图示电路是一种由集成运放组成的恒流源,其输出电流可从-50mA～+50mA之间连续调节。图中,由恒流集成电路4DH3与电位器R_ω产生可调基准电压V_R,运放A_1与电阻R_3～R_5组成基准电压转换电路,将V_R转换成双极性连续可调电压,再由运放A_2～A_4转换成恒定的电流输出,A_2,A_3并联可扩大电路的输出电流。由图可知,当运放具有理想参数时,运放A_1的输出电压V_(01)为 The illustrated circuit is a constant current source composed of an integrated operational amplifier. Its output current can be continuously adjusted from -50mA to + 50mA. In the figure, the adjustable reference voltage V_R is generated by the constant current integrated circuit 4DH3 and the potentiometer R_ω, the operational amplifier A_1 and the resistors R_3 ~ R_5 form a reference voltage conversion circuit, the V_R is converted into a bipolar continuously adjustable voltage, and then the operational amplifier A_2 ~ A_4 converted into a constant current output, A_2, A_3 parallel can be expanded circuit output current. As can be seen from the figure, when the operational amplifier has the ideal parameters, the output voltage V_ (01) of the operational amplifier A_1 is