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Measurement and instrumentation
CL 3005 multimeter
Ref :
291 156
ENGLISH
5. Read the value of the resistance on the digital display. If a high value
resistance is shunted by a high value capacitor, let the display stabilize.
NOTE:
In the 200 Ω range, the value displayed is increased by a fixed value of 10.
When the test cords are short circuited in this range, the device displays 010
in the 200 Ω range. We must subtract this value to obtain the exact
measurement. Thus, when we measure a resistance of 100 Ω on the 200 Ω
range, the display will indicate 110. Read the current value on the digital
display.
2.6 Diode and transistor test
The function of the diode test is to obtain relative measurements of the
forward drop in voltage in the diode and transistor junctions. This function
also helps measure in situ semiconductor junctions.
2.6.1 Diode test
1. Connect the red test cord to the "VΩ" socket and the black test cord to
the "COM" socket.
2. Place the Function/Range selector switch on "diode test".
3. If the semiconductor junction measured is connected to a circuit,
disconnect the circuit to be tested and discharge all capacitors.
4. Connect the test cords to the device.
5. Read the forward voltage on the digital display.
6. If the digital display indicates a capacitance overange (1), reverse the
connections. The placement of the test cords when the forward voltage is
displayed indicates the direction of the diode. The red cord is positive and
the black one is negative. If a capacitance overange (1) is detected with
the two cords connected, the junction is open. If we obtain a low value
(less than 1000) with the two cords connected, the junction is internally
short-circuited or (if we measure the junction in a circuit) the junction is
shunted by a resistance less than 1 kΩ. In the last case, it is necessary to
disconnect the junction from the circuit to check its functioning.
2.6.2 Transistor junction test
We can test bipolar transistors as diode junctions formed between the base
and emitter and between the base and collector of the transistor. We must
also carry out measurements between the collector and emitter to determine
if this junction is short-circuited
2.7 Battery test
1. Place the Function/Range selector on the BAT 1.5 V / 9 V range.
1.5 V / 9 V battery: Red test cord connected to the mA socket, black test
cord to the COM socket.
2. Connect the test cords to the "+" and "–" terminals of the battery. The
battery voltage appears on the digital display.
3. Test conditions: charging current of about 200 mA with 1.5 V battery,
charging current of about 6 mA with 9 V battery.
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