3.16. Example Measurement Setups
The M81-SSM can be configured for a wide variety of measurements. The following examples show the recommended wiring for a few common applications.
Resistance Measurement
Current source with voltage measurement
Figure 3.37 Resistance measurement using a BCS-10 module and a VM-10 module
The configuration illustrated above is a four-wire resistance measurement. It accurately determines resistance from milliohms to over a hundred megohms. Guarded tri-axial current source connections improve accuracy and settle time when measuring large resistors. This configuration resolves micro-ohm changes when set up to do lock-in measurements.
The configuration uses the balanced current source (BCS-10) module to provide current and measures the resulting voltage with the voltage measure (VM-10) module.
Earth and measure ground are connected together at the enclosure. The outer shell of the BCS-10 triaxial connectors provides earth ground while the outer shell of the VM-10 BNC connectors provides measure ground.
Voltage source with current measurement
Figure 3.38 Resistance measurement using a VS-10 module and a CM-10 module
The configuration illustrated above is a two-wire resistance measurement. It is capable of accurately determining resistance from a few ohms to over a hundred gigaohms. This configuration can resolve micro-ohm changes when set up to do lock-in measurements.
The configuration uses the voltage source (VS-10) module to provide voltage and measures the resulting current with the current measure (CM-10) module.
Earth and measure ground are connected together at the enclosure. Earth ground is connected using a screw on the rear of the CM-10 module. The BNC shells of the modules provide measure ground.
Figure 3.39 Resistance measurement using VS-10, CM-10, and VM-10 modules
Adding a CM-10 module to this configuration provides a four-wire measurement. This improves the accuracy of measuring small resistances.
Diode Characterization
Figure 3.40 Diode measurement using VS-10, CM-10, and VM-10 modules
The configuration illustrated above is a four-wire diode measurement. It is capable of quickly and accurately determining the I-V characteristics of a diode.
The configuration uses the voltage source (VS-10) module to provide voltage and measures the resulting current with the current measure (CM-10) module. A voltage measure (VM-10) module creates a four-wire measurement to improve accuracy when the diode is conducting large amounts of current.
The parameter sweeping feature and the data streaming feature allow for rapid I-V characterization. Lock-in capabilities allow for highly sensitive measurements.
Earth and measure ground are connected together at the enclosure. Earth ground is connected using a screw on the rear of the CM-10 module. The BNC shells of the modules provide measure ground.
Transistor Characterization
Field Effect Transistor
Figure 3.41 FET transistor measurement using VS-10, CM-10, and VM-10 modules
The configuration illustrated above is a FET transistor measurement. This configuration can quickly and accurately determine the I-V characteristics of a FET transistor.
The configuration uses two voltage source (VS-10) modules to provide voltage to the gate and drain terminals. The current measure (CM-10) module holds the source terminal at zero volts.
The parameter sweeping feature and the data streaming feature allow for rapid I-V characterization. Lock-in capabilities allow for highly sensitive measurements.
Earth and measure ground are connected together at the enclosure. Earth ground is connected using a screw on the rear of the CM-10 module. The BNC shells of the modules provide measure ground.
Configuring Unused Modules
When using the M81-SSM with multiple modules, it is often the case that not every module will be used in each experiment. To maintain measurement accuracy and prevent interference, either unload unused modules, or follow these steps:
Set the output of all unused sources (VS-10 or BCS-10) to the disabled state.
Configure the input of any unused VM-10 to be grounded.
Turn off auto-range for any unused CM-10 and set the range to 100 mA.