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.
82
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If the RPM of an AC generator doubles, and its frequency and voltage doubles, how much does its current decrease?
From what I understand, if the rotation rate of an alternating current generator increases, its voltage increases at the same rate...
I also have learned that the total power produced increases ...
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2
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123
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LED lights on Christmas card without coin battery?
I’m an elementary / primary school teacher and I would like my students to be able to create Christmas / holiday cards with LEDs, using either copper tape or graphite pens (like circuit scribe) … BUT ...
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187
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Where can I find information about "Enhanced Policies and Procedures Exam" for IPC?
I'm taking the CSE test for IPC-J-STD-001 and at chapter 7.Certification Exam Overview, I can see that there are 3 types of tests.
Policy and procedure test (10 questions)
Closed book test (25 ...
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91
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Output voltage of a step-down voltage regulator (or buck converter)
I've the following step-down regulator:
and I'm wondering how to get the following formula for the output voltage:
$$
V_{OUT} = \frac{T_{ON}}{T_{ON} + T_{OFF}} \, V_{IN}
$$
I calculated the current ...
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Definition of current capacity of a voltaic cell
I'm looking for the definition of current capacity of a voltaic cell, but online I found only sentences in which this locution was used without a definiton.
Can you tell me what is the definition ...
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1k
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Battery capacity in mWh instead of mAh [duplicate]
I know that the capacity of a battery is expressed in mAh, i.e. A/s (international system of units). Today I used a command in PowerShell (*) in order to get the battery capacity, but the unit of ...
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2
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257
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TRIAC phase angle control 120 VAC line ripple
I'm working on a phase angle controlled TRIAC dimming circuit (schematic attached below), and I'm seeing a lot of ripple/noise on the 120 VAC input as I near 50% power. I'm wondering what I can do in ...
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What type of SMPS is this?
What specific type of SMPS is this? I'm working on troubleshooting no power out.
I'm having trouble finding comparable circuits so I can learn how it works. It appears to be some sort of resonant ...
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59
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Microcontroller to realize a wireless electrical switch - Suggestion [closed]
I hope this is the right place where ask my question.
I'm looking for a small microcontroller to realize a wireless electrical switch; can you suggest me any microcontroller to do this please?
Thank ...
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87
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Reading recommendations to better understand how to understand the intended function of a circuit
This is a general question. Suppose I have a circuit like below from CircuitDigest:

My supervisor said that about the circuit that..
[The] circuit does actually involve an amplifier, even ...
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3
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508
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Sensitivity (or responsitivity?) of an electrochemical sensor - Definition
I read a paper about an electrochemical sensor where there is the term sensitivity expressed in ampere. What is its definition? I found a IUPAC definition here, but the units are ampere/watt or volt/...
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53
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Different number of bit for the ADC and DAC linked to a \$\mu\$controller - Electrochemical sensor
I am studying an electrochemical sensor (see figures below please) where the number of the bit of the DAC (Analog Devices AD5685R) is 14, whereas the number of the bit of the ADC (Analog Devices ...
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177
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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 ...
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177
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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 ...
- 492
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229
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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 ...
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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-...
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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 ...
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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 ...
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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}...
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4
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1k
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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 ...
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4
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604
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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 ...
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3
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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 ...
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4
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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?
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6
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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 ...
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3
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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)$$
Can you attached a LTSpice ...
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463
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Suitable electronic components and digital logic gates for simple application [closed]
I'm designing some educational toys to teach children about electronic and logic circuits. They are quite literally individual electronic components (switch, resistor, transistor, capacitor, ...) and ...
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2
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9k
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Optimal soldering iron specs for lead-free
I do most of my soldering with/directing children and so we always using lead-free solder (and thru hole and nothing too complicated).
I have a soldering iron station that has two settings, 20W &...
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87
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Serie, parallel and other configurations (relative to small signal) of capacitors in amplifiers - poles and zeros
When I study frequency responce of amplifiers, I must understand if capacitors are in serie, parallel etc. relative to input small signal (in my exercises there is always only one input small signal). ...
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451
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Break feedback loop of oscillator
How could I choise the break point on the feedback loop of an oscillator (goal: evaluate the loop gain \$\beta \space A\$)? The Sedra-Smith said that it is convenient to break the feedback loop at the ...
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Transfer function of amplifier (exercise)
The transfer function of the following circuit is (I read A(s) on the solution of my professor):
$$A(s)=A_{CB} \frac{s \space \omega_{pC2}}{(s+\omega_{pC1})(s+\omega_{pC2})}$$
where Nevertheless is ...
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7k
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LTSpice - varistor component
What is the constitutive relashionship between current and voltage of a varistor in LTSpice? For example, if I set the control voltage V=1V and Rclamp=2, what is the formula to evaluate the resistance ...
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520
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LTSpice - resistor controlled by RMS
Is possible to obtain a resistor controlled by RMS of a voltage in LTSpice? The syntax \$R=V(n001)\$ works, whereas \$R=rms(V(n001))\$ does not work.
Thank you for your time.
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Frequency of oscillator (exercise)
I tried to evaluate the frequency of the following oscillator:
The loop gain \$\beta(j\omega)A(j\omega)\$ is:
To find frequency I must impose the condition:
$$\angle \beta(j\omega_0)A(j\omega_0)=0$$...
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2
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2k
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Wien's oscillator - amplitude stabilization with Zener diodes (loop's gain)
How come the loop's gain \$\beta A\$ of a Wien's oscillator with Zener diodes is equal to the loop's gain of a Wien's oscillator without Zener diodes?
My professor uses the following expression to ...
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Conversion h-parameters from common emitter to common base (request source to verify)
I calculated the \$h_{ob}\$ parameter from h-parameters of a common emitter transistor:
$$h_{ob}=\frac {h_{oe}} {h_{ie}h_{oe}+\left(1-h_{re}\right)\left(1+h_{fe}\right)}$$
How could I verify the ...
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11
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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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226
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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 ...
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132
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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 ...
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2
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2k
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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 ...
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1
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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 ...
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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.
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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 ...
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Negative base current in NPN BJT
What happens if the base current goes out of the base of an NPN BJT?
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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.
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3
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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}$$
thus I can decrease \$V_{CE}\$ also decreasing \$V_{BE}\$. In this case, when \$V_{BE}<0.7 V\$,...
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2
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479
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Forward biasing of EBJ of npn BJT
I apologize for the stupid question, but I am a beginner in the analysis of BJT circuits. The Emitter-Base Junction of a npn BJT is forwand biased if the emitter current is positive?
Thank you for ...
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138
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Principle of causality and Laplace's domain [closed]
what are the conditions in the Laplace's domain which ensure the causality of a system? I would be grateful if you recommend me also references. My professor said that the degree of the denominator ...
- 492
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808
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Difference between dynamic resistance of diode and resistance of PWL model of diode
What is the difference between dynamic resistance \$r_{d}\$ of a diode and resistance \$R_{D}\$ of piecewise linear model of a diode? The book "Microelectronic Circuits - Analysis and Design - ...
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1
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4k
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RLC filter as amplifier?
is it possible that a RLC filter works as an amplifier? If it works at resonant frequency, then the output will be greater than the input.
Thank for your time.
- 492
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Possibility of poles with positive real part in RLC filter
are there the poles with positive real part in any function mode of the RLC filter?
The equation to determine the poles is the following:
$$RLCs^2+Ls+R=0$$
$$s_{1,2}=\frac{-L\pm \sqrt {L^2-4R^2LC}}{...
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