The feedback tag has no wiki summary.
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2answers
55 views
A phototransistor with LED and resistance in emitter
Earlier I used a simple phototransistor arrangement to detect an on/off signal via a laser pulse.
I connected the collector to Vcc(5V), and emitter was grounded through a resistance. The base was ...
2
votes
1answer
164 views
Voltage regulator with op amp(negative feedback) and MOSFET
The schematic above is a very good voltage regulator, excepting the high power dissipation for Q1 (also I'd use an NPN instead of a PNP). Can I replace Q1 and Q2 with a high current n-mosfet and ...
0
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1answer
262 views
Feedback for DC Motor Speed Control using PID
I'm working on a project in which I have to control the speed of a DC motor using an analog PID(using op-amps). The input will be provided with a potentiometer. The issue is that I can't figure out ...
11
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3answers
438 views
What does this circuit do? Op-amp with transistors in feedback
I'm an electrical engineering student and I find this circuit in a guitar amplifier schematic, and basically, I'm just wondering what it does, and how one would go about working out what it does. ...
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0answers
41 views
Impulse & Frequency Response Help
Suppose that 2 systems are connected in cascade; i.e., the output of S1 is the input to S2. The 2 systems are specified as follows:
S1: y1[n] = x1[n] + x1[n-1] + x1[n-2]
S2: y2[n] = x2[n] + x2[n-1]
...
2
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0answers
141 views
Oscillating system via negative feed back?
The Barkhaus criterion for system with positive feedback (being \$B(s)\$ the feedback network transfer function and \$A(s)\$ the gain network transfer function) afirms that for a system to keep ...
6
votes
2answers
280 views
Stability (phase margin) analysis in real feedback circuits
So I had a bright idea of using negative feedback to control offset current in my data acquisition circuit. Sure, you could do this in software, but removing the offset at the input stage would ...
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2answers
232 views
Negative feedback output question
What is the value of Vout if we know the value of Vin in this case?
It is a buffer amplifier, but it has two extra resistors so I think that the gain is smaller than 1, but how small?
...
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1answer
90 views
How to Design a State Feedback Controller using an algorithm
I'm studying for an exam and am having a great amount of difficulty wrapping my head around this as I have minimal electrical engineering background, and my notes are confusing. I have read a few ...
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4answers
157 views
Can I buy a motor that vibrates or pulses very precisely?
I'm trying to make an item with a number of pads that will pulse individually or in sequence with a given signal. I have looked at vibration motors but these are like the ones in video game ...
0
votes
1answer
302 views
Driving a power transistor with 2sc945
I'm designing a simple 15V to 5V DC voltage feadback mode non SMPS regulator.
I'm using E13007E2 power NPN switch mode transistor. And to drive that transistor
I'm using C945 another transistor.
...
4
votes
3answers
525 views
What is causing the oscillation in the feedback loop of an SMPS?
I am trying to make a switching constant current regulator for a Ni-MH charger. It accepts a current set input from the microcontroller using a PWM DAC. I basically want to source 2000mA and 200mA for ...
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2answers
546 views
feedback resistor
How to determine the feedback resistor in negative feedback op-amp configuration ? How does the feedback resistor affect the signal output of op-amp ? What is the consequence of using high resistance ...
0
votes
3answers
611 views
Why do I get feedback in my speakers in my car?
I have a Galaxy Nexus which I have with my everywhere. One of my favorite uses of this device is to play my music. Unfortunately, I have noticed something bothersome and I was wondering if I could get ...
2
votes
3answers
292 views
What is a typical example of a combinatorial feedback loop?
By looking at some of the details of the Altera timing analyzer TimeQuest, the concept of a "combinatorial feedback loop" was mentioned. The obvious search is not terribly helpful and there doesn't ...
2
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2answers
203 views
Instrumentation Amplifier with Common Mode Feedback output
I'm currently attempting to design a small circuit that takes in a differential signal at < 4mv. I want to amplify this by around 1000 times.
I was reading up on Instrumentation Amplifiers, and ...
2
votes
2answers
117 views
Confusion in feedback for switchmode dc/dc converter
I have a slight confusion in how the feedback pin works. The "\$V_{ref} \times (1 + R_1 / R_2)\$" seems like a shortcut to me, and I have trouble understanding how to feed a voltage in to it, to say ...
6
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1answer
286 views
Bias analysis in a dual BJT circuit with feedback
I am building an Wooly Mammoth audio circuit, and I am really interested in finding how and why it works. You can check out and simulate the whole thing here.
I must say I haven't been able to get ...
3
votes
2answers
238 views
Flip flop/latch with isolated differential input and differential output
I am looking to make something that takes a pulse of floating voltage (say from a feedback coil of on a transformer), and maintain a differential output voltage depending on the sign of the amplitude ...
0
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1answer
257 views
'feedback' function in MATLAB
How do I use feedback function in MATLAB when I have sys1 and sys1 as impulse responses (and ...
8
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3answers
785 views
Op amp analysis: when are the “negative feedback rules” applicable?
When we build op amp circuits that use negative feedback, like so:
... we can analyze the circuit very easily, by assuming that $$v^- = v^+$$ due to negative feedback (when also assuming the op amp ...
3
votes
3answers
461 views
Stabilizing opamps - am i doing it right?
I'm designing a high current linear regulator and learning about real opamps as opposed to ideal ones described in tutorials all over the net as i go.
My initial voltage regulation design was ...
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2answers
279 views
Is feedback transfer function the same as the transfer function for the whole circuit?
I have a circuit very similar to the inverting band pass filter circuit here:
I was asked a question about the circuit's feedback transfer function. Is this the same as the transfer function for the ...
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2answers
391 views
Why can't a feedback network use a capacitor? [duplicate]
Possible Duplicate:
Basic Frequency Control Circuit
In the following schematic, why can't R4 be taken away and the feedback network pass output feedback through C2 and R2?
8
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6answers
3k views
Why is feedback required in op-amp circuits?
I understand that, in order for an op-amp to function correctly, a DC feedback loop from the output to either the inverting or the non-inverting input (depending on the external circuitry) is ...
3
votes
4answers
627 views
Basic Frequency Control Circuit
How does R4 prevent the output voltage drifting towards one of the supply rails to the op amp? I understand that R4 has to have a high resistance but I do not know why?
Here is the schematic which is ...
2
votes
3answers
962 views
Four transistor/full bridge version of the Royer oscillator
For some time now, I have been trying to figure out what (in theory) would be the most efficient way transfer power across a transformer. Applications include high voltage power supplies and induction ...
4
votes
3answers
389 views
Can someone explain this tube amplifier circuit for me?
I have a tube radio that has really low output (I mean the sound is barely audible at full volume). Probably some capacitor in the LF amp failed. However, after I downloaded the schematic diagram, I ...
