Recent Posts

1

Mechanical & Automation Engineering / Re: Repurposing PVC Pipe for DIY Projects

« Last post by T3sl4co1l on Today at 01:06:18 pm »

It's a gimmick, a "DIY" vid for views and viral trending, neither practical in terms of build complexity nor functionality.

If you really must, solvent welding with THF and related solvents is the usual method.

Tim

2

Beginners / Re: Convert US standard 115V to International 230V

« Last post by Zero999 on Today at 12:56:18 pm »

Capacitor ESR decreases as frequency decrease and ESR increases as frequency increases. So whether it 50 to 60Hz or 100 to 120Hz it won't make any difference worth worrying about to output voltage ripple. This can be easily tested with any LCR meter with variable frequency. If your getting a huge change in value between 50Hz and 60Hz then the capacitor is nearing end of life anyway and needs to be changed.

Irrelevant.

The problem is 50Hz will increase the ripple on the smoothing capacitor, so the voltage will drop to a lower level during the troughs. This shouldn't be a problem with a properly designed power supply, as the capacitor should be adequately oversized, but it will be a problem, if it's marginal and perhaps the voltage is also on the lower end of the operating range.

3

Repair / Re: LED Strip lights flashing like a bad 90s rave

« Last post by artag on Today at 12:55:25 pm »

It looks like classic behaviour from a faulty or overloaded switching power supply - it starts, overloads, shuts off and after a short delay restarts. I wouldn't like to speculate why it's doing that but I'd start with that assumption.

Unfortunately switching power supplies are quite hard to work on as at least half the active circuitry is operating at mains voltage. Unless you have previous experience of them or want - very carefully - to use it as a learning experience with possible destruction of the whole setup, the easy way out is probably to replace the packaged power supply.

Nothing wrong with RoGeorge's suggestion and it might be a good (and cheap to try) start but it seems less likely than a power supply fault.

4

Test Equipment / Re: Program that can log from many multimeters.

« Last post by Gertjan on Today at 12:53:02 pm »

Hi HKJ,

Here are three updated definitions.

I added a few math functions to the HP / Agilent 3458A setup menu. (I needed the NULL / offset function):



Also I found a small bug in this definition. Checking my other definitions, I also found this small bug in the Racal-Dana counter definitions. So I updated those too.

AgilentHP3458A v1.03: AgilentHP3458A.zip
Racal1991-1992 v1.02: Racal1991-1992.zip
Racal1998-1999 v1.02: Racal1998-1999.zip

Best Regards, Gertjan.

5

Mechanical & Automation Engineering / Re: Repurposing PVC Pipe for DIY Projects

« Last post by langwadt on Today at 12:52:13 pm »

The builder is using CA glue. What's wrong with what he chose, seems to know what he's doing. You can use SCIGrip 16 if you don't want to use that.

CA glue is a bad choice for pvc

Why do you think that builder is using it? Just curious your thoughts on it. He (or she) doesn't seem like a person to make a mistake like that. 

easily available and it'll last long enough to make a video ..

6

Other Equipment & Products / Three most useful tools I got from AliExpress

« Last post by watchmaker on Today at 12:48:24 pm »

The ckt board holder is stable and holds.  Much better than the alligator clamping thingies.  The Proskit is a joy. We had to heat and strike to desolder.  The Iwiss tool does a great job and is highly polished.

7

Buy/Sell/Wanted / Re: The Bad Shopping Experience Thread

« Last post by AVGresponding on Today at 12:47:25 pm »

Scam warning.  I was scammed in the sell/buyer thread by this person purchasing a Leader 3217.  It was finally resolved by paypal on my end.   I hope Admins will back list him, not sure where to post this?



M3Knight - EEVblog user name
harveygrout75@gmail.com - Another Email account
markevans56@yahoo.com - Mark Evans is the paypal recipient

You need to email a mod/admin. They do not necessarily see posts unless they happen to read one at random or go to see something that has been reported to them.

8

General Technical Chat / Re: Cable Management

« Last post by EPAIII on Today at 12:47:23 pm »

I have been in electronics for over 55 years and the meter and test cables have always been a problem wherever I have worked as well as in my own shops. Just a few months ago I came up with a new idea and, so far, I really like it.

Being 80 years old I have a number of prescriptions. Being cheap, I have saved the empty, plastic bottles the pharmacy packages them in. All the pharmacies I have used have used a yellow plastic bottle with some kind of child safe cap. A pair of close wire cutters, the type made with sheet metal, makes short work of removing the lock on the bottles that I have collected. I have many, many of my small parts stored in these Rx bottles. For the most part I use the bottles with just the child lock cut off but when I decided to store my meter cables in a couple of them I decided to use my power band saw for metal work to cut the tops completely off, at an angle. I did this due to the shortage of space on my electronic work benches. I plan to make a base for the ones in the first photo with my 3D printer as soon as I can get a round-tuit.

As seen in the second photo this is also a good way to store computer cables as well.

In addition to that, I have literally hundreds of small parts stored in these Rx bottles. I print round labels for the tops and consolidate them in cardboard bins and mini-bins on shelves in my shop.

And the best thing about using these Rx bottles is they are free. Well, I don't pay anything extra for them, that is.

9

Test Equipment / Re: Cheap oscilloscope for checking mains power quality? Also logging equipment.

« Last post by artag on Today at 12:47:16 pm »

I have no direct experience of using it for mains quality so take it with a pinch of salt, but I find distortion very hard to judge on an oscilloscope. Other problems such as transients are by definition occasional so won't show up unless you have the trigger just so.

A general purpose piece of lab equipment that would be more suitable is a spectrum analyser. That seems like overkill but it only needs a low frequency response - maybe to the 5th harmonic of 60Hz  to show distortion.

But a spectrum analyser offers far too much to be used only for this and so is not normally used. There's a reason sapecific test equipment such as mains power  analysers exist : it's customised to do the exact job and robust enough for field use. There are also scopes that are ruggedised for the job - such as the obsolete Tek 555PS - and have appropriately rated probes and inputs that are suitable for use on high power circuits (it's easy enough to measure voltage with respect to earth, not so easy with respect to neutral).

My recommendation would be to look for a specialised unit but buy it secondhand.

10

Other Equipment & Products / Re: Crimpin’ ain’t easy (or: best hobbyist crimping tool/system?)

« Last post by watchmaker on Today at 12:44:51 pm »

Is IWISS getting better? Look at the polish.