I'll guess that the main use for this tube will be in window displays or theming. It provides a nice splash of vibrantly coloured light.
The construction is different to what I was expecting. The tube opened easily, but kinda self-destructed in the process. I'm guessing the LED strip is glued on with a custom jig.
The driver chip is very minimalist, but I wonder if linear regulators are going to be the standard from now on.
In hindsight, the live connection being repeated at one end may be due to the design possibly being for use in retrofit tubes with a feed at both ends. The LED PCB would then have an extra power track on it. Those tubes have lost favour due to posing a shock risk to maintenance operatives putting them into live fixtures.
I got this tube from this UK eBay listing:-
https://www.ebay.co.uk/itm/332843575855
They do 2', 4' and 5' versions. I ordered the shortest, partly because it was less likely to get destroyed in the post.
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A total Ashens moment when I decided to taste test some Stilton cheese that had been in my fridge so long that it was six months out of date. Then I decided it was a bad idea. Particularly when I was going to be on a flight to Glasgow later in the day.
For those not familiar with the Ashens reference you can find his channel (with taste tests on VERY out of date food) here:-
https://www.youtube.com/user/ashens
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The perfect accessory for those instances where you want to take a selfie, but lack proper facial moistness.
Aside from the traces of green corrosion on the PCB (probably caused by flux), there has been no sign so far of this unit leaking all over the phone it's attached to. That may vary by unit though.
The LED ring has a fairly dense array of LEDs, but sadly they are not well matched for parallel use and some show significant current hogging.
The capacity of the cell tested at an ungenerous 200mAh on the first discharge/charge cycle, despite having the size of a larger capacity cell.
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And finally the 20V tool PCB for the 20/40V battery pack system. This shares the same complex power management system as the others for ultra low standby current.
It's quite perplexing. I think two of the inputs are analogue for voltage monitoring.
An unexpected feature of this module is that it doesn't control the tool directly, but just sits between it and the battery. When the tool is used this module detects the load, wakes up and switches on the MOSFETs to allow the tool to be powered fully. The bulk of the circuitry is to allow the module to sleep when not needed.
If woken, the unit remains awake while the load is present, but quickly shuts down into a sleep mode again. During sleep the processor is powered down completely and other sections of circuitry are also deactivated.
Although you can trick the tool into running by putting a 10K resistor between negative and the central thermistor contact, it will lose the ability to sense if a non-compatible battery pack is low, so may over discharge the pack if it doesn't have its own internal under-voltage shutoff.
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This is one of many similar products that cashed in on the pandemic by offering products that would sterilise phones and other objects with UVC energy.
To be fair, this one has a better design, since it allows for greater distance between the UVC LEDs and the object, and it actually drives the LEDs at a fairly significant current. It could actually find use as a lab sterilising device, although the LEDs can't yet compete with traditional mercury vapour UVC sources.
The circuitry in this unit is surprisingly complex. It has the signs of being a "proper" design without the usual penny pinching shortcuts found in similar products. The thermal sensing in the lithium cell is a nice touch, but can't really protect against charging at very low temperatures. It seems mainly to protect against cell overheating.
The way the voltage booster is controlled by software is odd, but presumably more versatile. It appears to be using a fixed voltage and a low value resistor in series with the LEDs to set the current.
One good thing about the pandemic and the flurry of dubious sterilising products is that the development of UVC sterilising LEDs has been moved forward significantly by creating a huge market for them.
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I'm aware that these preserved eggs are very popular in China, but they don't fit with our westernised tastes. These "century eggs" are based on a traditional method of preserving eggs where they were encased in various earths containing natural chemicals that penetrated and preserved the egg.
Modern high output production techniques use more concentrated chemical mixes to accelerate the process, and some apparently use lead based compounds which are not suited for food use.
As you can see from the video, they made an impression.
Please be aware that this video contains profanities and lewdness befitting a gathering of friends.
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I'll just assume that this unit is a clone of one of the many similar looking products. It's hard to tell which came first in a sea of lookalike products. I'm sure the true flashlight connoisseurs will know.
In the UK we call these torches, which is kinda bizarre, since it's literally a progression from the original blazing stick that was used for light in the long distant past. According to Wikipedia the word torch comes from the French word torche, representing the fuel carrying wick wrapped around the end of the stick. So basically speaking this torch is an electronic blazing stick that fits on your keyring.
This link finds them on AliExpress. Target price around 10 pounds.
https://www.aliexpress.com/w/wholesale-EBL0269.html
The lithium cell claims to be 500mAh, which is viable for its size, and it is charged at a current of around 350mA. The USB C charging port does not have the load identification resistors, so some smart chargers may not detect its presence and will not charge it. A plain dumb charger will charge it.
The front LEDs have five modes. Brief high power output and four latched intensities, with current draw at 4.2V as follows:-
Momentary high power = 2000mA
High = 660mA
Medium = 140mA
Low = 67mA
Night light = 13mA
The small side LEDs have two chips each and are run at 100mA.
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You'll still find lots of these in old equipment. Sometimes you'll smell them too, and if one blows up while you're working in the panel the vile smell will make you leave the area fast.
This is a selenium rectifier. It was popular from around the 1930's until the much better silicon diode took over. It consists of a metal plate with a coating of doped selenium and a tin-cadmium electrode. When heated the tin-cadmium diffuses into the surface of the selenium and creates a semiconductor junction with a forward voltage of around 1V under load, and a PIV (Peak Inverse Voltage) of around 20V.
The low reverse voltage means that for higher voltages the diode plates have to be stacked, and each one adds another forward voltage drop to the stack. This makes the selenium rectifiers much less efficient than modern silicone diodes.
You'll find these in various industrial machines like elevator controllers, bowling pinsetters and various old (but rugged) factory machines. If you're lucky they will still be working, but if you're unlucky the rectifier will have failed with a pungent smell. If you're even more unlucky the rectifier will fail next to you with a loud electrical parp and a jet of extremely stinky smoke that will force you to leave the area.
It's claimed that the smoke is harmful to breathe, but to be honest you're not going to stay around anyway, as the smell is sometimes described as rotten eggs. I'd say it's that plus a sickly sweet smell too.
The modern replacement is the humble 35A block rectifier, which will fit most applications and is easy to mount. It has the advantage of having spade terminals so all you need to do is work out which wires are from the transformer, cut and crimp them, and put them on the AC terminals of the rectifier. Then trace the wires going to the smoothing capacitor and do the same, making sure the positive and negative go to the correct terminals of the rectifier. Changing the capacitor may be a good idea too.
Note that for higher voltage applications the new rectifier will have a lower voltage drop resulting in a higher DC voltage. Although unlikely to be an issue, it may push some older components over the edge. In some instances you may be able to compensate with a slightly lower voltage secondary transformer tap, or a slightly higher voltage primary tap which will result in lower secondary voltage.
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Sometimes I just get the urge to hunt down really dubious listings. It's not hard to find them. These AA and AAA rechargeable cells will probably be OK for solar garden lights, but they aren't quite the capacity claimed.
The internal structure is interesting though. I guess the springy metal mesh is designed to keep the layers jammed together, and against the case.
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