Hioki SM-8213 - Page 24

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3. OPEARATING PRINCIPLE
The SM-8200 Series super megohmmeters consist of a constant voltage power supply and a high
sensitive current measuring section to be combined to compose a resistance measuring circuit.
The current measuring section is composed of a current detective resistor, low drift voltage
amplifier and an integrator-type A/D converter.
A measured resistance value is computation-processed by a CPU to display the result on a liquid
crystal display (LCD).
Fig. 3.1 shows a circuit composition of the SM-8200 Series.
Fig. 3.1 Circuit Composition
Amplifier
＋
－
C
i
r
c
u
i
t
D
i
s
c
h
a
r
g
e
Supply
Power
High Volta ge
Power Supply
Switches
VOLTAGESELECTOR
Control Keys
Signal Output
DC
Ａ／Ｄ
Converte r
DC
Curre ntto Voltager
ＡＣ Li ne Source
（Option）
Discharge
Controller
Converte
RANGESelector
ＲＳ－２３２Ｃ
（－）
（＋）
DISCHARGE
DISCHARGE
CHARGE
CHARGE
MEAS
MEAS
ＬＣＤ
ＣＰＵ
Ｒｘ