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Testing feedback functionality of a PID controller
I have built an LTspice simulation of a PID controller based on this youtube video.The basic schematic is presented. The AD797 model was used to construct all the blocks.A PID controller was built by...
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Positive feedback loop in the Wien oscillator
Let's say you got this circuit given which works as a Wien oscillator. To my understanding here Ri is the negative feedback loop and the total impedance of R3 & R4 & L2 & R1 are the...
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How is this circuit with feedback stable when the phase margin seems to be...
I am working with a driven right leg circuit, whose purpose is to attenuate the common-mode voltage \$V_{cm}\$ on the body by sensing the common-mode voltage, amplifying it (and reversing polarity),...
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Is it OK to use the inverting input of the opamp as reference input?
In order to measure negative current without a negative supply, I mix the current sense signal with the positive reference. Now, when the current increases, the control signal decreases. To stabilize a...
View ArticleHomemade EEG circuit common mode feedback
I am currently building a DIY EEG circuit using this guide. This guide is for when there are two inputs. How can I modify this so that I can also input two EMG signals too?It is common knowledge that...
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PCB-Design LM2670 Feedack
I need feedback on my LM2670-5V TO-220 PCB board layout. The PCB layout is from Altium. It has 4 layers Signal, GND, GND; Signal with 2 oz copper planes. The copper traces are 50mils. All components...
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Common mode feedback fixing mechanism question
In the photo taken from this video (at 23:38), they use a voltage divider to get the average between the outputs.Then the author says that when output voltage on one side rises so the average is rising...
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NCP11187 - SMPS Design Issues
I have been working on a SMPS design using the NCP11187. It should output 24V DC nominal with a maximum ripple of no more than 100mV Pk-PK and be able to output up to 50 Watts. I have generally...
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Buck converter - how to stop oscillations in steady state
I'm modelling a buck converter feedback loop in LTspice:The converter steps 10 V down to 3.3 V and has a 3-Ohm load. The switching frequency is 40 kHz. The opamp is a UniversalOpAmp5.The Bode plot of...
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Why should we avoid extremely large resistance values in the feedback circuit?
In this note on page 22, it says,In practice we should however avoid extremely large resistance values in the feedback circuit.It says so after designing this circuit:The requirement of the circuit...
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Need of Cmfb in fully differential amplifiers
Instead of using cmfb circuit to set output dc common mode voltage Why can't we put at dc bais voltage at inverting or non inverting inputs of differential amplifier that way Vocm is set through...
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Role of feedback capacitor in nano-amp current source
I am designing a nano-amp current source to drive a capacitive load, which can vary from about 50 pF - 200 pF.Analog Devices has a helpful application circuit in a datasheet (page 14) for the LT6082C...
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Implement a voltage feedback method to reduce the crosstalkin resistive matrix
I'm new in electronics and i want to develop a resistive matrix that is pressure sensitive. Right now, I have a 7x7 matrix and I'm implementing this using multiplexers, a reference resistor and an...
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Is it correct to route feedback and GND signals like this in a 1kW push-pull...
I am working on the PCB layout of a DC/DC converter with push-pull topology, designed to deliver 1000W power with 24V input and 400V 2.5A output. The PCB is designed as a 2-layer board.In the image...
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How can I see parallel RC circuit effect on feedback line?
I want to observe the effect of the parallel RC circuit on the feedback line in the circuit shown below. The circuit is based on the MCZ33810EK engine controller.I expect this added structure to...
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Phase shift near saturation mitigation in input stage amplifier -- How does...
I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer.Apologies for the quality... this is the best scan I could find. The design is furnished with the...
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Designing two stage CE amplifier with negative feedback [closed]
I'm trying to design two stage ce amplifier with negative feedback using 2n2222 transistors. The circuit must have certain voltage gain, Rin, Rout, Vcc, low and high frequency filter. This is the...
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How do I apply block reduction techniques to the following block diagram
The question prompt is to find a final transfer function Y(s)/R(s) for the below block diagram, and then to find the time domain version of it by taking the Inverse Laplace.My professor recommended we...
View ArticleConfusion of terminology for control systems
I am confused about the following definitions (if there are any):Reference inputreference signalsetpointreferenceI don't understand specifically what they are referring to. Do they refer to an external...
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Output impedance with feedback of a current series feedback amplifier
In a chapter pertaining to feedback and oscillator circuits in the textbook "Electronic Devices and Circuit Theory" by Boylestad and Nashelsky, there is a derivation for the output impedance with...
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Unable to model Transresistance amplifier with feedback correctly
I spent the whole day trying to figure why transresistance amplifier modelled with z-parameters does not match with nodal analysis results but I sill can't figure out. I desperate need help on this...I...
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Loop factor k without loading effect
I can't find the feedback factor k, for the closed-loop gain in ex 12.40 of fundamentals of microeletronics by Razavi.The exercise does not use methods to take into consideration the effect of...
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Why might the gain of a Type I compensator be low at low frequencies?
I’ve measured the frequency response of the type I compensator (v(ctrl)/v(in)) in this simple current stabilizer circuit and found some unusual results.Measurement setup: isolation transformer 1:1, 2x...
View ArticleSeeing feedback voltage only on a regulator instead of 2.5V. Any ideas?
I'm trying to debug a hardware issue where I am only seeing the feedback voltage on the output of a regulator that is part of a PMIC. The voltage divider that goes into the feedback pin have the...
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Finding transfer function of a compensator circuit similar to a type 2...
I know how to find transfer functions of op-amp circuits using equations derived from using Kirchhoff's current law (nodal analysis), and normally I don't have any problems solving them. However, I...
View ArticleChoice of DC-DC converter feedback voltage (0.8V vs 0.736V)
I am choosing a DC-DC Buck converter for my application (AP62200 family). The part in question is offered in 2 versions - one with 0.8V FB voltage (AP62200) and one with 0.736V (AP62200T). Is there...
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Quadrature Sinewave Oscillator
There's a circuit which Horowitz presents as a Quadrature Sinewave oscillator (figure 7.43 - page 454). It includes 3 op-amps. Two for integration (creating sines and cosines) and one to close the...
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Explanation on why there is no feedback in the circuit for higher voltages of...
simulate this circuit– Schematic created using CircuitLabI don't understand the reasoning behind the analysis of this circuit. The professor started by saying that if diodes D2 and D5 are ON and D4 and...
View ArticleHow to add feedback system for a CNC machine which drived by stepper motor?
I have an old CNC machine to retrofit. In this machines stepper motors without are used and those motor are not double shaft, so how can I make a feedback for this system if it is possible?
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AC-DC using NDR as startup
I have been reading about the Wikipedia article on negative resistance and in particular, I'm interested in this circuit (also linked at Wikipedia):I was wondering if we could convert this into DC and...
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