System SourceMeter® Instrument Reference Manual  Section 2: 
 
2600BS-901-01 Rev. B / May 2013  2-51 
 
Input/output LO and chassis ground 
As shown below, SMU input/output LOs are available at the rear panel terminal blocks. Input/output 
LOs are not connected between channels and are electrically isolated from chassis ground. 
As shown, there is a low-noise chassis ground banana jack that can be used as a common signal 
ground point for Input/Output LOs. This low-noise signal ground banana jack is connected to the 
chassis through a Frequency Variable Resistor (FVR). 
The FVR (in the figure below) is used to isolate the SMUs from high frequencies that may be present 
on the chassis of the Series 2600B. As frequencies on the chassis increase, the resistance of the 
FVR increases to dampen its effects. 
 
Keep in mind that the chassis should never be used as a ground point for signal connections. High 
frequencies present on the chassis of the Series 2600B may result in higher noise. The chassis 
should only be used as a safety shield. Use the chassis screw for connections to the chassis of the 
Series 2600B. For Models 2634B, 2635B, and 2636B, connect to ground on the ground module not 
to the chassis screw. 
 
Figure 16: Models 2602B, 2604B, 2612B, and 2614B input/output LO and chassis ground 
terminals (Models 2601B and 2611B similar)