| 摘要 |
PURPOSE:To stably output temperature measured values with no observational error by interposing a buffer amplifier among a plural number of bipolar transistors, and thereby letting output terminal voltage have nothing to do with a current amplifying factors of the transistors. CONSTITUTION:A circuit is made up of two NPN type transistors Q1 and Q2, an operation amplifier A1 in which the emitter of the transistor Q1 is connected to a normal phase input terminal, and the output terminal is connected to a resistor R2 and an anti-phase input terminal, a resistor R1 and the resistor R2 connected to the bases of the transistors Q1 and Q2 respectively, and of constant current source I1 and I2 connected to the emitters of the transistors Q1 and Q2 respectively. And since the operation amplifier A1 allows its output to be feed-backed to its own anti-phase input terminal as it is, the amplifier acts as a buffer amplifier the voltage gain of which is one time. By this constitution, voltage equal to the terminal voltage of the emitter of the transistor Q1 is outputted to the output terminal of the operation amplifier A1, dependability on an output current amplifying factor is gone while the current is completely proportional to temperature, so that the circuit thereby acts as a temperature sensor. |
