Questions tagged [circuit-analysis]
Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network. Consider using in conjunction with tags for the particular analysis technique(s) in question: "nodal-analysis", "mesh-analysis", "superposition", etc.
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STM32 Understanding GPIO Settings
In STM32 Standard Peripheral library, we need to configure the GPIO.
But there are 3 functions which I not sure how to configure them;
GPIO_InitStructure.GPIO_Speed
GPIO_InitStructure.GPIO_OType
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How do Circuit Simulators actually work?
I recently had the opportunity to play around with LiveWire, which is a circuit simulator and began wondering how exactly they computed the voltages across each component and the current going through ...
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Why use complex numbers to represent amplitude and phase of AC
Why is it that in AC circuits, sine waves are represented as a complex number in polar form? I don't logically understand from a physical perspective why there is an imaginary part at all. Is it ...
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Why can current only flow in loops? [duplicate]
In the following image:
Why can't current flow across the following wire?
It's a simple question, but I've kind off always wondered.
Thanks!
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Why is the time constant 63.2% and not 50% or 70%?
I am studying about RC and RL circuits. Why is the time constant equal to 63.2% of the output voltage? Why is it defined as 63% and not any other value?
Does a circuit start working at 63% of output ...
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Two black boxes display the same impedance at all frequencies. Which has the single resistor?
Two black boxes display the same impedance at all frequencies. The first contains a single 1 Ohm resistor. Each end is connected to a wire, so that two wires protrude from the box. The second box ...
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Why is root mean square used when calculating average power, and not simply the average of voltage/current?
$$P = I_{\text{eff}}^2 \times R$$ where \$I_{\text{eff}}\$ is the effective current. For power to be average \$I\$ must be average current, so I am surmising that the effective current is the average ...
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What is a flip flop?
There seem to be a number of different definitions of flip-flops and latches out there, some of which are contradictory.
The Computer Science text book for the course I teach is probably the most ...
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Do electrons actually flow when a voltage is applied?
It's said in books that a circuit is a closed path and thus that electrons come back to the source. If that's the case, what would happen when there were an earth fault in a circuit? How would the ...
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Why does this vintage DRAM chip enable circuit require such a beefy resistor?
This is a small part of a mid-1970s chip enable circuit for a set of DRAMs. The DRAMs are TI's TMS4060 part (aka the Intel 2107 aka several others), and are 4096x1. So a typical bank requires 8 of ...
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Why do I need a ground when simulating a circuit? I thought voltage was relative between two nodes!
Electronics is very new to me.
I took the most basic circuit I could think of: A voltage source of 1V and resistor of 1 Ohm
As far a I understand I should get a current of (I = V/R) 1 Ampere. But ...
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How can we test the lifespan of electrical components?
We work with some electronic devices in our projects. We are at the stage where we need to create some test strategy to validate the lifespan (e.g. 1 to 5 years) of our devices for which we provide ...
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Half-wave diode rectifier - is textbook wrong?
I've noticed that in all resources on diodes and rectifiers, they show the output voltage as the positive half-wave of the input signal. However, that seems wrong.
I understand that there's a voltage ...
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Why would a circuit designer use parallel resistors?
I've been reviewing this reverse engineered schematic of a bmax6 style lipo charger.
To my understanding this circuit is used to dissipate excess charge in a cell when balance charging. The circuit ...
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What is the true circuit behind an opamp?
So, first year EE student, and I just learned about op-amps. I understand the ideal model, and know how to analyze them, and understand the idea behind them/the circuit that we were shown that is ...
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I think I found an error in an electronics book. Are my equations correct here?
I'm reading Practical Electronics for Inventors, 4th edition, to freshen up my long forgotten knowledge of electronics. I love the book so far, but I just came across an equation there which seems ...
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What is the use of an op-amp whose output and inverting input are connected to ground?
I am in first year of Engineering school and I was given an assignment containing this circuit, which drives pressure sensors in a pitot tube :
I am struggling to understand the whole circuit, and ...
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How does the tester screwdriver work?
How does the tester screwdriver work? If I put the tester screwdriver inside the "hot wire" of an electrical socket, it lits up if I press my finger against the metal cap on top of the screwdriver. ...
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What does this transistor circuit do?
I found a schematic which had this bit of circuitry between the +9 V (which apparently the author assumed to be > 9 V, more like 10-11 V) barrel connector and the +9 V supply rail.
I tried to ...
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Do working electrical engineers in circuit design ever use textbook formulas for rise time, peak time, settling time, etc
This is a very general question. In undergrad electrical engineering, students are usually taught about step response to LC (second order) circuits.
This is usually when many parameters are ...
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Diode Logic Gates
For some reason, I understand transistor logic gates, and I am able to solve problems, but for some reason I do not understand the and / or logic gates constructed by diodes. If someone can explain it ...
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Using diode mode on my multimeter to debug circuits. A good idea?
I've seen a few YouTube videos where the presenter, who appears to be experienced in board repair of Apple (and presumably other) circuit boards recommends to use your multimeter in "diode mode" to ...
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How do you determine the effective resistance of a finite grid of resistors?
Disclaimer: I am a geophysicist with limited electrical engineering background. I am not sure if this problem is incredibly easy, incredibly complex, or completely nonsensical.
My goal: Determine the ...
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Under what conditions is the star-mesh transform invertible?
We all know and love the Δ-Y (delta-wye) and Y-Δ (wye-delta) transforms for simplifying three-resistor networks:
Image from Creative Commons
The Δ-Y and Y-Δ transforms have the nice property that a Δ ...
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Why was so much TTL logic design "negative true"?
I've been spending time with schematics debugging busted 1970s TTL-based computing circuits. I'm sure this is a more general question but I'll ask it in this context since that's what I'm exposed to.
...
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Why isn't the current split between the transistor and the LED in this NOT transistor circuit?
In the following NOT transistor circuit diagram, the current flows through the 1K resistor and through the LED when the switch is open. This turns the LED on. When the switch is closed, however, the ...
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Op-amp inverter followed by buffer. Why?
In a schematic I've been trying to understand I came across this sub-circuit:
It's an op-amp inverter directly followed by a buffer. VIN comes from a DAC in a microcontroller and this circuit ...
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What are the various 'properties' of a diode?
I have come across various properties of a diode, phrased differently in different places (product sheet, everycircuit, etc.). For example:
The wavelength is the simplest and that is the color of ...
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Why, in a passive circuit with a sinusoidal input, do all voltages and currents have the same sinusoidal behavior as the input?
I am familiar that in any circuit composed of linear passive elements and a sinusoidal input, all voltages and currents through and across any element will exhibit the same sinusoidal behavior and ...
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Resistance depending on voltage - the chicken and the egg?
If I understand correctly:
The resistance of some circuit components (like diodes) depends on the voltage across them.
When two components are connected in series: \$\frac{V1}{V2} = \frac{R1}{R2}\$
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Tips on analyzing circuit with multiple op-amps and bjts
In a homework exercise I need to sketch the Vout-vs-Vin graph, having it first obtained analytically. I know that Ur and Vin are both nonnegative, and the circuit is shown here:
It seems like there ...
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Reasons to use combinations of resistors (parallel or in series): Looking for educational examples
I teach physics at high school level, and one of the topics I cover involves instructing students on how to calculate the total resistance of two resistors, whether in parallel, in series or simple ...
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Current in a circuit is 50% lower than predicted by Kirchhoff's law
I am a math teacher and in my Linear Algebra class we were solving systems of linear equations that come from Kirchhoff's laws. We were trying to use a physical circuit to validate our computations. I ...
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Shocked by beginner circuit kit
I was trying to visualize a beginner circuit problem on my breadboard and I plugged in my circuit, touched a resistor and got a nasty shock. I am a cs student playing with circuits to build some logic ...
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Vintage germanium transistors: How does this metronome oscillator work?
I'm trying to restore and learn from a simple metronome assembled by my uncle in the 60's. It has a nice sounding beat and used to work until very recently — although unstable. I've ...
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Digital Logic circuit - exam question
I have a question from exam that I failed to solve:
I need to build a digital logic circuit that is receiving 4 bit number and return true if the number is ...
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Can I get help troubleshooting a simple hobby electronics circuit? Multimeter not measuring current drawn
I am following the experiment in the popular electronics book - "Make: Electronics third edition". However, when replicating one of the experiments mentioned in the book (specifically ...
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What is the role of the transistor and diode in a soft start circuit?
Please can someone explain the purpose of both the transistor and diode in this soft start circuit
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If a circuit only has a current source and no voltage source where does the voltage come from to supply the circuit?
For example this circuit, A current source is something with would alter the voltage across it to meet a certain current.
But where is there a voltage source to do this or even have a voltage at Vx. ...
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What is wrong about this application of Kirchhoffs Current Law?
At a recent exam I had this very simple problem concerning Kirchhoffs Laws:
I am concerned with problem c
Now my understanding of this is:
I can combine both nodes, and since all currents in the ...
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A 1USD 11W led bulb circuit and parts analysis
I know this is not a huge deal, but still I want to do it because for Three reasons: 1, it only costs 1 usd. Yep, this is a very cheap led bulb, and I need to take it apart to see if it's trust worthy....
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Why can I use P = I²R but not P=V²/R when calculating energy lost in a circuit?
I am working through a book of problems and am confused by the answer to this one:
A 12 V battery supplies 60 A for 2 seconds.
The total resistance of the wires in the circuit is 0.01 Ohm.
Q1. What ...
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Why are crystal oscillators used in clocks instead of RLC circuits?
The timing of quartz clocks is regulated by a crystal oscillator. This crystal oscillator effectively forms an RLC circuit. If this is so, what properties does a crystal oscillator have that makes ...
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Pull up resistor question
Like many others I'm in software so apologies in advance if the question sounds dumb. I watched some videos, read some articles and also read some answers here, such as: Pull-up resistor clarification
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Internal resistance of a battery
I am trying to figure out where I went wrong on the following problem:
simulate this circuit – Schematic created using CircuitLab
The two batteries are identical, and each has an open-...
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How do I use superposition to solve a circuit?
Yes, this is a pedagogical question. While answering another recent question, I wanted to refer the OP to concise instructions for using superposition to solve circuits. I found that all the easily ...
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Saving data without a microcontroller?
Is there a way to save voltage data directly (without a microcontroller) to anywhere, like EEPROM, SDCARD, etc.?
For example, I am using an MPX pressure sensor which gives 0V to 5V analog output. ...
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The Intuition for RLC circuits
I'm reading through Hayt's Engineering Circuit Analysis 9e and it does a fairly good job of giving the intuition for "where" the energy is going in a damped RLC circuit, but I'm hoping that someone ...
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What is the difference between impedance and reactance?
I mean how are they physically different? What does it mean to have imaginary numbers in the reactance?
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Do electrons actually jump across contacts?
When we connect two conductors together in a junction, do electrons actually move from one conductor to another?
Does it also affects the masses of the two conductors?
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