| 摘要 |
PURPOSE:To realize a balance characteristic being equal to the time of using a mechanically variable resistance, and also to make the titled circuit small in size, by setting a base voltage of a transistor and a voltage drop of a resistance to a prescribed value, when a balance control voltage is equal to a reference voltage. CONSTITUTION:When a balance control voltage VBAL of a terminal 11 is equal to a balance control reference voltage VB of a terminal 12, a base voltage of a transistor (TR) 8 becomes VB/2-VBE, the TR 8 becomes off and a base voltage of a TR 14 becomes about '0'V. Also, a base voltage of a TR 7 is VB/2+VBE, a current flows to the terminal 11 from a positive power source 2 so that a voltage drop of a resistance 9 becomes about VB/2, and a base voltage of a TR 13 becomes about VB/2. In this way, even if a balance is in channel 1 side, its output Vo1 becomes the same as that of the time when the balance is in the center. Also, in case of VBAL=VB, even if the balance is in a channel 2 side, its output Vo2 becomes the same as that of the time when the balance is in the center, in the same way. |
