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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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19 views

Efficiency Test of Permanent Magnet (PM) Motor With Variac&Fixed Resistance

We have a 3-phase permanent magnet motor and want to test its efficiency in generator mode. We can give a mechanical input power with an external motor (torque meter and tachometer installed) and we ...
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1answer
31 views

Understanding of torque constant and efficiency of a permanent magnet motor from datasheet

I am trying to understand the efficiency of the following permanent magnet synchronous motor Motor Datasheet (note we are using the medium voltage model), and its relationship with the input voltages ...
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2answers
98 views

Running an electric motor beyond its ratings

I ordered a 36V 500W brushed DC motor but unfortunately a 24V one came. I'm faced with the dilemma of returning it and waiting for a month before getting a refund, then ordering a new one and waiting ...
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1answer
47 views

Are there any modern tradeoffs that come with designing more efficient DC-DC switching power converters?

Are there common metrics that usually degrade (ex. ramp time, line/load regulation, low-load efficiency) when pursuing more efficient designs, especially for isolated converters? If you saw a new ...
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1answer
50 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
290 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
78 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
82 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
164 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
184 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
36 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
105 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
69 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
100 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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2answers
47 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
211 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
99 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
947 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
58 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
463 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
112 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
122 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
85 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
96 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
28 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
39 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
253 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
105 views

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
188 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
79 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
52 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
81 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
79 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
632 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
341 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
164 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
81 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
428 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
78 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
133 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
1k 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 ...
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1answer
131 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
109 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
314 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 ...