| 摘要 |
PURPOSE:To obtain the title circuit, which is composed of the minimum number of elements and pins and executes a stable operation, by logarithmically changing the difference between an added result obtained by adding the potential difference between the respective Bs (base) and Es (emitter) of two transistors (Trs) and potential difference between the respective anodes and cathodes of two diodes for the difference of the voltages respectively applied to the respective Bs of other two Trs. CONSTITUTION:Voltage VB of a constant voltage source 18 is applied to the respective bases of transistors (Trs) 1 and 2, and the respective anodes of diodes 3 and 4 are connected to the respective emitters of the Trs 1 and 2. Further, the collectors of Trs 5 and 6 are connected to the respective cathodes of the diodes 3 and 4, and different voltages are applied to the respective bases of the Trs 5 and 6. The difference between an added result obtained by adding the potential difference between the respective base and the emitter of the Tr 1 and 2, and the potential difference between the anode and the cathode of the diode 3 and 4 logarithmically changes for the difference of the voltage applied to the respective base of the Tr 5 and 6. Namely, when voltage Vin is impressed to an input terminal 17 of this circuit, the variation is converted into a logarithm and appears at output voltage terminals 19 and 20. |
