Nokia’s banana phone from The Matrix is back | Lrd12 Overload Relay

The control buttons are for the most part intelligently arranged and readily accessible, but the small space available for them on the right side of the body does mean that you need to hold the camera in your left hand to be able to access them properly: They’re really too close to the right side of the camera to keep your fingers wrapped around the grip and operate the buttons with any degree of comfort. On the angled top/back panel, the EV adjust button is perfectly located, right under your thumb, with the AE lock and movie recording buttons on either side of it. The movie button does require a deliberate reach to get to, but is nonetheless easy to identify by feel when you’re looking through the viewfinder; just slide your thumb over until it hits the viewfinder housing, and you’ll be right on top of the movie button.

I came here to post those two points! The corollaries to 1) are that should something go wrong, you have a chance if there is someone else there who knows CPR. I like mandatory CPR training for lab workers because of this. AEDs are good too. Rules against playing with things that can shock you while working alone are also good, but much harder to follow–I’ve spent decades working alone in research labs. CPR fails way more often than not, but electrical shocks are an important exception to that rule. And you almost got the extra credit for correctly spelling arrhythmia.

The place to start when talking about mains-voltage equipment is your bench. We realise you’ll probably be working at your kitchen table or wherever you happen to be, but it’s best to start an article like this with a baseline, of what you really should have when doing this stuff. There are three things we’d consider essential in the mains power system on a mains-voltage bench. An isolation transformer to power the item you are working on if it needs a mains supply, a residual current circuit breaker for the rest of your mains supplies, and an emergency isolation switch for all bench power.

For maximum resolution and shooting speed, plus built-in GPS, choose the Sony A55. Give up a little speed and resolution and drop the GPS, though, and you can save upwards of $200 with the Sony A33.

Varistors primarily consist of arrays of zinc-oxide (ZnO) balls, in which the ZnO was altered with small amounts of other metal oxides such as bismuth, cobalt, or manganese. In the MOV manufacturing process, these balls are sintered (fused) into a ceramic semiconductor. This produces a crystalline microstructure that allows these devices to dissipate very high levels of transient energy across their entire bulk. After sintering, the surface is metallized, and leads are attached via soldering.

• A 24-V dc circuit • Current waveform for surge is 8 × 20 μs; voltage waveform is 1.2 × 50 μs (these are typical industry-standard waveforms) • Peak current during the surge = 1000 A • The MOV must be able to survive 40 surges • Other circuit components (control IC, etc.) must be rated to withstand 300 V maximum

Then if one is only looking at getting warm water, then one can also just have the heat pump use ambient indoor temperature to make the warm water. It will efficiently give warm water, but heating the house would be just as efficient as using a large resistor. (But at least the warm water got cheaper. (and it cools down the house during summer if one empties the warm water out doors or down the sink.))

Lenovo is announcing a second ARM-powered Windows 10 laptop this week, and this time it’s a Yoga. The Lenovo Yoga C630 WOS (Windows on Snapdragon) is, as you might have guessed, powered by Qualcomm’s latest Snapdragon 850 processor. It’s the first Windows laptop we’ve seen with the Snapdragon 850, and its a chip that Qualcomm specifically designed for always-connected Windows 10 PCs. This new processor ushers in the latest generation of ARM-powered Windows 10 laptops.

You do in fact need to be a licensed engineer/electrician to design stuff with mains voltage, or you need to have your work inspected and signed for by one. It’s not just a matter of good instruction – it’s illegal for the regular Joe to even repair mains powered circuits beyond swapping a frayed power cord.

Good safety design will deliberately include a point (usually mains input) at which the creepage clearance is lower than any other place on the circuit board. This almost guarantees a *predictable* result from an extreme over voltage event.

The spark-gap Tesla coil itself was

I don’t know where do you see low voltage traces close to mains voltage. Trace from R8 to the opto is 2.64. How far do you think it should be to meet your standards? Conformal coating is telling you anything?