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Questions tagged [education]

The education tag is deprecated and should not be used for new questions. Please consider using other tags to indicate your area of interest.

0
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1answer
58 views

Pseudobipolar signal example - Analog Devices AD7682

What is a pseudobipolar signal? I read this word in the datasheet below: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7682_7689.pdf Can you show me an example with a plot ...
0
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0answers
48 views

Impedance magnitude and phase error - Mathematical formula

Today I read a paper on which there are the terms magnitude error and phase error relative to a comparison between measurements performed with a biosensor and with a benchtop electrochemical impedance ...
0
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0answers
63 views

A circuit with Schmitt trigger and inverter.

During the exam I was asked to explain a schematics. The question is to show the outputs (draw) from point B,C,D,E and what will be the time when E switches. The input voltage is being increased from ...
0
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1answer
40 views

Ion-selective electrode: high input impedance to measure the voltage

I read that an ion-selective electrode has an high impedance (\$100 \, M\Omega\$) and that it's necessary a high input impedance to measure the electrode voltage. I'd like to understand the above ...
0
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1answer
25 views

Impedance response of a linear system is independent of the perturbation amplitude?

I'm studyng electrochemical impedance spectroscopy. On my book there is the sentence: "Impedance response of a linear system is independent of the perturbation amplitude.". Why? If I have a non-...
3
votes
4answers
338 views

Is the Nyquist plot useful in actual electrical engineering?

I am currently doing a course on linear control theory, and we are covering Nyquist Plot to study phase and gain margin. I find myself unable to appreciate this concept. One, the proof of the Nyquist ...
-2
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1answer
59 views

Does an Electrical Engineering course cover a lot of software? [closed]

I want to study Electrical Engineering in university, but one thing that I have doubts about is the software side of things. I absolutely love electronics, but electronics engineering is not a widely ...
0
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0answers
31 views

Symbol of a bipol with specific voltage and specific current (ideal power supply?)

Does it exist a symbol of a bipol which gives a specific voltage and a specific current? I know only the following symbol for battery (and other symbols with the same meaning): but it only shows that ...
0
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1answer
46 views

Delivered energy of a RLC circuit - proof

I have an RLC circuit with two resistances \$R \$ and \$R_i \$ in serie. On my book there is the expression of the stored energy (\$C \$ capacitance, \$E \$ voltage on the capacitor): $$W_s = \frac{1}...
2
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4answers
213 views

Voltage buffer with ideal Op-Amp (positive feedback) - Instability

I know that the circuits which employ negative feedback are stable, whereas those which employ positive feedback are not stable. How can I prove that a voltage buffer (ideal op-amp) which uses ...
0
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4answers
289 views

Simplest Inverter

Theoretically, what is the simplest inverter circuit possible? I mean, really basic. With the least amount of components. It doesn't have to be nice. It doesn't have to step up the voltage, or ...
-3
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3answers
306 views

Discrete one-shot lamp timer circuit

I'd like to use a momentary switch with a simple circuit (like the one below), that will illuminate two lamps for a short period (i.e. 10-20 seconds) with a single push. Obviously 555 timers are ...
17
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4answers
4k views

Why are 555 timers so prevalent? [closed]

I've noticed is that 555 ICs seem to be extremely common. Why is the 555 so prevalent, or ubiquitous; what about it so useful?
0
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6answers
281 views

Time delayed deactivation of a circuit

In a simple electronic circuit with a momentary switched LED (or bulb, tube etc.); what can be done to trigger the LED for several seconds before proceeding to break the circuit? In other words; I ...
0
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2answers
3k views

Fourier transform - LTSpice

Is it possible to get the Fourier transform in LTSpice? For example I'd like to plot the Fourier transform of the following signal: $$s(t)=A \space sin(2\pi f_0t)$$ Can you attached a LTSpice ...
0
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1answer
350 views

Suitable electronic components and digital logic gates for simple application [closed]

I'm designing some educational toys to teach children about electronic and logic circuits. They are quite literally individual electronic components (switch, resistor, transistor, capacitor, ...) and ...
0
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2answers
3k views

Optimal soldering iron specs for lead-free

I do most of my soldering with/directing children and so we always using lead-free solder (and thru hole and nothing too complicated). I have a soldering iron station that has two settings, 20W &...
2
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0answers
84 views

Starting point for a 10 year old [closed]

I am a EE and would like to get my 10 y.o. nephew familiar with the fun side of electrical projects. I'd like to start with basic principles and projects to re-enforce the basics. The goal is to ...
0
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1answer
77 views

Serie, parallel and other configurations (relative to small signal) of capacitors in amplifiers - poles and zeros

When I study frequency responce of amplifiers, I must understand if capacitors are in serie, parallel etc. relative to input small signal (in my exercises there is always only one input small signal). ...
-1
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2answers
207 views

Break feedback loop of oscillator

How could I choise the break point on the feedback loop of an oscillator (goal: evaluate the loop gain \$\beta \space A\$)? The Sedra-Smith said that it is convenient to break the feedback loop at the ...
3
votes
1answer
98 views

Transfer function of amplifier (exercise)

The transfer function of the following circuit is (I read A(s) on the solution of my professor): $$A(s)=A_{CB} \frac{s \space \omega_{pC2}}{(s+\omega_{pC1})(s+\omega_{pC2})}$$ where Nevertheless is ...
0
votes
1answer
956 views

LTSpice - varistor component

What is the constitutive relashionship between current and voltage of a varistor in LTSpice? For example, if I set the control voltage V=1V and Rclamp=2, what is the formula to evaluate the resistance ...
1
vote
2answers
190 views

LTSpice - resistor controlled by RMS

Is possible to obtain a resistor controlled by RMS of a voltage in LTSpice? The syntax \$R=V(n001)\$ works, whereas \$R=rms(V(n001))\$ does not work. Thank you for your time.
1
vote
1answer
191 views

Frequency of oscillator (exercise)

I tried to evaluate the frequency of the following oscillator: The loop gain \$\beta(j\omega)A(j\omega)\$ is: To find frequency I must impose the condition: $$\angle \beta(j\omega_0)A(j\omega_0)=0$$...
5
votes
2answers
770 views

Wien's oscillator - amplitude stabilization with Zener diodes (loop's gain)

How come the loop's gain \$\beta A\$ of a Wien's oscillator with Zener diodes is equal to the loop's gain of a Wien's oscillator without Zener diodes? My professor uses the following expression to ...
0
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1answer
1k views

Conversion h-parameters from common emitter to common base (request source to verify)

I calculated the \$h_{ob}\$ parameter from h-parameters of a common emitter transistor: $$h_{ob}=\frac {h_{oe}} {h_{ie}h_{oe}+\left(1-h_{re}\right)\left(1+h_{fe}\right)}$$ How could I verify the ...
17
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11answers
2k views

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 ...
0
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3answers
88 views

Behaviour of a capacitor+resistor (frequency domain)

why a capacitor behaves as an open circuit when \$\omega<\omega_p\$ and as a short circuit when \$\omega>\omega_p\$ (where \$\omega_p=1/RC\$ is a pole)? My question is generic. Thank you for ...
0
votes
2answers
117 views

Band-Pass Gain of a filter (exercise)

could you help me to find the band-pass gain of the following filter please? The correct expression of pass-band gain hasn't the term \$ C_{B}R_{B} \$ to the numerator (said my professor), instead in ...
3
votes
2answers
823 views

How to calculate currents and voltages with transistors circuit

I'm reading the Art of electronics and trying to calculate current and voltages of the following scheme: simulate this circuit – Schematic created using CircuitLab I wrote the current as the ...
1
vote
1answer
561 views

Mesh analysis in BJT circuits

Is it possible to use mesh analysis in BJT circuits? I tried to do it, but it does not work. EDIT: the exercise in which the mesh analysis does not work is the following (the correct value of ...
0
votes
0answers
55 views

My nMOSFET (maybe non existent). N canal with Vgs=0?

if I realize the following nMOSFET: is it possible to obtain n canal with \$V_{GS}=0\$? Thank you for your time.
1
vote
2answers
2k views

Can I use Minecraft redstone to teach digital circuits? [closed]

I'm sorry if this question is off-topic. If it is, I would be thankful to know at which StackExchange site I should ask this question. Let me say first, I never played Minecraft myself. But I heard ...
2
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1answer
658 views

Negative base current in NPN BJT

What happens if the base current goes out of the base of an NPN BJT?
0
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1answer
304 views

Negative beta forced in saturation region of BJT?

is it possible to have a negative value of beta forced in the saturation region of a BJT when \$V_{CE}<0\$? Thank you very much.
0
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3answers
416 views

Saturation on characteristic curves of BJT

how come there is saturation region when \$V_{CE}<0.3 V\$? I know that: $$V_{CE}=V_{BE}-V_{BC}$$ thus I can decrease \$V_{CE}\$ also decreasing \$V_{BE}\$. In this case, when \$V_{BE}<0.7 V\$,...
0
votes
2answers
171 views

Forward biasing of EBJ of npn BJT

I apologize for the stupid question, but I am a beginner in the analysis of BJT circuits. The Emitter-Base Junction of a npn BJT is forwand biased if the emitter current is positive? Thank you for ...
-1
votes
1answer
88 views

Principle of causality and Laplace's domain [closed]

what are the conditions in the Laplace's domain which ensure the causality of a system? I would be grateful if you recommend me also references. My professor said that the degree of the denominator ...
1
vote
2answers
406 views

Difference between dynamic resistance of diode and resistance of PWL model of diode

What is the difference between dynamic resistance \$r_{d}\$ of a diode and resistance \$R_{D}\$ of piecewise linear model of a diode? The book "Microelectronic Circuits - Analysis and Design - ...
6
votes
1answer
2k views

RLC filter as amplifier?

is it possible that a RLC filter works as an amplifier? If it works at resonant frequency, then the output will be greater than the input. Thank for your time.
1
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2answers
79 views

Possibility of poles with positive real part in RLC filter

are there the poles with positive real part in any function mode of the RLC filter? The equation to determine the poles is the following: $$RLCs^2+Ls+R=0$$ $$s_{1,2}=\frac{-L\pm \sqrt {L^2-4R^2LC}}{...
0
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2answers
832 views

Difference between cutoff frequency and break frequency

what is the difference between cutoff frequency and break frequency? Maybe the first refers to the attenuation of the frequency response module of a \$\frac{1}{\sqrt2}\$ factor compared to the maximum ...
0
votes
1answer
86 views

Analytic solution of a Graetz bridge rectifier with inductive filter

how could I solve the following circuit? In particular I would find the analytic expression of current on inductor. I tried to solve the differential equation (hps: S1 and S4 on): $$L \cdot \frac{di}...
2
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2answers
184 views

What's the difference between the terms Electronics and Electrical? [duplicate]

So can anybody tell about what's the difference between the terms Electronics and Electrical ? How do we differentiate them from one another?
6
votes
1answer
327 views

CMOS transistors for educational purposes

I am currently teaching my daughters Digital Electronics, ages 9 and 12. In doing so, I wanted to introduce them to CMOS logic, since I feel that a hands-on approach is always better than just doing ...
3
votes
3answers
215 views

Groovy i2C/SPI peripherals for education?

I'm helping someone teach an embedded programming course at my university, and he's starting to cover i2C in class. SPI is next. We're trying to come up with a groovy, easy-to-interface, low-cost i2C/...
1
vote
3answers
3k views

Back EMF of an inductor in a DC circuit?

Will an inductor in a DC circuit act as a voltage source and oppose the applied current creating the magnetic field? Or is it because of the steady state direct current there is no change in I there ...
0
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3answers
790 views

Autodesk Autocad for PCB design

I recently completed an Advanced Diploma level course subject for PCB design that taught Autocad as the design software. Whilst I am aware of the power of Autocad my subsequent surveying of ...
0
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2answers
344 views

FETs transfer characteristics in 4 quadrants

Recently I was given a following problem on the test: Usually, transfer characteristic (Id(Vgs)@Vds) of JFET and MOSFET is plotted in the 2 quadrants. Plot it in all 4. After the test we were not ...
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1answer
66 views

Analog modulation trainer

i am making communication trainer as my FYP i am confused on analog communication module .. I have 2 options first one to make different blocks of analog like mixers, filters , amplifiers ,phase ...