An adaptive spiral phase plate based on liquid crystals and the transmission electrode technique is proposed and experimentally demonstrated. This innovative structure can generate a continuous spiral voltage profile that is completely reconfigurable using only two low voltages. The liquid crystal layer produces an optical phase shift that depends on the voltage distribution. These two effects cause light passing through the device to be twisted like a corkscrew around its travel axis. Because of the continuous phase shift, the proposed device is expected to exhibit a high conversion efficiency. In addition, this device is more efficient and simpler than previously reported optical vortex generators. Moreover, the device is completely reconfigurable, i.e., the operating wavelengths and topological charges are tunable. The device can reduce current devices' fabrication costs and generate different orbital angular momentum modes with improved light efficiency, simplicity, and the possibility of reconfiguration.