User`s guide

5 Operation and Connections Tutorial
106 Model N6705A User’s Guide
Additional Load Considerations
Response Time with an External Capacitor
When programming with an external capacitor, voltage response time
may be longer than that specified in Appendix A. Use the following
formula to estimate the additional up-programming response time:
Response Time = (Added Output Capacitor)X(Change in Vout)
Current Limit Setting
Note that programming into an external output capacitor may cause
the DC Power Analyzer to briefly enter constant current or constant
power operating mode, which adds additional time to the estimation.
Positive and Negative Voltages
Either positive or negative voltages can be obtained from the output
by grounding (or "commoning") one of the output terminals. Always
use two wires to connect the load to the output regardless of where
or how the system is grounded. The instrument can be operated with
any output terminal ± 240 VDC including output voltage from ground.
Protecting Sensitive Loads from AC Power Switching Transients
NOTE
If your load is connected directly to the output binding posts and is not
connected to chassis ground in any way, you do not need to worry about AC
power switching transients appearing at the output binding posts.
Operating the AC line switch can inject common mode current spikes
into the DC output leads, resulting in voltage spikes that may damage
loads that are highly sensitive to voltage or current transients. Note
that any electronic device meeting international standards for EMI
compliance is likely to generate similar current spikes. This situation
arises from the presence of EMI filters at both the AC input and the
DC output of the DC Power Analyzer. These filters typically include
common mode capacitors connected to the chassis of the DC Power
Analyzer. Since the AC input has an earth ground, any load that is
also earth-grounded provides a possible return path for common
mode currents.
The following steps will help mitigate common mode current spikes
appearing at the output binding posts when the DC Power Analyzer
is turned on or off by the AC line switch:
 Install a separate “bonding” wire from the load’s common point,
to the ground terminal of the DC Power Analyzer. This provides a
lower impedance path that helps direct injected currents away
from the DC output leads (and the sensitive load).
 Disconnect the load from the output before turning the DC Power
Analyzer on or off. This will always protect the load from
common mode currents.