Hello! This is a circuit for a motor being driven by an opamp. I do not understand the purpose of the C1 in there. Is it some sort of external compensation for the inductive load (motor) ?
Also, if you can, please tell me what a linear power opamp is? I mean what would a non-linear power opamp mean?
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So , if it is DC motor , it will create high value of spikes , and as you probably know , each capacitor will be short circuit in transient time . so , it won't allow that spikes , be across the opamp !
and as i told it's other duty can be as a compensation network .
PI controller is the most likely explanation. It would be achieved if the pole frequency set by R2C1 is located below the controller closed loop bandwidth. In this case, the controller has a P gain of unity. A controller P part is required for stability with the integral acting control system.The capacitor in the negative feedback path acts as a PI controller that stabilizes the loop. That is the main purpose of the capacitor.
Hi ZekeRis that the feedback capacitor would increase its loop gain at high frequencies
The circuit has two feedback loops, and there is a principle possibility that the "inner" feedback loop (OP output to Vin-) becomes unstable. In this regard, the load impedance matters, a capacitive load can bring up instability in a frequency range above the outer loop's bandwidth. But it's not the case for the present circuit.The character of the load (resistive, inductive,...) is of less importance.
I'm disagree about this , because at high frequencies the impedance of capacitor will become low . and thus the feed back resistor will become short circuit . thus , gain become low .
These transfer properties require a separate controller (preferrably with PD-T1 characteristics) - however, if speed is not important, an additional PT1 element can also stabilize the loop.
Can you explain how introducing a T1 delay element would help stabilize it?
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