How To Measure Dc/Ac Current - HP HP34401A User Manual

T A K I N G M E A S U R E M E N T S
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.
DISPLAY
FUNCTION
DC I AC I 4W
DC V AC V 2W
First Shift, then Select
AC or DC
Figure 4. How to Measure Current
MATH
Period dB
Freq Cont Null
Figure 5. Probe/Meter Placement to
Measure Current Through Meter
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 and can damage the DMM.
i
4
4W Sense
V
HI HI
LO LO
dBm
AC or DC Current
Min/Max
I
Shift
I
+ DMM
Circuit
Under Test A
_
-
+