| 摘要 |
PURPOSE:To prevent the malfunction due to shift in touch period of both contacts by holding the position detection signal of a potentiometer, which has a position detecting contact and an operation detecting contact, with a capacitor. CONSTITUTION:A potentiometer 1 consists of a volume VR consisting of a pair of a band-shaped resistance material and a band-shaped conductor and a switch S consisting of a pair of band-shaped conductors. Since both ends of the volume VR are connected to a power source +B and the earth, the volume VR outputs a voltage value corresponding to the position, which is depressed with a finger, to an A/D converting circuit 16. A capacitor C is connected in parallel to the input side of the A/D converting circuit 16, and the voltage which is inputted once is held for a long time. Consequently, even if the position is not detected when the operation detecting switch S is depressed, the malfunction of an electronic volume 18 is prevented because the voltage based on the preceding position detection is taken in. |
