| 摘要 |
PURPOSE:To detect accurately the ratio between two input signals by connecting an additional circuit which keeps a fixed level for the current flowing to one of a pair of transistors constituting a differential amplifier and detecting a current flowing to the other transistor. CONSTITUTION:The input signal voltages VA and VB applied to input terminals 7A and 7B are supplied to transistors TR11A and 11B via amplifiers 10A and 10B respectively. The collectors of these transistors are connected to a power supply voltages VS via diodes 13A and 13B as well as to the bases of TR15A and 15B constituting a differential amplifier. The collectors of these transistors 15A and 15B are connected also to the voltage VS via resistances 16A and 16B. At the same time, a common emitter connection terminal is connected to the collector of a TR17 and grounded via the emitter of the TR17. Then an arithmetic circuit 18 which sets the current flowing to the TR15B at a fixed level is provided together with the TR17. Thus the voltage Vout corresponding to the ratio between signals VA and VB is delivered to an output terminal 7U. |
