Fluke 8808A User Manual page 93

If the relative readings value of a dc voltage measurement is shown in the primary
display and the dc voltage itself is shown in the secondary display, the Meter takes a
single measurement and updates both displays with it.
Updating Primary and Secondary Displays with Separate Measurements
If the measurement function in the primary display is different from that in the secondary
display, the Meter updates each display using a separate measurement.
Taking Voltage and Current Measurements Using the Dual Display
Most applications of the dual display listed in Table A-2 can be performed using a single
set of test leads connected to the INPUT VZYR HI and LO terminals. However, to
measure the voltage and current of an input signal requires three leads. Be sure that the
voltage and current measurements share the same common as shown in Figure A-2. Then
simply follow the precautions you would follow if you were making normal current
measurements without a current clamp.
Primary Secondary
Display Display
Volts DC Volts AC
Volts DC Current DC
Volts DC Current AC
Volts AC Current DC
Volts AC Current AC
Volts AC Frequency
Current DC Current AC
MN MX Actual Value
REL Actual Value
Table A-2. Sample Dual Display Applications
Monitor dc level and ac ripple of power supply Troubleshoot
amplifier circuits
Check power supply load regulation
Monitor UUT current draw and circuit voltages
Monitor loop current and voltage drop across transmitter
Line and load regulation tests
dc/ac or ac/dc converters
Line and load regulation tests
dc/ac or ac/dc converters
Line and load regulation tests
Transformer (magnetic circuit) saturation
Measure ac amplitude and frequency for line voltage and ac signal
analysis
Measure frequency response of an amplifier
Adjust ac motor control
Read noise in telecommunication applications
Adjust portable power generator to optimize power output
Set frequency compensation for a network
Measure ripple and dc current draw of switching power supply
Measure current dissipation in protective fuse resistors used in
power supplies
Measure ripple and noise on a line
Show the minimum or maximum value recorded and the present
measurement
Show actual measurement and the difference between this value
and the relative base.
Applications
Appendices A
Applications
A-3