AC Voltage
This section describes how to configure AC voltage measurements from the front panel.
Default delays are selected to give correct first readings for most measurements. For the most
accurate measurements, the input blocking RC time constant must settle to 1/50 of the AC
signal level.
Signals greater than 300 V (rms) or 1 A (rms) will cause self-heating in signal-conditioning
components. These errors are included in the instrument specifications. Internal temperature
changes due to self-heating may cause additional error on other functions or ranges. The addi-
tional error will generally dissipate within a few minutes.
For example, consider a 100 mVAC signal with a 10 VDC bias. The 10 VDC bias should be
settled to 1/50 of 100 mVAC, or 2 mVDC. The corresponding settling time can be calculated
using the blocking RC time constant of 0.22 s as follows:
settling time = ln(bias/settled value) * 0.22 s
settling time = ln(10 VDC / 2 mVDC) * 0.22 s
settling time = ln(5000) * 0.22 s = 1.9 s
This additional settling delay should be applied after connecting the signal to the DMM's ACV
input or after selecting the ACV function with the signal already connected. If the DC bias
remains constant, subsequent measurements can be made to full accuracy without additional
settling delays.
Step 1:
Configure the test leads as shown.
Step 2:
Press
[ACV]
on the front panel.
Features and Functions
60
Keysight True
volt
Series Operating and Service Guide
