2470 High Voltage SourceMeter Instrument Reference Manual
Section 5: Source-measure considerations
2470-901-01 Rev. A /
May
2019
5-19
Make sure the external voltage never exceeds the voltage limit setting of the current source.
This causes excessive current to be drawn from the external battery or source.
If you are using the current source to charge or discharge batteries, the following precautions
must be observed. Failure to observe these precautions could result in instrument damage
that is not covered by the warranty.
Be sure to set the output-off state of the current source for high impedance. This setting
opens the output relay when the output is turned off. With the normal output-off state
selected, turning the output off sets the voltage limit to zero. This 0 V source limit condition
will cause excessive current to be drawn from the external battery or source.
Carefully consider and configure the output-off state, source, and limits before connecting
the 2470 to a device that can deliver energy. Devices that can deliver energy include voltage
sources, batteries, capacitors, and solar cells. Configure instrument settings before making
connections to the device. Failure to consider the output-off state, source, and limits may
result in damage to the instrument or to the device under test (DUT).
When using the current source as a sink, always set the voltage limit and configure
overvoltage protection (OVP) to levels that are higher than the external voltage level. Failure
to do so could result in excessive current flow into the 2470 (> 105 mA) and incorrect
measurements. When the instrument is operating in limit, be aware that the instrument
always tries to maintain the limit.
Measurement settling time considerations
Several outside factors can influence measurement settling times. Effects such as dielectric
absorption, cable leakages, and noise can all extend the times required to make stable
measurements. Be sure to use appropriate shielding, guarding, and aperture selections when making
low-current measurements.
Each current measurement range has a combination of a range resistor and a compensating
capacitor that must settle out to allow a stable measurement.