Rotten Chinese Cheapskates

Yes, they are all that way.

I have made several LED ringlights for stereo microscopes. I take a piece of copper-clad and turn it on a lathe to make a ring that fits snugly around the bottom of the microscope. I then carve a gap so that the copper has two concentric rings. I tack-solder 8 white LEDs on it, with a 1K Ohm resistor in series with each. This is powered by a "9 V" wallwart that actually puts out about 11.8 V at light load. Works like a charm.

I make a piece of cardboard with a 3/8" hole in it, so I can mask off all but one LED at a time and aim each LED at where the microscope is viewing.

Jon

Interesting. Let me know if you also come up with an adaptor for using a dslr to take pictures through a stereoscope!

The market provides what people want to buy.

No, the market provides *what* people buy. What they want is something different as clearly indicated by this post.

I like to buy stuff on eBay because it it cheap. But it is very hard to tell what is quality and what is not. I rely on the power of complaint to get my money back if I don't like an item. Otherwise I would never buy that way. I get what I want maybe 2 out of 3 times. The remaining times I get a refund.

When the batteries run down and you replace them with a better make with a lower internal resistance, say Duracells, the LEDs will start to fail, firstly by flickering as the bond wires become intermittent, then just failing.

Cheers

Sigh. Cue Bill Sloman.

I wish. The market is driven by profit, which requires several things.

- the belief that people will buy it. Not always correct

- the ability to produce it at low enough cost and sell it for enough to get a profit. This routinely means changing designs until end users get unhappy.

The situation is then twisted by widespread failings at all parts of the process.

- reviews that talk out of their rear, and routinely praise terrible products

- sales blurb that intentionally misleads purchasers

- shortcomings of product engineers, and more so of management

- the wish to design products that fail unnecessarily to sell more

- products that don't even work aren't too hard to find

- dangerous products people buy only because they know no better

- sociopathic designs or company actions etc

The market provides what the people want is the ideal, but ideals are seldom reached in the real world.

If people had full & realistic information about the products available it would go a fair way toward improving things.

NT

Of course things are driven by profit. Companies that can't make a profit tend to die.

It is hard to tell if things in a bubble pack are going to be good or junk. So most people go to Home Depot or to Ebay or Harbor Freight and buy what's cheapest. Which is generally Chinese garbage.

Reviews help a little.

I guess that Home Depot doesn't stock much of the best stuff because it's too expensive and doesn't sell. And most US-named brands are actually made offshore because they can't be competitive making stuff here.

I'm not sure about "widespread failings." Most of the stuff that we but is good enough and, being absurdly cheap, is actually a good value. You can buy a dozen OK Chinese LED flashlights for the price of a serious Maglite.

Looking around me, I see computers, monitors, keyboards, mice, USB drives, printers, furniture, all good stuff and likely all made in Asia.

The big failing is the destruction of US worker-guy jobs, linked with gross exploitation of asian workers. Fat cats make out on both ends.

(It's amazing how cheap white LEDs are. They must cost a penny each in China, or likely less.)

Camera to microscope adapters are always tricky. I often have to machine th em and design a relay lens. This is because: it's an overpriced option ofte n only available at manufacture, and there are no technical standards for t he adapters. Expensive niche item that should be low cost and standardized.

STEVE

An common and interesting failure mode is several-Hz on/off oscillation.

Please tell us more about what sort of relay lens you would typically expect to need, and how you know how strong to make it.

I've encountered this kind of "low cost" product. The LEDs don't maintain anywhere near a constant brightness, but get dimmer and dimmer as the batteries drain. If you're going to spend your time (at whatever $N00/hour) using a microscope (that cost $M000), you surely don't want to compromise it by neglecting a $0.20 driver chip - even if that might make sense for a $3 torch.

No, John is right. People don't want to pay for useless electronics. That's what the market demands (see: Muntz).

I just buy the quality I want or don't buy. I don't buy form eBay, or anyone else, unless I know exactly what it is I'm buying. I don't mind paying for what I want but most will buy by price. It's what they (we) demand and it magically appears.

Rickman is playing BS, today.

What does this 'relay lens' of yours do, actually?

Not necessarily- they could be using LEDs with fairly high current ratings, for negligible to none additional cost, to withstand an otherwise excessiv e current for the few minutes it takes for the AAA to discharge down to mor e reasonable internal resistance. Looks like brand new alkalines have aroun d 0.2 ohm IR, that would make 0.6R for the stack so that a 0.75V drop is on ly 1.25A making 1.25/9=140mA /LED, which might be right for VF 3.75V, you do the iteration. See, there's nothing to get hysterical about here, Lizzy

-in-a-Tizzy. The Chinese have the labor to bin the LEDs to within 10% IV ce rtainly. What do we learn from this? Cheap does not mean stupid, any damned fool can make something expensive, sometimes cheap means clever, then the product is described as low cost and not cheap. ...

New products are different, most people didn't know they wanted them.

George H.

If you want constant brightness, plug it in.

What would it take, power wise, for a ring flash to take normal photos? I think something equivalent to a 100 W/s flash would do it. Would it be possible to operate the LEDs in a flash type mode? Would the LEDs respond fast enough. I suspect it will be hard to replace the HV Xenon flash tube with a low voltage high current device.