DAC voltage testing is one of the alternative methods of ac voltage testing and is applicable for a broad range of medium-voltage, high-voltage, and extra-high-voltage cables. Damped alternating current voltages are generated by charging the test object to a predetermined voltage level and then discharging its capacitance through a suitable inductance.

During the discharging stage, a DAC at a frequency dependent on the test-object capacitance and the inductance is present. The capacitance of the test object is subjected to a continuously increasing voltage at a rate dependent on the test-object capacitance and the current rating of the power supply.

Most DAC applications are based on the combination of voltage withstand and advanced diagnostic measurements, such as partial discharge and dissipation factor. DAC testing is an advanced maintenance tool, offering more than a simple "go or no-go" decision.