The efficiency tag has no wiki summary.
26
votes
2answers
406 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
votes
2answers
109 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 ...
3
votes
2answers
110 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
votes
1answer
95 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:
...
0
votes
1answer
83 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
votes
1answer
124 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 ...
6
votes
3answers
243 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 ...
1
vote
1answer
475 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 ...
1
vote
1answer
108 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 ...
7
votes
3answers
272 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
votes
1answer
111 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
301 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 ...
5
votes
1answer
206 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
votes
4answers
474 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" ...
3
votes
1answer
145 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
votes
3answers
2k 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 ...
0
votes
1answer
301 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 ...
1
vote
1answer
255 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.
2
votes
3answers
620 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 ...
3
votes
2answers
309 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 ...
5
votes
5answers
640 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 ...
3
votes
1answer
2k 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?
Thanks in advance.
1
vote
3answers
921 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
votes
2answers
2k 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
votes
5answers
276 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
votes
2answers
121 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, ...
8
votes
4answers
1k 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 ...
5
votes
3answers
319 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 ...
3
votes
1answer
420 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
votes
4answers
3k 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 ...
