| 摘要 |
PURPOSE:To obtain a desired gain without causing uselessness of gain with a single amplifying circuit of simple circuit constitution, by amplifying a signal given to one terminal of a speaker through phase inversion and providing the signal to the other terminal of the speaker. CONSTITUTION:An audible frequency signal given to a terminal 8a of the speaker 8 via a coupling capacitor 4 from a sound source 1 is divided at resistors R1, R2 and a voltage dividing signal from a connecting point 14 is inputted to an amplifier 15, where the inputted audible frequency signal is phase-inverted and amplified, and inputted to the other terminal 8b of the speaker 8 via a coupling capacitor 16. |
