HP HP34401A - How to Measure DC and AC Current

TAKING MEASUREMENTS
4
FUNCTION MATH
DISPLAY
DC I
AC I
Ω
4W
Period
dB
dBm
DC V AC V Ω 2W Freq Cont Null
Min/Max
HI
HI
LO
LO
I
V
Ω
Ω
4W Sense
Shift
First Shift, then Select
AC or DC
AC or DC Current
-
+
Figure 5. Probe/Meter Placement to
Measure Current Through Meter
+
A
Circuit
Under Test
DMM
_
I
How to Measure DC and AC
Current
To use the DMM as an ammeter, connect the leads in which the current flows to the current
(I) and LO terminals (Figure 4). To measure the current, either the DC I or AC I key must be
selected by pushing SHIFT and DC V or AC V button.
Next, connect the leads of the probes to the
circuit in series with the location of the
current in question (Figure 5). The current
(I) lead connects to the “+” (pos) part of
the circuit and the Lo to the “–“ (neg). If
these are reversed, a negative value for the
current is obtained.
CAUTION: Do not exceed the maximum allowable current input
(3A DC). Never apply a voltage over the current input terminal (I) of
the DMM. This will cause a large current to flow through the small
input resistor r
i
and can damage the DMM.
Figure 4. How to Measure Current