there are two types of the applications, one is to create positive and negative voltages, one is to build higher output voltage. Connection methods are shown as below：

 (1) Positive and negative voltage

(2) Increase the output voltage (current does not change). If there is no reverse blocking diode in the power supply, we should add an external blocking diode to prevent the damage of power supply while starting up. The voltage rating of the external diode should be greater than V1+V2. Transit current rating of diodes shall be greater than rate output current of S.P.S.