I suspect that (re. the fusion issue) the generations of domesticated and emasculated academics wont ever be able to face the truth objectively, and pile into the one, best way of achieving success with fusion. They would far rather stick in their own little pure-theory cul-de-sacs.

Perhaps there is a role for hard-bitten capitalists who take no prisoners and can bang heads together.
Unfortunately there is no-one in the UK financial elite who has the imagination or bottle to do it.

20 years of hurt coming up.

Modern circuit boards contain very small, densely packed components. Some integrated circuits (microchips) contain millions of transistors, switching millions of times a second. If you attempted to power such a densely packed circuit with 12Vdc it would overheat and destroy itself. For this reason, the most complex integrated circuits (some with more than 1000 pins) are powered from just 1.2V.

Another reason for using lower voltages is electromagnetic emissions. When circuits are switching at MHz or even GHz frequencies it is best to do this at a low voltage; otherwise your electronic circuit becomes a radio transmitter that could potentially interfere with other equipment.

Thanks IanG for a very clear summary of voltage conversion.

My company designs electronic products, including switch-mode power supplies, so we are one of those parties guilty of using so many different voltages.

When we design an electronic product the voltages we select depend on a number of factors:

1) minimising the number of power circuits.
2) reducing heat.
3) compatibility with peripheral equipment.
4) compatibility with existing battery chemistry (if a battery powered product).

Most digital logic is now 3.3V; however, many complex processors and logic devices use 1.8V at their core to keep heat to a minimum amongst very densely packed transistors. A 5V rail may still be used for analogue circuits (and USB), but is becoming rarer. A 12V or 24V rail is typically used for high power components such as stepper motors, valves and display backlights.

To convert from mains to say 1.8V in a single step is very difficult to achieve with high efficiency; therefore it is better to step the mains down to say 12Vdc using a fast switch-mode (SMPS) regulator, then use further SMPS or linear regulators to obtain the lower voltages.

Regarding Cyan's comments, he is correct in stating that the mains voltage has been selected because it is distributed over long distances. Localised distribution transformers could be used to supply most electronic products at a lower voltage. There could be a second power line to houses for equipment that can work on the lower voltage; however, I think appliances such as cookers and showers are best served with a high voltage.

1. Transformers can only be used with AC supplies and the mains in the UK has a frequency of 50Hz. This is not ideal for the materials used in transformers which tend to be iron – hence the weight.

2. Transformers are used to step up or down the voltage by virture of the ratio between primary and secondary windings. You still end up with AC which in general is no use for electronic circuits which need DC to operate.

3. The next stage is converting AC to DC. This is where the inefficiences arrise. For anything above a few watts you need to go to a switched mode PSU.

4. Switched mode PSUs as I recall turn the mains straight into DC, then a high frequency (several thousand Hz) switcher turns it into AC. This is then put through a much more efficient transformer made from ferrite metial which is smaller and lighter and more efficient. The output is at the desired voltage and with some fairly complex feedback loops you end up with a a steady DC and only a few percent efficiency loss.

5. Different voltages? The circuit designers will optimise their designs and I guess they all make different trade-offs. So we end up with different voltages. Digital logic traditionally used 5 volts but I think 3.3 volts is more common now? Analogue circuits have components optimised fr distortion say in an audio amplifier.

This is all old knowledge and I accept may well have changed by now.

You did ask….:/

Changing life-styles and reducing energy consumption are, I agree, the measures we can and should take immediately. They could make such a huge difference.

The discussion which so annoyed Cyan, was not meant to replace ideas of consumption reduction at all. Norr to advocate a high-tech-will-save-us outlook.

It was meant to bring in to our discussions other parts of a broad consideration of how we could run a better society. I hope any society we build will have space in it for science and forward thinking.

ANYWAY, I have a question.

I was really interested in what Cyan said about different an unecessary transformers n consumer goods. Could anyone here say more? Maybe Cyan if he's still talking to us?

Is there really no intrinsic need for the different voltages? If it really is simply laziness that different components use different voltages, then it seems to me another example of the failure of the market to do anything helpful. But before I feed this morcel to my prejudices I wanted to know a bit more.

I am NOT knowledgeable about electronics.

Just thought I'd recommend Richard Heinberg's work which certainly gave me a few things to worry about when I read The Party's Over a few years ago.

If we are at or near the peak of oil production and we need to continue producing more and more energy then something is going to give quite soon. His book basically focuses on the fact that we're far too late with developing other technologies.

I agree with other comments supporting reduction of consumption now. Unfortunately, unless humans are forced, they will consume until there's nothing left.

But I have never advocated doing nothing. I clearly said I suport the practical, known solutions. The solutions based on social change and usingless or using what we have more wisely.

But in what testament does it say such things preclude research for the new?

My point form the start has been to say we should not waste our resources on saving the wealthy owners of banks from their greed and folly, while starving research into things that might help us all.

Is that such a bad thing to argue for?

If you hate fusion and are convinced it is folly, fine. Why blow a fuse? This isn't a fusion web site. Soon I shall write about the need to support Stem Cell research. Maybe you'll hate that too. Or maybe you won't.

I could also write about the simple solution of requiring building regs to be brought up to zero carbon emmission standards and using a government subsidy to help keep the prices affordable for the buyer.

Stay and participate if you can. If you can't. Then good luck to you.

You don't need to withdraw. Not on my account anyway. The others can speak for themselves.

By all means be forceful. Impolite isn't necessary.

Perhaps someone "…dreams future of limitless energy.." But it's not me. Neither am I trying to imagine some perpetual motion machine. Nor am I unaware of the laws of the conservation of energy.

Nor have I anywhere in this discussion nor anywhere else for that matter, said we shouldn't do the practical, low tech, known and simple things that, as you say, would go a long way to solving many of today's problems.

I am not trying to shout you down. But you do seem to be trying to shout others down. Is it necessary? This isn't Wired Magazine. This isn't a 'technonology will solve all our problems' blog. No one here, I don't think, believes in utopia's or technological or otherwise. References to perpetual motion machines are silly and so are misplaced claims that someone is dreaming of limitless energy. "We dream…"? Who's we? Someone may be. It's not me.

I'm not saying you are "too conservative" nor "not open minded". I am saying you seem slightly authoritarian.

The central premise of your reply, I think, correct me if I have mis-read you, is that, –

"Dreams of what new technologies 'might' do in thirty years, are a distraction from the raw practical problems of peoples lives now. I would rather we do what we know works first. Hope more often prevents progress than aids it."

Why is it either/or for you? Why can't we do what we know now, I am in favour of all you mentioned, and pursue new ideas? What is the problem?

Every technology was thirty years ago once. Penicillin was. So was the printing press and so was the transistor. But your charge is that they were a dsitraction from the "raw practical of people's lives now." Were they really? If they weren't then, how are you so sure today's technologicl and scientific drams might not have some benefits?

The practical and immediate problem in my grandmother's life, which brought her to a few breaths of death while being operated on, on her kitchen table in a mining village before WWII was that, at the time, the NHS was thirty years away. But someone had a dream. A damn good one.

The problem you raise is, to condense the above quote is that, "Dreams…are a distraction…."

No they aren't. Not even scientific ones. Dreams are what make people believe they can be better, can do better, can create a better world than those before them were sure was practical. Hope does not prevetn anything. It is AN essential ingredient.

My best friend was a practical man who spent his working life putting in sewers and clean water for those who hadn't any. He solved practical problems with known technology. But what drove him on was the dream, the hope, that what he was doing was building a better world. At his death he felt he had been cheated. He had worked for a better world and the bankers of this world had perpetuated all the inequalities and poverty of the old world. The used the known and the true and the tried and trampled on my firend's dreams. It helped to kill him.

If your future has no room in it for dreams and those who dream them, it will be a dreary and chilling place.