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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2answers
81 views

Role of the neutral conductor in three phase systems

In a symmetrical and balanced three phase system no current flows on the neutral conductor. Obviously the real electric power distribution systems are not perfectly balanced, so there is a current on ...
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Hypothetically, 6 or more phase line with same mechanical energy?

So I don't understand a concept of mechanical to electrical energy conversion. Let's assume I have a 3-phase generator and need X amount of mechanical power in order to get 200 Volts Phase-Neutral. ...
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How many watts does a 40 MHz radio frequency signal create?

I am new to the study of electromagnetic frequencies and electrical engineering as a whole. I am trying to understand how to convert a radio frequency into energy, or calculate the power density of ...
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1answer
68 views

voltage potential energy clearance?

1 coulomb = charge of 6241509074460762607.776 protons(fixed amount of energy passing thru certain point). So 1 volt = 1 joule(energy) per 1 coulomb. and 2 volts = 2 joule(energy) per 1 coulomb. does ...
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872 views

A passive sensor does not need any additional energy source?

I am currently studying the textbook Handbook of Modern Sensors - Physics, Designs, and Applications, fifth edition, by Jacob Fraden. In this textbook, the author states the following: All sensors ...
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1answer
35 views

Energy dissipation of a resistor in an AC circuit

I am given a resistor of known resistance with a sinusoidal voltage across it, and am asked to calculate the energy dissipation between t=0 and t=1. Not sure how to do it. Would I Use P=V^2/R and ...
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48 views

Design of a 5kW residential Solar system with battery- need help with electrcial diagram

A design project asks for a design proposal of 5kW solar panel with inverter and battery system for a residential house. I have completed the energy estimation, panel size, orientation, and selected ...
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1answer
18 views

Using solar to recharge a Li-po battery

I'm looking for help determining what size of solar (PV) I should use to recharge my Li-po battery after discharged. Battery Characteristics :Capacity:1600mAh Nominal Voltage: 3.7V Charging ...
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4answers
75 views

How does energy dissipates in a purely reactive circuit?

Suppose in a home, power factor drops to zero. It means that the circuit becomes purely inductive. If the energy meter is connected at incoming power supply point,will the energy meter still keep on ...
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1answer
49 views

Why is my equation for getting the energy of a capacitor wrong?

I have a question. Because \$Q=CV\$, \$U=VIt\$ and \$Q=It\$ The energy in joules of a capacitor from what I get is \$U=QV\$ with \$U=C(V^2)\$ But why when I see on the internet it is \$U=(C/2)(V^2)\...
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What is the speed of “electricity”?

In a distribution grid, what is the speed of energy signal Is it strictly the same? And how is synchronisation achieved? Is an electric grid essentially an orchestra where everyone is the chief ...
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510 views

Producers consumers balance in the grid

In a large distribution grid, it is said that consumers and producers must be in balance; what that means physically, in correct (not simplistic) mathematical formulation, is not clear: perfect ...
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84 views

Dissipation and Impedance

it is known that power losses (which become heat) in circuits are due to resistances, because of Joule Effect. But sometimes I read that dissipation is due to the real part of a certain impedance, and ...
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0answers
41 views

Energy dissipation in a circuit with only capacitors [duplicate]

Context: Consider a circuit with only two linear time invariant capacitors. If I charge one the capacitors and then throw a switch that closes the circuit, there will be some redistribution of charge. ...
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20 views

ATM90E32 Energy representation and calibration

Thanks to this forum I just understand how this ATM90E32 represents the energy data as [ CF ] but now I have a more kind of complex issue... Now the energy registered by the ATM90E32 is not similar ...
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1answer
102 views

ATM90E32 total energy reading

I'm developing a simple power meter using the ATM90E32 from Microchip. For now, I can read all values: frequency, power factor, voltages, apparent power, etc. Now the issue is with the energy, I need ...
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4answers
487 views

Is there a minimum amount of electricity that can be fed back into the grid? [closed]

This is not fully related to electrical engineering, but I have been reading lately about Feed-in-Tariffs and solar energy production and I cannot find any information on the amount of energy that can ...
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2answers
80 views

What is the energy density of voltaic piles?

I heard voltaic piles have very small power but long lifetimes so I was wondering what their energy density per unit volume and energy density per unit mass is. If specifying a type of voltaic pile ...
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2answers
62 views

Getting negative energy in a coil (RLC-circuit) after opening the switch

I've the following circuit: simulate this circuit – Schematic created using CircuitLab The switch was 'forever'closed and a certain time \$t=0\$ I open the switch. I tried to find the energy ...
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31 views

BJT - How does an applied voltage at BE and BC affect the band diagram?

Let's say we have an energy band diagram of a BJT at equilibrium. Then, we apply -0.7V to BE, while 0.7V is applied to BC. How will these voltages affect the band diagram? I would appreciate it if ...
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1answer
70 views

Assembling and Dis-assembling a Charged Capacitor

If I have an electrolytic capacitor, which is a cylindrical body in which the two plates are rolled-up with a dielectric paper in between them, of very high value (say 1F) and I charge it using a DC ...
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1answer
66 views

Measuring Energy (Watt-hour) from Microcontroller

I have microcontroller device (ESP32) that doing some process and the begin to sleep. This cycle is for 12 hours (00:00-12:00). And after that, begin full sleep for 12 hours (12:00-00:00). So my ...
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2answers
99 views

Why can the energy of local computing be written as \$f^2\$,not \$v^2\$

I saw this formula in this book: Wireless Information and Power Transfer: Theory and Practice And in the formula 14.8, it said: \$f_{i,n}\$ is the CPU frequency for the nth CPU cycle required for ...
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1answer
114 views

Mosfet or bjt choice for low voltage joule thief application

I make solar energy harvester using joule thief circuit with a small solar cell as the input. The output voltage from the solar cell is 0,5V. But the generic transistor, exactly silicon material need ...
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2answers
82 views

Energy lost in in Peltier device?

Suppose I power a Peltier device to heat up/cool down some water. Then I later use the same Peltier device, in reverse, to convert the separated heat energy back into electricity. I have read ...
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5answers
2k views

Heat lost in ideal capacitor charging

If we use an ideal capacitor to charge another ideal capacitor, my intuition tells me no heat is generated since capacitors are just storage elements. It shouldn't consume energy. But in order to ...
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1answer
43 views

C=Q/U equivalence for inductor

In order to calculate the time it takes to charge a certain capacitor with value C at a given constant current of a value I to a voltage of value U, I can use: $$ C = \frac{Q}{U} = \frac{I\Delta t}{U}...
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2answers
409 views

How to calculate total current, power, energy consumption from device?

I have a circuit/device that using ESP32 as microcontroller. I want to calculate how much total current and power that my device drawn. So, the current draw will be like this: My question is: The ...
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0answers
59 views

Generate energy from waves that move my ship?

I'm currently building a small solar powered robot boat. I expect it to work fine (because why not.. :-) ), but I'm already looking for other ways than only solar panels to generate electrical power. ...
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0answers
217 views

Is the duck (curve) still a duck? [closed]

In 2013 the California Independent System Operator (CAISO) published this image, dubbed it "the duck curve", and took the internet by storm (or, at least the part of the internet that tracks trends in ...
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3answers
49 views

MW of installed capacity

I am conducting research on wind turbines, specifically into how many hectares wind farms use. I have come across the phase 'installed capacity'. If wind farms typically use up 10 hectares per ...
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0answers
95 views

creating artifical neutral point in delta connection

I am trying to measure 3 phase 3wire and 3 phase 4 wire L_L voltage and L_N voltage.Circuit i am looking is common for both. In star connection i will get an neutral point for reference to read the ...
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2answers
970 views

How can I deduce the power of a capacitor from its datasheet?

I am looking for suitable capacitors for a sound amplifier I have designed. The speaker power should be at least 7 watt (for the sound to be loud enough). (I attach a figure of the design) So, I ...
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4answers
775 views

Active Energy, Reactive Energy or just Energy?

I understand the concepts of active power, reactive power and apparent power. I am not sure I am getting the complete concept about the respective energies. I am using an energy monitor to record ...
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1answer
43 views

Temperature dependence of the energy bandgap and Simulink way

I know the equation about the temperature change of band energy but Simulink must find another way to define it like below. dEg=-2.677 10^-4 I can't find a single reference about that equation. ...
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1answer
71 views

Supercapacitor for Wind Energy

I am building this wind turbine project and the problem I am facing is the irregular winds that does not keep the inverters running continuously. I initially decided to solve this problem by employing ...
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6answers
3k views

Why don't we think about battery storage for all sources of electricity on a utility scale instead of just renewables? [duplicate]

One of the repeating solutions that comes up when talking about renewable energy power generation and the intermittency of it is battery power storage. This has got me thinking, it takes hours or ...
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2answers
111 views

Photodiode Output measurement

I'm using Hamamatshu s8559 photodiode to convert x-rays into it's respective energy. I'm using a 10 bit ADC converter. The problem I'm facing is I have no relationship between the Photo-current ...
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1answer
24 views

Peak Period Forecasting in electric grid

I am currently working on the day ahead load forecasting using a regression model over a microgrid level. I wanted to know is there a way I can detect peak period i.e period where demand is high from ...
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2answers
101 views

Hspice does not give correct energy consumption for a RC circuit connected to a DC supply

Here is the circuit I am trying to simulate - a RC circuit driven by a DC voltage source. I measure the output across the capacitor. Assume Voltage source is 1 V. Assume capacitor is 1fF. Case 1: ...
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3answers
48 views

Is there an industry standard definition for “load”?

I come across load meaning either power or energy from time to time in the context of residential loads or load forecasting. As such I was wondering if there is a convention as to whether "load" more ...
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2answers
67 views

Graphical nature of signal energy

In signals, we learn that the energy of a signal is the integral of its square. E.g. \$E=\int_{-\infty}^\infty x^2(t) dt\$ We know that integrals are the areas under the function in a graph. But ...
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1answer
26 views

Time it takes for B to go to zero with R and L given

Given that your solenoid has inductance L and resistance R with initial current I such that there is uniform B inside the coil, I would like to figure out how much time will pass before B goes to zero....
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0answers
130 views

How to safely switch a big inductive load with a Triac using a capacitor snubber?

I am building a Spot Welder with a big powerful transformer. I have to switch a big inductive load of 70mH (input of a transformer) The switching will be done with an SSR (Opto Triac Zero crossing SSR-...
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1answer
54 views

Why are thresholds for energy detection and preamble detection different in 802.11 standard?

Assuming a 20 MHz band, it is -62 dBm for the data and -82 dBm for the preamble. Source: August 2013 doc.: IEEE 802.11-13/0994r0
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2answers
99 views

What is the effect on kWh if the power company reduces line voltage to a residence? [closed]

We just received our power bill and it is showing a 30% rise in kWh for the past month. Nothing has changed in our home. We were even gone one full week in the month. To make it more interesting, ...
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0answers
38 views

how to compute battery charging power

I have a very basic question about battery charging power. In a very simplified scenario, assume a battery with voltage 3.7 is connected to another rechargeable battery with voltage 3.2 which results ...
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0answers
119 views

RS485 registers for calculating total power consumption (kwh)

I have an energy meter (OHIO A2000) which has been now discontinued by the manufacturer. Anyway, I'm following the manual for extracting energy parameters through Modbus RS485 communication. I'm ...
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1answer
141 views

Determining Battery Charging and Discharging Rate Based on Max Current and Nominal Voltage

I am having difficulty in figuring out some basic stuff and confused with multiple equations. I am working on a simulator which simulate a hybrid vehicle journey for some period of time. During ...
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1answer
33 views

About parallel circuit [duplicate]

Consider a power source supplying 240 v 50/60hz 6amp I know that there is nothing like it but I chose that for my comfort of understanding now if I connect 15 loads drawing 240 v 0.35 amps in parallel ...

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