Questions tagged [efficiency]
A measure of the overall effectiveness of a system. For example, in power conversion, it would be the ratio of output power to input power.
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Energy-efficient method to fit a 7-segment display + computing, into a tight space? [on hold]
Note: there's a 50/50 dis/agreement about this sort of thing on Meta (see here), so I'm hedging my bets that this will be allowed.
I'm currently working on designing a device that has to be ...
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1answer
49 views
Headphone sensitivity/efficiency
Most commercial headphones are advertised to have sensitivity greater than 90 dB/mW. But to my understanding, even with 100% efficiency that's not possible (if we use 10 log (I/I0) where I = 1 mW, we ...
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3answers
191 views
Heatsink on underside of PCB
I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the ...
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3answers
76 views
The relationship between power, heat and efficiency
I've been thinking about this conundrum.
Given we use joules to move a metal block over a surface, we do work.
So imagine a motor, that spins and pulls a string, moving said metal block over one ...
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4answers
79 views
Do smaller transistors improve computational efficiency because they decrease the duration of signal transfer?
There has been a massive improvement of computational power of computers per $ over time. As far as I understand, this has been driven almost completely by the massive increase in transistors per ...
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2answers
158 views
How to efficiently read a battery voltage level with ADC
There is a circuit powered by a battery (3V button cell) and another circuit with a microcontroller (Attiny85 in my case) reading perfectly the battery level (through ADC3 pin) each 5 minutes interval....
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2answers
131 views
Class A Audio Amp - Improving Efficiency With A Mosfet CCS
I'm designing a class A audio amplifier but am struggling with the efficiency of my circuit.
I know of 'push-pull' Class A designs, but only want to use a single output mosfet.
I would like to hit a ...
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0answers
31 views
Astable multivibrator inverter
I'm new to electronics and trying to make an astable multivibrator oscillator. The PSpice simulation doesn't work (it says netlist error when I place a mosfet or a diode) and I get a really low ...
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1answer
102 views
What is the equation for mechanical efficiency of a 3 phase induction motor?
I know that mechanical efficiency is n= power output/power input, but I don't know how to find each of those. I have to find the efficiency at full load running speed.
I was only given mechanical ...
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2answers
65 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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1answer
94 views
Aluminum Electrolytic Capacitor - current, power, efficiency
How to find out the efficiency of an aluminum electrolytic capacitor like this one.
How to find out resistance of such a cap in order to calculate the time it takes for it to charge up or discharge?
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44 views
Determine efficiency, voltage, current from motor characteristic curves
I would to identify efficiency, voltage, current for a particular Brush less DC motor in our lab given characteristic curves.
Electrical specifications are
The operating conditions are
...
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2answers
135 views
How to measure DC motor (used as generator) efficiency using homebrew methods?
Background
I'll be making a "micro thermal power station" in the single-digit watt range at home (one-off, educational project. Bear with me).
A heat source, likely ethanol, will cause a stirling ...
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3answers
95 views
Which is more efficient: A much larger than needed step-down voltage converter, or one rated closer to the actual load?
I'm designing a custom audio system for my electric motorized pedicab. The motor of my cab runs on a 48 V 33 Ah battery, and I have planned to use a 48 V to 12 V step-down converter to simultaneously ...
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2answers
583 views
5V vs 12V addressable LED efficiency
Despite hours of googling, I could not come to clear understanding how efficiency of 5V addressable LEDs compare to their 12V counterparts.
If 5V is supplied to WS2812, and the red LED only needs 2....
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1answer
44 views
PWM phase voltage and current measurement for power consumption calculation for a BLDC MOTOR
I have been trying to log both voltage and current from the battery of an electric two wheeler for finding out efficiency at inverter, battery level.
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2answers
251 views
Relationship Between Number of Coil Turns in DC Motor and the Efficiency of Energy Retrieval From Regenerative Braking
When learning about regenerative braking, I began to ponder as to what the relationship between the number of turns in the coil of a DC motor is to the efficiency of kinetic energy retrieval from the ...
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2answers
103 views
electronically efficient breadboard wiring
I have checked stachexhange for my answer, but no luck. I hope I can be helped here.
I am building ben eater's 8-bit, and have a general question about wiring: Is it better (less impedance/resistance)...
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3answers
102 views
Are activated open-collector and open-drain circuits wasting energy?
Consider the following reference circuit for a 6N137 optocoupler. My understanding is that this circuit uses a pull-up resistor on the output node so when the optocoupler led is activated, the ...
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3answers
83 views
Why is power factor such a meaningful quantity?
In my current electrical engineering course the concept of power factor has been a large topic, defined as the ratio of real power to apparent power. It is a measure of resistive power consumption in ...
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2answers
81 views
How does the power efficiency of an appliance compare using 12V DC or 240V AC with an inverter?
With an off-grid system, if an appliance supports powering via both 12V DC and 240V AC, is there any difference with the power efficiency of either method excluding the draw of an inverter used to ...
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0answers
26 views
Display Design - would combining OLED with a white source be more efficient?
To be clear, I'm not an electrical engineer, nor do I claim complete knowledge of how displays work.
However, I have done research into displays (televisions, computer monitors, AMOLED phone screens)...
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1answer
34 views
led SMPS converter
Which type of converter is best for an LED light for getting better efficiency and high colour rendering index? We want to design a converter up to 80 Watts which gives indirect lighting and less ...
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3answers
72 views
Portable electronic musical instrument: energy from pressing keys, no batteries: feasible? [closed]
on one hand electronic musical instruments are very nice (lot of features: change tonality, change timbre, small number of mechanically breakable parts ), on the other hand they need external power ...
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2answers
31 views
Pros and cons of centralised vs decentralised power deliver for small devices
How does compare using one power supply for multiple devices vs each device having its own - regarding efficiency eg. power consumption?
Model situation:
Home automation using low power devices such ...
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2answers
219 views
Capacitor charging efficiency with a constant power source
I have a question. It is easy to derive the efficiency for loading a capacitor from a constant voltage or a constant current source, basically because exponential functions and constants are very, ...
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3answers
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Would I get a better lumen output and improved thermal characteristics for the same wattage if I get a higher rated LED? [closed]
I'm planning on building a bright DIY high CRI LED video/photo floodlight out of the following components and considerations:
High-power Neutral White (4000K?) LED rated at 95 CRI
No add-on lens so I ...
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2answers
152 views
Ohms law and LED driver efficiency? How can this possible be true?
I am having a meltdown with a Chinese supplier at the moment and hope dearly that someone can help.
I have an LED driver that is in my mind 28.8W. The output of the driver is 48 V @ 600 mA (48 V x 0....
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1answer
27 views
High energy efficiency through transformers
We are about to build a large facility, using lots of electricity. The facility is being built in module form, which are copies of one another.
We are unsure of whether the energy efficiency will be ...
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2answers
163 views
Do electric motors have the same efficiency when operating as generators?
Its in the title. I'm just curious and it turns out that either this is such a stupid question that no one has bothered to answer it, or i'm just not good at googling today. I guess I'm thinking ...
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5answers
9k views
How could have Banksy kept an RF receiver running for 12 years? [closed]
I'm talking about Banksy's "Girl with balloon" painting that shredded itself at auction.
I think the general consensus is that he didn't, and that it was set up before the auction (or a couple years ...
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0answers
77 views
Capacitive discharge excess being used for battery recharging
I am currently designing a circuit similar to a cattle prod that is intended to be attached to a drone. The cattle prod is powered by a lithium-ion battery, charging up a capacitor and then quickly ...
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1answer
50 views
Spice model search with advanced sorting functionality
Does anyone know of a search engine like Mouser/Digikey where you can narrow down parts based on voltage/package type/etc., but exclude all results without PSpice models? Unless I'm doing it all wrong,...
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1answer
79 views
Would it be energy efficient for phones to include actual GPS chip? [closed]
None of the smartphones today have dedicated GPS chips in them, they only have a GPS capability that stems from byproduct features of the modem chips. Because of that, the GPS capability is very ...
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2answers
77 views
Waste heat in battery pack - large pack vs small pack?
Are larger battery packs more efficient than smaller battery packs due to "resistance in parallel" rule, assuming eveything else being the same?
As an example let's consider two 48V battery packs - ...
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1answer
78 views
Dell power adapter does not get warm? [closed]
Usually I notice that power adapters get warm whether they are being used to power a device or not.
The rectangular Dell computer power adapters, however, do not seem to get warm unless they are ...
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1answer
498 views
MOSFET vs. relay power efficiency
Newbie question here. I am putting together a remote switching box for power circuits aboard a yacht. The design is for a central Raspberry pi to send orders to a few boxes, each controlling a number ...
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1answer
285 views
Confusing peltier efficiency COP/Volts and COP/Amps graphs question
Is peltier efficiency (COP) based on current and not voltage and could I have any voltage I want and get a high COP if I limit current?
Whats confusing is that one graph shows efficiency based on ...
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2answers
134 views
Smartphone internal charging circuit type and efficiency
USB usually provides 5V (or even more, for example 9V with Qualcomm Quickcharge) and the phones contain a single li-ion cell with 3.5-4.3V, so there must be some dc-dc converter in between.
I wonder ...
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3answers
79 views
Is there a Semisynchronous Buck Topology which mixes the advantages & disadvantages of both?
I was looking at "What is the purpose of using MOSFET instead of free-wheeling diode in Buck topology?" and the referenced PDF which discusses the trade-offs between a traditional asynchronous Buck ...
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5answers
381 views
Rated vs. actual power usage of a linear fluorescent lamp
After having some power issues, I've decided to investigate the largest power drains in our company, and I've arrived at a realization that 128 lights adds up to a lot of power (and that's not even ...
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1answer
77 views
Efficient electronics components [closed]
Imagine budget is not an issue and you are asked to design the most efficient circuit. With efficient, I mean that the power used to perform the functions is used solely for that and is not dissipated ...
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3answers
125 views
Will battery last longer with larger capacity but lower efficiency (high V through LDO) or vice versa?
Given a simple circuit of a draw around 28mA (when supplied 3.3v). I'm trying to maximize run time on a battery, but working with what I've got on hand... I have the following batteries:
5000mAh 3S ...
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3answers
984 views
Square wave to DC voltage with passive components
Good day,
I have a design challenge that I have been thinking about.
Is there a passive and inexpensive system that I can get a square wave (frequency not decided yet, but less than 8MHz) that will ...
0
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1answer
119 views
power efficiency's definition
Power Efficiency is defined as output power/input power, right?
And there are a little bit different definition of power efficiency ...output power/(output power+power loss).
Is these mean same ...
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2answers
92 views
Wireless power transfer efficiency calculation
So I'm looking into retrofitting a Qi transmit eval and receive eval kit with coils of a larger diameter than the stock ones, then looking at what playing with the separation will afford me for my ...
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3answers
288 views
How to estimate Li Ion Battery SOC?
In a simple model of a renewable energy system, I have a residential inverer and Lithium ion battery system with a round-trip efficiency (for inverter and battery, i.e. ac to ac) of 89% (at 25 degrees ...
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1answer
238 views
What is the most efficient 3-phase to single-phase AC transformer for a home grid
So a friend of mine is getting electrical power installed for an urban site he bought, and I'm just trying to be a good friend by looking into this.
The company doing the installation recommended he ...
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1answer
2k views
Laptop battery and adapter voltage ratings
Considering a 4-cell (laptop) lithium-ion battery, the cell voltages add (since they are in series) to 3.7 V * 4 = 14.8 V. However, the adapter says that it has a 19.5 V DC output. I want to know why ...
0
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1answer
44 views
Star rating of electrical appliances like AC / fridge
What distinguishes a 2-star rated AC/fridge from the one rated 5-star? What exactly is the technical reason for the difference in their efficiencies? Is it the compressor technology / the wiring / ...
