OK. It's not that my system is all that matters, but it's all that I control, I would be upset if it were in my control to stop wasting electricity and I didn't. None of these factors apply to me, except maybe R-410a if that is the old stuff, and I'm pretty certain I don't have a crankcase heater.
I don't have a variable speed fan controller either. My outdoor fan has one speed, and my indoor fan has one of three speeds, set by connecting wires.
But I'll have to upgrade someday and now I'll know to turn my AC off at the breakers after that, for the 11 or 10 months a year I don't use it.
Sounds inexcusable
I'd like to better understand that and what Dave said. I once asked about the difference between volt-amps and watts and didn't get a real answer iirc. I haven't googled.
I'd never heard it until it appeared here (about a week ago?). If you have to have a term to describe such power supplies, it's quite a good one. However, it's just one more step down the road where words don't actually mean what they say (most of which seem to originate in the USA). Ian.
On some of these smaller power supplies there is no transformer at all! I.E. no primary and secondary. They do have an inductor that is used to step down the power and rely on a Thysistor (aka. electronic switch) to turn on an off very fast. Usually 60 times a second (ac mains frequency). The voltage regulation is dependent on the amount of time the switch is on during the power cycle.
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One nice thing about this is that they can adapt to many mains voltages and mains frequency. Hence for laptop computers you only need one "International" power brik like supply.
I had not heard of this usage regarding power consumption until this thread, however 'vampire tap' in electronic parlance refers to a piercing type of cable connector, most often a coaxial connector used in Ethernet 10base5 wiring.
...hmmm, I never cease to be amazed by the Brits' continual misuse of case in referring to companies (in usenet postings) in the plural instead of the singular, e.g. "Hewlett Packard have a new line of servers" instead of "Hewlett Packard has a new line of servers".
Hey! You are right about the 'vampire tap'.
I'm in the CATV industry, and I've just remembered that, many years ago, I did see reference to 'vampire taps' as being the latest and greatest for coaxial ethernet. That took me back to the early 1960s, when similar tap devices were manufactured in the UK (by Thorn, I think). I may still have one somewhere. Nasty things!
Re the British incorrect use of plurals when referring to companies (or, indeed, any group), yes, this is very common, eg the 'government are', 'the team are' etc. However, being grammatically correct does sometimes grate a little. Maybe the Americans are not totally to blame for this sad world we live in. But, of course, we always (correctly) say 'maths' (for mathematics).
I never hear the royal "we" but I'm often forced to hear reference to the football "we" all the time. As in "we were robbed" mouthed by people who haven't kicked a ball since they were kids.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
Dave: There is not really enough info/numbers in the original posted question to calculate; but here is an attempt.
Answer: Very little.
Here's an assumption. If it use 100 watts while lap-top charging it probably uses less than 10% of that while not charging. That is less than 10 watts. And 10 watts is probably a bit of an overestimation any way.
Any more than that the charger alone would get slightly warm all the time! Something like the amount of heat from one of those on-all-the time night lights which IIRC are often 7.5 watts.
10 watts for one hour is one, one hundredth of a kilowatt hour. Using my cost of electricity (yours may be more or less) of about 9 cents (all charges included) per kilowatt hour, it will cost about 0.09 cents for every hour that it is plugged in but not charging anything.
Make that say one tenth of a cent; in other words it will cost around
2 to 2.5 cents per 24 hour day that it is plugged in and not charging. Hardly worth bothering about?
A 100 watt light bulb left on for the same 24 hours would cost about
20 to 25 cents. Again depending on you electricity cost.
In regard to the cell phone charger.
You do not specify if the 0.2 amps is the input or the output. Assuming it is the input: Approx 120 x 0.2 = 24 watts. But again that would while charging. That's probably less than one quarter of what the laptop charger needs, cell phone is much smaller isn't it? While not charging; again it probably uses less than one cent per 24 hour day.
This sort of question by those who are ignorant of electricity, although the info. is usually on the label somewhere, and most of us 'did it in science class in school?"; reminds one of the little old lady who used to go round plugging up her electric outlets "To stop the electricity from leaking out"!
One item that doesn't seem to be realized with all this saving energy/ conservation business is that any lost heat from using less efficient devices helps heat the house. We live in a cool area of North America where every month of the year requires some heating, in our case electric heating. We don't need or use air conditioning at all. So the lost heat from much cheaper (about 25 cents each) non CFL light bulbs etc. merely reduces electric heating! Our bathroom, for example, is heated almost entirely by the six 40 watt bulbs above the vanity. Only in coldest winter does the 500 watt baseboard electric heater operate!
They were real low grade shit. They were replaced by backmatched taps when systems were extended past the original 12 channel systems in the US. They caused mismatch problems, and wasted a lot of the signal on the trunklines or feeders. They worked, more or less on systems with just a few channels, and very few customers, but them, those people were already used to ghosting and snow. They had all been pulled from the 17 systems around Ft Rucker by 1972, including a couple short haul feeds that only had a couple channels.
Equally bad on ethernet I expect? Also, does ethernet require them to be non-directional (ie just resistive tap-offs, with no directional coupler)? Ian.
England has loads of slang that the USA doesn't use. Most of which we've never heard. Ask about this on alt.english.usage and the English posters there can give you lots of stuff.
I think you are in the position I'm in in our respective countries, knowing few or no people who recent slang. Old slang doesn't capture our attention because we know what it means.
traditionally, transformers do use power even when their device is not on. There is loss in the field. But more modern electronic ones do not require anywhere near as much. Recent cell phones I think are electronic transformers. Those I tend to just leave plugged in, LED and all!!
To calculate watts, you take instantaneous measurements of voltage and current and multiply them together, then integrate (average) the result over some time period. You can do this in analog circuitry using an analog multiplier device, or you can do it digitally by making many measurements of voltage and current per cycle and multiplying them digitally before filtering. Either way, you need a special meter that measures and multiplies two quantities instant by instant.
To calculate volt-amps, you measure and integrate voltage and current separately, then multiply the two numbers together. This can be done with two independent ordinary multimeters.
If the load is resistive (e.g. an oven, baseboard heater, etc) there is no difference between watts and VA. The current is always in phase with the voltage, the product of the two is always positive, and the two different calculation methods give the same answer.
But that's not true of capacitive and inductive loads. In capacitive loads, the current waveform is up to 90 degrees in phase ahead of the voltage waveform (i.e. peak current happens as voltage passes through zero, where its rate of change is greatest). If the phase shift is exactly 90 degrees (pure capacitance), then for half of the cycle the sign of the current and voltage are actually different, and the product of the two is negative for that portion of the cycle. The same is true for inductive loads (e.g. transformer with no load on it, unloaded motor) except the current waveform lags the voltage one by up to 90 degrees.
Whenever there is a phase shift between current and voltage, the VA remains the same, but the watts measured are reduced. Effectively, for one portion of the AC cycle the circuit accepts power from the utility, and for another portion of the cycle it feeds some of that power back to the utility. If the phase shift is a full 90 degrees (either ahead or behind), the net power is zero!
Both measures are important. Watts is the amount of actual power consumed by your device and converted into heat, light, or mechanical motion. Voltage determines the amount of insulation needed on wires and the number of turns of wire in a transformer, while amps determine the size of wire needed to carry the current and the resistive losses in that wire resulting from current flow.
So VA is generally the right measure to use when sizing transformers and wiring, not watts.
For anyone connected to the North American power grid. On the other hand, it might be worth unplugging for off-grid people who generate their electricity by solar panels or windmill and store it in batteries, since their per-kwh cost is likely to be many times higher.
Ethernet required a direct connection to the conductor of the cable, if I remember correctly. The receiver side was high impedance, so it didn't present a significant load to the signal, and the vampire tap was designed to create only a small hole through the shield and inner dielectric so it wouldn't produce much of an impedance bump. Plus the cable was marked with rings to indicate where you could put a tap without having multiple taps end up a multiple of a wavelength apart.
When transmitting, an Ethernet transceiver acted as a current source, putting a fair bit of current into the 25 ohm load (50 ohm cable heading off in each of 2 directions). If two transceivers decided to transmit at the same time, the high DC level on the cable was used to detect a collision.
Original Ethernet used a baseband signal, and on a moderate-sized network every station listened to every other one directly. There's no "head end" to echo upstream signals back downstream again. There's no notion of "upstream" and "downstream".
Here, they were called "Stinger taps" and I had an unused tap block and stinger, along with the strand clamp and drop hook in my toolbox, until at least 2001. It might still be around, but I haven't used that toolbox in so many years that i don't remember. I brought it home the day i was laid off, then I was declared disabled, and unable to work, so it has been under one of my benches here at home, ever since.
Actually, there are two types of coaxial networking that used 75 ohm cable. The simple, small network like Dave describes below witch were non directional, and one that is usually part of a community loop where pairs of one forward channel, and one return channel are used for data, with a heterodyne signal processor at the headend to upconvert the return channel to a forward channel witch is built with back matched taps.
This system predates the current cable modems, but used standard, off the shelf CATV components to build a private WAN along with the RF modems. Some were mixed systems, of RF fed to clusters of the simpler coaxial networking. The first system like that I heard about was the Ohio State University campus in the '70s or early '80s. Their private CATV system connected all the buildings, then tied the existing, smaller networks together. I met two of their IT people at a hamfest, and they were bragging about their design, till I told them about the systems I maintained for the US army, years earlier. There was no return channel equipment on the market, so we had a pair of 12 channel 'Vicoa' (Later called Coral) systems set up as forward and return to carry the weather data from an airfield to the main base where it added to the other nine forward channels that fed the classrooms and airfield ready rooms.
We also built the first emergency alert system into a CATV system that took control of the civilian CATV service to the barracks and on base housing. A custom made coaxial relay was added to the existing system to seize control of the private system. The ETV studio was 12 channel, like the civilian system. A toggle switch (with a hinged cover and a lead seal) would feed the same audio and video to all 12 modulators, and switch the remote relay so an alert could be spread, no matter what channel a TV was on. After we proved the concept, it quickly spread to other bases, and new builds of civilian systems. The last system I maintained was a 36 channel RCA headend, in the early '80s. It had the optional IF loop through and auxiliary IF input for the alert system. The Audio and video was fed through a separate modulator with a IF output amp, instead of a channel module. I rewired the rack by strapping the loss of signal output to the relay control, and connected diodes to isolate each channel from the emergency control system. I also looped the emergency video through the local access control room so I could flip one switch and feed the same signal to all
36 channels in an emergency.
The loss of signal mod caused a message to appear a half second after the carrier dropped out from a TV station, or satellite feed. That let the tech on night shift check the alignment of the converters after stations signed off, at night.
(Snipped because I found it less-relevant-than-I-expected to the subject line)
I was expecting to see stuff about power consumption by "wall warts".
Those have been called "vampires" by being 2-pronged/"fanged" constant consumers of small amounts of electrical energy that can become somewhat significant in terms of electrical energy consumption if one has several being powered 24/7, though this is well behind a refrigerator and behind most climte control and lighting electricity demand.
I do believe that there should be some "energy efficiency" requirements of those. I find many "switchmode" cell phone chargers to do well in that area, as I estimate from their heat output when loaded (mostly somewhat less than that of wallwarts" with iron core physical transformers) and when unloaded or largely-unloaded (they become outright cool to the touch when being connected to a cellphone that has detected that its battery got fully charged).
I also see many "wallwarts" with more-traditional iron core transformers easily consuming a watt or two less apiece if they get made with heavier gauge wire, more turns of wire per unit area of wound-around-core-cross-section, and/or thinner core material laminations preferably of some decent material - preferably "29M6" or only one or two minor steps cheaper than that. Maybe requiring next larger size (usually step up in most-traditional inch measurements for an "E-I" transformer core has longest dimension upped 5/16 inch, another upped 1/4 inch and the third upped 1/8 inch, and there are often some options to more mildly increase only the "stack thickness" of a laminated core by 1/8 inch that will even alone fairly often do well).
That may explain why they haven't become known as 'vampires' in the UK. Everything which plugs into a wall socket has to have THREE pins. The live and neutral receptacles have safety shutters, which are moved aside as the ground pin (which is somewhat longer) enters. Even in the UK, no self-respecting vampire would use three teeth. Ian.
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