Comments by "SeanBZA" (@SeanBZA) on "Technology Connections"
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Numitron backing is grey because RCA used what they had in spades, the sheet steel with aluminium coat that was used to make anodes and internal structures for thermionic tubes, and this was proven to survive the glass sealing and gettering operations. Thus they used the standard tools they had in the tube plant, the flat anode sheet, slightly formed to be a stiff backing, and punched out the holes needed to hold the filaments. Then used the technology they had to make glass beads with wire in them, and sealed those into the holes, making the filament supports, and then simply used a flat section of that steel wire that was bent over to hold a length of thoriated filament wire, also a common item in the tube shop. Length and diameter calculated for the brightness needed at the applied voltage, and then simply placed in location, the ends folded over, then spot welded together to trap the tungsten wire under slight tension. Then at the rear spot welds to a lead frame attached to a standard off the shelf 9 pin glass base, and you have the complete unit. Glass top attached, and then evacuated with the standard roughing pump, and as a bonus because of the low voltage, and no need to maintain an ultra low vacuum, the roughing pump and the heat sealing of the tube is all that is needed to operate, no need for a getter to be installed, and no need to flash it, just a RF heating during sealing to get a high vacuum, then seal.
Incidentally there were small versions made, the same size as your common 7 segment LED displays, and they were very popular, as they ran off 5V, and interfaced with logic. They worked best using CD4049/50 CMOS level shifting buffers, as those would source or sink 50mA no problem. Using a buffer/inverter per lamp, and a BCD decoder or counter per digit allowed those displays to be bright, and as bonus you could also use the blanking input on the drivers to use PWM to dim them.
Project to replace those displays with LED ones worked, just that it really did not drop display current use, it was still 5A of current at 5V, though it was good in that at least you had a display that now was available, using a tiny HP 7 segment red display. Do one conversion and you had 16 numitron displays to use to fix others, so we only converted 3 boards to the LED version. Biggest problem was the resistor value selected was too low, so the LED displays were running way too bright, so had to be dimmed. Rather than destroying the cordwood board made to fit them, I simply used 2 6A silicon diodes in the common line, to drop the voltage seen by the LED displays down from 5V to 3V8, which made them dim to exactly match the old displays. Those 2 diodes were hard to fit in the limited space left on the display board. Users liked the new crisp displays, the bright version got complaints that it was so bright it was unreadable at night with dark adapted sight, and it lit up the entire cockpit. Display dimming had to match the other display, and that board used unijunction transistors, and had a disconcerting habit of the power transistor unsoldering itself from the wire leads, it ran so hot. Base lead unsolders itself, transistor is still conducting, runs hotter and lamp blows. Select spare lamp and it also blows, unless enough time for transistor to cool below 200C junction temperature. Would have been nice to have had some of the more modern mosfets that can handle 50A, but not at the age of that design.
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@alexanderkupke920 Jet A1 is kerosene that has been dewaxed, removing all the longer chain molecules, so that it will not turn to slush at -40C in the aircraft fuel tanks. The wax that is removed is further classified by melting point, so you get soft waxes that melt around 40C or lower, often sold as Vaseline or petroleum jelly, and harder waxes that melt around 70C, which are used to make candles, and as a base for many cosmetics and shoe polish. Higher melting point waxes are also used in industrial applications for various things.
Diesel oil is very close to paraffin or kerosene, just has a somewhat less and slightly different range of melting and boiling points and density. To further confuse things you also have Rocket kerosene, which is a very highly refined Jet A1, that is designed not to freeze till around -100C, and which also has even less wax in it.
In general you can run the diesel vehicle on kerosene, but it will run poorly, as diesel has additives in it to lubricate the fuel system, which is needed, plus the wax will tend to clog fuel lines and injectors as it flows through and undergoes local cooling. Same for a jet engine, which will run on diesel, though it will smoke heavily, as the fuel is not being fully burnt before it leaves the combustion chamber.
Run a modern GDI engine on kerosene and it will very quickly fail, but older mechanical injection engines do not care, and will run on diesel, kerosene, Jet A1 or even vegetable oil, provided you can get it liquid enough to flow through the pump.
Lamp oil can be also a blend, with it consisting of a mix of kerosene, diesel and even lighter oils and benzene to make it light easier, and also can have aromatic oils added to it to have an odour other than the distinct one.
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Duracell also made blister packs of cells with the tester in, as discussed. The resistive element is actually screen printed conductive ink, which is based on silver powder, in a carrier based on printing ink, screen printed onto the plastic sheet, and then this thin sheet was dried, and the back had the thermochromic ink screen printed onto it, followed by the top layer being thermally bonded, to make a 2 layer sheet with the tester in it. Then the paper insulator was applied, pre punched out for the gap where the thermal heater needed insulation, and the one hole for the switch, the cutting die finishing separating the paper from it's supply roll. This was then punched out, and applied to the large sheet of battery label on the adhesive side, so you had a large self adhesive label, that had a release side applied, and this again got partly cut out, to leave the battery sleeve on the backing layer, excess being weeded off automatically. Then slit into working rolls, and applied on the line.
Very complex, and needing lots of precision sharp cutting dies, so no wonder they decided the much higher cost and complexity per cell was not worth it. Thus the shift instead to use almost the same test unit, just with 2 strips of adhesive on the top, to the blisters, saving a lot of money, as you only had one per 4,6,8 or 10 cells. Then cost was cut again, and with all the assorted contract manufacturers not wanting to pay the cost, they went back to just labeling generic cells off a random production line, as Duracell is now nothing but a brand name applied to whatever generic cell was the cheapest quote to make a few hundred million cells, no quality required as they are running off name recognition. After all, no longer will they replace or repair equipment damaged by leaking batteries, they will only pay you a voucher for the cost of a new set, if you pay to ship the leaking batteries to them, at your own cost.
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One reason they have not replaced them with LED is that they are old controllers, and thus also have old conflict monitors, which are there to monitor all the lights, so that no fault can cause the light to show go on cross directions at all, any fault that might do that will cause the conflict monitor to disconnect the controller and go to a flashing red all round as a safe indication of it being a 4 way stop. Old controllers are there till they run out of spare parts or the pile of others removed from service, and will only be replaced with new controllers when the old ones are out of stock completely.
Newer controllers can have LED drive as standard, but are difficult to retrofit to the old controller, as they probably are from the 1980's, where the controller also had current sensing that allowed remote monitoring of lamp failure, allowing non reported lamp failures to be repaired without having to have a monthly check on all lamps by a crew, and also this showed the relays were working correctly, giving a backup for the conflict monitor.
Had this happen here, where the last 2 Automotor mechanical controllers were replaced eventually with Siemens controllers, hope the old controllers were kept for the transport museum though. On some of the controllers they had to add "cheater" lamps in the controller case to provide enough load to make the controller and conflict monitor happy with LED loads, but as almost all the controllers also had lamp soft start built in the lamp life of 8k hours was more like 20k hours as they were either kept slightly powered by a low current or had soft start resistors to keep inrush current low.
If the municipality wanted to save money they could also just get by replacing the red and green lights with LED, leaving the orange as incandescent, as the 5 second on time per cycle is really low power overall, but red and green are the major power draw. Plus the burst of heat in amber helps to keep the snow off, though here, where the last time snow fell was millions of years ago, extra heat is not exactly needed. Have seen LED clusters showing 2 colours on the same pole, then a 30 second flash as conflict tripped and made it all flash red, before cycling back again to normal for the rest of the timing cycle, and then rinse and repeat.
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Major driver was cost of licence. Sony had a per machine royalty, while JVC was a lot less worried, with both much lower costs and a lot less actual chasing up, so that manufacturers would look up the cost of making a machine design, and choose the cheaper option and make VHS. As well the actual mechanics were easier to make, quite a few clone manufacturers could do the entire machine easily enough, but only found the head drum assembly too difficult, so resorted to buying them as spare parts for larger brands. Did drive Matsushita crazy for a while IIRC, with the number of head drums they were selling to the repair market, till they finally found out why, and probably started offering them as a ready to use part instead, getting in an extra profit for essentially already paid for production capacity. Then the cloners got to the point they could actually make the whole machine in house.
Sony however wanted tight control, which both costs money, and also stifles innovation and changes to the mechanism, while VHS found a solution to big drums in the VHS-C with the smaller drum, faster rotation and extra heads with switching, but which left a standard azimuth track on the tape, which also was used in a few full size smaller units as well. Assorted mechanism types were to get it either smaller, lighter, cheaper, or more compact for some application. Last VHS decks I saw consumer side were essentially one single plastic injection mould of all the parts, integrated with a single sheet metal stamping, to make the deck, complete with all of the tape mounts and eject mechanisms.
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@AaronSmart.online Ceiling fans are a definite must in the tropics and sub tropics ( so most of the EU, aside from those places around the Med, are out), and all of them I have met start off as high, medium and low. mostly because they tend to have bearing issues with time, and the bearings ( or bushings, depending on how old the fan is and who made it) will tend to become sticky with time, but so long as the fan is able to start turning they will run. Thus you start on high, to get the best chance of the bearing getting it's hydrodynamic film built up and thus reducing wear, as a slow moving bearing or bushing is going to have very high loss,, simply because of metal on metal contact.
In general the fans only start to give issues when older, and often I cure it with a new capacitor, as most ceiling fans I meet are not shaded pole types, but split phase. Bearings getting stiff it is possible to lubricate them, but often the housings are pressed together, making it hard to get to them for a good repair, and the modern trend is to use that horrid CCA wire as well.
The ones on my ceilings are around 20 years old, and still work well. The smaller fans almost all are split capacitor, though the old GE fan is rather odd, in that it achieved phase rotation by having variable reluctance in the pole pieces, using thinner sections of the poles to provide a saturating magnetic field. As the field saturates it appears to shift, allowing the fan to start as the field is moving, and not just varying with time, just like the shaded pole does, but without the need for the copper shorting coils to bring about the field saturation in the motor. higher starting torque simply because there is no circulating current in the pole pieces, so more energy available to induce a rotor current, plus the rotor is skewed, so there is a bias as to start direction built in.
Yes 230VAC country, currently ( amazingly) 233.2 VAC , though it can go up to 247VAC at times, but after they replaced the 90 year old transformer across the park (it started leaking from the base valve, so went for repair instead of just a new valve) the newer one ( still around 30 years old, they are refurbished because of the cost of new ones) is set more closely to 230VAC instead of the old one being 240VAC. I lived in a place with the original 130 year old 250VAC supplies, and there cooking was great, but appliance and lamp life was not, though your lamps were extra bright. That will never change, as they would have to replace over 50 transformers at once, so keep the taps on the low side instead to meet spec for high voltage.
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Monochrome CRT you can get to 20k lines with ease, just requires a very small beam diameter inside the CRT, this determines the spot size on the CRT, and you can make a very small spot if you are prepared to have a low brightness. Colour CRT you could get 2k screens, but they were both insanely expensive and a bear to align, and would have colour fringing if you moved them at all, and also would have fringing with any ferrous metal moving nearby them. The most common use for high resolution CRT's was film digitising, using the CRT as a line source and then slowly scanning the film past the line, with a photomultiplier tube getting the video signal off the transmitted light. The resolution possible on the best was better than most film stock. Colour was done using a colour filter wheel or dichroic mirrors to separate the colours and handle them separately, the CRT providing the white light source to drive them. Simpler ones were used regularly to transfer film to video for TV transmission, using a variety of methods to get the video signal off the film at TV scan rates with the film running at 24FPS.
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Well, the 3 colour tube projection TV sets have a non shadowmask display, though the front screen is lenticular to provide a brighter image in the forward view by concentrating the light in that direction in rear projection sets, the ceiling mount ones use just a diffused screen ( or one with a reflective layer to provide optical image brightness gain to the centre for the same reason, higher perceived brightness for the same CRT brightness) to scatter the image in the room. Line resolution in a mono CRT and rear projection 3 CRT set is more to do with bandwidth of the video circuit, or how fast it can go from one predetermined brightness to another predetermined brightness ( typically 80% to 20%) and then how many of these cycles it can do in a single horizontal line before the difference between the 2 levels is no longer displayed. Thus you get the 500 odd pixel display resolution, which basically translates to the roughly 7MHz bandwidth the TV channel has allocated to it, the set cannot display more lines than that without exceeding this bandwidth, and this is the big reason for the resolution. Vertical it is fixed by the number of lines in the interlace, with the 2 half frames each drawing an image with half the lines, then the other half of the frame filling in the image in the blank space between the lines drawn on the other half of the frame. Overall it looks like a single image, but it is 2 with a line offset between them, the eye integrates the 2 half frames into a single one.
With monitors that are not TV sets you can get higher bandwidth, up to 70MHz or more for the last of the CRT monitor displays, which meant you could get much higher resolution, allowing you to use a much finer pitch shadowmask in the CRT to get a sharper image, though the trade off is both more complex alignment in production, more complex drive circuits to get the beam to stay aligned perfectly in all the positions it scanned on the display, along with the smaller phosphor dots meaning you had to drive them with higher power to get a bright image, thus the big risk of image burn on these CRT units. CRT displays also used an aluminium sputtered backing on the phosphor layer to reflect light back to the front instead of losing it in the inside of the CRT, which did not affect the electron beam, but which doubled the brightness, though the thick dark glass reduced this again to give increased contrast ratio on the image..
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@willford7717 To be fair to company coffee, it does taste crap even when fresh, simply because I will bet you nobody has ever stripped the machine and cleaned the basket, or even the carafe, let alone run descaler through the water circuit.
I do go to a place where they have the automatic machine, and the first thing I do there before pressing is run the cleaning cycle, which puts out a lot of nasty gunk every time. Then select espresso, and then cappuccino, and pour the first into the second. Only ever tried the stuff they call tea once, it tasted terrible, sort of vaguely tea like smell, but it was definitely not a good tea at all.
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How about coffee bags, which is ground coffee in a tea bag, which you brew in a tea pot, exactly the same as tea, or in the actual cup itself, like a tea bag, removing when at the desired strength, and enjoying the brew as you like.
Me, I drink instant coffee, and yes there are some brands that are better used as brown colour for dirt, but there are a lot of instant coffee blends on the market. Filter yes if I am out, but for what you get at the price, it is not always worth it. I go past the overpriced green logo coffee place to the shop behind them, which serves to my taste a better brew, and at the same time I can indulge in my fast food meal, a chicken salad with hot sauce, and peri peri chicken livers. Place the order and 2 cups, first for while I wait, and second for the walk home.
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In floor ones also come with a cam and spring, because they are almost always dual action, able to open either way. Made so you do not need a left and right one for double doors, only a single box buried in the floor, and the closer screwed to it. They do have speed adjustment for each side separately, so you can adjust them to be one direction only by screwing the other side valve all the way in, so it will not allow flow. they are also able to handle much heavier doors as well, and last for decades. Most common make by me is dormer, known to last a half century in use. They can also be rebuilt as well, as dormer does have kits of spare parts for them as well. you do need however to demount the door to do so, which means you need to pick up a very heavy door off the lower pivot after you unscrew the lever that retracts the top pivot. Or in the case of the one side, cut through the pivot on top first, as the adjuster had rusted solid in the 50 years of being there, so I got the 2 new complete units, and the one door was a breeze, just needed Rockset 5 minute cement to fit the new box in the old one, but the other one needed 2 days of work to get the door hardware off, and the new hardware on. Lots of 5 minute epoxy and wood to fill holes from old screws, and then grind the new socket to fit the pin, and same for in the frame.
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@danl6634 I installed an inrush limiter on a 7.5kW motor, because the original installer connected the DOL starter incorrectly, and it was starting in delta, then switching to star. Then dropped a phase in the one contactor due to arcing or dust. I replaced the lot, plus put it all, along with the 7.5kW soft start unit, into a dust proof cabinet, and set run up time to 30 seconds. Solved the issue of the unit tearing itself out of the floor bolts. Of course the biggest issue was to remove that 130kg cast steel frame motor from the gearbox, where the shaft was kind of not willing to separate, even hanging the entire motor mass off it. Had to use a BFH and crowbars, and the trolley I had under it suffered badly. New one was light, only 78kg, so easy to lift up with the chain block, and that shaft was well greased.
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@TechnologyConnections The way those work is to use either the condensing coil fan to sling the water over the condenser coil, or to use a condenser coil below the evaporator coil, so it drips down via gravity and then is channelled over the condenser fins. This then allows the evaporating water to provide extra cooling for the coil, improving efficiency. The big drawback of this is the uncoated coils corrode really fast, and in general only last 3-4 years before they are only a mass of corrosion products on the inside, blocking the air flow, and bare piping that is running hotter than safe ( higher pressure, greater erosion inside the microgrooved pipes, oil breaking down from the high temperature into acid and carbon) and ultimately failing. Outside they look fine, but are totally blocked once you get to the fan chamber.
Window wall units do the same, unless you remove the rubber bung and install the optional drain line, though most of the new ones do not come with a drain, and expect you to replace the entire unit after 4 years, from the case and coils being rotted through. Note the warranty is only 3 years on the compressor only, the rest of the unit is only statutory warranty ( often a year) and in general you find they never get a warranty claim, as if the compressor fails within 25000 hours ( they rarely do, even though they are cost cut way down, but that is another story) that is a rare failure. Coils however are often badly rotted after only a single season if you live near the sea, like I do.
Split units have to have the 2 drains, though often the outdoor unit drain is rarely installed, as in heat pump mode the outside air will be very low humidity anyway in winter. They do build up amazing amounts of sludge and bacteria though unless regularly serviced and cleaned. The inside plastic parts are black, so the sludge mat does not show visibly, even if the rest of the unit is light coloured plastic.
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Not as critical, as the interference pattern causes a large variation in return light, but any pit approaching the required depth causes some interference, and the return light is less. The receiver in the player is not too concerned about the actual variation, just that, relative to the transmitted light returned from the smooth surface, there is some loss, and that this is enough for the player to discern the pits from the lands. There is a variable gain stage that compensates for the variation in return before the data slicer in the laser electronics turns this very analogue voltage into a digital signal for further processing. This analogue voltage is also filtered and forms part of the focus, as it tracks the average distance between the laser focus lens and the actual data layer on the disk, and the lens is kept a constant distance despite the actual disk having variability of up to 2mm per rotation in use.
Then there is the fact the receiver is actually 4 separate photodiodes in a quadrant, so the signal is the sum of all of them, but the difference between opposite pairs of the diodes is used as info for the focus system and the 2 linear tracking servo loops that keep the laser beam following the single long spiral track faithfully, despite it not always being concentric in the disk itself.
Incidentally almost all the laser modules were developed by Sony, and you find a whole range of KSSxxx laser modules used in CD and DVD players, all operating on pretty much the same principles, but with various layouts and mounting methods used in them for various players. Now almost an industry standard module, often no longer made by Sony, but still with the KSS part number.
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Same for washing machines, I live in a soft water area, so use a quarter of the "manufacturer recommended" dose, and it works well, with no residue, and no floating growth in the machine either. Also not connected to hot water, and the generic Unilever store brand detergent as well, because, shockingly, the biggest difference between brands is the scent package, and the amount of brighteners added, along with possibly a slightly different amount of borax as filler.
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Not mandatory here in South Africa, but many of the new units come with this by default, as the units are imported and thus they comply with the big US market safety and ancillary wise. Older units do not have anything other than chimes, and some that are from the 19th century are still in use, just having to have safety upgrades ( door glass with safety glass instead of window glass, inner doors instead of the lattice steel, an emergency light and bell in the car) to comply. The new ones are almost always, in a retrofit or as a lower cost add on to existing structure, a motor room less one, and the hydraulic powered elevator is almost unheard of here aside from in some very old, no longer approved for passenger travel, goods hoists that have no in car controls or lighting. Even a goods hoist new has to comply with passenger car regulations.
When you upgrade an older unit ( controller and car interior upgrade, replacing only the inner skin, the floor and the lighting, plus the call panel and trailing cables, along with a new controller driving the existing motor and gearbox, sheave and cabling and shaftwork) you typically get the audible signals and direction signs as part of the package, though they might not be installed in some buildings due to lack of space and no wall boxes.
Your building I would speak to the elevator service company, and they can plug the modules back in to the controller, and simply unscrew each panel and use the volume control built in there to drop the volume down to quiet. Suggest to the building owner that the penalties for non compliance with the ADA are pretty high, and deliberate non compliance can result in multiple lawsuits against them in person.
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There is no audio in that application, just video, and often just mono video as well, as this needed less memory. Most switchers used a 2k RAM chip and a video flash ADC to sample the video, using 4 sample and holds to drive the ADC, and using the sync signal to determine where in the RAM to do the write. Output was a simple scan of the entire RAM to a DAC to generate video. The one I have somewhere used a Z80 and a 6116 SRAM for memory, with the control program being in a 2716 EPROM, plus the flash converter and a quad SH chip, along with some simple sync detection. Unused inputs would be set to a blank screen, and it could either do 2 or 4 on a single output, or switch in sequence, genlocking the output so the TV would not twitch during the switching.
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The fob on car works well for metros, who use a particular chain in the area, and thus all the vehicles can simply come in, and fill fuel. At the same time the CCTV also captures both the vehicle details, driver details, and the link also does double duty, with it also transferring info about mileage driven as well, so this all is automatic. The vehicles that either fill up too much, or who do not match the description on file, are all flagged automatically.
I had the same, a tag that worked at the local garage, simple to go there, tap and fill up, no other things, as each driver had the tag linked to them, not the vehicle, but the recon at the end of month would have all data available, so looking up this was easy, just email a query, and it came back a day later complete with images and full data from the pumps themselves.
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