Questions tagged [energy]

Energy is defined as the amount of work that can be performed by force, measured in Joules. Energy is Power over Time. This is a poor tag to use. Please consider if your question relates to Energy as defined in physics, not as a synonym for Power or capacity.

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Is this method of proving energy is conserved in an LC oscillator correct?

Assuming no energy loss due to heat or EM waves $$U=\frac{Q^2}{2C} +\frac{LI^2}{2}$$ differentiating both sides with respect to time, $$\frac{dU}{dt}=\frac{QdQ}{Cdt}+IL\frac{dI}{dT}$$ but we know that ...
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Power loss in a capacitor vs inductor

Is there are a general rule of thumb if one of these stores energy more efficiently than the other? When properties are approximateily comparable, are energy losses bigger with a coil or with a ...
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When calculating the energy delivered by a pulse in an oscilloscope, what is the uncertainty in the timestep increment? [duplicate]

I am trying to calculate the energy delivered by a short electrical pulse. I am using an oscilloscope to capture the waveform and then exporting it to a CSV file. My scope took measurements at a rate ...
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2 answers
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How do I convert generated cooling capacity in kW to kWh?

I have to program a relatively simple program so I can display values on dashboard representing the part kWh a system is responsible for generating. This will be represented as a percentage. I have a ...
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1 answer
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Alternatives for batteries for energy storage [closed]

If it is not the indicated Stack App, let me know, please. I don't really know if this topic is about chemical stuff because of batteries composition or just a electronic energy problem. I've been ...
2 votes
1 answer
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Why does air conditioner power draw fluctuate during the day?

My air conditioner is controlled by a thermostat like most are. When the set temperature is exceeded, the system turns on the air conditioner using the R and Y wires of the controller. As I ...
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Identify chip labelled SC1186E

I am trying to identify the manufacturer and function of, and hopefully locate a data sheet for, this chip labelled SC1186E. It is in a three-phase power meter, so my guess is, that it is an ADC front ...
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6 votes
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Confused about MW to MWh conversion

I have various datasets of energy production in MW. I need to present everything in MWh. I need to know if my data is already by the hour (logging a value for each hour of each day of an entire year), ...
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How to convert kWh to half hour time series?

I have an energy reading of 50 kWh. The duration of this reading is from 09:00 to 10:30 (or 1.5 hours). If I want to make a 30-minute time series, how could I convert 50 kWh into 3 half-hourly ...
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Calculate the power consumption

I have project put the ESP32-S2 in active mode for 10 second and then go to modem-sleep mode. I want to compute the power consumption for the active mode. According to this, the ESP32-S2 current ...
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Matching generation and consumption in renewables

To balance power generation and consumption, traditional power plants such as thermal and hydro have governors that regulate the steam/water that flows into the turbine. The energy that renewables ...
2 votes
2 answers
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Which topology should I use for energy harvesting

I am making a energy harvester design but am confused which of the following circuit should I use to amplify and filter my harvested voltage. The first topology is the synchronous switch harvesting on ...
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1 answer
472 views

What role do electrons play in a circuit other than establishing an electric field?

In a simple electric circuit consisting of a load (such as a filament lamp) and a power source (a 5 V battery), when the switch is turned on the electrons experience a "displacement" which ...
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Can V²/R be used to find energy of a DC transformer pulse?

A person I am working with is trying to determine the efficiency of a pulse transformer and I am confused by the procedure. We know the input energy because a capacitor is discharged across the ...
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2 answers
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Why does AC current go both ways but energy in only one way?

We all know the Alternating Current has no definite direction such as forwards or backward but goes both ways, so my question is that as AC flows both ways why does the electrical energy flow only one ...
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Open circuit photodiode energy

Where does a photo-diode use the energy it collects from light and other EM waves when not loaded? Does it dissipate it as heat, reflect it or something else?
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Doesn't the law of conservation of energy invalidate Ohm's law?

Imagine I have a power supply supplying a 12 amp AC current of 12 volts. The resistance of the circuit, consisting of only a copper wire and a resistor, is 1 ohm. In this instance Ohm's law holds true:...
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Mismatched rating in Ah and Wh. Why is that?

My question concerns the apparent mismatch between the Wh rating and the Ah rating often found on batteries. On one of my batteries the label says: 12V Leisure Battery TR350 TUDOR EXIDE DUAL 80Ah, ...
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3 answers
64 views

A machine's energy consumption per product

I need to find the energy consumed per product. Let's say we have product cycle of 10 seconds. The machine reports the average wattage of each second. ...
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A capacitor charge time - two methods two different answers

I am a bit puzzled and ask for your help about the following: A theoretical capacitor of 100 F is being charged with a constant power source of values V = 50V, I = 50A, ESR of capacitor = 5 mohm To ...
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Battery capacity and parallel vs. series battery connections

Say you have 4 200 Ah 12 V batteries connected in parallel, this as I’ve come to learn increases the amp-hour value and not the voltage, and say you have another system same as that but connected is ...
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5 votes
6 answers
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Why can't current change instantaneously in a given inductor?

I know the mathematical reason behind this. Given the inductor I-V characteristic we know that: I understand mathematically that a function which is differentiable must be continuous, but what is the ...
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How is energy conserved in an LC tank with voltage offset?

Consider an ideal LC tank oscillator offset by an ideal battery*: The core question is this: is the energy balance here maintained by the charge-voltage relationship of the battery? Energy seems to ...
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Energy cost conversion [closed]

If electricity costs $0.06 per kilowatt-hour and is used for electric heating with an efficiency of 100%, what is the equivalent price of natural gas per gigajoule if it can be burned with an ...
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Magnetic energy harvesting with a current transformer

I am planning to design a magnetic energy harvesting circuit with a current transformer (CR8349-1500) to charge a super capacitor. Load current rating is 0 to 35 amperes. From the current transformer ...
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1 answer
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Convert kWh during a 1 hour period to average 15 min kW output

If I have a photovoltaic system that outputs 100 kWh from 1PM - 2PM on a given day and I am trying to figure out what the average 15 minute kW would be during that time period, would that be equal to ...
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How to calculate watt hours gained charging battery?

I need an estimate of how many watt hours a battery has gained after charging to a certain number of volts. With a 12 V, 50 Ah lead-acid car battery, charged from 12.5 V to 13.0 V, is it as simple as ...
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3 answers
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How is a sleep mode of a micro-controller realized? [closed]

How can a micro-controller save energy? What does it mean if the micro-controller throttles its CPU? How can a micro-controller "turn off peripherals" that are not needed to save energy? I ...
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2 answers
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What does "highest ionizing energy deposition" mean?

I am looking for how to compute the thickness of shielding materials and have found the following research: ISNPS Technical Report ISNPS-1-2013 Tai and El-Genk.doc (unm.edu) The report is mentions the ...
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How to measure energy usage from a 12V battery over a daily pump cycle

I am working on a project right now where two different DC water pumps are being powered by a single 12V DC battery. I am trying to do some performance testing to find how much energy from the battery ...
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1 answer
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"Power Loss" in the Definition of Q-factor from wikipedia [closed]

The stored energy definition of the quality factor \$Q\$ from wiki Q-factor from wiki is given by $$ Q = 2\pi \frac{\text{energy stored}}{\text{energy dissipated per cycle}}= 2\pi f_0 \frac{\text{...
3 votes
3 answers
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Where does all the electric energy get dissipated in any electrical system?

I know that some portion of the electrical energy is dissipated as heat due to the efficiency, but where does the other energy go? If we are talking about a satellite in space, all of the electrical ...
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1 answer
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Real time server monitoring

First of all, I hope I am posting my question on the right place. I am looking forward to any possible advice. I am using a Dell server (model: PowerEdgeR710) and I saw that on the LCD panel the ...
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3 answers
129 views

How much electricity can be generated from stove's heat?

Yesterday I asked a whether it is profitable to put a thermoelectric generator (TEG) between a stove and a freezer regarding electricity terms. I was missing a point, which was that heat was being ...
2 votes
2 answers
325 views

What if we attach a TEG between a freezer and stove?

I have been thinking about this, that if we attach one part of a thermoelectric generator between a freezer and other part on a stove. This would create a temperature difference and generate ...
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1 answer
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How to (theoretically) capture 59 megajoules of power in 5 seconds to store like a battery for a month? [closed]

On Dec 21, 2021 EUROfusion Scientists in Culham, UK produced 59 megajoules in 5 sustained seconds from their nuclear fusion experiment. What theoretically would be required to capture that energy and ...
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3 votes
1 answer
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Why multiple series resistor on single phase metering reference design with HLW8012 and BL0937 IC

We need to implement energy monitoring in our smart plug. We are considering 2 ICs HLW8012 and BL0937 for this purpose and following are their reference designs in their data sheets. I am trying to ...
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1 vote
1 answer
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How to understand information as energy?

Cpu or gpu making calculations and creating information (decrease in entropy) is converting 100% of energy it pulls from the wall into heat. How should we understand the created order in terms of ...
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How does direct piezoelectric effect convert mechanical energy into electrical energy?

I am studying direct piezoelectric effect and if I understand it well the idea of direct is that if we apply force in an hexagonal cell unit for example, we create a polarisation, but how do we ...
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2 answers
69 views

can we trade off electric power for time?

The voltage and current are exchangable for a constant power. Can we increase the power of the source by decreasing the time of the supply ? From this equation Power = Energy / Time The total energy ...
11 votes
6 answers
2k views

Why is the energy in a battery QV, but the energy in a capacitor QV/2

If I know the total charge in a battery, let's say 5000 Ah, and I want to find how much energy is stored in the battery, I multiply the total charge by the voltage E = Q·V; for example, for 12 V I ...
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1 answer
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Possible problems of AC energy metering using rectified waveforms

I'm building an energy metering circuit with discrete parts and precision is not a big deal in this case. One friend had the idea of rectifying both the voltage and current waveforms before sampling ...
6 votes
3 answers
982 views

Does an EEPROM consume power only during the transition edges or during entire read/write cycle?

Iam trying to simulate the loading behavior of an EEPROM. It is powered by a 5V LDO. When would the EEPROM actually consume power? Does it consume power during the entire read/write cycle time? As ...
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The probability that an electron occupies the fermi level at 0K

I was trying to find the probability that an electron occupies the Fermi level at 0K. Fermi function: {exp[(E-Ef)/kT] + 1}-1; (k = 8.314 J/mol/K) According to my calculations, the answer would be 0.5. ...
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4 answers
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Where is my capacitors energy missing?

To avoid "mistakes", may I recall that, mathematically, \$\infty \times 0 \$ can be ... finite! Otherwise, why use a Dirac impulse? After reading this and this, I have yet a "question&...
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Does DC energy propagation speed depend on current? What about AC?

I understand that the speed at which energy propagates from the source to the load is much faster than the drift velocity and current of the electrons in a wire. I am wondering if the magnitude of the ...
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1 answer
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Leaving the plug attached to the socket [closed]

It would be really helpful for me to leave the USB plug (the "brick") plugged into the power socket. I would not connect the cable, which could potentially short if it touched a conductor, ...
0 votes
1 answer
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What does it mean by "in the range of 1000:1" for an accuracy of 0.2 in energy metering?

Most of the time whenever I come across electricity metering or CTs, there is always a term like an accuracy class e.g. 0.2, 0.5, 1, 2, etc. I have an idea about what this accuracy class means. But ...
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Programming - battery energy logging; creating negative and positive data output from a single sensor

I'm using a single bidirectional Hall effect sensor to read the current coming to and out of a battery, but an application requires 2 separate sensors; one for incoming and 2nd one for outgoing energy....
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Calculation for energy consumed over a period of 24 hours

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.5 Power and Energy gives the following practice problem: ...
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