Sa pagamit ng Multitester: take your digital multimeter and set it in the DC mode and connect both the terminals of the multimeter with the output wire.. If your output is DC then it will show you some output whether positive or negative.
But if your output is Ac then you will not get any output in the multimeter. So next step is to switch your multimeter in the AC mode. (this step is required only if there is no output in DC mode of multimeter). Now connect your multimeter with the output and surely you will get an output in the display if your output is AC.