0-13
(2) Difference in result of measurement with a circuit tester
The circuit tester power supply voltage depends on the tester type. 1.5 V, 3.0 V or 6.0 V is used.
The resistance of a semiconductor, such as a diode, varies with the circuit tester power supply
voltage.
The diode characteristics are shown in the figure below.
The resistance values of the same semiconductor measured
with two types of circuit testers having different power supply
voltages are different.
This manual describes the results of measurement with a
circuit tester whose power supply voltage is 3.0 V.
(3) Difference in measurement result by measurement range (analog type)
In the analog type circuit tester, changing the measurement range switches over the internal circuit
to vary the circuit resistance. Even when the same diode is measured, the measurement result
varies with the measurement range.
Always use the range described in the repair manual for
measurement.
0
1
2
3
4
5
6
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
(V)Forward voltage
Germanium
diode
(mA)
Forward current
Silicon
diode
Resistor Meter
0 Ω
Variable resistor
Resistor
Resistor
Range:×10
Range:×1
Power source: 1.5V
Red
Black
(SW1)
Current flow
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