TOS7200
21
Warning for Residual High Voltages
Discharge time
The length of the discharge time varies according to the properties of the DUT and the test
voltage.
Discharge is conducted at a resistance of approximately 25 kΩ in testing.
When no DUT is connected, the tester itself requires this following lengths of time to reduce
the internal capacitor voltage to 30 V.
Test voltage 1000 V: Approximately 0.5 ms
Assuming that a 0.05 μF capacitor is tested, the following lengths of time are required to
reduce the charge to 30 V.
Test voltage 1000 V: Approximately 5 ms
If the DUT is disconnected during a test or before the completion of discharging, assuming
that the DUT has a capacity of 0.01 μF and a parallel resistance of 100 MΩ, approximately 3.5
seconds at 1000 V is required for the DUT to discharge to 30 V.
When the approximate time constant of the DUT is known, the time required for discharging
to 30 V after the output is cut off is calculated as the time constant times the value given
above.
Action When in Emergency
In case of an emergency (such as electric shock hazard or burning of DUT), take the following
actions. You may do either (a) or (b) first. But be sure to do both.
(a) Turn OFF the power switch of the Tester.
(b) Disconnect the AC power cord of the Tester from the AC line receptacle.
WARNING
• In Testing, the test leadwire, and DUT are charged to a high voltage. The tester is
equipped with a discharge circuit, but some time is nonetheless required to discharge
them after the output is cut off. There is a danger of electric shock during discharge.
To avoid electric shock, take the utmost care to ensure that the DUT, test leadwire, and
highly charged parts around the output terminal are not touched. If it is necessary to
touch them, be sure to confirm the following:
The DANGER lamp has gone out.
• As soon as the output is cut off, the tester’s discharge circuit starts forced discharging
(discharge function). Do not disconnect the DUT during a test or prior to completion
of discharging.
The discharger function operates until the DUT voltage (or output terminal voltage) becomes
approximately 30 V.
