Voltage testing device and method for power supply

A voltage testing device comprising:

• a computer, the computer comprises a control module, an adjusting module, and a display module;
• and
• an oscillograph, the oscillograph comprises a control unit, an obtaining unit, a storing unit, and a voltage wave producing unit;
• wherein the control module is configured to send initial setting parameters to the control unit;
• the control unit is configured to store the initial setting parameters in the storing unit;
• the obtaining unit is configured to obtain initial testing parameters when the oscillograph is connected to a power supply;
• the control unit is further configured to send the initial testing parameters to the adjusting module;
• the adjusting module is configured to send a current voltage offset and a current voltage undulating value to the control unit according to the initial testing parameters;
• the obtaining unit is further configured to obtain voltage values of the power supply during a period time after the storing unit stores the current voltage offset and the current voltage undulating value, and to send the voltage values to the voltage wave producing unit;
• the voltage wave producing unit is configured to produce a voltage wave according to the voltage values, and to send the voltage wave and the voltage values to the control module;
• and the control module is further configured to display the voltage values and the voltage wave on the display module.