User manual

Making Measurements 2
Testing Diodes
U1190A Series User’s Guide 39
Tes ting Dio des
Set up your clamp meter to test diodes as shown in
Figure 2- 15. Probe the test points, and read the display.
Figure 2-13 Diode display
CAUTION
To avoid possible damage to your clamp meter or to the equipment
under test, disconnect the circuit power and discharge all high-voltage
capacitors before testing diodes.
NOTE
• Use the diode test to check diodes, transistors, silicon controlled
rectifiers (SCRs), and other semiconductor devices. A good diode
allows current to flow in one direction only.
• This test sends a current through a semiconductor junction, and then
measures the junction’s voltage drop.
• Connect the red test lead to the positive terminal (anode) of the diode
and the black test lead to the negative terminal (cathode). The cathode
of a diode is indicated with a band.
NOTE
Your clamp meter can display the forward-bias of a diode up to
approximately 1.8 V. The forward-bias of a typical diode is within the range
of 0.3 V to 0.8 V; however, the reading can vary depending on the
resistance of other pathways between the probe tips.
U119XA UG.book Page 39 Thursday, September 15, 2011 4:03 PM