MASTER BKGRD 6-26-07
1
MASTER BKGRD 6-26-07
Taking Measurements
Checking Diodes
You can check diodes, transistors, and other semiconductors for opens, shorts,
and normal operation, and determine the forward �oltage and polarity for diodes.
You can also check LeDs.
1. power off the circuit under test and discharge all capacitors.
2. Rotate the function dial to
/
and press
SELECT
.
appears.
3. Connect the test leads to the de�ice you want to check, or remo�e one of
the leads of the component from its circuit and connect the test leads to the
component. Note the first reading.
4. Re�erse the test leads and note the second reading.
if one reading shows a �alue and the other is o�errange (
OF
appears) the de�ice
is good. if
OF
appears during both readings, the de�ice is open. if both �alues are
very small or zero, the device is shorted.
Notes
:
• when you test a silicon-type semiconductor, the �alues might �ary depending on the
temperature.
• The �alues that appear during a diode check show the actual forward �oltage (2.0V
ma�). if the �oltage e�ceeds 2.0V,
OF
appears. The meter cannot check this diode.
•
To
check polarity of an unmarked diode
: C
onnect the test leads to the two
sides of the diode. Measure and note the �oltage. Then, re�erse the test
leads, measure and note the second reading. The side of the diode where
the meter shows a higher �oltage using the red test lead is the anode (+)
side. The side of the diode where the meter shows
OF
using the red test lead
is the cathode (–) side.
Measuring Logic
WARNING
: Do �OT apply more than 5 V DC between terminals. This could
damage the meter or the circuit being tested.
1. Rotate the function dial to
LOGIC/Hz
and press
SELECT
once.
LO
appears.
2. Connect the test leads to the de�ice you want to check.
LO
appears if the logic is low (the �oltage is lower than 1.0V).
Hi
appears if the
logic is high (the �oltage is higher than 2.0V) The actual �oltage appears if the
logic is between 1 and 2 V.
Содержание 22-812A
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