# Questions tagged [closed-loop]

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### Dependent vs. independent current paths

Taking the following circuit: The path on the left will be on and the same, whereas the path on the right is dependent on what is connected to the base of the transistor (not shown in the above ...
46 views

### Determining/Specing the proper stepper Motor

I am trying to properly spec a proper stepper motor for a project I am working on. I am attempting to provide roughly 3000 pounds of compressive force (about 13300 Newtons) using a p series NEMA 34 ...
57 views

### Confusion regarding root locus. Open loop or close loop?

Which transfer function ,open loop or close loop do we use/need as a pre req to perform root locus analysis? I have also attached a snapshot of the relevant webpage of university of Michigan. I have ...
103 views

### Circuit stable in the Bode diagram, unstable in step-response

I am designing a simple current control circuit and trying to simulate it in LT Spice. The circuit is not optimized for some real-world application, it's more a learning method for me to get grip on ...
259 views

### How does opamp open-loop gain affect closed-loop gain in a circuit?

The gain of an opamp circuit is basically $$A_v=-\frac{R_f}{R_i}$$ But how come the gain of the opamp itself does not appear in the equation? How is the opamp amplifying anything in the circuit? What ...
46 views

### Calculate closed loop gain with Oscilloscope measurements

Using these reading from Agilent MSO-X2012a oscilloscope: from this circuit: How do you calculate the close loop gain using these measurements. I already calculated by hand and got Av = 11V.
168 views

### Phase margin is 90 degrees but transient step response shows overshoot

The bode plot of the loop is as shown here The transient step response looks like this The block diagram looks something like this - Basically a single stage opamp(OPAMP in fig) with high gain(...
103 views

### To prove that Close Loop transfer function is sensitive to perturbation in H(s) but not to perturbations in G(s)

The feedback control system with high gain K is shown in figure
115 views

### how to display an output variable from a speed sensor to a 7 segment display in C. DSPIC33E

I have just started an electrical engineering degree and been set an assignment to create a closed loop motor speed control system in C programming language. The PIC is a DSPIC33E (BLO032) and the ...
122 views

### Proportional Control Balance Beam

Bit of an unorthodox question I'm sure, but I'm making a balance beam (two rotors on either end of a see saw) with proportional control, and I can't seem to get it to balance at 0. The proportional ...
82 views

### What is the difference between 'x' and 'plus' symbol in the block diagram

Generally speaking, what is the difference between the 'x' and the 'plus' symbol in a closed loop block diagram? For example, in (https://ieeexplore.ieee.org/document/6983570) , what's the ...
195 views

### SG3525 Closed Loop Inverter Waveform Problem

I'm using a sg3525 ic on a full bridge dc-dc converter in closed loop. The system is working fine, I don't have a problem with it. Output is just like what I want. The problem is inverter part's ...
131 views

### Sample time of PI controller

I have designed a closed loop current control (PI controller) of a DC-DC converter in continuous time domain and it is working fine. The next task is discreetization of the controller and implement it ...
163 views

### Where does the negative sign come from in this transfer function?

I have a transfer function that was given to me. It's been a really long time since I've done block diagram math, so sorry if this is a newbie question. Based on the block diagram below (I forgot to ...
213 views

### Implementing PID in PWM feedback to lower the settling time

I have created the following simple PWM feedback: The step response is: I have tried to add PID controller and I ran the following code to test it: ...
86 views

### Why doesn't current flow in the other loop?

I am just now learning about how transistors work, so please let me know if I have a misunderstanding. I ran a simulation of the circuit drawn below, and the results were that current flowed only in ...
88 views

### Closed current loop control without H-Bridge, PWM

I am trying to find a way how to control the Voice Coil Motor (VCM) or PMSM motor with a closed current loop without the use of an H-Bridge & PWM. Does anyone know how to make an analog closed ...
216 views

### Cannot predict closed-loop gain of this amplifier

This is the circuit I am currently analyzing: (link to LTSpice file) I am trying to predict each stage closed loop gain and overall gain (with all loops closed). First thing I did is calculate DC ...
90 views

### Find optimal gains transfer function

I have the following closed loop transfer function: $$G(s) = \frac{K(s^2 + 200^2)}{0.05s^3 + (1+K)s^2 + 200{K_v}s + 200K}$$ Where $K$ and $K_v$ are gains. My goal is to find the optimal gains ...