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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3answers
33 views

Which low pass frequency filter to configure to measure/calculate DC-DC converter efficiency?

I am measuring the DC-DC converter active power (P in watts) efficiency of a TI (Webench) LM3150 PCB that converts 12 to 5VDC. In the answer of question Measuring precisely the efficiency of a power ...
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0answers
45 views

How does temperature affect the performance of an SMPS?

I have an SMPS (laptop AC adapter) rated for 180 W that is presently operating at capacity. The output seems to be limited by internal resistance, but I can't really tell. I'm trying to get it ...
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3answers
91 views

“Efficiency” of Switching Power Supplies and Theoretical Energy Loss

I have heard that switching power supplies that convert, say, 110 VAC to 12 VDC, are very efficient. I understand that the power transistor that is regulating voltage is either on or off and spends ...
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1answer
46 views

Rechargeable battery configuration for 5V

I have 6x 18650 (3.7v) cells. I'm trying to build basic power-bank and wondering what battery configuration would be better for minimizing power loss in voltage regulation/conversion process? Edit: ...
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2answers
29 views

Stepping-down DC voltage (at low current) in the presence of an audio circuit

I'm trying to add a bluetooth audio receiver to an old 12V battery-powered boombox. The receiver board takes 5V and shouldn't draw much current, but I'm trying to understand which type of DC-DC ...
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0answers
67 views

What is the charge-discharge (Wh) efficiency for lead acid batteries at different SoC and charge current 10-35A/100Ah C10?

There is a 1996 Sandia study with the title "A study of lead-acid battery efficiency near top-of-charge and the impact on PV system design" for charge and discharge lead-acid battery efficiency at ...
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1answer
69 views

Wide input voltage range buck converter/circuit to 3.3V 150mA

I am building an appliance that should work in very wide range input voltage: In some scenarios input is 5VAC, in other scenarios it can be 250VAC. It's not a problem to convert AC to DC, then ...
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0answers
64 views

PWM Chopping current and Decay Modes of motor drivers

This is my first experience with driving stepper motors, so please bear with me. I was looking again through the datasheet of the stepper driver DRV8811 and came across calculations that needed to be ...
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1answer
100 views

Using diodes to increase efficiency

So I have the schematic below and I am to insert diodes into the circuit to increase the efficiency of the circuit (can only insert diodes, not change the wiring). 'Target' is where I want the power ...
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1answer
209 views

DC 5V USB to replace AAA-battery source: down converter

I have a portable lithium battery-powered speaker which takes auxiliary sound input from a single AAA-battery powered pocket radio. The speaker includes a USB port for charging source devices: I ...
2
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1answer
74 views

Inherent exploitability and power state machines

I'm working on understanding power state machines in regard to mobile computing devices. Most of the information on this subject seems to stem from this article. It's not particularly important to the ...
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1answer
43 views

Using distribution transformers vs direct connection to primary switch gear

I am trying to learn more about transformers and low voltage electrical distribution. Say you have a medium sized industrial building with a primary switchboard feeding several load centers ...
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1answer
177 views

How to calculate a circuits efficiency with the help of LTspice

Note that this is not a question for circuit critique (and lots of things could be said about this circuit) but this circuit is only the base for the discussion of further points. Here it is (an ...
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4answers
487 views

Does a 1 watt 660nm LED put out more radiant flux than a 1 watt 630nm LED?

Given two LED chips consuming same or very similar amounts of DC power, One emitting light peaking at 630nm, The other at 660nm, In terms of output of (but light irrelevant to the sensitivity of ...
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1answer
99 views

Looking for an efficient audio amp circuit

It seems like all the circuits that I find are using outdated and inefficient technology that requires massive heat-sinks at anything beyond headphone levels. Is there any particular reason that there ...
0
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1answer
93 views

Comparison of the efficiency of DC motor current limiting / control methods?

I'm using the wheels and motors of an RC toy car as a simple robotics platform. The car has 2 motors, one drives the back wheels, the other steers the front wheels. The steering motor is stalled by ...
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1answer
88 views

Difference between spectral efficiency and bit rate

I am reading articles about error correcting codes, facing to a term "spectral efficiency". Due to the context, I guessed that it means "bit rate", but I wonder are these two terms equivalent or not? ...
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2answers
201 views

Low voltage cut out switching for a 6v input SLA to 5v output circuitry - or alternative ideas

I am currently modifying a wireless video door phone system with remote door release system, for use with a walking frame, for my elderly mother in-law, who lives alone. The 7"monitor runs a 5v 1a DC ...
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3answers
506 views

What causes old power supplies to start humming?

I have a number of mains-powered devices that have begun humming (I assume at 50Hz, though I haven't measured it). These include clock radios, a speaker system, a lamp (20W halogen with a transformer ...
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1answer
133 views

Real world efficiency of a LM3150 Webench DC power supply design?

When designing a DC/DC step down converter with TI Webench with these parameters: Vin min: 11.4 V Vin max: 12.6 V Output : 5.0 V Iout : 8.0 A Ambient temp: 30 ºC Then turn the efficiency knob ...
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0answers
59 views

Analyse data discrepancies: Efficiency of wire vs current

Please help me explain why the efficiency of the wire does not follow a distinct path (ie R^2 value is low). Graph 1 Efficiency of wire vs current: http://postimg.org/image/p49bzm4ab/ Is is to do ...
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1answer
165 views

Topology for a DC-DC step up converter for a single AA battery with 50V 10mA output

I need to design a very compact step up DC-DC converter for the single AA battery (input voltage 0.7-1-5V) with an output of 50V 10mA. The load should drain in a typical case about 2mA, but in certain ...
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1answer
617 views

Power calculation of a transformer using only current and resistance

If I use \$P = I^2R \$ for primary and secondary will that tell me the effective power being dissipated? Uf I divide secondary power by primary power and multiply by 100%, would that tell me the ...
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6answers
1k views

Why is electric heating so expensive? [closed]

The loss of electricity in transmission and distribution is only 6%, so why is it that electric heating is so inefficient? I would imagine that the generators at power plants are far more efficient ...
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1answer
162 views

Most lumens per watt

I recently started designing a pcb for flashing lights I want to use in a pavillon at festivals, garden parties and the like. Now my question is, can anyone tell me which kind of LED that has the ...
3
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1answer
73 views

Measuring precisely the efficiency of a power converter

I am trying to measure the efficiency of a DC/DC boost-converter in several operating points as precisely as possible. Right now I am measuring my input-voltage and output-voltage with a multimeter, ...
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0answers
413 views

Dual active bridge converter

I'm having issues calculating the power losses associated with the operation of a bidirectional isolated Dual Active Bridge DC/DC converter. The converter is controlled using Phase Shift Modulation ...
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3answers
512 views

More Energy Efficient 1 or 0

Is it more energy efficient to have active high or active low pins (I'm thinking shutdown, reset, active type of pins)? Pins that one would not expect to change very often so they will be in one state ...
0
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1answer
140 views

Measuring the efficiency/acoustic power of a transducer

I was wondering what was the best and the simplest way of measuring the efficiency of a transducer. Finding the output acoustic power in respect to the electrical input power under a water medium.
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1answer
621 views

How efficient is wireless electricity compared to wired electricity?

I am looking for data showing practical data/information on the efficiency of wireless (induction) transfer of electricity vs. wired transfer. There is some information out there but the source makes ...
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2answers
2k views

Calculating Efficiency of a circuit

I made a boost converter, and now I want to calculate the efficiency of my circuit. I know the formula to calculate the efficiency which is given by \$ Eff = \frac{P_{Output}}{ P_{input}} \cdot ...
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2answers
66 views

Efficiency of a multi-output power supply

I purchased a device labelled "AC Adapter" that labels the input to be 110 to 240 VAC, 50/60 Hz, 1.5A max and the output is labelled as 12, 15, 16, 18, or 19 volts, DC, 4.5A max or 20 or 24 volts, DC, ...
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1answer
317 views

Aluminum winding in inverters

I am planning to buy inverter. I finalized one model; however, I was told that it uses aluminum windings whereas the other model has copper windings. They recomended I should buy the one with copper ...
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5answers
485 views

Are opamps as a voltage regulator effcient?

If I setup an opamp in a non-inverting configuration as follows: Vrail+ is 7.5V, Vrail- is GND (0 V) Vin is 2.5V, Vout = 3.3V (in other words, the gain, aka, 1+R2/R1 is 1.32 [V/V]) Iout = 100mA ...
5
votes
1answer
127 views

How do I calculate the hysteresis losses of a straight line inductor?

In using a particular type of conductor for an antenna in AC frequencies between 3MHz and 30MHz (HF), it was suggested that magnetic hysteresis losses may be significant if the permeability of the ...
3
votes
1answer
686 views

What makes automotive alternators so inneficient relative to other applications?

Automotive and some marine alternators typically have an efficiency curve with a peak of 60%. Image from http://www.intechopen.com Whereas alternators to other types of applications reach 96% of ...
3
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2answers
1k views

Why are ARM9 and ARM11 processors still used when the Cortex-A5 is more efficient? [closed]

Many consumer devices that require a low-power processor capable of running for several days to a few weeks on a charge still use ARM9 or ARM11 processors. However, the ARM Cortex-A5 is more powerful ...
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4answers
2k views

Calculating Input power from a source

How can I calculate what the current "I" output can i have for determining my Efficiency. I am building a simple linear regulator and is it possible to know during design of the circuit , what the ...
2
votes
1answer
249 views

Is there a rectifier scheme for tri-phase which is more efficient than the bridge rectifier?

Because of the topology of tri-phase bridge rectifier, every phase is active (i.e.; feeding the load) only for 33% of the time. It feels like we are not fully utilizing all the three phases, and ...
0
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1answer
574 views

What type of pumps are most energy efficient to lift 200 liters of water over 15 feet?

Trying to design a rain-water harvesting system for our home. A long-term goal for me is to go "off-grid", or reduce dependency on grid-power, as much as possible. My need is to evacuate about 200 ...
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3answers
207 views

Efficient power supply for embedded project

I'm working on wireless sensor network project consisting of sensors based on ATmega328 and MRF24J40MA. The sensor is expected to stay asleep most of the time, waking up on regular intervals to ...
0
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3answers
136 views

Getting started with electronics with minimal space?

I've wanted to get started working with breadboards and basic circuits, but I have very little space with which to work or to store any tools. The largest contiguous surface I have is a weak 2ft by ...
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2answers
154 views

Efficiency of different solar panels

How can I work out the efficiency of two different solar panels (12V and 24V, and both of different makes i.e. different efficiency each one) connected in series?
2
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2answers
664 views

Why do some Integrated Circuits get so hot?

I was reading an article about Radeon 6990 recently and it was recommending 1200 Watts of power supply and the entire machine to be kept dipped in mineral oil because air cooling would kill it in a ...
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1answer
501 views

Efficiency of a SMPS

I will like to understand the term efficiency in a SMPS design. Is there a way to determine the best efficiency for a particular design?
2
votes
3answers
951 views

DC Motor Efficiency at Fixed Torque

I am in a muddle here, so thanks for making the effort to have a read. I understand that electrical power going into motor is given by: \$P_e=I^2R\$ I understand that mechanical power out is given ...
29
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2answers
799 views

If we could start our electrical grid from scratch with today's technology, which would be the most efficient choice? AC or DC?

Lately, I’ve been reading about the many advantages of HVDC transmission systems for long distance transmission, undersea links, and others. The historical reason of why AC was picked over DC was ...
2
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2answers
1k views

Energy-efficient LED driver circuit

I want to light a normal LED for as long as possible on two AA or AAA batteries. It does not have to blink or so, just stay on. The LED doesn't have to light at the max, as long as it's visible from ...
5
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3answers
163 views

Performance analysis of embedded firmware

I'm working on a project where I want to make the software the most power efficient it can be on the system. What ways can I do performance analysis of my system? I'd like to run the system off AAA ...
4
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1answer
1k views

AVR assembly: Most fastest way to increment two combined bytes

What could be the fastest way to increment two combined bytes in assembler (assuming I'm working on a 8-bit CPU)? Currently I'm doing this: ...