Checking Diodes - Fluke 8845A User Manual

8845A/8846A
Users Manual
None

Checking Diodes

The diode function sends a current through a semiconductor junction while the Meter
measures the voltage drop across the junction (or junctions). Measurements are displayed
in the 10 V range at a relatively fast measurement rate. "OPEN" is displayed for voltages
10 % above the compliance voltage setting. Typical junction voltage drop on good
junctions are 0.3 to 0.8 volts. If enabled, the beeper will make a short beep when a good
junction is detected. Shorted diodes will indicate a significantly lower voltage.
With the higher compliance voltage (up to 10 V), the Meter's diode test function can test
zeners up to 10 volts, diode stacks and LEDs. The selectable current and maximum
voltage allows you to tailor the diode test to the expected voltage for the junction being
tested.
To check a diode:
1. Press S twice on the 8846A or D once on the 8845A. An example of the diode
2. Select the test voltage and current appropriate for the diode being tested by pressing
3. Connect the test leads as shown in Figure 4-8.
Function modifiers:
None
4-16
test display is shown below.
+
F1
the associated soft keys.
Figure 4-8. Diode Testing Connections
0.5994
F2 F3 F4 F5
INPUT SENSE
V 4 W
2 2W/4W
HI HI
1000 V CAT I
300V
600V CAT II
LO LO
1V
FUSED
00
4
10A
mA
REAR FRONT
caw13f.eps
caw024.eps