The circuit diagram is a reverse operation of the capacitor circuit , it is used to simulate the inductor. Inductor will resist the current changes , so when a DC level added to the inductor when the current rise is a slow process, and the voltage drop on the inductor resistance is particularly important.
Inductor will be more easier for the low frequency through it, it features exactly the opposite capacitor , an ideal inductor is not resistance , it allows the adoption of direct current without any restrictions on the frequency of the signals is infinite infinite impedance .
If the DC voltage through the resistor R1 suddenly added to the op amp ‘s inverting input at the time of the op amp ‘s output will not be any changes, because the voltage through a capacitor C1 with the same added to the positive phase output terminal , the operation Amp showed high output impedance , the same as a real inductor .
With the constant capacitance C1 is charged through the resistor R2 , R2 decreasing the voltage , the op amp current draw through the resistor R1 . With the constant charge capacitor , and finally through two input pins and output pin voltage is ultimately tends to virtual ground (Vcc / 2).
When the capacitor C1 is completely full, the resistor R1 limits the current flow , which shows a thread in the inductor resistance. The serial resistor limits the inductor Q value. Real inductor DC resistance of the inductor are generally smaller than the simulation more. There are some restrictions on simulated inductor :
Section of the inductor connected to the virtual ground ;
Simulated inductor Q values can not be very high , depending on the serial resistance R1;
Analog is not as real inductor inductor can store energy as the real role of the magnetic field inductance can cause a very high inverse peak voltage, but the voltage is limited by the inductor simulation op amp output voltage swing , so the response of the pulse by Limited Voltage swing .