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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What's the most economical way to digitally measure 240V mains voltage, current and power factor?
I'm looking to capture and analyse measurements of the mains energy that I use per circuit.
I've found a few consumer products that offer powerpoint energy monitoring such as the Kill-A-Watt, but PC ...
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Why are deep cycle batteries rated in amp hours instead of watts hours?
Why are deep cycle batteries rated in amp-hours instead of watt-hours? For example if I see a 85Ah battery, I multiply 85Ah x 12V to get 1020 watts. As household electricity use is measured in watt ...
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Does turning a lighbulb on and off repeatedly use more energy than just leaving it on for hours?
Let's say I have a 60W bulb in a lamp in my bedroom. If I kept the lamp on for 2 hours straight but the next day, I switched it on and off 10 times in intervals of 5 minutes. Which scenario would use ...
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Why is an inductor not a good antenna?
[An antenna must have] current flowing along its length, so that the resulting fields radiate that energy into space. (Receiving antennas are just this process in reverse).
[This] explains why ...
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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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A capacitor stores half the energy when charged from a battery each and every time? [closed]
I understand that when a battery is connected to a capacitor that half the energy is stored in the capacitor while the other half is lost to heat or whatever other losses are involved once the ...
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How to compare mAh and Wh
When looking at consumer electronic devices with batteries I sometimes see the battery capacity listed in Wh (watt hours) and sometimes in mAh (milliamp hours). I would like to be able to compare the ...
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Why is it so problematic to have close to zero standby power consumption?
Each electronic device consumes electric power when it is "idle" unless it has a mechanical switch. I can understand that for example a TV with a remote control needs to "be ready" to receive a ...
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How do I design a current transformer?
I want to make a Current transformer using toroidal ferrites to measure 220/50-60Hz AC current(40A max). Is it possible? And how can I calculate secondary turns count?
Ferrite properties:
H = 2000, ...
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How do residential analog and smart meters measure power?
I'm building my own digital meter in order to upload the data to a SQL database; up until now I know that there are several parameters being measured into a digital watt-meter:
volts, current, ...
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What's the highest theoretical energy density for a chemical battery?
This is more a physics/chemistry/nanotech question, but what's the theoretical best energy density you could get out of a chemical battery (or fuel cell), if you could arrange atoms in any manner you ...
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Is a microwave's output power proportional to the mass of its contents?
My friend and I are having a heated debate.
On the one hand, he thinks that a microwave oven that is empty, consumes almost no power (not considering lights, lcd, etc). He says that once you put an ...
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PIC voltage measurement
I am running a battery powered device, and would like my microcontroller (PIC) to report on the supply voltage.
This is so I can determine how many batteries is used in the supply, and also the state ...
Kheng
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Alternative Energy Storage
Can anyone suggest an alternative to energy from a battery?
I'd like a system to replace my deep cycle leisure battery, I currently use this 110 AH leisure battery with a 1200W inverter.
I run my ...
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What is the difference between inductive coupling and resonant inductive coupling?
The resonant inductive coupling is better than inductive coupling, the difference between them, is that resonant inductive coupling use the "resonance" in their favor.
But what is the difference in ...
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