| 摘要 |
PURPOSE:To obtain a signal generator using a three wire type potentiometer generating no dislocation in a zero point position by providing a span adjusting circuit consisting of a pair of operational amplifier circuit and a selecting circuit for selecting by a gate signal according to a polarity from a polarity discriminating circuit. CONSTITUTION:The span adjusting circuit 1 consisting of a pair of operational amplifiers 1a, 1b having variable resistances VR1, VR2 for executing the span adjustment according to the polarity of the signal of the three wire type potentiometer P2 as one constituting element of the circuit, a polarity discriminating circuit 2 for outputting a gate signal according to the polarity of by discriminating the polarity of the signal of the P2 and the selecting circuit 3 consisting of a pair of switches SW1, SW2 selecting by the gate signal according to the polarity are provided. Thereby, the three wire type potentiometer having no center tap is used and a signal generator capable of independently executing the respective span adjustment of positive/negative polarities having no dead zone can be obtained at low cost. |
