| 摘要 |
PURPOSE:To make a device small-sized and inexpensive by a frequency characteristic of the same voltage gain as before even if a series resonance coil is disused by connecting the first capacitor to an inverted input terminal of an operational amplifying circuit, also, connecting the second capacitor to an output terminal, connecting the third resistance between the inverted input terminal and an earth, and driving a head by an output from the output terminal. CONSTITUTION:A resistance R16 is connected between an output terminal 6 and an inverted input terminal 4 of an operational amplifying circuit 5, also, a capacitor C12 is connected between the output terminal 6 and a coupling point 8, a capacitor C11 is connected between the coupling point 8 and the inverted input terminal 4, and resistances R14, R15 are connected between the inverted input terminal 4 and an earth, respectively. A coupling capacitor C10 is connected between a signal input terminal 1 and a non-inverted input terminal 3, and the hon-inverted input terminal 3 is connected to a bias power source EB (not shown in the figure) through a resistance R18. A series circuit of a resistance R17 and a capacitor C13 is connected between the output terminal 6 and a head 2. |
