| 摘要 |
PURPOSE:To simplify the circuit and to attain clear display, by using a boosting coil in common, to drive an EL element and a piezoelectric buzzer. CONSTITUTION:A signal C outputted continuously during the ring tone and a signal D outputted continuously during the display are given to an OR gate 15, its output is given to an AND gate 17 together with an output of a sound frequency oscillator 16 and a signal E is produced. When a transistor 18 is intermitted with the signal E, a counter electromotive force is generated in the boosting coil 19. The boosted voltage is applied to the EL element via a switch 23 interlocked with a push switch 12. Further, a voltage extracted from an intermediate tap is intermitted at a switching circuit 20 with the signal A and applied to the piezoelectric buzzer 21, where a ring tone is produced. Thus, the circuit is simplified and clear display independently of the lightness by simplifying the circuit. |
