How Intel’s 9th Gen chips show the way forward after Moore’s Law | 220v Contactor Relay

If you insure that your HV and LV systems are completely separate, and joined only by UL registered galvanically isolating components, only then can you be prepared to say that the logic portion of your system is safe. And doing that maybe won’t make fewer things capable of going wrong, but at least fewer things capable of spectacularly dangerous failure.

It works, but the losses are significantly higher, and if you’re drawing much power you’re going to need heavy, expensive low-voltage sides on both transformers. In a pinch, fine, but if you’re going to be buying them it’s better to spring for a single transformer.

If you know the Wattage of the transformer and the input voltage of the oven then you can calculate the approximate current the primary (thicker wire) can carry. Example: 500W 220V gives 500 / 220 = 2.273 Amps. This is the current the coil is designed to carry, and this current should normally take the core close to saturation without generating too much heat. The coil resistance can be measured and an appropriate DC voltage applied. I suggest a current of around 1.5 times as long as the power is not ON permanently. Regarding the use of both coils, the secondary coil is much finer wire and will require a proportionately higher voltage. Assuming the output voltage to be 2500, then the current required will be 500 / 2500 or 0.2 A. The secondary coil has worse properties for dissipating heat, so I would only allow a 25% over current, but just try it and if it gets too hot to hold, reduce the voltage. Allow 20 minutes for the coil to cool between tests. Putting the coils in series, or in parallel does not make sense because they have such different characteristics: better to find two ovens with the same transformer and use both primary coils or both secondary coils, which can then be connected in series to raise the working voltage or in parallel to keep the voltage down but double the current. As someone has already said above, disconnecting the coil produces a spark, that in the secondary coil will be a very high voltage – use a totally enclosed switch rated at at least 250V 10 A, with a 100 Ohm resistor in series with a 0.1 microfarad capacitor across the coil to reduce the sparking and increase switch contact life.

Always pay attention to the safety warnings, and never underestimate the stupidity of anyone, most importantly your self.

This certainly looks like one of the more impressive ARM-powered Windows 10 laptops we’ve seen so far. The first few devices ran on the same Snapdragon 835 chip found in Android smartphones from last year, and they showed early promise with some issues that still needed work.

Many thermostats are battery-operated, and once they power down so will your air conditioner or heater. Check that your thermostat is fully operational and the connections to the wall are good.

Did your kitchen light stop working soon after the closet light? Did you change a light switch last month? Facts about recent electric changes in your home could lead me in the right direction, so it’s helpful if you can list them up front. (Don’t miss these 41 secrets home inspectors won’t tell you.)

It would work, you could try just one winding on its own to start with but beware the voltage surge you get when disconnecting the current, as a minimum it should make a nice spark, even with a small battery driving it, at its worst it is shocking(!) I think the reason for winding your own coils is to get the optimum ampere turns for a chosen voltage, if you use what the transformer comes with you will have to work out what voltage gets you the highest magnetic strength without burning out the winding.

I can’t remember the exact numbers, but before the change, UK mains voltage was acceptable between something like 210V and 270V, depending on grid load. EU mains had a similar range. All they did, was tighten up the range. So now it’s nominally 230V, with 240V being within acceptable range. Which is good because the voltage stayed exactly the same. They just trimmed the range at the top end to be within the EU standards.

One nice thing about the Sony A55 and A33′s electronic viewfinder is that the Fn menu is also available in the viewfinder display; you can make many camera settings without taking your eye from the viewfinder eyepiece. As I became more familiar with the camera’s controls, this led to a very efficient shooting style, although it would take more than the few days I’ve had with the camera thus far for this to become second nature.

I was tasked with doing this last week at work and spent considerable time researching the best/safest way to do it with consumer equipment. As far as I can see the best solution is to use one of the many 433MHz RF controlled power adapters (Watts Clever sell them for as little as $10 each) and use the same record/playback trick used to record TV remote IR signals and play them back with an Arduino. Unfortunately the project requirements changed and I didn’t get to actually implement it but I see no reason why it wouldn’t have worked. Apart from being very cheap (~20 per unit) it keeps the mains voltage completely isolated from everything else, which is particularly important from a liability perspective when you have to deliver the units to an external client.

The main issue would be shock protection. A bare PCB with solder mask probably won’t cut it for UL or CE. If you have vias in the element traces, it will probably be really dodgy. On a commercial product which you can’t (are not supposed to) open and tinker with, there is probably a way to do this easily. For a DIY printer, not so much.