16
CHECKING FOR CONTINUITY
(1) Turn the rotary function switch to the
position.
Press the
FUNC
button once to select the continuity
check function. Until the test leads are plugged in, the
primary readout will show
OL.
, with the icon of a
continuity beeper (
) above it.
(2) Plug the black test lead into the front-panel
COM
jack
and the red test lead into the
jack.
(3) Touch or clip the test leads to any two points of the
circuit. The resistance between those two points will
be shown on the primary readout. If the resistance is
<50
Ω
, the beeper will sound continuously. If there is
no continuity (an open circuit or a resistance greater
than 600
Ω
between the two points),
O.L
will appear
on the primary readout.
CHECKING THE INTEGRITY OF A DIODE
(1) Turn the rotary function switch to the
position.
Press the
FUNC
button twice to select the diode check
function. Until the test leads are plugged in, the
primary readout will show
.OL
, with the icon of a
diode (
) above it.
(2) Plug the black test lead into the front-panel
COM
jack
and the red test lead into the
jack.
(3) Connect the red test lead to the anode (positive
terminal) of the diode to be tested and the black test
lead to its cathode (negative terminal), as shown
below.
(4) Read the diode’s forward bias voltage drop on the
display. A silicon diode typically has a forward bias
voltage of 0.7V. A germanium diode typically has a
forward bias voltage of 0.3V. A
0V
reading in both
directions indicates a shorted diode. An
.OL
reading
indicates an open diode. In either case, the diode is
defective and should be replaced.
RED TEST LEAD
BLACK TEST LEAD
DMM550_Manual_RR1_FINAL_070914_awb 7/9/14 1:55 PM Page 16
