Electrical Engineering V3 - Developers

[IMG]http://i.imgur.com/lHb7viu.png[/IMG] [del]I cannot find this bastard anywhere. It's a DC buck controller from the power board of a dead television. It has the markings 63E06 627 and there's another similar circuit with the same IC labeled 73E14 00A so it seems to be labeled with a serial number/date code and not a part identifier. I went through every datasheet on digikey for the sot23-6 buck controllers and found nothing that matched the pinout which I am positive is correct. I really truly hate surface mount parts.[/del] The parts are On-Bright OB2263 and OB2273 Current Mode PWM Controllers

[QUOTE=No_Excuses;50173242][IMG]http://i.imgur.com/lHb7viu.png[/IMG] I cannot find this bastard anywhere. It's a DC buck controller from the power board of a dead television. It has the markings 63E06 627 and there's another similar circuit with the same IC labeled 73E14 00A so it seems to be labeled with a serial number/date code and not a part identifier. I went through every datasheet on digikey for the sot23-6 buck controllers and found nothing that matched the pinout which I am positive is correct. I really truly hate surface mount parts.[/QUOTE] Don't hate on SMD now. The problem is that TV manufacturer often produce in quantities high enough to get custom labelled ICs from manufacturers. They do this to prevent people from doing exactly what you're doing: repairing their TVs. That way they can sell more TVs.

[QUOTE=nuttyboffin;50169431]How high of a current IGBT do you think you could make?[/QUOTE] From the simulations, not a lot. This class was to teach design and fab. Other devices were also put on the wafer such as BJTs and FETs. Because of this, our fabrication process was full of compromises to make sure everything works. Oxidation/diffusion times/temperatures and ion implantation dosing and energies were all compromised thru a lot of simulations from atlas and athena. The tests for the IGBT works but at limited capability. [QUOTE=LoneWolf_Recon;50170579] What lithography are you working at and equipment? My current VLSI classes has me designing at 600nm. (With the entire class getting all our flip flops being fabbed). [/QUOTE] The university has a clean room which we are using. The litho machine is a Suss Aligner. We're at like a 5um process (almost like we are in the 1970s) so that there is a higher chance that everything will work. I'm also in a class that uses a .5um process were we create a layout and send it to Mosis for fab.

[QUOTE=No_Excuses;50173242][IMG]http://i.imgur.com/lHb7viu.png[/IMG] I cannot find this bastard anywhere. It's a DC buck controller from the power board of a dead television. It has the markings 63E06 627 and there's another similar circuit with the same IC labeled 73E14 00A so it seems to be labeled with a serial number/date code and not a part identifier. I went through every datasheet on digikey for the sot23-6 buck controllers and found nothing that matched the pinout which I am positive is correct. I really truly hate surface mount parts.[/QUOTE] You could always take a newer one, and hand wire it in. That would be one way.

Work in progress, making changes to electronics desk. [t]http://i.imgur.com/iRFQ1YY.jpg[/t]

[QUOTE=nikomo;50181127]Work in progress, making changes to electronics desk. [t]http://i.imgur.com/iRFQ1YY.jpg[/t][/QUOTE] Needs more desk. [t]http://u.cubeupload.com/Chryseus/im4wlE.jpg[/t] (yes I've made no attempt to clean it)

I've got plenty of desk, I'm just lacking in equipment. [t]http://i.imgur.com/hPkOApk.jpg[/t]

Its an unsung rule that every workbench should have a decently sized whiteboard.

I would post mine, but i think the mess would give people cancer. I have too many bits and bobs. And empty cans.

[t]http://i.imgur.com/lcxJQAb.jpg[/t]

Nice collection. Your desk must be one sturdy bastard. [video]https://youtu.be/21pmwwPpKKA[/video] Ignore the narration, this video was to help me get a PLC Programming job (which I did get!).

We've got one of those nixie signal counters but we don't have the power cord for it. It's too bad because 1) nixie tubes are awesome and 2) we need a better counter than the one we have

[QUOTE=papkee;50187272]We've got one of those nixie signal counters but we don't have the power cord for it. It's too bad because 1) nixie tubes are awesome and 2) we need a better counter than the one we have[/QUOTE] That is a bummer, you could surely either modify the counter itself with a standard IEC connector or perhaps even hard wire it? Good excuse to take the covers off as well, its quite a work of art inside. One of my HP5245L nixie counters has a HP 5257A transfer oscillator plugin that allows it to count to 18GHz instead of the standard 50MHz, which is quite nice.

If I want to put my lamp on a timer, I need a 120v relay, controlled by 5v high, right? [editline]23rd April 2016[/editline] Controlled by arduino, that is

[QUOTE=proboardslol;50189228]If I want to put my lamp on a timer, I need a 120v relay, controlled by 5v high, right? [editline]23rd April 2016[/editline] Controlled by arduino, that is[/QUOTE] Yes a 120V relay with a 5V coil will do, make sure the current rating is in excess of what your lamp requires. Also do not attempt to drive a relay directly with your arduino, the coil current is typically higher than what a GPIO pin can provide, the below circuit will do the job safely: [img]http://i.imgur.com/tAAJTCg.png[/img] Do not omit the diode as you risk destroying the arduino from the high voltage spike produced when a relay turns off, 1N4007 will do the job fine, use a general purpose NPN transistor like 2N3904 or similar. Also if this is your first project involving mains make sure there is no connection between the high voltage and low voltage side (note the different ground symbols), if in doubt post a picture of your setup and someone here will help you out.

Depending on the current draw through the transistor, you may want to specfically use a fast-switching diode such as Schottky, and even go as far as incorporating a DRC snubbing circuit (very simple to build). Could save you a lot of heartache in the end.

Or check to make sure the relay its self has a diode in it. Many of them come with one build in.

[QUOTE=Chryseus;50189742]Yes a 120V relay with a 5V coil will do, make sure the current rating is in excess of what your lamp requires. Also do not attempt to drive a relay directly with your arduino, the coil current is typically higher than what a GPIO pin can provide, the below circuit will do the job safely: [img]http://i.imgur.com/tAAJTCg.png[/img] Do not omit the diode as you risk destroying the arduino from the high voltage spike produced when a relay turns off, 1N4007 will do the job fine, use a general purpose NPN transistor like 2N3904 or similar. Also if this is your first project involving mains make sure there is no connection between the high voltage and low voltage side (note the different ground symbols), if in doubt post a picture of your setup and someone here will help you out.[/QUOTE] You can buy [url=http://www.amazon.com/JBtek-Channel-Module-Arduino-Raspberry/dp/B00KTEN3TM/ref=sr_1_3?ie=UTF8&qid=1461471137&sr=8-3&keywords=relay]relay modules[/url] on amazon that do those already.

[QUOTE=Chryseus;50189742]Yes a 120V relay with a 5V coil will do, make sure the current rating is in excess of what your lamp requires. Also do not attempt to drive a relay directly with your arduino, the coil current is typically higher than what a GPIO pin can provide, the below circuit will do the job safely: [img]http://i.imgur.com/tAAJTCg.png[/img] Do not omit the diode as you risk destroying the arduino from the high voltage spike produced when a relay turns off, 1N4007 will do the job fine, use a general purpose NPN transistor like 2N3904 or similar. Also if this is your first project involving mains make sure there is no connection between the high voltage and low voltage side (note the different ground symbols), if in doubt post a picture of your setup and someone here will help you out.[/QUOTE] Thanks. I don't have any components yet (or even breadboard or soldering iron), so I'm in the"learning phase" [editline]24th April 2016[/editline] Trying to do some home automation. Still trying to figure out how to automate my blinds (can't replace them, apartment complex owns them)

is 1.8A too high for the collector pin on a tip120 transistor? The absolute maximum is rated for 5A, which it says is still too high My transistors are getting hot

[QUOTE=proboardslol;50193763]is 1.8A too high for the collector pin on a tip120 transistor? The absolute maximum is rated for 5A, which it says is still too high My transistors are getting hot[/QUOTE] heatsink it, otherwise go for mosfets, like the IRF540,

A MOSFET, because of it's much greater switching speed compared to a BJT, will definitely need a more advanced snubbing circuit. reverse emf, is equal to "change in current / change in time". If you don't use a snubbing circuit, at least make sure your snub diode is able to handle the current, voltage, and power pulse when the coil field collapses.

[QUOTE=the420DEWD;50194023]A MOSFET, because of it's much greater switching speed compared to a BJT, will definitely need a more advanced snubbing circuit. reverse emf, is equal to "change in current / change in time". If you don't use a snubbing circuit, at least make sure your snub diode is able to handle the current, voltage, and power pulse when the coil field collapses.[/QUOTE] I've never had an issue with using a regular old 1N4007 for snubbing, even with MOSFETs, a RCD circuit has a slower response than just a diode (unless there is some design I'm not aware of) which is of benefit in switching converters such as the flyback which utilises the back emf and certain motors. Forward recovery time (which is of importance here) is much less than the reverse recovery time so I doubt diode selection would be critical, even if the MOSFET enters reverse breakdown the total energy is unlikely to cause damage to your typical MOSFET in this situation. [QUOTE=proboardslol;50193763]is 1.8A too high for the collector pin on a tip120 transistor? The absolute maximum is rated for 5A, which it says is still too high My transistors are getting hot[/QUOTE] The maximum current rating isn't the only consideration, there is also the power rating, a given package can only dissipate so much heat before you require a heatsink, this is typically specified on the datasheet although I'm not surprised you missed it, power dissipation is given twice once for no heatsink and once for an ideal perfect heatsink. [img]http://i.imgur.com/nuJdpNS.png[/img] As you can see this shows 2W (at 25c ambient), the power dissipated by the transistor when fully switched on is roughly the collector-emitter satuation voltage multiplied by the collector current, in your case that's about 1.1V * 1.8A = 1.98W. So no surprise it's getting quite hot. (Also this is the reason why you should always think twice about using darlington pair transistors in switching applications (actually any application), their typical CE saturation voltage can be as high as 2V leading to high power dissipation, the sziklai configuration is much more preferable imo having the same CE saturation (0.3V) as a single BJT, as well as low VBE drop, either that or use a MOSFET.)

Hello Facepunch EE. Longtime lurker here with a question that I hope you can help with. So I have this Sunpak CL-3 NiCd battery pack for a handle mount flash, but the cells have gone bad so I'm going to rebuild it. After taking it apart, I found this. [img]http://i.imgur.com/LtzoGJ0.png[/img] Note that fuse S1 was found broken and I'm only assuming R1 is a thermistor (it's a small rectangular metal can that was taped to one of the cells in the pack). Also, R1 was built into the pack at manufacturing time (a Sanyo Cadnica 1800mAh 4.8V pack), while the other components are external and put there by Sunpak. Finally, the markings on R1 may be "488" instead of "48B" or "045G" instead of "046G"; it's a bit hard to tell for sure. I think the diode is there to protect against reverse polarity, and the thermistor from overcharging. (The official chargers is just timed I think, and it would explain why these components are only in the charge path, with the flash only seeing the raw battery). My main source of confusion comes with the fuse, S1. It's not meant to be replaced, being soldered in and further enclosed in something that I doubt was intended to be user-serviceable. Being in parallel with the diode it seems to be defeating the purpose. Also, with a rating so high I can't see any situations in which it would actually blow. Knowing its resistance might be useful, but since it's blown I can't measure that. Anyone know what's going on in this design? Also, since I'm going to be using a (smart, peak detecting) RC charger, I'm planning on just going direct from the battery to the charging jack (J1). Will this be problematic at all? As far as I know that's basically how RC batteries are made (no components, just cells and wires) and that's what the charger is used to.

[QUOTE=ddrl46;50186467][t]http://i.imgur.com/lcxJQAb.jpg[/t][/QUOTE] Is all of that calibrated?

Power supply would not come up. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_1276.jpg[/IMG] Huh. Usually when I find a failed transformer it makes a hell of a mess. This one just got...really really hot, presumably from a saturated core and melted the plastic partitions until eventually a winding presumably shorted. There's no damage to the surrounding components or board.

[QUOTE=Aathma;50218134]Is all of that calibrated?[/QUOTE] I have verified the specifications of most of my equipment with calibrated test equipment like my multimeters and a couple of calibration devices. Stuff like for example my HP8660C RF synthesizer I have fully gone through and adjusted, same goes for my HP 8756A network analyzer.

Have you guys seen this [url]http://limesdr.org/[/url] ? A 300$ (though 200$ early bird) USB 3.0 SDR with transmit and receive capability. Anything I'm missing or is this actually as great as it sounds?

All depends on the software the ends up running on/with it. If it has serious support for ham HF/VHF/UHF operation then it might be a good investment. After all, and SDR relies entirely on the "S" - software.

[QUOTE=papkee;50226773]All depends on the software the ends up running on/with it. If it has serious support for ham HF/VHF/UHF operation then it might be a good investment. After all, and SDR relies entirely on the "S" - software.[/QUOTE] They claim "Programming toolchain packages: GNU Radio, Pothos, SoapySDR, UHD." as per [url]https://www.crowdsupply.com/lime-micro/limesdr[/url]