| 摘要 |
<p>PURPOSE:To obtain a linear relation between an input voltage and an output voltage by connecting an output side of a 1st photocoupler whose input is connected to an output terminal of an operational amplifier to other input of the operational amplifier and connecting the output of a 2nd photocoupler to the output resistance. CONSTITUTION:The output of the operational amplifier I01 is supplied to light emitting diodes of photocouplers PC1, PC2 showing the same characteristic as a current i1 through a resistor R12 to flow currents i2. i3 to a pair photo transistor. The current i2 flows to the resistor R11 and its voltage is fed to an inverting input terminal of the operational amplifier I01. The path of the signal of input signal Vin i1 i2 forms a feedback system mixing the electric signal and the optical signal and acts like making the voltage across the resistor R11 equal to the voltage Vin. Thus, the voltages Vout, Vin have a linear relation independently of the current of the light emitting diode and temperature.</p> |
