| 摘要 |
PURPOSE:To attain variable sensitivity with high sensitivity by connecting one of collector terminals of the 1st and 2nd transistors (TR) of a couple of multi-collector structure using an emitter terminal in common to other base terminal respectively and connecting each emitter of the 3rd and 4th TRs to each base terminal. CONSTITUTION:TRs Q1, Q2 are TR pairs of multi-collector structure using an emitter terminal in common, the current is shared by a collector of each TR, and the other collector is connected to the base of each TR. Further, each base terminal of the TRs Q1, Q2 is connected to an emitter of TRs Q3, Q4 and differential input voltage V1, V2 are fed to each base of the TRs Q3, Q4. The relation between a differential input voltage V and a current sharing ratio (x) is expressed in equation I, where IK1, IK2, IK3 and IK4 are emitter currents of the TRs Q1-Q4 and the sensitivity is changed by changing a current ratio (t) of the multi-collector. |
