6-8. Terminal Current LI, Terminal Voltage LV &Diode Test
#
CAUTION
Do not measure the internal resistance of a diode with low reverse
withstand voltage using x 10kΩ range. The 12V voltage to be
applied at this test could damage the diode. Check the rating of a
diode before testing.
⑴
Current flowing across the
−
COM terminal and + terminal during
resistance measurements is indicated as LI. When LI flows into the
circuit under test there occurs a voltage drop. This is defined as LV.
Use the scale marked LI and LV for reading terminal current and
voltage. Circuit impedance may change according to the current that
flows into the circuit being measured or the voltage applied to the
circuit. Also, an abnormal condition may develope in the circuit due to
its self heating. Therefore, make resistance measurements at each
range w.ith the above in full consideration
Shown below are the values of terminal current
and voltage on each resistance range: Table 3
Resistance
Range
X1 X10 X1k X10k
Multiply by 10 Direct Reading 10 4
Max. Terminal
Current LI
150mA 15mA 150μA 60μA
Max. Terminal
Voltage LV
3V 3V 3V 12V
⑵
If the connection to the circuit is made as shown in Fig. 4, it is
possible to measure the forward current IF or reverse current I
R
of a
diode using the LI scale. It is also possible to measure the forward
voltage V
F
or backward voltage V
A
of a diode using the LV scale (Fig.
4).
⑶
As described for the resistance measurements, make the ohm zero
adjustment after every change of the measuring range.
To Next Page
Loading...
