Test Equipment Anonymous

[I've never liked the idea of switch mode bench power supplies, although I'm sure if you pay enough for them they are excellent. ... I feel obliged to test them with a DSO now. I'm not sure that either price or manufacturer is sufficient to guarantee behaviour in this respect :( Testing is fun, but...

Cubdriver wrote: ↑Thu Feb 26, 2026 8:23 amIMG_6754.png

I have one like that at the moment. Can't correlate a tinkling (for want of a better word) with anything except >50mph.

Current hope is fan/etc in ventilation system.

Will have to get daughter to attempt to localise noise when she's here in a week's time.

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...

Or other techniques... Make your own freezer packs with 120g/l salt in water, in 75% full plastic bottles. That should work for a few days, but not a week. To verify they worked and the temperature never rose, freeze some ice cubes and put them in a plastic bag. If the temperature becomes dangerousl...

Seeing that, yesterday I bought a bigger generator; one with 240V that'll actually run the heat as well as fridge & lights, etc. Surely you can just use the old skool technique: putting the fridge (and probably freezer) contents outside :twisted: Or prepare for next time and use the ancient tec...

Unfortunately in times past too many junior engineers were given the boring task of providing a power supply for the interesting bits.

I wonder why the power supply had the reputation of being a principal failure point?

That Power Designs 2020 is lovely! Ooooh, I'd give one of those a home. It is gorgeous, now :) Paid £8 (plus £50 P&P). Acquisition story at: https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1839581/#msg1839581 Beware: many PDxxxx are 115V only. The 2...

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 PL...

I did have it higher, but it was blocking the racking behind. I have a lot of things stacked in "storage" in my bedroom... My daughter's bedroom has been repurposed :) Still not big enough :( :lol: Time to add an extension or two? https://external-content.duckduckgo.com/iu/?u=https%3A%2F%...

The only motorised vehicles I've had are cars and a Land Rover. Hence when cycling in snow, spinning the rear wheel never happened

Vehicles of every kind behave poorly on sheet ice, and thaw-freeze produces that in abundance

I don't mind deep snow, and have regularly cycled in it - slowly with much effort. The winter of 81'/'82 is etched in my mind since I had just moved into my first house and couldn't get coal since it was all frozen in the coalyard. What I don't like is snow - melt - freeze. That's lethal: even cars ...

AVGresponding wrote: ↑Thu Feb 19, 2026 6:18 am I did have it higher, but it was blocking the racking behind. I have a lot of things stacked in "storage" in my bedroom...

My daughter's bedroom has been repurposed Still not big enough

500ms is quite enough time for the magic smoke to escape... Yes indeed. My test for current limiting behaviour is set 8V, 40mA and a 47ohm resistor as load. The voltage shouldn't exceed ~2V. One PSU I recently tested only had a mains switch, not an output switch. It was, um, suboptimal. The voltage...

500ms is quite enough time for the magic smoke to escape... Yes indeed. My test for current limiting behaviour is set 8V, 40mA and a 47ohm resistor as load. The voltage shouldn't exceed ~2V. One PSU I recently tested only had a mains switch, not an output switch. It was, um, suboptimal. The voltage...

Those TTi supplies are very good ergonomically; I particularly like the way the current meter shows where you've set the current limit, then shows actual current when the output is switched on. What I don't know is their failure mode. Farnell supplies and earlier TTI supplies failed to maximum volt...

Well, based on a quick test, here's a winner-winner-chicken-dinner story. Idly browsing Gumtree (fleabay's zero cost local craig's list and farcebook marketplace killer alternative), and I spot a TTI dual PSU for £40. Picked it up on the way to Nottingham, and it turns out to be a AIM-TTI PL303QMD-P...

https://media0.giphy.com/media/v1.Y2lkPTc5MGI3NjExaHg3NG9hdDhwcmkzNnduaTRoYWgzbnEwZHM5cTEwcWwzcHRzOXV2NyZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/F47BOXkbEXGkGfz1yN/giphy.gif https://media2.giphy.com/media/v1.Y2lkPTc5MGI3NjExbWdleXE4YXplNGhzZWZvNWxrdjQwYTE5NGt5bHBibWVxcDJkZWJvbSZlcD12MV9pbnRlcm5hbF9...

I prefer an iron for soldering (I use hot air for desoldering) too, and the small stuff is where the nail polish comes in While I'm happy to use an iron for desoldering small components, a hot air gun may be better for large components with many leads. I'm not comfortable using an iron for solderin...

A friend's cat. This is an evil bastard. It spent the entire evening nudging people off furniture that it clearly considered itself the owner of. Very cleverly it'd snuggle up behind them and then ratchet its way across the furniture slowly pressuring them into falling off :lol: IMG_2863_.jpeg And ...

bd139 wrote: ↑Wed Feb 11, 2026 6:40 pm A friend's cat. This is an evil bastard.

Tautology; no need to say any more.

I ought to start referring to capacitance values in Jars. https://en.wikipedia.org/wiki/Jar_(unit)

I wonder if it is coincidence that my recent Sullivan capacitor is up to 1000Jars in 9Jar increments?
viewtopic.php?p=12485#p12485

Very pretty. Shame about the "Kelvin, g, s" legend; it must be American. I have a (very mild) hankering for a torsion wire galvanometer as used at school with its illuminated line moving a glass display. Yes, that irked me too. Similarly measuring time in mhos is one of my bugbears. As is...

I prefer an iron for soldering (I use hot air for desoldering) too, and the small stuff is where the nail polish comes in While I'm happy to use an iron for desoldering small components, a hot air gun may be better for large components with many leads. I'm not comfortable using an iron for solderin...

Small components stay in place due to the viscosity of the solder paste - provided the air gun isn't blowing a gale.

For whole boards I use a thin layer of sand to spread the heat in a saucepan on the gas hob.

As you get older everybody really should come to appreciate Cassandra's plight more acutely.

Doing most things for the first time is more interesting than repeating experiences. But by the 10th time...