Test Equipment Anonymous

True RMS meters were preferred for THD measurements as they dealt accurately with noise as well as the mainly harmonic residual. Older distortion analysers didn't have them and spent a page in the manual apologising for it. They are used for accurate measurements with all sorts of power electronics,...

I have 3 and a half HP3400As. All have the IEC connector. They all have the photo chopper and nuvistor input stage. I believe there were production mods to replace the nuvistor with a FET input stage and the photo chopper with an IC chopper amp. Three work nicely and agree. The other, I can't quite ...

They are available from time to time in certain parts of the country. https://en.wikipedia.org/wiki/Kinver_Rock_Houses Electricity, mains water and sewage are not necessarily laid on which may make them inconvenient for TE. I was at primary school with kids who lived in the rock houses. They were mo...

I've been looking for such use cases. In most cases the benefits would be marginal, and the problems caused by increased complexity and dependencies would be significant. I've seen a few reports by "ordinary people" which indicate that has been the case for them. I expect that will gradua...

The problem arises in two cases. Firstly if you have a 500W UPS for a single freezer. Looks OK on paper, but doesn't work. Secondly if there is a prolonged power cut during which the temperature of several freezers rises to, say, -15C. Then all the motors will switch on simultaneously - and might e...

For the first problem there just has to be adequate UPS backup. For the second problem, some sort of monitoring and staggered start and alarm system. For instance, she might be on holiday abroad or somewhere far flung in the UK. Just an alarm system would enable someone - you? - to go across and sor...

Then assuming you have half a dozen of these freezers, all in their working temperature range and switching on and off semi-randomly, and there's a power cut and the UPS takes over, you only have a problem if more than two decide to switch on in the same short (approx 1 second) period, which on the ...

I was not amused to find my 3kW UPS takes 100W from the batteries even if there is no load. One of my principal uses for mains would be freezers. While 90W when running, they can take 1kW or so during startup. It's not clear to me what's going on here. Do the freezers take 1kW for a second or two w...

Exchanges had dirty great lead-acid batteries, with each cell the size of a domestic washing machine. Nominal voltage around the exchange was 48V, distributed by dirty great aluminium bus bars near the ceiling. Also 48V on the lines to customer premises; current limited, of course. 48V was deemed t...

It will depend on the kind of disaster you are planning for. I find power cuts usually last about an hour and affect a few streets. They happen maybe twice a year. The last one was caused by a problem at the local sub station, lasted about two hours and took out most of the village. I've no idea whe...

"Making" and SBCs such as Raspberry Pi cater to the same sheddy, tinkering instinct the amateur electronics rags covered. It's a constructive interest and no bad thing. .... I know someone who came home to a freezer full of rotting food, because while she was on holiday, poorly thought ou...

It reminds me of a lot of the projects that were published in the electronics comics years ago. A contraption to raise an alarm when your outside LPG bottle was getting low. A device to raise an alarm if the deep freeze had failed and was thawing out. Definitely of use to someone and interesting to ...

IoT seems to be one of those things, which seems as if it ought to be useful and has a considerable Gee Whizz factor. Some people do find aspects useful, but it's not a Godsend to millions. Things like baby cams are definitely suspect. As I recall the Bosch washing machines with internet control wer...

I resist IoT nonsense. Our Logik fridge/freezer was chosen on the basis that the label at the back of it includes a circuit diagram, and it hasn't any silicon. I have the same attitude. My Bosch dishwasher broke after >30 years, so I had to get one without a mechanical timer :( I need a freestandin...

I would still be running XP on a laptop, but MS wouldn't let me reinstall it. Linux installed much faster, minutes vs days :) I think most people were happy with Windows 98 or NT. With security updates, the ability to use new hardware such as USB etc, it was all they wanted. Microsoft had to make t...

Most digital products these days are plain gouging. I once lusted after an Audio Precision audio test set. But I did the sums and it was way more expensive than a PrismSound dScopeIII, so I bought the dScope. It's fine. Now, apparently, if you buy an (expensive) crate of Audio Precision hardware, y...

Vibe coding. Give it the plans to the airliner, nuclear power station etc, tell it you want control software and a few minutes later, out it pops ready to be installed. It gives a more immediate meaning to "implement and run", "implement and run for your life". They could resurre...

There's a difference between AI applied to specific problems, such as scanning X-rays and looking for abnormalities, and LLM panaceas which are supposed to reveal unlimited opportunities, and require truly enormous and otherwise useless capital. Considering the scale of the capital investment, a tri...

I'm not saying the AI boom has reached that level of excess, but it has a ring about it. Just so. You can probably make money provided your timing is excellent/lucky. Mine isn't; like other people here I can spot long-term trends, but trading requires short-term skills. Looking into of the finances...

Without looking at it too closely, and considering the immense amounts of money being sunk into it, much of it shuffled around between the major players, I'm inclined to believe this LLM thing is a bubble which is about to pop. It's not a total dead end, but there does appear to be irrational exube...

America Had No Radio Crystals in 1941 — So Engineers Cut 30 Million From Brazilian Quartz https://www.youtube.com/watch?v=a1_l8Qdsq5A Fascinating. Back in the day when quartz crystals weren't enclosed, radio amateurs often lapped crystals to a frequency. The frequency tends to drop with age and lap...

Without looking at it too closely, and considering the immense amounts of money being sunk into it, much of it shuffled around between the major players, I'm inclined to believe this LLM thing is a bubble which is about to pop. It's not a total dead end, but there does appear to be irrational exuber...

Did the creators of this thing die with a sword in their hands and so were able to cross the Poison Sea, and sit at the table of Woden, who sits in his hall drinking mead and receiving news of the world of mortals from two ravens? If not consider all claims of this being a Valhalla Scientific instru...

Back to our raison d'être... I've recently tested a PSU set to 40mA 30V, with a 47ohm resistor so it should limit at ~2V. It output 30V for >100ms, then exponentially fell and undershot, and after a second got to the correct value! Here are some results for PSUs available to me. The good: AIM-TTI P...

I didn't mind a few inches of snow when I was working, as long as it didn't hang around long enough to wear its welcome out.