An external plaster using an aqueous hot melted type adhesive base material stably containing water-soluble drug having good drug releasability, so that bioavailability of the drug is enhanced, is provided. A card of deep-drawable material is placed between the upper and lower die and an elastic body is placed between the card and the lower die or between the card and the upper die. Variable capacitor arrays are coupled in parallel on the class-E power amplifiers and controlled in response to system parameters including duty cycle of the input signal. Therefore, allocating areas, such as a spare area, for disc defect management other than an area for storing user data, to the data area is possible. The circuit operates using two opto-coupler devices while conventional circuits require four opto-coupler devices.