Who is on crack? Me or the chinese DMM?

[raspberrypi]

Or am I just blind. I have a variable DC supply plugged into a simple little circuit that uses two resistors a light sensitive cell( changes resistance when its under light), and an NPN to light up some little ada fruit black light LED.

Am I not seeing the meter right, it looks like my circuit is pulling 5.5 AMPS! Volts is on the left in parallel with + and -, amps is on the right hooked up between the + of the supply and the + of the light dimmer circuit. These meters kind of suck because they have no auto range circuit, but costs 8 bucks so I can't really complain. What am I doing wrong? When I put the meter on milliamps it doesn't display since they didn't make the display say OL its hard to tell if you are not hooked up or you are but you are above the range.

[Avacee]

The amps range is set to 20mA and you are plugged into the mA socket - looks like you are drawing 5.5mA, 0.05mA and 6.5mA

[CatalinaWOW]

I couldn't see the difference in hookups or setups in the three pictures, but all appear to be displaying a potentially reasonable current.  5.5 milliamps in the first, 0.05 milliamps in the second and 6.5 milliamps in the third.

May not be intuitive, but since the scales are labeled in mA, the display is in mA also.  This is not unique to cheap DMMs, it is true on virtually every one I have owned.  If it were a Fluke or some other name brand people would tell you to RTFM, but the cheap DMMs may or may not have had a meaningful manual.  Another way to bring home the thought is to think of the resistance scales.  Usually you read the display as ohms, kohms or megohms depending on a switch or dial setting.

[xani]

Maaaaaaaybe you should've bought auto-ranging meter but I guess it is too late for that

[raspberrypi]

Maaaaaaaybe you should've bought auto-ranging meter but I guess it is too late for that

I needed cheap and quick. I'm going to invest in two eevblog ones when I have the funds.

[alsetalokin4017]

Yes. In the last photo for example the meter is set to the 20 mA range (20m) and is reading 6.46 mA.

On my meters I've used a white or silver marker to mark the "dot" or arrow indicator on the knob to make it easier to see where it's pointed.  Or on the red plastic meter knobs I mark the arrow with a black marker. Whatever makes it easier to see.

These cheap meters are fine for the kind of work you are doing. They actually are quite accurate, and the construction is "good enough". If you drop it or step on it, it is easy and cheap to just toss it and buy another one. When you start paying 60 bucks for a meter that really isn't much better than these... it gets a lot harder to toss it if it breaks. Of course, once you get serious and buy yourself a Fluke 87-V.... the whole picture changes.

(I do wish the cheap ones had better transistor sockets though. Most of the ones I've tried have really loose contacts and it's hard to get a transistor to make good connections in them.)

[raspberrypi]

1. You are in mA mode, so what's wrong with it?
2. Use punctuation. Otherwise reading your posts is just as hard as listening to poorly implemented TTS.
3. Don't play with electricity when you're on high, or when your vision is impaired.
4. Buy a proper DMM. UT61E is cheap, and is massively better than the DT880 crap you have, and is half the price of EEVBlog Brymen while being more accurate.

1. I'm legally blind
2. I'm legally Blind
3. Thats called giving into a disability and very discouraging when you are trying to get your life back on track after losing your vision.
4. My fluke just broke.

To every one ELSE in this thread, thank you I couldn't see the scale and it seems to be upside down of how you would think it would work. It is good to know I have the resources of qualified people to help out with something so simple as not seeing the scale, and saves my hours of frustration.

I am going to get I are on high, now.

[CatalinaWOW]

1. You are in mA mode, so what's wrong with it?
2. Use punctuation. Otherwise reading your posts is just as hard as listening to poorly implemented TTS.
3. Don't play with electricity when you're on high, or when your vision is impaired.
4. Buy a proper DMM. UT61E is cheap, and is massively better than the DT880 crap you have, and is half the price of EEVBlog Brymen while being more accurate.

1. I'm legally blind
2. I'm legally Blind

I am not sure which form of blindness you have, but there are visual aids that can help to resolve many of the issues of the visually impaired.  For item 1 everything from using your cell phone in macro mode so you can see a magnified version of the display up through specialized camera/display systems.  Or more old school the magnifying goggles worn over glasses.  The set I have cost well under $10 at one of the surplus stores (All Electronics if I remember correctly).   A set of loupes (a couple of bucks at Harbor Freight) helps a lot.  For item 2 there are many, many aids for the visually impaired built into Windows and other operating systems.  I have worked with colleagues who are totally, not just legally blind, and they manage to communicate well.  I can't speak to the level of difficulty, but they manage.  Their ability to perform high level engineering jobs always earned my respect.  They clearly use their memory very effectively.

[SkyMaster]

 

EMPATHY: The ability to understand and share the feelings of another.

[rstofer]

One issue with meters lacking auto-ranging is probing more or less unknown circuits.  I'm not sure it is a good idea to probe 200V while on the 2V scale.

In general, we should know what to expect of the meter reading.  We know we can't stuff 5A through a 5 Mohm resistor with a 5V source.  Just a quick mental calculation shows we are down in the uA range.  If the reading doesn't correspond with our quick calculation, the reading is wrong.  Or we're measuring the wrong thing!

In the day of the VOM, it was unwise to start at a low scale and peg the meter.  Meters were expensive and unbending a needle was seldom satisfactory.  And, obviously, VOMs didn't auto-range.  There was a time before fused meters and measuring 480VAC on the 10A scale was a disaster.  Plastic meter case everywhere!

[DimitriP]

EMPATHY: The ability to understand and share the feelings of another.

1. He is not Canadian.
2. He is not Canadian.

(Yes it sounds repetitive but I've seen it being done before and it does the job).

[Seekonk]

I hate auto ranging meters. Just as you get used to looking at certain numbers the scale changes.

Think of it, with only 3  1/2 digits how could you display 0.05 milliamps. That is why all meters do this.

Asking a question on the internet is something everyone should avoid.

[tooki]

1. I'm legally blind
2. I'm legally Blind
3. Thats called giving into a disability and very discouraging when you are trying to get your life back on track after losing your vision.
4. My fluke just broke.

To every one ELSE in this thread, thank you I couldn't see the scale and it seems to be upside down of how you would think it would work. It is good to know I have the resources of qualified people to help out with something so simple as not seeing the scale, and saves my hours of frustration.

I am going to get I are on high, now.

There's nothing wrong with those meters for this application, they're more than accurate enough, and perfectly safe at these types of voltages. You've learned to pay closer attention to the range, and all is well in the world (aside from a certain prick here who needs a dose of empathy/compassion).

But I am curious, what did you mean that the scale is "upside down of how you would think it would work"? It looks like a standard range switch for a manual ranging meter, i.e. clockwise, the ranges go up (like how the needle on an analog meter turns clockwise as the signal increases).

[EPTech]

Hi there,

I do not know the severity of your blindness but here is an idea: Take a picture of just the dial, scale it to a full sheet size, print it out and hang it in front of you.

Or have somebody make spread sheet with the the ranges written in large and the number of clicks and direction you need to turn the switch from the off position to get to that range.

I can imagine that magnifying glasses are not always an option as you need both hands for most of the work on the bench.

[Nusa]

If you do get another meter, I suggest finding one with a serial or usb output and matching PC software. Aside from the obvious datalogging capability, it gives you the flexibility of putting your meter output on a PC screen.

For instance, my UT61E came with software that repeats the meter display on my PC, as well as logging the data and graphing it for me. If an even larger display is needed, the standard screen Magnifier program should work.

I've also seen a few projects where the serial output was used to make a talking multi-meter.

[Cerebus]

Hi there,

I do not know the severity of your blindness but here is an idea: Take a picture of just the dial, scale it to a full sheet size, print it out and hang it in front of you.

Or have somebody make spread sheet with the the ranges written in large and the number of clicks and direction you need to turn the switch from the off position to get to that range.

I can imagine that magnifying glasses are not always an option as you need both hands for most of the work on the bench.

I think that part of the problem here is that, if I remember correctly, RaspberryPi has lost his sight relatively recently and so hasn't learned some of the coping techniques that come naturally to people who have been sight impaired for a long time. I had a blind friend who seemed to effortlessly remember the physical position of settings on controls. It only seemed effortless because he'd been doing it for a long time. Without looking I haven't a clue where all the settings are on my Fluke except that the DC ones are in the anti-clockwise half, AC clockwise and volts is the first thing away from the vertical either way. Gives one pause for thought, I don't know how well I'd adapt if I found myself severely visually impaired in six months time.

[EPTech]

Yes, indeed, that is exactly what I am saying.

I would surround myself with visual aids like the one I suggested just because of the fact that I obviously do not know where the VAC setting is on my meter is.

That being said, I wish for him to keep on doing electronics stuff as he does, utmost respect.

Happy measuring.

[CatalinaWOW]

There are often community resources for training blind skills.  Unfortunately it is very common, so the need is widely filled.  They give tips and training.  Things like gluing little felt dots at appropriate places around a dial to provide additional tactile reference.  Or always making the black lead shorter than the red lead, and putting a rubber band around it, so that it can be distinguished by touch.

I am lucky, other than presbyopia my vision is basically intact.  But I have many peers and colleagues who have not been so lucky.

[ebastler]

[...]
________
SIGSEGV is inevitable if you try to talk more than you know.

You might want to re-read your signature every now and then, and give it some thought?

[james_s]

I hate auto ranging meters. Just as you get used to looking at certain numbers the scale changes.

Think of it, with only 3  1/2 digits how could you display 0.05 milliamps. That is why all meters do this.

Asking a question on the internet is something everyone should avoid.

My meters auto-range by default but you can manually lock in the range if you want. I find that very convenient, it will autorange and then if I'm having problems with the range jumping around I just hit the range button and it holds the range it last selected.

[IanB]

There is really no reason for the first post in this thread. Firstly the poster was apparently able to read the numbers on the display quite accurately. Secondly there are photos of the setup that can be zoomed in or enlarged to any amount, and which clearly show the selector turned to the 20 mA range and the test lead plugged into the mA socket. Thirdly, even without good sight there is the tactile feel of turning the selection knob. It is easy to learn that the 20 mA range is 5 clicks to the right from the off position.

[Cerebus]

Now I have to admit when I was typing the first and second posts, I was biased. I thought this was some kind of trolling, as, being frankly, the OP does have a history of trolling. Now since I know the OP is indeed visually impaired, I wrote the third post, which is solely for the purpose of giving help.

The O.P. has had the signature on the post you were commenting to for quite some time because some people couldn't account for the possibility that other people, as it turned out literally, see things differently which caused him to be accused of trolling or similar by others, and now by you. Perhaps you should have bothered to read that signature and then you wouldn't have failed to be cognisant of his handicap and made such a fool of yourself.

[guenthert]

I promised myself to stay out of this kind of discussions, but I can't help myself right now.  I don't quite understand why blueskull is now on the receiving end of the collective eevblog wrath.  I read his post as earnest, if harsh, attempts at help.  I'm in the lucky position to be only slightly vision impaired (but getting into an age where this becomes worse).  I find reading labels on chips quite difficult at times, as they are really of amazing low contrast.  So I wonder, if electronics is really the best venue, if one is legally blind.  Is then looking for something else to do giving in to disability, as the OP states or is it giving in to reason (and given the topic he's not giving up too much)?

I actually came here because of the thread's title -- I can't stand those categorical rejection of Chinese products.  A good share of all products come from China now and it's certainly not all poor quality (as it might have been in the seventies and eighties).  Afaik, the iPhone comes from there too.  The old-timers might fondly remember the 'Made in W. Germany', but surely there were duds with that label too (I think the VW Golf I, sold as 'rabbit' in the US, was one).

[Cerebus]

The O.P. has had the signature on the post you were commenting to for quite some time because some people couldn't account for the possibility that other people, as it turned out literally, see things differently which caused him to be accused of trolling or similar by others, and now by you. Perhaps you should have bothered to read that signature and then you wouldn't have failed to be cognisant of his handicap and made such a fool of yourself.

I tried not to vent here and being polite towards the few previous posts questioning my attitude, which are both completely PC platitude to me, but since you've just tripped off my tolerance threshold, let's add more fuel to the fire.
Why I think the OP has the tendency of trolling? Let's put technical issues aside, forgive him for asking questions which seem to come from sci-fi, let's talk about common sense first.
Should one ever think of pointing a 1.7W laser to people? Should one ask how to build a billion dollar radar from his backyard? Should one post in a public forum challenging FCC laws enforcement?
These are all common sense questions. These don't need a degree in EE to know the answer. Even without a good common sense, a one minute Googling will tell the answer. Asking one minute Googlable questions is itself a disrespect to people who spent time answering.
If the OP can be pissed off just by some school kids calling LEDs "leads", then I guess anyone should be allowed to get pissed off by the OP doing anything wrong, trolling or seemingly trolling being one of them.

So let me see, your justification for this is "Two wrongs make a right". You were, at best, insensitive towards a handicapped person when the evidence for their handicap was staring you in the face, at worst deliberately offensive - only you know which it was. It doesn't matter who it is, or what they have done, you don't pick on people over things they have no control over, be that colour of skin, handicap, gender or whatever. That's not PC platitudes, it's common decency. That's what's got people's panties in a bunch about your behaviour.

[timb]

The O.P. has had the signature on the post you were commenting to for quite some time because some people couldn't account for the possibility that other people, as it turned out literally, see things differently which caused him to be accused of trolling or similar by others, and now by you. Perhaps you should have bothered to read that signature and then you wouldn't have failed to be cognisant of his handicap and made such a fool of yourself.

I tried not to vent here and being polite towards the few previous posts questioning my attitude, which are both completely PC platitude to me, but since you've just tripped off my tolerance threshold, let's add more fuel to the fire.
Why I think the OP has the tendency of trolling? Let's put technical issues aside, forgive him for asking questions which seem to come from sci-fi, let's talk about common sense first.
Should one ever think of pointing a 1.7W laser to people? Should one ask how to build a billion dollar radar from his backyard? Should one post in a public forum challenging FCC laws enforcement?
These are all common sense questions. These don't need a degree in EE to know the answer. Even without a good common sense, a one minute Googling will tell the answer. Asking one minute Googlable questions is itself a disrespect to people who spent time answering.
If the OP can be pissed off just by some school kids calling LEDs "leads", then I guess anyone should be allowed to get pissed off by the OP doing anything wrong, trolling or seemingly trolling being one of them.

So let me see, your justification for this is "Two wrongs make a right". You were, at best, insensitive towards a handicapped person when the evidence for their handicap was staring you in the face, at worst deliberately offensive - only you know which it was. It doesn't matter who it is, or what they have done, you don't pick on people over things they have no control over, be that colour of skin, handicap, gender or whatever. That's not PC platitudes, it's common decency. That's what's got people's panties in a bunch about your behaviour.

Just FYI, not everyone can see user signatures. For example, Tapatalk does not show the normal user signature at the bottom of their posts, nor does it show the custom user tag that's under their username like  the normal forum web view does. In Tapatalk, I see their profile picture, username and post, that's it. (Which is actually quite nice as it's a lot less cluttered!)

Also, since you're trying to be PC, you should know handicapped is no longer the apropos term. Try "handicapable" instead. "Differentlyabled" is also acceptable. ;>

Anyway, I had no idea the OP was visually impaired until he said something, although it explains a lot now that I know. He's also fairly young if I recall correctly, so everyone should keep that in mind and cut him a bit of slack. I think he's honestly trying and maybe just has a weird sense of humor on top of everything else (or doesn't understand about sarcasm and the internet), that's why his posts come off the way they do.