# Questions tagged [energy]

Energy is defined as the amount of work that can be performed by a force, measured in joules (J). Energy is power integrated over time; power (W) is energy per second (J/s). This is a poor tag to use. Please consider if your question relates to energy as defined in physics; don't use it as a synonym for power or capacity.

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### Assumptions in a ideal circuit which consists of ideal wires(zero resistance)

Let us say a circuit consists only of a battery and ideal wires. Assuming steady state, if we remove the battery and now complete the circuit with only ideal wires, is it safe to say that the ...
50 views

### Monitoring sub panel energy use with CTs [closed]

I am trying to monitor the energy use in a shack with a sub panel that is rented behind our house. The cheapest and easiest way seems to be an AC 100 A digital meter with split core CT. My question ...
57 views

### Conservation of energy during electromagnet repulsion

Scenario Consider a coil with some internal resistance connected to battery. To give some example values, let's say the battery has capacity 4 Ah and voltage 1.5 V. So the total energy of the battery ...
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77 views

### Protection for Three-Phase Energy Meter PCB

I intend to measure 3-phase power grid supply using three energy meter boards that will be connected to an ESP32 device, the current is measured using Current Transformers (CT) that came with the ...
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43 views

### RF power transmission control in U-blox GSM modules

I am using the SARA-U270 GSM module and want to test energy-saving techniques. One technique I would like to try is power transmission control, adjusting the transmission power in dBm based on the ...
• 179
108 views

### Energy stored in a saturating inductor

We all know that the energy stored in an ideal inductor is $E=\frac{1}{2}LI^2$. However, real inductors with a ferromagnetic core don't have constant inductance. Particularly, when a specific field ...
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40 views

### Connecting an energy meter with 6 CTs? [closed]

I want to install an energy meter to monitor the energy consumption of a transformer. The secondary side of this transformer is a parallel circuit, making it impossible to connect three current ...
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40 views

### Lithium polymer battery size versus energy density

I am building a small device that needs to use a rechargeable lithium polymer battery. The dimensions I am looking for are 351125 { 35 mm (H) x 11 mm (W) x 25 mm (L) }, which is the standard way these ...
1 vote
81 views

### Most energy efficient way to make a LED blink using a multivibrator [duplicate]

I'm using this LED. I want to make this LED blink at MAX brightness (100 mA) at 1 Hz. I need to use a multivibrator and therefore can't use any IC chips. The circuit is powered by a 3.7V battery with ...
141 views

### Time average stored electric energy in a volume

I am studying the book Microwave Engineering Third Edition by David M. Pozar. At the moment I am at chapter 1.6. At the beginning of this chapter Pozar states that In the sinusoidal steady-state case,...
71 views

### Average energy efficiency is very high

I am computing the energy efficiency of a wireless system, given by the ratio of how many bits are received over how many energy is consumed. $$EE=\dfrac{bits}{joules}$$ For a given scenario, I have ...
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### What makes it hard to lower energy and power consumption for a computation: looking for serious but pedagogical reference

I would like to get "general" culture about what limits engineers in reducing the power and energy consumption to compute. Please correct me if I am wrong but for power, I know that there ...
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1 vote
180 views

### Whats the meaning of Im, Is and Ih

I would like to know what's the meaning for the abbreviations of Im, Is and Ih in leakage currents measurements, as it is depicted in these graphis. Could anyone help me?. The link of the source is: ...
38 views

### Why does the valve symbol have a Clase symbol,or short-circyit symbol before the earth [duplicate]

Could anyone explain to me why the valve symbol have a shortcircuit symbol or termination symbol before the earth???
113 views

### Meaning of this power system line diagram symbol

Please explain to me what this symbol means, in single line diagram? Source of image: My project diagram. Here is another example I found: Here is a magnified part, showing the symbol: Source of ...
1 vote
77 views

### How can I store a energy from a low output?

I need a simple answer to a simple question: How can I store energy as in a battery to use it as energy for an LED lamp or something else? The available power is 50mV- 60mV and 70mA - 80mA.
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1 vote
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### Potential energy of a uniformly charged parallel plate capacitor filled with dielectric

For a uniformly charged parallel plate capacitor (dimensions l × w × d), its potential energy is given by: $$U = \frac{Q^2}{2C}\$$ Now if we insert a material (dimension x × w × d) of dielectric ...
1 vote
97 views

### Energy density vs voltage battery

I find on this website the following sentence: It is said that higher voltage battery have higher energy density. But it appears to me not so evident: If I consider the 2 following batteries: If I ...
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1 vote
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### CMOS (Energy Supply of voltage) [closed]

Can someone please explain why, when $ln$ is transitioning from low to high, the energy supplied is $C_{vdd}\cdot V_{dd}^2$?
2k views

### Could a very high voltage and very low current allow a non-superconducting magnetic energy storage system?

A very low current with very high voltage can travel through high resistant wires without much loss. Could this type of current be used on magnetic energy storage without superconducting materials? ...
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### Does reciprocity apply in appliances power consumption?

Normally, microwave ovens have a timer and a power selector. Similarly in other machines, you can control the power and the time you use that power. Is it generally true in real life that the final ...
75 views

### Calibration of the Atmel M90E32AS Energy Metering IC

I'm working on an energy metering project featuring the Atmel M90E32AS, connected with an ESP32-S3. From the Application Notes of the IC, I understand that it needs to be calibrated first. However, I'...
142 views

### Parts of a power cable

This is a snippet of 6kV/Single core/240 sqmm copper cable. The parts of the cable are as follows. Stranded Copper Semiconducting Cross-linked compound XLPE Semiconducting Cross-linked compound ...
270 views

### How to compute the energy efficiency in bits/s/watt

The energy efficiency (EE) in wireless communications is usually calculated as the ratio of data rate to power consumption: how many data (in bits per second) are delivered per consumed power (in ...
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### Does minimizing stages necessarily give best outcome when designing circuit under a delay constraint?

In the context of digital design, a common situation is to have to design a circuit for minimum energy under a delay constraint. Suppose a given circuit can be implemented with various stages. Is it ...
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### Energy reservoir capacitor

How to calculate the appriopriate capacitance for an energy reservoir capacitor that would serve as an alternative IC power supply in case of main power supply failure. Is there a specific formula or ...
1 vote
212 views

### Need to understand the current sensor connection in this circuit

I'm working on creating a smart power meter for my home, and I found this tutorial. I want to understand each part of the circuit, and the tutorial covers everything. However, it doesn't explain why ...
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1 vote
100 views

### Electric potential - 2 power supplies

I'm studying among other things electrical engineering and I'm kind of in a discussion with a colleague about an 'experiment': he claims that when i measure the voltage between the + output of power ...
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### Mosfet Switching Energy

How can I calculate the energy required to switch a Mosfet knowing the peak power, and the drain to source capacitance?
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1 vote
141 views

### Why doesn't the cross section of a material affect flux density?

I am trying to design an inductor. I have free hand of using any geometric form and ferromagnetic material. It's my first time doing it. I studied magnetics design in college and I always thought that ...
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64 views

### Time bounds for power and energy in RL and RC circuits (natural response)

I am curious about how the time bounds in power (t>=0+) and energy (t>=0) are developed in the natural response of RL and RC circuits. For the RL circuit, the natural response of the current is \$...
50 views

### Are the signals differential?

I want to use this IC for a metering purpose. Are the signals IxP/IxN & VxP/VxN differential signals?
1 vote
481 views

Recently I have been thinking about a circuits problem that caused me a lot of confusion. First of all we know from thermodynamics that energy is conserved. I wanted to show a problem that seemed to ...
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1 vote
30 views

### Understanding Energy consumption - 3-phase Power Meter - Active (forward, reverse) and Apparent [duplicate]

I'm looking at 3-phase power data from a machine using a Fluke monitor. I've got 'Energy Analyze Plus' software which then calculates lots of interesting things and I'm trying to understand what I ...
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328 views

### Designing boost converter for a supercapacitor source and LED load

I have a 2.7 V 100 F supercap, that would equal 364.50 J of energy based on E = 1/2CV^2. If my load is a series of 4 LEDs with a stack forward voltage of 12 V and forward current of 3 A that would ...
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52 views

### Relationship between RMS-current and energy stored in a solenoid

Regarding the formula for energy stored in the magnetic field of a solenoid (U=1/2LI^2), I presume that the RMS value for an alternating current could be used for the I-value. Is this correct?
4k views

### How do you understand the kWh that the power company charges you for?

I really didn't know how to phrase this question. But here are the details. First I understand the simple 10 x 100 W for 1 hour is 1 kWh. But what I want to know is at what time interval does the ...
4k views

### Why do capacitors have less energy density than batteries?

The basic operating principle of a battery is, in order to charge it, the electrons are removed from cathode and moved to anode by applying voltage. And to discharge, the electrons move from cathode ...
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1 vote
77 views

### Boost Converter - Coil energy transfer into Capacitor - Help needed!

I am trying to design my own boost converter and so am learning about coils. Let’s consider this example: The switch of our boost converter has just opened, there was 100 mA flowing though the coil, ...
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435 views

### "To Gap, or Not to Gap" Inductor/XFMR - Energy POV

This post/question is coming from a question I asked within the comments section of here: How to calculate air gap in flyback transformer? The great answer given talks about his solution to the ...
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111 views

### The two capacitors are in series but positive end of one plate is connected to positive end of the other

Like the title says, my task is to find the initial voltage across the terminals. The two capacitors are in Series with positive end of one plate connected to that of another. The given information ...
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96 views

### Find suitable charging voltage for capacitor based on energy and time required for discharging

We need to calculate the charging voltage required to dissipate a certain amount of energy via R-Load. The problem will be as follows: If we need to dissipate 400 J through the R-Load in a time period ...
99 views

### Exceeding max RPM of wind turbine [closed]

I have a wind turbine that reaches its max output power at 1000 RPM, and I want to know if there's any problem if I make it go faster than that (e.g. around 1250 RPM). I have a TESUP Yuzo. You can ...
1 vote
86 views

### How much transmission power increase is added by an undriven element identical to a simple dipole antenna 1/4 wavelength away?

These wonderful old videos helped me understand how antennas work. https://m.youtube.com/watch?v=md7GjQQ2YA0 The explanation for making antenna transmission unidirectional relies on using an undriven ...
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744 views

### DALI protocol - D4i. How to access to memory bank DTR0, DTR1 at byte level using C code?

I'm currently stuck using DALI protocol with D4i drivers. I want to access the memory bank of one driver and read the energy parameters. I know the opcode to read memory locations is 0xC5, since the ...
205 views

I am currently designing a power measuring board that incorporates ADE7953 and ESP-32 microcontroller, however although i have read the Datasheet document for ADE7953 and searched online forums I am ...
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1 vote
44 views

### Energy consumption after removing a part from a PCB

Does removing the buzzer chip from a PCB reduce the energy the PCB uses? Is it save to remove the buzzer? It's an FMQ.
1k views

### Understanding the flux linkage in transformers

I am having difficulty understanding the concept of flux linkage in transformers, particularly how the secondary winding receives its flux when all the flux is said to be confined to the iron core. I ...
1 vote