| 摘要 |
PURPOSE:To simplify and facilitate a circuit adjustment for temperature compensation by adjusting an electric current flowing through a logarithmic amplifying circuit in a reference state and then by adjusting the amplification factor of the amplifying circuit by damping an input signal so that an output voltage will reach a reference value. CONSTITUTION:When the value of input signal 1 is equal to a voltage equivalent to output voltage E=0V, change-over switch 7 is placed at the lower position to apply logarithmic amplifier 8 with the input signal through attenuator 6, so that a certain voltage will be developed at output terminal E. For example, when the damping factor of attenuator 6 is 1/2, output voltage E(1/2) is 0.301A. However, kT/q=A, where (k) is the Boltzmann constant, T is an ambient temperature (absolute temperature) and (q) is electron charge. In this case, when the amplification factor varies wth the ambient temperature, output voltage E is adjusted to 0.301A by variable resistor 10 of post-stage variable amplifying circuit 9. Thus, the temperature compensation of the logarithmic converter can be made easier and simpler. |
