Kikusui TOS9213S Operation Manual page 218

[3] Discharge circuit
[4] 1 kV DC/DC converter
[5] IR voltmeter
[6] Voltmeter
[7] Current detection circuit
A-2
Equipped with a function for forcibly releasing a charge in the DUT contained at the
end of a DC withstanding voltage test or an insulation resistance test, thus prevent-
ing electric shock.
High-voltage generation circuit for insulation resistance testing. At an output of
1000 V, the converter enhances the output from the reference-voltage generation cir-
cuit by approximately 200 times to obtain 1000 V. At -25 V to -1000 V (a maxi-
mum rated current of 1 mA), the converter realizes a low-ripple stable test voltage
with a voltage regulation of 1 % or less.
Digital voltmeter for insulation resistance testing with an accuracy of ±(1 % of read-
ing + 1 V). The output voltage is divided using a high-precision, high-voltage resis-
tor. These voltages are input to the A/D converter and displayed on the LCD during
the test. The insulation resistance is obtained by dividing voltage by current which
detected on the current detection circuit in the insulation resistance meter.
Equipped with a high-precision digital voltmeter with an accuracy of ±(1 % of read-
ing + 30 V) and an analog voltmeter with an accuracy of ±5% f.s.
(a) Digital voltmeter
The digital voltmeter divides the output voltage using a high-precision high-voltage
resistor, and converts divided voltages into DC voltages in the AC/DC conversion
circuit. These voltages are collected by the A/D converter and displayed on the LCD
during the test. The voltmeter constantly monitors the voltage on the output termi-
nal, even when no test is under way. When a voltage is detected, the voltmeter turns
on the DANGER lamp.
(b) Analog voltmeter
Rectifies currents flowing into divider resistors, and drives the DC voltmeter. Con-
ducts voltage measurement in AC/DC withstanding voltage testing, as well as insu-
lation resistance testing.
(a) Current detection circuit for withstanding voltage testing
Converts the current flowing into the output terminal into a voltage using the refer-
ence resistance, and further transforms it into a DC voltage in the AC/DC conver-
sion circuit. This voltage is input to the A/D converter and displayed on the LCD.
(b) Current detection circuit for insulation resistance testing
Converts the current flowing into the output terminal into a voltage in the current-
voltage conversion circuit, and collects it in the A/D converter. The insulation resis-
tance value is determined by dividing the voltage measured on the voltmeter for
insulation resistance testing by the current obtained in this current detection circuit.
The insulation resistance value is then displayed on the LCD.
TOS9213S/ TOS9213AS