| 摘要 |
PURPOSE:To obtain the variable resistor constituted electronically, by connecting two active elements having the same characteristics formed on one pellet in series with two active elements of opposite polarity and applying the output of the integrator. CONSTITUTION:The active elements Q1, Q2 of the same characteristics are formed on the one pellet and the active elements Q1', Q2' of opposite polarity formed on one pellet are connected in series with the elements Q1, Q2. The elements Q1, Q1' constitute the feedback amplifier with the operational amplifiers OP2, OP2' respectively, Q1, Q1' are respectively connected to the constant current source E1 and E1' of opposite polarity, and the junction of Q1, Q1' is grounded. The inverting input terminal of the amplifiers OP2, OP2' is connected via the constant voltage source D2. The internal impedance of the active element Q2 is proportional to the potential of the output point c of the integrator constituted with the resistor R, capacitor C, and operational amplifier OP1, the internal impedance of the element Q2' is proportional to the potential of the constant voltage source point C', and the sum of the both impedances is proportional to the voltage of the power supply DZ. Thus, the variable resistor of electronic constitution can be obtained at the output of the amplifier OP3. |
