The ratio of output power to input power

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1answer
56 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
342 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 ...
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1answer
78 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 ...
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0answers
48 views

Do I need an antenna analyzer to make a good aerial?

I assemble a low-power FM transmitter (100MHz carrier wave) with a whip antenna. Can I get a reasonable efficiency using only EZNEC-like soft or do I need an antenna analyzer? By reasonable ...
3
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1answer
126 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 ...
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2answers
464 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
131 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 ...
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1answer
130 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 ...
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1answer
232 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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2answers
131 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 ...
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3answers
117 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
127 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?
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2answers
293 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
113 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?
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3answers
289 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 ...
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2answers
705 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 ...
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2answers
504 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 ...
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3answers
156 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 ...
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1answer
499 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: ...
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1answer
123 views

How can I reduce the power consumed with wall warts?

I have been designing a project that requires a 5V for some components and 12V for others. I am planning to leave this plugged in 24/7 so I want it pretty efficient. I know they don't waste that much ...
2
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1answer
163 views

Why do solar cells have very low efficiency?

Recently I came across a news posting about solar cells (the link is given below). http://cleantechnica.com/2013/01/22/new-thin-film-solar-cell-efficiency-record-set-20-4/ It says that "A new ...
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3answers
524 views

Can a charge-pump be 100% efficient, given ideal components?

A recent question about cyclically charging a capacitor reminded me of something I read once. As I remember, it demonstrated that it's impossible to construct a charge pump that is 100% efficient with ...
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1answer
851 views

A basic buck converter circuit to power 3W LEDs from PC power supply?

I'm just finishing up my first electronics course (edx.org), and I want to build some LED grow lights for starting seedlings in the winter. I have high power LEDs, like this one here, and I have a PC ...
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1answer
135 views

How can I reduce power consumption of my device? [closed]

What are some proven and effective ways to reduce overall power consumption of a given circuit? Things like: Choose efficient, modern components; Use high-efficiency components over ...
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3answers
648 views

Step voltage up or step voltage down when using batteries?

When using batteries to drive a load via a voltage regulator, is it better to step the voltage up from two batteries in parallel, or step the voltage down from two batteries in series? If there is no ...
2
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1answer
170 views

How will transformer efficiency change if the transformer is connected backwards?

Suppose I have a transformer designed to convert 220 volts into 5 volts and when it works in this mode being 95% loaded its efficiency is 97%. Now I connect the secondary winding to a 5 volts power ...
2
votes
1answer
488 views

AC-mains capable SSR (Solid State Relay) with very low leakage current?

Requirements: Can switch 230VAC Can switch at least 0.5A (i.e. ol' good 100W incandescent lamp) Wastes no more than 3mW in off state Low-on resistance is always good too The stated power usage ...
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1answer
300 views

Practical efficiencies of available solar cells

I had a completed answer to this but when I went to post it it was closed, so : I understand that "multijunction" cells, particular those made from Copper Indium Gallium diSelenide, are the most ...
4
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4answers
912 views

Efficient low-power buck (step-down) regulator IC for Li-Ion - 3.3V conversion?

It's not easy for electronics novice to find good element base, so I hope this suitable question. Requirement: Efficiently power a lean, 3.3V-based MCU design from a Li-Ion battery. "Efficient" ...
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1answer
211 views

What is the energy efficiency between FM radio tower broadcasting over an area vs point to point streaming via Internet?

Doing some research, it seems that an FM radio tower in a densely popoulated area can maximally transmit about 50kW of power. If you assume a certain amount of people tuning into the station, is that ...
5
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3answers
4k views

How to drive high powered LEDs as efficiently as possible

I have come across some very high powered LEDs. Datasheet for LEDs http://www.cree.com/led-components-and-modules/products/xlamp/arrays-nondirectional/xlamp-cxa2011 My question is: for these high ...
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1answer
411 views

How to Increase RF Amplifier Efficiency?

I've inherited another engineer's RF design and I would like to increase the transmitter efficiency. It's a 406 MHz radio that is using 14W to send out 5W (36%). The amplifier in use is ...
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1answer
402 views

Effect of oxidation on solar cell bus-bars

Does oxidation of bus-bars have a major effect on the performance of the solar cells? I've been trying to find some answers but no outcome yet.
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3answers
905 views

Most efficient way to achieve 3.6V or less from NiMH or Li-Ion batteries (when fully charged)

I have a micro and RF module both which I'd like to power from either 3 AA NiMH cells or a single 18650 Li-ion cell. Haven't decided which I'll use yet. My current requirements aren't that much (~2mA ...
4
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2answers
446 views

What efficient techniques exist for rectifying high voltage?

I want to rectify 120V (mains North America) at a relatively high amount of current (5 amps), so naturally my first idea is to just find a bridge rectifier. After finding one capable of the current ...
6
votes
5answers
787 views

Determine efficiency of converter

I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method. I ...
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1answer
4k views

How does the efficiency of a transformer change with it's load?

How does the efficiency of a transformer change when the load changes, and why is that so?
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3answers
2k views

How to efficiently charge a capacitor from AC source

I want to charge a capacitor at 200V DC from a 220V AC power supply (peak voltage = 311 V). Also I want no power disipation once it reaches full charge. This goes inside an equipment that discharges ...
5
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2answers
4k views

Efficient low power regulation? i.e. 9 -> 5 Volts

For the sake providing as much current as possible to a small circuit, regulated down from ~9V to 5V (or 5V->1.5V), I have looked at some possible options. What I was originally going to do (maybe a ...
3
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5answers
327 views

Efficiency of a power supply

I need some info on efficiency of power supplies. Imagin a power supply with 91% efficiency that can provide a maximum of 800watts. Does the rated 91% efficeincy is for all loads that going out from ...
2
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2answers
138 views

Multiple power supplies of different current ratings for efficiency

I've got a 30V 2A isolated DC/DC supply. I need to be capable of outputting 1A for short periods of time (3 sec, exception condition only), so with temperature derating that's what I picked. However, ...
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4answers
2k views

Gate capacitance vs. Gate charge in n-ch FETs, and how to calculate power dissipation during charging/discharging of the gate

I am using a MOSFET driver (TC4427A), which can charge a 1nF gate capacitance in about 30ns. The dual N-ch MOSFET I am using (Si4946EY) has a gate charge of 30nC (max) per fet. I am only considering ...
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3answers
598 views

Process Size and Power Consumption

So to the background of my question, there has been a rumor around that Apple might use Intel's fab to manufacture their A4 or A5 chips as they no longer source them from Samsung. The article then ...
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1answer
544 views

Driving a high-power LED at very low levels *efficiently*

So, I have these garden lights powered by solar cells. I also happen to have a power-LED over from a broken flashlight, I think its a Cree R2 or Q5 or similar. These lights charge a 1.5V 600mah Nimh ...
4
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4answers
5k views

which kinds of electrical equipment need a pure sine wave inverter to work correctly?

I am planning to purchase a good inverter, and pure sine wave inverters cost about 3 times as much as modified sine wave ones of the same power. I am thinking about a 2000W continuous/4000W peak ...