An electroporation device produces electric signals that may be adjusted in response to a cover area of electrodes, so that the electric signals are tolerable when delivered to cells within the cover area. The electroporation device can include an applicator, a plurality of electrodes extending from the applicator, a power supply in electrical communication with the electrodes, and a guide member coupled to the electrodes. The electrodes are associated with a cover area. The power supply is configured to generate one or more electroporating signals to cells within the cover area. The guide member can be configured to adjust the cover area of the electrodes. In some embodiments, the electrical signals may include opposing waveforms that produce a resultant interference waveform to effectively target the cover area, and each waveform may be a unipolar waveform or a bipolar waveform.