8808A/SU 120V Fluke Electronics, 8808A/SU 120V Datasheet - Page 98
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8808A/SU 120V
Manufacturer Part Number
8808A/SU 120V
Description
USB CABLE KIT SW DMM 5.5 RES
Manufacturer
Fluke Electronics
Type
Digital (DMM)r
Datasheet
1.8808A_120V.pdf
(100 pages)
Specifications of 8808A/SU 120V
Includes
Test Leads
Style
Bench
Display Digits
5.5
Display Type
VFD, Dual
Display Count
200000
Function
Voltage, Current, Resistance, Frequency
Functions, Extra
Continuity, dB, Diode Test
Features
Hold, Min/Max, RS-232 Port
Ranging
Auto/Manual
Response
True RMS
Lead Free Status / RoHS Status
Not applicable / RoHS non-compliant
Other names
614-1069
A-8
8808A
Users Manual
Making Low-Level Current Measurements
There are many applications where obtaining the utmost accuracy in low-level current
measurements is critical. For example, determining the leakage current of a battery
operated device in its standby mode is critical in determining the time before battery re-
charge is needed. Traditional multimeters make these measurements using a shunt
method shown in Figure A-3. The shunt resistor converts the current to be measured to a
voltage, which is called the burden voltage. Since the internal impedance of the current
source is in parallel with the shunt resistor, the current flowing in the shunt resistor is less
than the actual value, thus causing an error.
Another method of low-current measurement is the feedback resistor method shown in
Figure A-4. The feedback resistor converts the current to be measured into a voltage. The
high gain operational amplifier forces the burden voltage to be rather low and thus
induces an error. The zero burden voltage measurement method used in the Meter gives a
more accurate measurement of low-level (leakage) currents.
I
IN
Figure A-4. Zero Burden Voltage Low-Level Current Measurement
Figure A-3. Shunt Method of Low-Level Current Measurement
I
IN
R
Internal
R
Internal
R
SHUNT
R
A
Feedback
A
V
V
OUT
OUT
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