| 摘要 |
PURPOSE:To perform multiplication of high accuracy with simple circuit constitution by constituting an analog multiplier which can directly operate the input voltages of multipliers and multiplicands and compensating the effect of temperatures without providing any special temp. compensating circuit. CONSTITUTION:A constant current source circuit A1 which is constituted of an operational amplifier 4 flowing the current proportional to the 1st input voltage EiA to an FETQ1 as well as a composite photocoupler 2 which is provided with one light emitting diode LED and the 1st, 2nd phototransistors PT1, PT2 on the same pellet, and is disposed in a manner that the light from the diode LED may be uniformly received, are provided. The diode LED of this coupler 2 is caused to emit light by the output of the operational amplifier 1 constituting a voltage/impedance converter A2 inputted with the 2nd input voltage EiB and the output of the TrPT1 is negatively fed back to the amplifier 1. The output of the TrPT2 is connected in series to the FETQ1 of the circuit A1. The product of the 1st, 2nd input voltages EiA, EiB is outputted with high accuracy to the output E0 of the TrPT2 without providing any special compensating circuit. |
