Power Definition and 998 Threads

The solution said that Average power= net change in energy/time, but why is that true? If you have a different way of solving it, it would be helpful too

Figure: My attempt at a solution: 1st kirchoff law: $$J=2I_0+I_0=6\, \textrm{A}$$ $$V_1+8=10\rightarrow \boxed{V_1=2}$$ $$V_1=6-V_S\rightarrow \boxed{V_S=-4\, \textrm{V}}$$ We are looking for ##P## generated in ##J## $$V_J=V_1-2\cdot J=2-2\cdot 6=-10\, \textrm{V}$$...

I need to design a circuit which takes around 28V of input and outputs the 200v with 20A. Can any one help me.

I will like the equation describing the amount of wind power available to a wind powered vehicle driving directly downwind. I'm interested in the ideal case so max theoretical power available to a wind only powered vehicle driving directly downwind. I do know what the equation is but I like to...

There is a power line of undetermined voltage hanging just 4 feet above my RV and the stream running next to us. If during the rain, a branch from the redwood tree above us falls and causes the hot line to land on the RV and stay there, is there a way to prevent us being shocked while we try to...

Would it be a feasible power source to have several Stirling Engines sticking through an outdoor wall near your fire place in a cold climate? Issues I can think of: Presumably it would be a heat sink and require you to consume more firewood. Engineering it to not have passive leaks might be...

Large power generators (for example 200 MW) are cooled by H2 in gas form. H2 temperature is +45 to +75 "C. So why hydrogen dew point is important in generator while the lowest hydrogen temperature is 45 "C? And in some Power Stations is monitored online... Thanks, a lot

Hello! I am sorry if this questions is silly but I really don't know much about electronics. I have a pulse generator (this one) and I want to test it with a low voltage for now. I have a bench power supply (something like this). I am confused about how to make the connections. For the pulse...

Let ## n ## be a positive integer and ## p ## be a prime. Then the exponent of the highest power of ## p ## that divides ## n! ## is ## \sum_{k=1}^{\infty}[\frac{n}{p^{k}}] ##. Observe that ## n=823 ## and ## p=3 ##. Thus \begin{align*}...

Hello. I have a question regarding an power amplifier (signal generator). I have three exciters and want to connect them to the power amplifier. One exciter have a impedance of 8ohm and power of 25 watt. The ampliefier have one output with the electical data: 4 ohm : 500watt; 6ohm: 330 watt and...

Hello - thank you for reading this, and thank you in advance to anyone who replies and clarifies the mystery of "ground." I have finally gained a full understanding of how a full-wave rectifier, two-power tube electric guitar amplifier works in a push-pull manner, but one thing remains after I...

Impossible?!? By my estimation the equation that describes this motion is given by: $$Pt = \frac{1}{2}m{ \dot x}^2$$ or $$\dot{x} = \sqrt{\frac{2P}{m}} \sqrt{t}$$ but this implies: $$\ddot{x} = \sqrt{\frac{2P}{m}} \frac{1}{\sqrt{t}}$$ So, no matter how small we make the power, we appear...

Why do some UPSs have both Volt-amp and watt rating? According to APC, the connected load shouldn't exceed the UPS's VA and watt rating. Why? If I had a UPS with 1000VA and 500W rating, why can't it power a load consuming 1000VA @ 900W? If a UPS can output 1000VA, why does it care how much...

Summary: Calculating engine power required for semi trucks under different circumstances. Hello everyone, I would like to ask you for help if that is allowed. For a current project I need to calculate engine power needed in watts under different circumstances. This is something that I will...

I spent the past several weeks making this 3D model of a nuclear power plant control room.

Proof: Suppose for the sake of contradiction that ## 2^{n}+1 ## is prime but ## n ## is not a power of ## 2 ##. Then ## n=ks ## for some ## k\in\mathbb{Z} ## where ## 1\leq k<n ## and ## s ## is an odd prime factor. This means ## (a-b)\mid (a^{q}-b^{q}) ##. Let ## a=2^{k}, b=-1 ## and ## q=s...

If I have a motor with a full load power factor of 0.8 and starting power factor of 0.3 and I install a VSD to run it with a datasheet power factor of 0.95, will the power factor during starting be 0.3 or 0.95? And at full load? Cheers!

First Assume the following basic circuit: I read in many textbooks that the electrons in the circuit are accelerated by the positive voltage and decelerated by the collisions, so the speed is constant. We also know that the circuit current is I = 10A so the power consumed is P = V * I = 100W...

Kathy Joseph makes wonderful videos (and now a book) about the history of electricity. Her research is very thorough. I just watched the video below, and found it instructive. Especially interesting is how Nikola Tesla and Westinghouse in the USA got the fame and credit for three phase power...

I believe I am doing everything right up until the point where I have to try and find a recurrence relation. I honestly have no idea what to do from there. I've listed my work in getting the powers of n and the indicies to all match. Any help appreciated. Here is the original DE...

Hi, For years I wanted to understand why we have a 3 phase supply and not a 2 phase supply in AC. In Quora I found an interesting answer and was convinced about the purpose mentioned: Answer to Why there is no two phase electrical inputs instead of three phase and single phase? by Paul...

During a reactor assembly calculation, I need to determine axial and radial flux distribution over the surface. When I use F2 and F4 tally I get some value with unit 1/cm**2 What does the value means, neutron flux is supposed to be in the 10^14 range but output values are 10^2 range. Can anyone...

Hi, I wanted to know a couple of things regarding the construction of the stator and rotor of a generator in a power station. Firstly, how the copper windings inside the stator are arranged. I understand it’s a three phase winding where each phase has a set of two coils like this: Source...

THIS IS NOT HOMEWORK I design audiophile power amps as hobby. I need to match power transistors. It is A LOT HARDER than I thought. I built a test fixture to hold up to 50 transistors at a time. I try to match sets of 13 to about 1mV which is very tight as Vbe change is about -2mV/deg C. I have...

What are the effects of brownouts and power spikes on linear power supplies in particular; e.g., a linear power supply that provides 24 V to an inductive angle encoder? Thanks for any information you could provide.

I'd like to take Solar Panel power output and use it to power an AC outlet on the ultra-cheap. I know a lot of people use Solar to connect to a purpose built inverter and also have a battery somewhere in the mix to provide a stable output but wondering if the following (using the assumptions...

An interesting article on some of the history of, and discoveries by, the 44+ year old Voyager spacecraft s. The bean counters originally planned a 4 year mission for Voyagers 1&2. However, the scientists and engineers involved saw a golden opportunity that wouldn't repeat for another 176...

Hello everyone! I was doing some dimensional analysis to find an equation that gives a acceleration as a function of time, using constant power. I came up with the equation $$a = k\sqrt {\frac P {mt}}$$ I differentiated velocity with respect to time in order to check my work and also checked out...

I have a jazzy pride 1121 power wheelchair that I need help with. I have installed larger tires so I wasn't limited to where I could take it in my yard. Because of the increased size of the wheels, it now lacks the power to climb inclines. I was told that possibly a more powerful controller...

Hi all I am Belgian and I have difficulty with english formulas. I'm trying to calculate the power and torque required of a motor to rotate a load. Here is the problem: I have a motor (axis up) on which is fixed a cylindrical load of 15Kg. The diameter of this load is 400mm Calculate the power...

This year, the grim outlook goes to other parts of the USA. Not just Texas. NERC is the most credible source we have for US electric reliability topics.

hello i found this equation in a course about x rays , and i couldn't find it anywhere else they said that it is the theoretical expression of the energy spectrum , and dφ/dE is variation of the power emitted by the Coolidge tube as a function of the energy of the x ray. but i didn't understand...

I know the moment of inertia and the rotating speed of a shaft, and the allowable vibration is 2mm/sec. How is the force calculated? What is the formula to calculate the force on the shaft bearings which are a know distance from centre of gravity? Thanks

##\frac{N_S}{N_P} = \frac{240}{12\times 10^3} = \frac{1}{50}## ##I_S = \frac{N_P}{N_S}I_P = \frac{N_P}{N_S}I_P = 50\times 2 = 100## Amps ##P_{loss} = I_S^2R##, but I don't know how to find R

In doing a project on phototransistors I am using my smartphone as illumination source. In order to find the responsivity of the induced current from the light, I need to know the surface power density, which I could estimate, if I knew the effective optical power of the light from the...

I am new here and I am seeking for help:) Thank you so much. In engineering, electrical formula often analogy to mechanical formula. eg. power[W] = pressure x volume flow rate vs power[W] = voltage x current My question is could we make the simplest unit between electrical and mechanical...

a) An inductor should be added because that would cancel out the lag of the voltage with the current so that P = IV is at a maximum since V is ahead of I in an inductor b) ##cos(\phi) = \frac{R}{Z}##, ##R = Zcos(\phi) = 60\times 0.5 = 30 ohms## ##X_l - X_c = \sqrt{Z^2 - R^2} = \sqrt{60^2 -...

(An even longer-winded version was written and deleted out of mercy.) Assume an AC voltage at zero degrees applied to an ideal parallel RLC circuit. For a predominantly inductive circuit, the vector diagram for current should show the supply current in the fourth quadrant (i.e. with lagging...

https://www.cnn.com/2022/05/14/us/texas-heat-wave-ercot-conserve/index.html Why would they make plants like this? If demand gets too high, the plant just stops? And potentially knocks out other plants? Wouldn't it make more sense to cut off a few places at a time so that the plant can...

Just earlier today i was practicing solving some ODEs with the power series method and when i did it to the infinite square well i noticed that my final answer for ##\psi(x)## wouldn't give me the quantised energies. My solution was $$\psi(x) = \sum^{\infty}_{n=0} k^{2n}(\cos(x) + \sin(x))$$...

I'm about 25,000 words into my latest novel and the story arc is coming together nicely, but one aspect I need thoughts on please is what would happen inside a spaceship that has been grievously damaged in battle to the point that it has been abandoned by the fleet as a 500m long wreck...

I am confused with the negative voltage supply connections in electric circuit. If i have circuit as below with -5V source it is same as below In the 2nd circuit the 5V is directly shorted with the ground, does it mean the circuit is not correct? Am i missing something? Please advise.

Question: Equations: My solution: Could someone verify my answer?

I know how to solve the question but I am a bit confused about why there is a current of 3 A and a voltage of 110 V requirement for the refrigerator but the power plant only supplies 110 V. How can there be a voltage drop on the refrigerator load of 110 V, when there is also a voltage drop on...

I have searched the internet and spoken to the manufacturer of my equipment and can not find an answer. I am using RFExplorer (test equipment) to measure the power generated by my ham radio antenna. The only options for displayed power is mV/m or nW/m2. I am trying to find out how to convert...

I am looking for the power in watts, total, put out by and LED. This for example, if I enclosed the complete device in an integrating sphere, what power output would be measured in watts. Unfortunately a lot of the vendors report power in Candela. I could not get a response on this, but I am now...

im kinda confused on why can't you just use the formula P=I^2R. Can you just use Vrms or Vamp (not sure which one is it) and the value of R which is 105Ω to solve for I Then just plug it in the formula P=I^2R. But when i did that it the wrong answer so is this formula don't work for AC...

Summary:: A 90 kg firefighter needs to climb the stairs of a 20-m-tall building while carrying 40kg of gear. How much power does he need to reach the top of the building in 55s. So first the total mass of our system is 130 kg. Using this mass, I found the potential energy the firefighter would...

In a capacitor discharge through a plain resistor, the capacitor power supplied at any instant is VI; the power dissipated in the resistor is I²R. So VI = I²R. Consider a railgun operated with a capacitor bank. At any instant of capacitor discharge, the power supplied is VI. The total power...

Hi to all much appreciation for you all,please is there anyone who can help me the schematic diagram of power amplifier ROYAL L1200