# Questions tagged [equation]

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32 views

### Calculating inductance of inductor that has ferrite core and a large air gap

I'm working on a coil on a PCB that will have a small ferrite core place in the center, with a large gap. I'm trying to come up with a decent equation to estimate the inductance of this inductor. I'...
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### Solving simple parallel/series without Req

Given the following circuit with three resistors, R1=100Ω, R2=200Ω, R3=300Ω: To solve this using the $R_{eq}$ trick: ...
62 views

### Number of independent KVL and KCL

I know that the number of KTL and KCL is related to the number of nodes $N$. For KCL there are $N-1$ equations while for the KTL there are $L-(N-1)=L-N+1$ equations. However I didn't understand ...
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### Difference between parallel and standard form pid controller in simulink?

What is the difference between parallel and standard form of pid controller that is provided by pidtool in Matlab simulink? In terms of block diagram?
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### Syntax of complex numbers [closed]

In inductive reactance equation $X_L = j2\pi fL$, why do we write "j" in front of "2πfL"? Does it matter where we put it? Could you show me example where denoting real and imaginary number makes ...
76 views

### Matlab code to derive the overall difference equation relating two systems

Using Matlab, I am trying to: Get the overall difference equation relating to z[n] to x[n] and check if z[n] = x[n] is a valid solution to the overall difference equation I have two signals given ...
57 views

### Evaluating a logic circuit expression

My test says the answer is c) A OR B. To me it looks like: Q = AB + (A+B) What am I doing wrong? Which of the following is a logical expression that is equivalent to the logic circuit shown ...
85 views

### Differential equation for a notch filter RLC circuit

I'm trying to write and solve a differential equation for this simple RLC notch filter and I'm not sure what I'm doing wrong. simulate this circuit – Schematic created using CircuitLab So ...
90 views

### 3 Resistor Voltage Divider Formula

I'm trying to analyze this circuit and spend almost 2 days to make a formula for it but I don't get it , anyone know what it's called or how can I make formula for it ? I want to calculate I1,I2,I3 ...
118 views

### Maxwell Equations for modeling a DC Motor

I have seen so many videos about this and none helped me. I can't calculate B. (equation:$E = 2*N*area*B*cos(\theta))$. I mean... when I calculate the field B, I find high values for the current. ...
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### expressing a boolean function in another way

The following boolean expression is given: g(p,q,r) = ((p->q') -> r) Depict this boolean function only by using the operations ∧ (AND), v (OR), ¬ (NEGATION). How can I do this? I thought I could ...
68 views

### How to write inductor ODE equation properly?

I've drawn a following scheme, and now want to write ODE system for describing inner processes, in order to explore it: simulate this circuit – Schematic created using CircuitLab I wrote the ...
332 views

### LTSpice “Unknown parameter ”\“”

I am trying to simulate an electrical model (Mason Model) of piezoelectric system in LTSpice. So, I use parameters and formulas to evaluate the value of the passive elements in my circuit. I use the ...
72 views

### I need an equation to calculate the time for a power percentage of a half cycle sine wave into a resistive load

I need to calculate the time a thyristor/triac needs to be on for a desired percentage of full power of each half cycle of the AC line input. On for the full half cycle will give me 100%. On for 1/2 ...
142 views

### Differential equation of an OP AMP circuit with RC elements

I have to find the differential equation which describes the relation between input and output voltage for the circuit below. Per how the RC components are arranged, I simply can not find a ...
46 views

### Calculate U(t) when capacitor C1 charges C2 via a resistor R

simulate this circuit – Schematic created using CircuitLab The switch SW1 is activated at t=10s and charge from C1 is transferred to C2. The power supply charges continuously with 1kV 1mA. How ...
92 views

### Amplification equation for AC coupled Common Emitter stages

Do anyone can tell me how to get amplification equation for this circuit of coupled common emitter amplifier? simulate this circuit – Schematic created using CircuitLab Edit 1 Equation for ...
41 views

### Switched circuit analysis - getting rid of “glue” equations

I have the following circuit: simulate this circuit – Schematic created using CircuitLab I would like to derive 3 differential equations, describing it, since it has 3 dynamic components [Csh, ...
306 views

### Zener diode equation proof (chacteristic curve)

I'm trying to prove this equation(at least I think that's the correct one): which produces this graph: I can prove the one that describes the PN diode but I am not sure what I should do differenly ...
53 views

### Inverse Z-transform Problem [closed]

I'm rather stuck trying to compute the inverse Z-transform y[n] of the function below. I'm having trouble selecting the correct formulas from the table to achieve the right solution. Any help with ...
76 views

### WolframAlpha results for logic statement input

I was trying to simplify the following Boolean logic equation using wolframalpha.com. (not (A) and B and C) or (A and (not(B)) and C) or (A and B and not (C)) or (A and B and C) When I entered it ...
61 views

### Finding the unknowns of a current equation leads to non-sense

Suppose a series RLC circuit that is critically damped. Circuit is RLC in series with a DC voltage source $V_S$ and a switch initially open. Capacitor and inductor are both discharged. at t=0 ...
68 views

### Trying to understand the magic the author of this PDF did explaining the critically damped equation

I am reading this doc about the equations for the step function for the RLC circuit, critically damped solution. At page 16 we have these lines... But there is a magic between these lines... How ...
I am reading this doc I see this magic happening on the third line of equations... How in the name of Math, does this $Ae^{st}$ appeared there? Magic?