Power Definition and 998 Threads

Hi. Not homework. I left that behind me 40yrs ago:) How much power (if any) does a plugged in but unconnected wall wart (transformer/rectifier) consume? Eg. I have a phone charger labelled as: Input: 100-240V~50/60Hz 0.3A. ____________ Output: 5V - - - -...

I've attached my attempts at the solution and the actual question below. I believe the only issue I am having is I don't know how to get rid of "I" in both my final inductor and capacitor equations as the HW states I shouldn't have anything in term of I. I believe I need to put "I" in terms of...

Can we use the electricity from the muscle to power an engine (like a prosthesis)?

Yes, this is a question. I already converted an old PC power supply (350 Watt) to replace the bower bricks for my Internet modem and router. What I would like to do now is install a 2-3 hour mini-UPS in the mix so I can remove it from my computer's UPS. I have spent days online scouring the web...

This problem is trivial, but I cannot make sense of my answer (I am not even going to bother with the cost calculation. First, I used P=IV with P=15 MW and V=120 V to find I=125 kA So far so good. Then I calculated the resistance per meter as R=\rho\ell/A=(1.68\times 10^8\Omega\cdot...

I am looking at capacitor selection for a switched capacitor converter and I'm not sure which voltage rating to look for. I've was going to consider the DC rating since they're holding off a DC voltage, but they are subject to PWM excitation since they're switching between nodes at different...

If some technology (such as versions of fusion power) makes generating electric power vastly cheaper, will it be necessary and expensive to increase the capacity of current power grids in the USA and other countries? Or is it the case that current power grids have a lot of excess transmission...

I plotted the x(red dots) coordinates and y coordinates( black dots) of extremums of functions x^x^a (the x coordinate of the dots is a and y coordinate of the dots is x or y coordinate of the extremum). Is there a function, on which are located all the black dots or all the red dots? P.S. The...

An elevator of mass M is accelerating downward with constant acceleration A. Friction force acting on the elevator is constant and given by f (The initial speed of the elevator is zero.). Find the power generated by the engine of the elevator (in terms of M, A, g, f, and time t). For this...

Hi, PF This is the quote: "If ##m## is an integer and ##n## is a positive integer, then 6. Limit of a power: ## \displaystyle\lim_{x \to{a}}{\left[f(x)\right]^{m/n}} ## whenever ##L>0## if ##n## is even, and ##L\neq{0}## if ##m<0##" What do I understand? -whenever ##L>0## if ##n## is even: ##m##...

In reading scientific papers on atmospheric pulsed Lidars there is often a table that includes system information such as the type of laser, the power in uJ or mJ and the rep rate. Examples of the power would be usually somewhere between 50 uJ and 30 mJ. Rep rates are between 10 and 10,000...

So I am converting an old gas lawn tractor to electric. I have a 48v 2000w motor to drive the axle. For the deck, I sourced two 40v old Ryobi deck motors (I don't have them yet). Since my power supply will be a 48v lithium battery, I wanted to run the two deck motors off the controller running...

I wrote the following equations using node voltage, my issue is that I'm confused about why the RC branch at the output doesn't effect the value of the Gain for the amplifier; the equation involving VA / ( 20k - j12k ) is omitted in the solution. IAC = IAB + IBC V- = V+ = VB = VS ( VA-VC...

Could somebody check my solution?

The voltage and current are given as ##v(t) = 359.3\sin(\omega t + 15) volts ## and current is ## i(t) = 100\cos(\omega t + 5) ##. My question here is do i need to convert the voltage into cos terms or current into sin terms. suppose if i convert the voltage into cos terms, the calculations will...

I am trying to calculate the power calculation of a general circuit with voltage leading the current by a phase difference of ##\theta##. The instantaneous voltage is given by ##v = V_m\sin(\omega t +\theta) ; i = I_m\sin(\omega t) ##. The instantaneous power is then ##p = V_m I_m \sin(\omega t...

Hello All The power output of piston engines fitted to aircraft were (and still are?) specified in terms of their HP rating, whereas jet engines are typically rated in terms of their trust. For example, a Mosquito two engined fighter/bomber was equipped with two Merlins, each producing...

I am referring to the application note from TI, the below is the power bridge circuit. The truth table is as below a. I try the first values of A=0, B=0, C=0 the circuit would then become like this according to me It is open above point O, then how the voltage of ##\frac{-V_{DC}} 2## will be...

Hello, If I am trying to calculate the heat removed from a chiller system through this formula on engineering toolbox.com: Does COP or efficiency of the equipment come into play with this calculation? For example if a chiller is fully loaded isn't it running more efficient for a watt/ton...

I am learning about noise that follows a Poisson distribution. When I do a Fourier transform of the data with only Poisson noise to get the power spectrum, what is the average value of the power spectrum?

Are our common home appliances mostly designed to protect itself against tough and unusual conditions like sudden power outage or very short power outage? (i.e. power goes off and resumes within short time)? I have an AC unit that it is labelled to suggest not to restart the machine after...

Hi. There has been a fair amount of research into electric generators and motors with superconductive coils. If traditional iron cores is used that obviously limits the power density because of the iron cores magnetic saturation point. But for coreless/ironless designs i don't understand what...

Summary:: Electric Power Systems book recommendation Hi everyone, I finished my Electrical Engineering degree 15 years ago and wanted to refresh/review/update my knowledge on Electrical Power Systems. I'm looking for a book recommendation that has: components of a power system, control of...

A)Use de moivres therom to express power in simplest polar form Workings Do i need to divde the 60^o by 10 aswell

Okay, so I don ' t have any real specs but i just want to know how big is the difference between water from tap versus the one from fire hose versus the pressure washer?

So I tried to solve this in two methods, but I keep getting different results, and I don't know why.

Hello there, I was trying to solve this problem. I have no problem with part A and C. But in part B, my guidebook arrived with different answer. Can anybody point out what my mistake is? I am using the same method as the elevator motor problem which states : "A 650-kg elevator starts from rest...

First and foremost, I found the max stretch of the spring using the strain energy formula(x=√((2*0.25J)/k)) ). Then, the maximum force exerted(Fmax=k*xmax), in order to find out the seconds needed for the force in [N/s] to reach its maximum value. Now, I got confused about how to find the...

The answer should depend on the result. If the result is more of what's going on and what's going up, like pollution, extinction, and temperature, then no, the world doesn't need more power, and the solution lies elsewhere. If we can stop polluting with particles and gassing out as we...

1/2mv^2 = 1/2mv^2 - 1/2kx^2 but can't plug in numbers for x or m mv+mv=mv+mv but no mass given very lost

hi guys i am trying to solve the Gaussian integral using the power series , and i am suck at some point : the idea was to use the following series : $$\lim_{x→∞}\sum_{n=0}^∞ \frac{(-1)^{n}}{2n+1}\;x^{2n+1} = \frac{\pi}{2}$$ to evaluate the Gaussian integral as its series some how slimier ...

I have found the input power through the efficiency formula, and I deducted that the input energy must derive only from water's kinetic energy... from which have mass/s and then finally the volume/s. After all the calculations and having multiplied the volume/s by 60, I get the result of 6.48 x...

I am reading up on quasars because I am interested in the magnetic beams that emanate from their poles, accelerating material. I read that the magnetic beams are generated by the orbiting debris the quasar is consuming. Sorry, that doesn't sound right to me. I assumed the black hole core is...

It is an example problem and i could understand the solution and the answers are ## R = \frac {V_{rms}^2} {P_{av} } = 9.6 \Omega## ##I_{rms} = \frac {P_{av}} {V_{rms}} = 12.5 A## ##p_{max} = VI = 2P_{av} = 3000 W## But main problem is the statement given by the author below the solution which...

$\tiny{s8.2.6.3}$ Find y' $\sqrt{x}+\sqrt{y}=1$ \begin{array}{lll} \textit{isolate }y &\sqrt{y}=1-\sqrt{x} &(1)\\ \\ \textit{square both sides} &y=(1-\sqrt{x})^2 &(2)\\ \\ \textit{differentiate both sides} &y'=2\left(1-\sqrt{x}\right)\left(-\dfrac{1}{2\sqrt{x}}\right)&...

I have the following equation, $$ C_\ell(z,z') = \int_0^\infty dkk^2 j_\ell(kz)j_\ell(kz')P(k),$$ where $$j_\ell$$ are the spherical Bessel functions. I would like to invert this relation and write P(k) as a function of C_l. I don't know if this is a well known result, but I couldn't find...

Hi all, Checking my answers here as it doesn't seem to match with the answers given to me. Would appreciate if anyone could point out the mistakes I made. First I will compute Rth. Offing all independent sources, applying a known voltage across R (in this case 1v) and using mesh analysis...

I may have written myself into a corner. I am not looking forward to your answers. It involves the very core of my story, so I can't be coy with the deets. I know there are way too many factors for proper analysis, just looking for rough ideas. There are a couple of parts to this, I'll start...

I learned that solar panels have their maximal power output at a particular voltage and current level. If we want to get the max power, we have to connect a load with a specific resistance. However, in reality, how does the solar plants solve this problem? I guess they won't allow the power...

In optical communications, one of the modulation methods is to control the optical power (Simplest case, for example, bright = bit 1, dim = bit 0). I learned that we can achieve this by a Mach-Zehnder modulator (MZ modulator). Simply speaking, the principle of MZ modulator is to split the input...

I want to mount a camera on the front of a tractor(Sony RX0M2, similar to a gopro). The camera will eventually be used for image processing. A PQ-12 micro linear servo (see here) will be used to turn the camera on/off. It is being run by a Raspberry Pi 4B. All components in this project will be...

Hi, I have a simple question that I don't have a fundamental understanding of: do resistors dissipate reactive power (in addition to active power)? For context, when we are looking at a transformer (single phase) equivalent circuit (similar to the one in the image attached), we are asked to...

As per me the energy required by a man with 60 age and 21 age to cover same distance is same.

I have a question related to linearity of power spectral density calculation. Suppose I have a time series, divided into some epochs. If I compute PSD by Welch's method with a time window equal to the length of an epoch and without any overlap, I obtain this result: If I calculate the...

I would like to estimate the magnitude of a radio signal received from a transmitter by first principles: Transmitter antenna length ##L=1## m Transmitter antenna area ##A=1\hbox{ cm}^2## Number of electrons per unit volume in antenna ##n_e=10^{28}## Radiation resistance of antenna ##R_R=10\...

I think the greek knew about magnets and magnetic stones. They also knew about statistic electricity the Egyptian knew about a fish which would shock you . My question is why did it take so long for someone to wrap a magnet around a coil. What is the earliest in human history that humans could...

I tried to use the ratio test, but I am stuck on finding the range of the limit. $$\because \left|x-1\right|<1.5=Radius$$ $$\therefore -0.5<x<2.5$$ $$\lim _{n \to \infty} \left| \frac{A_{n+1}(x-1)^{n+1}}{A_n(x-1)^n} \right|$$ $$\lim_{n \to \infty} \frac{A_{n+1} \left|x-1\right|}{A_n} <1$$...

Our teacher said that powers in division have to be subtracted when the same base , but still , I am not getting the right answer.

I am reading Micheal Searcoid's book: Elements of Abstract Analysis ( Springer Undergraduate Mathematics Series) ... I am currently focused on Searcoid's treatment of ZFC in Chapter 1: Sets ... I need help in order to fully understand the Axiom of Power Sets and Definition 1.1.1 ... The...

I understand that the power of reflectance and the power of transmittance (regardless of it being S-polarized or P-polarized light), when added together, would equal to one. In other words, ##R+T=1##. However, how do I go about checking for this fact? Using the equations from the "Relevant...