# Questions tagged [theory]

Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context

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### Can we solve all linear circuits using only KVL and constitutive relations?

Can We Solve for Node Voltages and Branch Currents in Any Linear Circuit Using Only KVL and Constitutive Relations? In circuits with a single loop, it's trivial to solve using only Kirchhoff's Voltage ...
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### Theoretical equation to describe capacity fade

https://www.researchgate.net/publication/357842717_How_do_Depth_of_Discharge_C-rate_and_Calendar_Age_Affect_Capacity_Retention_Impedance_Growth_the_Electrodes_and_the_Electrolyte_in_Li-Ion_Cells I am ...
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### Does KVL guarantee identical voltages/currents in similar circuits?

I have a question that is a bit abstract. Assuming I have two proper linear circuits, A and B, which have: The same ideal components (for example, voltage source, inductor, capacitor, resistor) The ...
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### Getting different answers for number of electrons in 1 amp? [duplicate]

I was looking up the number of electrons in a current with 1a and I keep on getting different answers. Some websites put the number at 6.24, some at 6.25 and others at 6.28 (all * 10^18) Is there some ...
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### Could QAM using a grid-like distribution be a quantization limitation?

This is a follow up from this previous question discussing why QAM encoding is spaced in a grid like pattern like this one: versus another with more efficient packing: After looking at @Attie and @...
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### Why does QAM use a grid-like distribution versus a more efficient spacing?

"Stand-Up Maths" recently did a video about QAM/data encoding. He presented a diagram of the encoding spacing for QAM: I'm from a software engineering background and I couldn't help but ...
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### Solar Array Theory Misunderstanding

I am new to solar panels and I understand their is a lot more physics involved but I am trying to understand this basic concept. Wherever I look it is told that PV panels add Their voltage in series ...
113 views

### Need help to find the natural response of an RC circuit

Here is the question I am trying to solve: I am stuck with the point that I am not sure Vo is found as -50v or +50v. Another issue is that Ic(t) is calculated by derivative formulas or another simple ...
191 views

### Need help to find Thevenin resistance and Thevenin voltage

Here is the question I am trying to solve(there are 2 things I need to find. These are Vth and Rth): Here is my attempt: ( please check Vth if it is true ) I couldn't find Thevenin resistance at all ...
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### Phase velocity expression

We have a $\beta l$ expression which is represented as phase velocity. I know $\omega_o=2\pi f$. What is the exact expression for phase velocity used in here?
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### EE applications for parametric equations

I am trying to learn electronics, specifically audio amplifiers. I paused my study after realizing that my math skills (or rather my lack of math skills) were holding me back. I undertook a study of ...
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### Why is base current needed after transistor is switched on?

If there already is a current flowing from the collector to the emitter, can’t the electrons just keep jumping over the PN junction? Why does killing the base current make that impossible?
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### How many transistors at minimum do you need to build a general-purpose computer?

I'm wondering what the simplest design for a general-purpose (Turing complete) computer is. To my surprise, I haven't found much on the web. Surely this is a known problem?
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### Get voltage and current noise P-P values for 0.1 to 10 Hz from integrating the curve in the datasheet and comparing the results to the datasheets valu

Usually from OpAmps datasheets, you can get the RTI noise values for both current, and voltage noises exact RMS values for 0.1 Hz to 10 Hz. For a wider frequency range the noise density curve is flat, ...
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### How to calculate break down amperage of wire based on length, resistivity, and cross sectional area?

For this question, I'm assuming the current is continuous, the shape of the wire is cylindrical, and the air is STP air. (I bridged a fuse with a piece of soldering wire, and I'd like to be stupid in ...
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### Preventing power LED runaway with voltage and PWM [closed]

Using near-minimum voltage for the LEDs to light up, and PWM to control brightness by not allowing the frequency/brightness to go above a certain point. Comments are telling me its not okay to not to ...
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### Electrical theory regarding load sharing

I am having issues understanding why raising frequency of one AC generator while in parallel with another causes it to pick up more load. Any help would be appreciated. I operate with turbine powered ...
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### Designing a common emitter audio pre-amplifier

I am trying to design and simulate a common emitter audio pre-amplifier using 2N2219 with characteristics based on industry standards (audio frequency response, etc. Corner frequency must be less than ...
619 views

### AC voltage and frequency as complex number?

For some software I am writing, I coded classes of electrical systems that receive a voltage and return the current response. For the DC case that's easy: I pass a real number as argument, the voltage,...
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### Why BJT thermal voltage can be not equal to kT/q in SPICE3

In SPICE, apart from effects such as basewidth modulation and base-collector leakage the collector current is given by the expression (according to the original SPICE2 PhD work) But actually, ...
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### How to show that all power in an RC circuit is delivered to the resistor

I am new to electronics and I've been working my way through the Art of Electronics. I've have been able to complete all the exercises up to this point but I have been struggling on this one. Right ...
1 vote
237 views

### Why is my best placement of a directional antenna so weird?

I moved to an offgrid house with a 3G/4G repeater, with a short, enclosed directional antenna. It was wobbling and poorly mounted on an unstable wood plank at the base of a window, so I decided to ...
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### What would a theoretical Group II, Group IV Transistor's Properties be? [closed]

This question is for more than a theory. I would like to disprove that what I'm working on is not a Group II, Group IV transistor. I know they CAN exist. I don't know why they don't exist or what ...
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### Transistor analysis with 2 voltage sources

I want to calculate the DC currents of this circuit, and based on the superpostion theorem, I thought of ignoring Vqdc9 first, in order to calulate I2, I21 and I22, as shown in figure 2. After that, I ...
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### Is there a method to convert a Butterworth response into Chebyshev and Bessel responses?

I wonder if once there is a completed/aproximated a design model of any of the responses mentionated, it can be operated mathematically (or there is a method/recipe) to generate the other responses? ...
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### How is the slope of the frequency response of an analog active filter defined?

I have seen different types of filters, and different slope values at -20 db, -40, etc. The literature says that the order define the slope, but how? How can it be mathematically justified? For ...
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### How/where does a generator + motor dissipate heat?

I've got a mystery that I can't wrap my head around. A generator is generating 1 kW of electric power. The current goes through copper cables to a motor, which is consuming say 950 W of electric power....
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### ESP32 Input Voltage Divider, Concept

Thank you for reading. I have read many other voltage divider explanations and calculators on this site as well as the web. My application is using a voltage divider to lower a possible 5 V signal (...
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### Will the net current drawn by a microcontroller equal the current supplied by it

Purely a theoretical question. Consider a microcontroller whose only job is to turn 1 pin high and in the process the microcontroller supplies I1 current throught the pin. But suppose we have to turn ...
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