Aluminum electrolytic capacitors are the main components used in almost all electrical equipment. Leakage resistance is one of many electrical features that a capacitor is tested. Leakage is generally expressed as a leakage current at a particular voltage (usually the operating voltage).
The test sequence is synchronized as follows:
Static - The 7169A relay is normally closed and the 7158 relay is normally closed.
Applied voltage (holding time) - The 7169A relay is connected to the normally open contact and the 7158 relay remains normally closed.
Measuring current - The 7169A relay remains in the normally open position and the 7158 relay is connected to the normally open contact.
Discharge Capacitor - The 7169A relay is connected to the normally closed contact and the 7158 relay is connected to the normally closed contact.
The leakage of the aluminum electrolytic capacitor is measured by applying a fixed voltage to the capacitor and measuring the generated current. The leakage current will decay exponentially over time, so the applied voltage must reach a known period of time (holding time) before measuring the current.
After testing the capacitor, the voltage source should be set to zero. Sometimes the capacitor must be discharged before it is removed from the test fixture.
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