Fluke 8508A 3458/HFL
8508A vs 3458/HFL
Functional & Versatility
Parameters
Comments
Full Scale (dc & ac Voltage) 200mV, 2V, 20V, 200V, 1050Vrms
120mV, 1.2V, 12V, 120V,
1050Vdc (ac = 700Vrms)
8508A maintains >10Gohm input impedance
to 20Vdc. This compares with 12V on
3458/HFL. The 8508A 1050Vrms
measurement is often used to calibrate
calibrators at 1000 Vrms output.
Full Scale (dc & ac current)
200uA, 2mA, 20mA, 200mA, 2A &
20A
100nA, 1uA, 120uA, 1.2mA,
12mA, 120mA, 1.05A
3458A/HFL has lower current ranges with a
sensitivity of 1pA compared with 10pA on
the 8508A – the 3458/HFL datasheet does
state that lower ranges have ‘typical’
uncertainty only. 8508A states typical above
10kHz and 2GOhm for resistance.
A 20Amp range on the 8508A improves
calibration of Multi-product calibrators. This
reduces the need for additional external
shunts.
AC Measurement
(Bandwidth)
AC Voltage - 1MHz (2%)
AC Current - 100kHz (0.4%)
AC Voltage - 1MHz (1%)
AC Voltage - 10MHz (15%)
AC Current - 100kHz (0.7%
Typical)
A DMM with 10 MOhm input impedance is
generally not useful for precision ac
measurement above 1MHz. A 50 Ohm
termination at these frequencies is more
desirable.
The 8508A high frequency Current
uncertainty will help maintain good TURs
when calibrating Multi-Product calibrators.
Full Scale (Resistance)
2Ω, 20Ω, 200Ω, 2kΩ, 20kΩ,
200kΩ, 2MΩ, 20MΩ, 200M
Ω,
2GΩ, 20GΩ (eleven ranges)
12Ω, 120Ω, 1.2kΩ, 12kΩ,
120kΩ, 1.2MΩ, 12MΩ,
120MΩ, 1.2GΩ (nine ranges)
8508A has a wide resistance measurement
range. 8508A measurement resolution of
10n
Ω this compares with 10uΩ on
3458/HFL
200 Ohm Resistance Range.
Selectable excitation current -
10mA & 1mA
Fixed excitation current -
10mA
Errors due to self-heating within the resistor
under test are minimized when the
multimeter low excitation current is
maintained. Use in conjunction with RTD or
low resistance measurements.
