12 Selector Guide 13 Glossary 14
previous home next
Introduction .............................................................. 2
Low Current Measurements
Measurement Circuit .............................................. 2
Leakage Currents and Guarding ....................... 3
Noise and Source Resistance ............................. 3
Low Current Measurements Zero Drift ......................................................................4
Generated Currents ................................................ 4
Overload Protection ............................................... 6
HI
AC Interference and Damping ........................... 6
Measurement Circuit Using a Coulombmeter to
Introduction The correct measurement circuit for making a current RS RM
Measure Low Current............................................. 7
Testing and characterizing metallic materials, low measurement is shown in Figure 1. Ensure that the High Resistance Measurements
temperature superconductors, nanoscale materials, measurement instrument is at a low voltage point in the VB Constant-Voltage Method.................................... 8
highly doped semiconductors, photo-diode dark circuit. This ensures that the instrument is less likely VS IM
Constant-Current Method .................................... 8
currents, and electron beam currents from accelerating to be damaged by an over-voltage applied across the Guarding ...................................................................... 9
devices requires making current measurements at instrument. Also, when the instrument is near circuit LO
Settling Time ............................................................ 10
nanoamp levels and below. Either the generated common, noise voltages tend to be lower. Thus, a better Low-I Application: Avalanche Photodiode
measurement can be obtained. Reverse Bias Current Measurements .................. 11
current is low or very low power materials, such DMM, Electrometer, SMU,
or Picoammeter High-R Application: Voltage Coefficient
as single-atomic-layer graphene, must operate with Current Source Testing of High Ohmic Value Resistors.............. 12
very low currents to minimize power dissipation VS VS