hybridfree/eevblog-posts huggingface dataset:
Supply current information - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: August 31, 2024, 04:25:33 am
content: I am using this IC (https://ww1.microchip.com/downloads/aemDocuments/documents/UNG/ProductDocuments/DataSheets/USB251xB-xBi-Data-Sheet-DS00001692.pdf) and this IC (https://www.nve.com/Downloads/il5xx.pdf)For the USB Hub IC, I will be using one upstream port and 2 downstream ports. In that case, what should be my supply current?​I found in the table 6-4, page 41 of the USB datasheet, since both the downstream ports will be High speed, it mentioned 85mA per downstream port, but also mentions the in the last row of the table as "1 port base +25mA "I am not able to understand what does 1 port base +25mA mean? And why and when I should include in my calculation?I thought since I am using 2 downstream ports, my supply current would be 2*85mA = 170mA. Am I correct or missing something? And I am planning to use 480Mbps high speed.And for the isolator part, the total supply current is mention as input supply currents on page 8 which are less than 10mA values? Can I take those values for both VDD1 and VDD2 supply inputs? Can someone clarify?
Supply for valve equipment - Page 1
Forum section: electronics / beginners

author: medical-nerd
author_rank: Regular Contributor
timestamp: December 23, 2019, 08:14:47 am
content: HiyaI've just obtained a valve power supply giving approx 300V DC plus heater output. I want to use this as the supply for a 'valve breadboard' where I will be building valve receivers using subminiature valves such as the DC70 and more normal valves.I want to supply a range of voltages : 300V, 150V, 100V, 50V depending on the design.What would be the easiest way to do this - is a simple resistive divider the best choice??CheersSteve

author: Gyro
author_rank: Super Contributor
timestamp: December 23, 2019, 09:34:07 am
content: This circuit is fairly ubiquitous...https://www.elcircuit.com/2012/07/0-300v-variable-high-voltage-power.htmlIt's performance isn't great (it uses the incoming 300V rail as it's reference) but it is cheap to implement and does have rudimentary current limiting (at the risk of cooking the Mosfet). It ought to be good enough for basic dropping of the HT rail voltage for low current use though.

author: Jwillis
author_rank: Super Contributor
timestamp: December 24, 2019, 03:22:40 am
content: Aside from the filament the rest of the valve doesn't require a whole lot of amps. The DC70 uses around 200mA at 1.25 V for the filament but the rest will at most take 25mA at 150V .You could simply get some medium amp zeners . Just series them to get the appropriate voltages between each zener. I did this to make a supply for a tube radio and its still works great. Something similar to the circuit below.The value of the zeners can be any combination you need .
µSupply, portable battery powered power supply - Page 1
Forum section: electronics / beginners

author: Mr_Auto
author_rank: Newbie
timestamp: October 07, 2018, 08:18:36 pm
content: Hii was thinking recently of making small battery powered power supply, i came across Dave's µSupplyhttps://www.eevblog.com/projects/usupply/it seem very simple and straightforward, i wanted to stay at 'part 3', so no digital control, just 2 pots, maybe change the regulator to TL3083of course, that design is from 2011, and had some major changes in actual schematics for digital control in rev A,B,C as opposed to schematic i captured from videoi even made that schematic in EasyEDAhttps://easyeda.com/Mr-Auto/Zasilacz-podr-cznySo question is, is it good idea? i really like the linear nature of this circuit and having range from near 0Vshould i change approach, maybe go with other ic?what your idea of this whole concept?

author: ogden
author_rank: Super Contributor
timestamp: October 07, 2018, 08:50:48 pm
content: Quote from: Mr_Auto on October 07, 2018, 08:18:36 pmIn case you pick lt3081, circuit will become very simple, like one shown in theproduct page. You need to replace Rset and Rilim resistors with pots and basically that's it. Note that Dave's supply you show, have slow current regulation speed. It can exceed set current for quite a time - when load is connected to enabled output of the supply.  Just noticed that LT3081 have quite low resistor as "default load". You better take that part from Dave's circuit or even better - design current mirror so it works at leastdown tobelow 1V.
Supply voltage for DC backup switch/relay - Page 1
Forum section: electronics / beginners

author: pwnell
author_rank: Regular Contributor
timestamp: July 13, 2024, 11:43:42 pm
content: Considering this device on Amazon:https://a.co/d/8RwpMJlIt specifically mentions it works with 12 - 48V IN/OUT. They also mention that the IN1, IN2 and OUT voltages must be the same - i.e. battery, DC supply and load must share the same voltage level. I cannot identify the small IC on the circuit board to understand what they use for voltage regulation / detection, but my question is - if I have 24V DC supply, 12V battery and a load that accept 12V and 24V, can I use this in principle? What is the danger of using different battery and DC supply voltage if the load can deal with it just fine? If there is a real issue, would a strategically placed diode fix this?

author: Whales
author_rank: Super Contributor
timestamp: July 14, 2024, 12:29:04 am
content: What they're probably trying to say is that this board does not do voltage conversion. If you input 17V then it will output 17V. They have probably had customers misinterpret the 12-48V rating to mean they can wire any combination of things within that range to it at the same time.The SOIC8 chip has an inductor next to it, so it's probably a switchmode power supply (to provide 12V for the relay coil). At a guess they'd be using the ENABLE pin on this chip to detect whether or not the relay needs tripping.> if I have 24V DC supply, 12V battery and a load that accept 12V and 24V, can I use this in principle?Maybe. I'd have to reverse engineer the whole circuit on that PCB and get the datasheet for that chip. With certain wiring arrangements itmightcause the switchmode chip to fail.

author: pwnell
author_rank: Regular Contributor
timestamp: July 14, 2024, 03:55:51 am
content: That is what I thought. I will post the part number of the IC once the unit arrives.

author: calzap
author_rank: Frequent Contributor
timestamp: July 14, 2024, 07:44:05 am
content: It’s basically a cheap UPS. Most of the onboard circuitry is probably there to provide 12 VDC to the relay coil from the non-battery power source via the power adapter terminals. When adequate power from that source is available, the relay directs it to the output terminals. When adequate power from the non-battery power source is not present, the relay connects the battery input to the output terminals.Shouldn’t matter (but no guarantee) if the battery and power adapter are different voltages. Even if the adapter and battery started at equal voltages, circumstances could easily cause them to become different. For example, the battery could lose charge over time or the adapter could slowly fail.Mike

author: pwnell
author_rank: Regular Contributor
timestamp: July 18, 2024, 12:23:17 am
content: It is this guy:https://www.lcsc.com/datasheet/lcsc_datasheet_1811081614_XLSEMI-XL7005A_C50848.pdf
Supplying both DC and AC power to a device? - Page 1
Forum section: electronics / beginners

author: MatazaNz
author_rank: Newbie
timestamp: April 10, 2019, 10:01:33 pm
content: I'm building a very simple dehydrator that utilises a 12v PC fan, and a 275w heat lamp bulb. To begin with, I'm just going to have a standard AC extension cable going into a dual outlet splitter. A cheap 12v DC power supply in one outlet, and the other outlet going to the heat lamp (Well, the socket the heat lamp is screwed into). While this will work fine for my uses, it will be very hacked together, and I feel like I can take it as a learning opportunity.My initial thought is to have an IEC socket input, like a standard PC power cable, then have that going to a power supply, which will give a 220v AC output line and 12v DC output line. However, I don't know if I'm able to have a power supply output both DC and AC, or should I split the AC input before the power supply and only have a DC supply?I'm only just beginning to learn electronics (I have a basic understanding, after watching Dave for a little while, and reading material online), so forgive me if there is something obvious I'm missing. Is this something that I should try not messing with right now?

author: ArthurDent
author_rank: Super Contributor
timestamp: April 10, 2019, 10:11:39 pm
content: If the heat lamp is rated to operate from 220 then there is no reason not to connect it directly to the 220 line where it comes into the dehydrator on the IEC connector. Wire fuses and switch in the circuit as well.

author: MatazaNz
author_rank: Newbie
timestamp: April 10, 2019, 10:19:58 pm
content: Quote from: ArthurDent on April 10, 2019, 10:11:39 pmMakes sense. So I can split the output (Or would it technically be input?) from the IEC connector into 2, and have one line going directly to the lamp, and one going to a DC supply? Is it really as simple as that? Switches and fuses are definitely on my list (One input fuse, and a switch each for the fan and the lamp is what I'm thinking)

author: ArthurDent
author_rank: Super Contributor
timestamp: April 10, 2019, 10:33:47 pm
content: If you can find one of the combination IEC/fuse/switch combinations you could make the wiring simple.https://cdn.instructables.com/FFJ/JLT1/IYB2EI0X/FFJJLT1IYB2EI0X.LARGE.jpg

author: james_s
author_rank: Super Contributor
timestamp: April 11, 2019, 10:14:11 pm
content: Yes you can wire up both the power supply and the lamp to the same IEC socket, this is no problem at all. Keep all the line voltage connections safely isolated from anything conductive and keep the low voltage wiring away from the line voltage wiring.
Supplying op amps with full wave rectfier  - Page 1
Forum section: electronics / beginners

author: Asim
author_rank: Regular Contributor
timestamp: September 05, 2014, 03:52:16 am
content: Hello allI am working on a power supply design and i will be using op amps in the design, so instead of using a regulator to power the op amps, can I use the rectified voltage as a supply for the op amps ? Is it good idea in terms of stability?

author: Dave
author_rank: Super Contributor
timestamp: September 05, 2014, 04:12:43 am
content: It all depends on the opamps you choose and their PSRR (power supply rejection ratio).Generally, it would be a good idea to put some voltage regulators there. You could make them as crude as zeners with emitter followers, if you absolutely want to avoid using voltage regulators.Edit: Corrected a typo.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 05, 2014, 06:06:40 am
content: Where would you ever have rectified but unfiltered DC in a power supply circuit??

author: David Hess
author_rank: Super Contributor
timestamp: September 05, 2014, 01:45:43 pm
content: Quote from: T3sl4co1l on September 05, 2014, 06:06:40 amI think he means unregulated but not unfiltered.I would include a simple zener shunt or series regulator to protect the operational amplifiers from voltage surges.As Dave points out, ripple is only a problem if the power supply rejection ratio of the operational amplifiers is low. In precision designs, PSRR may be a limiting factor.
Suppressing sparks when attaching buck converter to battery - Page 1
Forum section: electronics / beginners

author: darellon
author_rank: Newbie
timestamp: December 13, 2016, 12:43:55 pm
content: Hi all,i have bought a cheap DC/DC converter (24v to 19v, 15A,http://www.current-logic.com/shop/index.php?main_page=product_info&cPath=5&products_id=319). When i attach a 24v battery pack to the converter input i get sparks. Is there any way to suppress these sparks when i attach the converter?

author: Cliff Matthews
author_rank: Unknown
timestamp: December 13, 2016, 12:59:48 pm
content: Welcome. How big is the input cap on the converter? For simplicity, put a switch in series and turn it on after you connect, or rig-up a series pass low rds MOSFET with a delayed gate drive (just don't let it turn on slowly).
Suppression Diode - Unknown Polarity  - Page 1
Forum section: electronics / beginners

author: aaron
author_rank: Regular Contributor
timestamp: November 16, 2015, 11:58:22 am
content: Hi Everyone,I'm building a gate controller using two SPDT relays to control an actuator. I've suppressed both relay coils with a 1N4004, which is fine. (I think). But the output for the actuator also needs suppression, correct? But the polarity reverses every time I reverse the direction of the actuator motor. What should I be doing in this application?Also, should I be adding 1nF capacitors parallel with the coils?Thanks!

author: Jeroen3
author_rank: Super Contributor
timestamp: November 16, 2015, 12:00:02 pm
content: You can use a bidirectional TVS diode.
Surface coating and electrical conductance - Page 1
Forum section: electronics / beginners

author: nukie
author_rank: Frequent Contributor
timestamp: May 31, 2011, 02:04:03 pm
content: Hello all, I have a question. Google gives me answer my small brain could not understand, so I need help.I read that AC current travels on the surface of a conductor. So given two different conductor made out of different material, say brass and nickel. Coat it with gold. Now both have same surface resistance, so what about electrons flow rate ? Assuming both conductors are equal in physical dimension.

author: Zero999
author_rank: Super Contributor
timestamp: May 31, 2011, 02:20:02 pm
content: It's only true at high frequencies which is why silver plating high frequency conductors is useful in reducing their resistance.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 31, 2011, 02:30:34 pm
content: A warning on silver plating.Normal plating as used for sporting trophies,etc has additives to increase the brightness &durability.These increase the RF resistance to a higher figure than plain copper.Special plating is used for RF conductors.VK6ZGO

author: Time
author_rank: Frequent Contributor
timestamp: May 31, 2011, 05:52:53 pm
content: You should read about the skin effect. Thats the phenomenon you are interested in.http://en.wikipedia.org/wiki/Skin_effectAll AC currents know this effect it just becomes more apparent from an engineering stand point in higher frequencies. I believe the skin depth for 60 Hz in copper is about a cm or something.

author: nukie
author_rank: Frequent Contributor
timestamp: June 03, 2011, 03:29:41 pm
content: Yes skin effect is what prompted my question.I was looking at my meter probes and some banana jacks and it got me thinking why some are gold plated while most are chrome/nickel plated. I prefer standard plating, gold would be too soft and wear out too quickly especially around the contact areas.Now I also understand why those high frequency wifi antenna jacks are mostly gold plated. Thanks guys!

author: the_raptor
author_rank: Regular Contributor
timestamp: June 03, 2011, 04:06:25 pm
content: Gold oxidises less then chrome/nickel AFAIK. It might wear off from frequent disconnection and reconnection but it won't easily build up an oxide layer thick enough to impede electrical current.In PC repair I have seen non-gold plated connections fail after a handful of years and require cleaning.

author: Zero999
author_rank: Super Contributor
timestamp: June 03, 2011, 06:03:30 pm
content: Quote from: nukie on June 03, 2011, 03:29:41 pmThen you've completely misunderstood.Connector are gold plated to improve corrosion resistance and has nothing to do with the skin effect. Copper is a much better electrical conductor than gold and is much cheaper too. Gold plating reduces the contact resistance because an insulating oxide doesn't form on it.http://en.wikipedia.org/wiki/Electrical_conductivity#Resistivity_of_various_material
Surface mount high power LEDs among some other things - LED plant light - Page 1
Forum section: electronics / beginners

author: Ilmarinen
author_rank: Newbie
timestamp: January 03, 2015, 10:26:50 am
content: I'm building a plant light for home. I have built one previously using the Luxeon Rebel Color Stars - The ones that were already mounted on PCBs. It seems like the PCB versions are quite limited in availability, though. Of course it need not be necessarily Luxeon Rebel Colors as long as the chip is good and the wavelength is suitable.What I would like to ask the people here is that how is working with the bare LED chips? They seem very small and a hassle to work with. Also with the cathode and anode mounted on the same side as the thermal path they would require some isolation/grinding in order to glue them to a piece of copper for heat dissipation.I'm thinking about 150-200 ?mol/s*m^2 and looks like it would be 30-40 high power LEDs. What kind of powering option would people recommend for that? Previously working with 10 LEDs I just used a constant current driver - Should I just go for a 100+ Watt constant current driver for this too?I attached the spectrum of the lamp I previously built - I am probably making a similar spectral composition but also adding some white LEDs to get at least some of the rest of the active spectrum.

author: SeanB
author_rank: Super Contributor
timestamp: January 03, 2015, 10:42:31 am
content: Buy the bare LED units and then buy some MCB power plates to mount them, along with some solder paste and extra flux. Then you can simply reflow them using a skillet ( or in the rest of the world a frying pan) as a heater.

author: Zero999
author_rank: Super Contributor
timestamp: January 03, 2015, 02:33:29 pm
content: I thought you needed more blue than that but I suppose it depends on what you're growing.It's much easier to buy the LEDs pre-soldered to the PCB and it's often not that much more expensive. The problem is an aluminium PCB js required to dissipate the heat properly so it's a pain to solder to.

author: Ilmarinen
author_rank: Newbie
timestamp: January 03, 2015, 04:03:35 pm
content: Quote from: Hero999 on January 03, 2015, 02:33:29 pmIt was for growing lettuce and 10% blue light to 90% red light has been found to produce good growth(Goins et al. 1997). Blue light is also more important for photomorphogenic effects and the red spectrum for photosynthetic effects. This time around I'm making a more all-around lamp so I'll muck around with the spectrum a bit more.It would be quite fun to use the chips directly but if it's going to be a huge pain in the ass then I'll just try to find some pre-soldered ones. What SeanB suggested doesn't seem too difficult, though.
Surface mounted components - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: January 11, 2014, 11:34:24 am
content: Hello, I want to try my hand with surface mounted components, however looking on the sites including E-Bay, I can't see anyone selling starter kits or mixed bags of components, do any of you know, if anyone sells such bags of mixed components, I don't want to get to heavily into it yet, just want to try it out and not have to buy a reel of 1000 resistors etc. I live in the UK any advise please.

author: Bored@Work
author_rank: Super Contributor
timestamp: January 11, 2014, 11:49:57 am
content: Mixed bags? Very unlikely, because people would have trouble to identify and sort the components in the bag.Kits, like SMD resistors or caps. Yes, e.g.http://www.ebay.com/itm/500pcs-25-values-15K-220K-Ohm-0603-SMD-Chip-Resistor-5-Resistor-Assortment-Kit-/171197358516Training kits with unspecified components? Yes. Likehttp://www.ebay.com/itm/Skill-Training-SMD-SMT-Components-Practice-Board-Shield-Kit-For-Beginner-DIY-/300980479147

author: M0BSW
author_rank: Frequent Contributor
timestamp: January 11, 2014, 11:57:29 am
content: Oh thank you this is a good starting place, I see what you mean about the mixed bags, I'm getting mixed up with proper sized components

author: con-f-use
author_rank: Unknown
timestamp: January 11, 2014, 11:59:01 am
content: http://stores.ebay.com/Sure-Electronics/Passive-Components-/_i.html?_fsub=4522616016&_sid=208644246&_trksid=p4634.c0.m322

author: M0BSW
author_rank: Frequent Contributor
timestamp: January 11, 2014, 01:07:02 pm
content: Quote from: con-f-use on January 11, 2014, 11:59:01 amThank You , just put an order in, added this site along with the other two sites mentioned.
Surface mount resistor EIA-96 code question - Page 1
Forum section: electronics / beginners

author: joethebuilder
author_rank: Newbie
timestamp: April 08, 2017, 01:49:00 am
content: Hi all new to site but have watched the You tube channel for years. I am hoping someone can direct me to the right place, I have a SMD resistor with a EIA-96 Coded on it i believe it has 200 ohms symbol and a F after the symbol. i have a EIA-96 chart that i found online but mine only goes to 96 F. any help any one could give would be awesome
Surge protector or UPS for test equipment - Page 1
Forum section: electronics / beginners

author: drakke
author_rank: Regular Contributor
timestamp: February 05, 2018, 09:29:08 am
content: I have a Tripp-LITE surge protector that I use to plug in my test equipment. Do I need a UPS?We occasionally have small power spikes and outages (< 1 second) that trip my PC's UPS.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 05, 2018, 01:23:16 pm
content: I have 3 UPSs running here in my office, including 1 for my bench. I have the surge protectors plugged into it to provide all the outlets I need. We get the occasional blip in power and I don't notice it as my lighting is also plugged into the UPS. I use APC SmartUPS 1500s which also have automatic voltage regulation as a bonus.

author: drakke
author_rank: Regular Contributor
timestamp: February 06, 2018, 02:00:58 am
content: Thanks. APC SmartUPS 1500 are a little too expensive for my use (just a hobby).Can I plug my test equipment into my PC's UPS through the surge protector?My UPS is a smaller APC BackUPS 550G that I use basically to keep my computer from crashing during a total power failure not to operate during a power failure.As for test equipment all I have is a Rigol DS1074, three power supplies, and a Siglent SDG1025 function generator.I really don't want to buy another UPS if it can be avoided.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 06, 2018, 03:30:21 am
content: I don't think it would be an issue. I have a lot more gear p l us 2 computers sharing a large monitor and I barely load mi NH e down at all. If your &PS has a load indicator like mine, it will let you know what you can get away with.
Surge Protector´s circuit breaker or a dedicated one - Page 1
Forum section: electronics / beginners

author: grevan
author_rank: Contributor
timestamp: December 06, 2016, 08:02:02 pm
content: Hi guys,i´m plannig of buying two surge protectors, one for each of my 10A outlets. The Belkin surge protectors i was looking do have a circuit breaker incorporated.Do you think those built-in circuit breakers are good enough or do you think it´s better to add a dedicated 25A circuit breaker in front of the 2 outlets?Thanks.

author: fubar.gr
author_rank: Unknown
timestamp: December 07, 2016, 05:07:48 pm
content: Many of those surge protectors come with a circuit breaker. I guess this is to protect against a MOV getting shorted after a big surge.Installing a second circuit breaker would be an overkill. In any case, the wall outlet should be protected by a breaker in the electrical panel and that should be more than enough.

author: grevan
author_rank: Contributor
timestamp: December 07, 2016, 05:39:22 pm
content: Thanks fubar, that´s what i thought.I´m just trying to adopt some safety measures, although i won´t work with high voltages, just notebook and TV repairs.
Surplus stores in the East Bay area? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: January 19, 2018, 08:41:14 pm
content: Hi,I will be visiting the Easy Bay area (of the SF Bay Area) for a week. Are there any good surplus stores for electronics I should check out?

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 19, 2018, 09:51:42 pm
content: There used to be Mike Quinn by the Oakland Airport, but they are long gone:https://www.imsai.net/history/quinn/quinn-1.htmNot surplus, but in Berkeley there's Al Lashers:http://quirkyberkeley.com/lashers-electronics-quirky-parts/In the South Bay there'sWeird Stuff in Sunnyvale:http://www.weirdstuff.com/Halted Specialties in Santa Clara:http://www.halted.com/Excess Solutions in San Jose:http://www.excesssolutions.com/Not exactly surplus, but Anchor Electronics in Santa Clara is a nice little store:http://anchor-electronics.com/There's some others listed in this old article, mostly in south bay, not sure if they're all still around:https://www.edn.com/electronics-blogs/the-emc-blog/4412972/Review--Bay-Area-surplus-stores

author: cdev
author_rank: Super Contributor
timestamp: January 20, 2018, 12:04:54 am
content: The Fry's chain is also worth checking out if you have never been there before. There is one in Fremont.I remember going to Mike Quinn's Electronics way back in the day.There also used to be a electronics surplus store in SF's Civic Center area (!) I forget its name. It was close to Market Street on its (NW) not its (SE) side.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: January 21, 2018, 04:05:29 am
content: Fry's ugh!There are some nice analog scopes on craigslist, located in Berkeley. I was just there and was tempted...but resisted.https://sfbay.craigslist.org/search/eby/sss?query=berkeley+oscilloscopeDisclaimer: I have no idea what I am doing much less what you are doing.P.S. Visited Quinn's as a teen. That dates me.
Suspended LED Lighting Installation Projects The Pulse of City Life in Stockholm - Page 1
Forum section: electronics / beginners

author: timmy88
author_rank: Newbie
timestamp: February 10, 2020, 12:23:52 pm
content: Designed by David Svensson, a total of 400 meters of a neon resembled warm white LED from GE is a work of art representing the pulse of city life in busy Stockholm station.The project, a piece of suspended light, is built by metal profiles and a ceiling where the warm and white light of a series of LED strips is projected, in the quest to represent the basic visual language of the line.

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 10, 2020, 11:34:32 pm
content: It's worlds better than the one Finnish National Gallery bought from Teemu Mäki for 20,000mk (about 3,350€) in 1994, a video called "My Way, A Work in Progress" that contained parts of his older piece "Sex and Death", including a scene where he kills a cat with an axe, then masturbates and ejaculates on the corpse. (He did have to pay 1,400mk fine and 1,700mk to the local animal shelter where he got the cat from, in 1991.)He has never apologised or expressed regret for this.Some art is good, some "art" is simplistic, some art is literally crap in a blender. Mostly, it's just "elite" buying stuff they don't understand or know anything about, but hope will make them look cultured and refined.
Svideo/Composite video no signal, timing issue? - Page 1
Forum section: electronics / beginners

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: December 30, 2019, 07:36:50 am
content: I have a Denon receiver that can upscale composite and svideo to HDMI.Connected to an old DVD/VCR combo, either input works fine.However, I'm wanting to use this with old game consoles, Sega Megadrive, Super Nintendo, Commodore 64, etc.So far, not a single retro console has worked.I have known of timing issues with analog video signals before, but is this something I can measure, and "fix"?Thanks!

author: Benta
author_rank: Super Contributor
timestamp: December 30, 2019, 09:22:44 am
content: The old video outputs from game consoles etc. do normally not output equalization/serration pulses during VSYNC. This might be your problem.

author: ender4171
author_rank: Contributor
timestamp: January 03, 2020, 04:20:10 pm
content: If it's a timing issue, you can get a Time Base Corrector (TBC), but they are quite expensive (looking at close to a grand for a good one). Have you tried using the DVD/VCR as a middle man? I.e. connect the console to the input of the VCR and then the output of the VCR to the receiver? DVD and VCRs often have a rudimentary TBC built in, so that may be a useful work around.
SVOD programmer stands for and Programming description - Page 1
Forum section: electronics / beginners

author: sdancer75
author_rank: Frequent Contributor
timestamp: July 03, 2019, 12:41:54 pm
content: Hi,Does anyone know what doesSVODabbreviation stands for, and where can I find detailed instructions for using it?Googling this does not seems to be very popular.Thanx
SW6106 USB-PD charger - did i fry the IC? - Page 1
Forum section: electronics / beginners

author: ExtraThiccBoi
author_rank: Contributor
timestamp: August 27, 2019, 08:58:33 am
content: Hi,i just got this pcb. It's a pretty neat little thing with all the standards needed for charging all modern phones.My unit was flaky since the start, i had the resolder some things because they didnt have proper contact and didnt work.When i finally fixed it (my first go ever at SMD), i had the 12000mAh battery pack flapping around in the breeze and at one moment it touched the battery terminals but with reverse polarity. A little bit of magic smoke came from around the IC area. I took it away and cooled it down. After plugging in the pack correctly, The LEDs lit up and it seemed all fine. Normal USB-A port works fine with 5.030V regardless of load. If i give it 18W USB PD, the chip and the large inductor get quite toasty, like 50 degrees, but i can still touch them no problem. It even USB-PD charges my phone fine, but also gets toasty. Is the IC fried? The ebay listing explicitly says to not connect the battery in reverse otherwise it will kill the IC. The IC itself seems to have no reverse polarity protection at all.I include the schematics, my pcb is similiar to the reference design, it has only 5 leds (4 status, 1 for USB-PD) and no Micro-USB port. I'll probably reverse engineer it for fun.If anyone can tell why would connecting the battery in reverse kill the IC i would highly appreciate it, always eager to learn more!The IC is available on aliexpress, banggood etc., so if it is really fried, i could try replacing it (and learn how to solder QFN packages in the meantime).Thanks for any helpDatasheet (in chinese):https://www.waveshare.com/w/upload/0/05/SW6106_Datasheet_V1.0.pdfThe PCB:https://www.ebay.com/itm/QC3-0-Type-c-PD-Lithium-Li-ion-18650-Battery-Quick-Charger-Module-DIY-Power-Bank/192764366706?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
SWAG on pin-outs for 4-pin fan - Page 1
Forum section: electronics / beginners

author: groinksan
author_rank: Contributor
timestamp: February 01, 2020, 09:30:30 pm
content: I have a bunch of fans that I removed from a Cisco switch we were dumping. Fan is a SUNON PSD1204PPBX-A. Specs: 12 VDC, 12.2 WI tried Googling for the pin-out assignments, but could not find one. So, I'm using the process of deduction. There are a total of eight pins on the connector. The fan is actually two fans in one, so I'm sure each fan is a typical 4-wire fan. However, unlike 4-wire fans used in PCs, the colors on my fan don't match up.Checking continuity first, pins 1 and 5 are on the same network, as well as pins 4 and 8. Based on the color of the wires, I'm guessing that pins 1 and 5 are Control (pin 1 isRED,) and pins 4 and 8 are GND.Next, pins 3 and 7 are also on the same network. My guess is that these pins are 12VDC. The remaining pins are 2 and 6, and each pin has its own network, therefore my guess is this is the SENSE signal, as the switch is capable of detecting a bad fan.So in summary:1, 5 - Control2 - SENSE for fan #13, 7 - 12VDC4, 8 - GND5 - SENSE for fan #2Am I correct?

author: Simon
author_rank: Unknown
timestamp: February 07, 2020, 11:24:04 am
content: https://www.eevblog.com/forum/beginners/super-wild-arse-guess-pin-outs-for-a-4-wire-fan/msg2898434/#msg2898434Please don't duplicate topics. It just rubs people the wrong way when they find themselves in a parallel universe.
Swapping a rotary encoder? - Page 1
Forum section: electronics / beginners

author: dog80
author_rank: Regular Contributor
timestamp: July 27, 2013, 01:55:38 pm
content: I have this Philips alarm clock:http://www.vandenborre.be/WEB/images/products/superzoom/philips_aj3551_135895_2.jpgThere are two rotary encoders on the front, one for setting the hour and the other for setting the minutes. The problem with the minutes encoder is that it doesn't have many "notches" and requires too many turns for my liking until it reaches the desired minutes.I haven't opened it up yet so I have no idea what's inside. But can I simply swap the rotary encoder with a "faster" one? Or maybe is there any way to make the existing one faster?

author: Paul Price
author_rank: Super Contributor
timestamp: July 27, 2013, 03:56:16 pm
content: There are different type of rotary encodes some with more than double the cheaper detents per revolution, good luck in finding one that exactly matches the mounting and shaft dimensions.If you have the time and MCU programming finesse, hack it, put in your own custom controls to set alarm and clock time or to emulate the pulse train output of the existing rotary encode. It only uses two wires to determine direction and "notch."You can emulate the waveform feeding into the existing MCU. To set, the pulse trains requirements are that the first train of on/off transitions either lead or lag the second sequence of pulses so as to determine direction and "notches."Just compose your own "acceleration" algorithm to advance by x10 or x20 secs/mins/hrs, etc and determined by speed of rotation by your hand.

author: jeroen74
author_rank: Frequent Contributor
timestamp: July 27, 2013, 11:05:55 pm
content: I have that same alarm clock! and IHATEit! It's full of bugs that basically makes it useless for its basic function, waking you up. It looks nice though. I gave it one simply job (and bought another cheap alarm clock to wake me up)... play music all the time very softly and even that it does not very as it randomly turns off it radio; sometimes a couple of times per day, but sometimes it plays weeks without any problem. Definitely a good candidate for Dave's ' bad production design' videos!The knobs haves enough detents, it's just the software debounce filter that keeps you from adjusting the time any quicker.

author: dog80
author_rank: Regular Contributor
timestamp: October 27, 2013, 08:20:56 am
content: An update:I eventually opened it up and used my waveform generator to simulate the pulses from the encoder. Turns out there is a limit on how fast the numbers can change. A rotary encoder with 24 notches (instead of the original 12) would be probably the limit. Any faster than that and the numbers actually slow down.
Swapping Arduino modules - Page 1
Forum section: electronics / beginners

author: admiralk
author_rank: Regular Contributor
timestamp: August 23, 2018, 09:11:30 pm
content: This is probably another really stupid question, but will it hurt a Nano if I run +5V to both the VIN pin and the 5+V pin?The reason I ask is because I have a little sensor circuit that I would like to get a board made for and would like to have the option to use a Nano or Pro Mini, depending on what is handier / least expensive at the time. It is mostly pin compatible with either, with the exception of the VIN / RAW pin. Since, it is my understanding that, the RAW pin does not work with 5V, I need to run power to the VCC pin, which is in the same position as +5V pin on the Nano. It is no problem to tie two together and just leave the RAW pin out, if I use a Pro Mini, but I need both for the Nano, unless I can power it from an output pin, and I am just confusing myself.

author: 09d08
author_rank: Contributor
timestamp: August 23, 2018, 09:56:52 pm
content: The VIN pin of the arduino nano is connected to the input of the LM1117 (schematic below) so connecting both the VIN and 5V pins to a 5V supply is harmless. You can try it with a linear regulator if you want to be sure.

author: admiralk
author_rank: Regular Contributor
timestamp: August 23, 2018, 10:58:08 pm
content: Thanks. I had a feeling connecting the +5V to power would have no effect, basically because it is the same thing, sort of like connecting a wire back to itself. I get paranoid when ordering a board though, silly mistakes cost a bit of time.

author: admiralk
author_rank: Regular Contributor
timestamp: August 30, 2018, 09:59:05 pm
content: Even though it seems like it would be OK, it just does not sit right with me, having the input tied to an output. I decided to add a couple pads, now I just need to put in a jumper if I use the Mini.

author: Brumby
author_rank: Unknown
timestamp: September 01, 2018, 05:16:25 am
content: I was going to suggest you put in a jumper option - but you got there already.

author: admiralk
author_rank: Regular Contributor
timestamp: September 03, 2018, 09:03:04 pm
content: I originally thought of adding a jumper, with pins, but that seemed like overkill, and I really did not want the pins sticking out of the board. For some reason I was thinking of switching modules after it was built. Then I thought of just cutting the trace, if I used a Nano. Then I realized the simplest solution was to leave a gap, and fill it in if I needed to. Sometimes my thought process runs backwards.
Sweep function control for MHS5200A function generator using serial monitor - Page 1
Forum section: electronics / beginners

author: proppa
author_rank: Newbie
timestamp: March 09, 2019, 04:52:04 pm
content: Hi,I have used these previous threads to attempt to control the function generator using serial monitorHowever, there's no code on how to use sweep function for channel 2? I can only at the moment set channel 1. can anyone help?https://www.eevblog.com/forum/testgear/mhs-5200a-serial-protocol-reverse-engineered/Was wondering if someone can point me the right direction or have a solution.Attached are the protocols.
sweeping a value over time in LTSpice  - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: May 18, 2014, 04:05:15 pm
content: I know about using .step param in LTSpice but it ends up running multiple simulations and thenoverlappingthem.I'd like to sweep the value of a pot over time in steps and run the simulation for a certain amount of time in one long pass.For example, this is what I get at the moment and it's not what I'm looking for.

author: c4757p
author_rank: Super Contributor
timestamp: May 18, 2014, 05:53:00 pm
content: LTspice can do time-dependent resistors directly! Just set resistance equal to a function of time:Code:R=1k*timePreferable to the dependent source method, which I've found to occasionally cause convergence issues.

author: dentaku
author_rank: Frequent Contributor
timestamp: May 19, 2014, 02:45:44 am
content: Well, I think I got it.I now have the pitch being swept over time instead of in steps over multiple simulations. I had to replace the pot with just two resistors again.Quote from: c4757p on May 18, 2014, 05:53:00 pm
Switch circuit for detecting negative rail - Page 1
Forum section: electronics / beginners

author: jmw
author_rank: Frequent Contributor
timestamp: September 06, 2022, 01:10:56 am
content: Or ... can I buy a MOSFET without a body diode?I'd like to build a low power (±6 V, 100 mA) split-rail power supply for other circuits that uses a charge pump IC to generate a negative rail, but turns it off (via an enable line) when a negative voltage input is supplied externally, since external will probably have lower ripple and source resistance. So I need a little switch circuit to pull the charge pump enable line down to ground if it detects negative voltage applied to the V- input. I've tried a few simple topologies with FETs and BJTs but can't anything that works well.Can't do this since the body diode conducts, drain is at a higher potential:With BJTs, this doesn't work once a load is attached since even the leakage current through D1 is enough is turn the switch on and pull the enable line down or close to ground. It does work if D1 is a very low leakage type, but I'd prefer the lower forward drop of a Schottky and a circuit that isn't so finicky.Everything I try gets stymied by a body diode or collector-base diode. Is there a simple idea that will work reliably here, and is there a general problem solving approach when one of these transistor body diodes gets in the way?

author: m k
author_rank: Super Contributor
timestamp: September 13, 2022, 05:19:48 pm
content: Why single side?
Switch configuration code/naming convention? - Page 1
Forum section: electronics / beginners

author: Watth
author_rank: Frequent Contributor
timestamp: September 23, 2023, 06:29:35 pm
content: Hey EEVfolks,Would you have a reference/guide for switches (toggle/lever, etc.) configuration naming?For example, if I want to find a toggle switch with a neutral default position, and a temporary position for up and down what should I look for? Something like (On)-Off-(On)?Thanks!

author: TimFox
author_rank: Super Contributor
timestamp: September 23, 2023, 06:42:28 pm
content: Yes: the (parentheses) indicates "momentary" and the middle location of the code without parentheses indicates the center position.For example, here is a page from Mouser's search engine, narrowed down to 78 examples:https://www.mouser.com/c/electromechanical/switches/toggle-switches/?bushing%20size=15%2F32-32&illuminated=Non-Illuminated&m=C%26K%20Switches&mounting%20style=Panel%20Mount&product%20type=Toggle%20Switches&instock=y

author: Benta
author_rank: Super Contributor
timestamp: September 23, 2023, 07:12:09 pm
content: That's one system.I've seen mom-off-mom as well. Depends on the manufacturer.

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 24, 2023, 01:17:22 am
content: What is the functional/usage difference between switch type on-off-on vs on-none-on, i.e. PT101 and PT103 in the following image?

author: themadhippy
author_rank: Super Contributor
timestamp: September 24, 2023, 01:27:51 am
content: Quotecould it be that position 2 dont exist,the switch can only be in position 1 or 3.QuoteOr in some places biased

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 24, 2023, 01:38:58 am
content: I see. "None" means the position does not exist and its really a two-position switch.

author: EPAIII
author_rank: Super Contributor
timestamp: September 24, 2023, 07:07:39 am
content: It's a table so they just had to put something in the middle box or someone would ask what does a blank box mean.Quote from: eblc1388 on September 24, 2023, 01:17:22 am
Switch help - Page 1
Forum section: electronics / beginners

author: PsychoMaster
author_rank: Regular Contributor
timestamp: February 26, 2015, 06:39:11 pm
content: HiI have a spst switch at 24v carrying up to 8 amps and would like to know what capacitor to use to protect the switch contacts.Thanks

author: SeanB
author_rank: Super Contributor
timestamp: February 26, 2015, 07:15:53 pm
content: 24V at 8A nothing will save the contacts long term. If AC then it will last reasonably well with just a 100n and 4R7 in series across the switch contact, but at DC the arcing will wear it out eventually and no RC circuit will help. If it is a small switch I would recommend getting a Bosch 24V automotive 30A relay ( the real ones, not the cheap fakes) which will survive well with 24VDC.I have a half dozen sitting around that are used, and aside from having a 24V coil, which I rarely, use they do perform well on DC battery use.

author: PsychoMaster
author_rank: Regular Contributor
timestamp: February 27, 2015, 05:06:48 pm
content: Thanks for that ,if only my brain was working I should have thought of that as I have quite a few Bosh auto relays already.Great thing to be able to get insight from other folk and save the day.Cheers
switch mode adapter with output voltage listed as a range - Page 1
Forum section: electronics / beginners

author: rstor22
author_rank: Regular Contributor
timestamp: May 21, 2018, 10:30:41 pm
content: I found the following switch mode adapter (model 3A-061WP12) which indicates the output is 9-12V 6W it also says @12V 0.5A.What does this range of 9-12V refer to?https://images-na.ssl-images-amazon.com/images/I/91-sceQP4TL._SL1500_.jpghttp://p.globalsources.com/IMAGES/PDT/SPEC/098/K1009205098.pdf

author: Audioguru
author_rank: Super Contributor
timestamp: May 22, 2018, 12:29:46 am
content: It might be a bad translation or some of them have poor voltage regulation.

author: rdl
author_rank: Super Contributor
timestamp: May 22, 2018, 03:01:18 am
content: A few years ago, I tested a 9 volt regulated switch-mode adapter from a well regarded supplier in NYC. At less than 80% of its 1 amp rated output current the voltage had dropped to nearly 7.5 volts.
Switch mode power supply - Page 1
Forum section: electronics / beginners

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: November 21, 2012, 03:13:51 am
content: This is probably a silly question but I'm not afraid to admit I'm a n00bI got this digitally controlled switch mode power supply module from China which supposedly can output up to 60V at 10A (and surely I won't go anyway near that). It doesn't come with an AC to DC module though, so I will have to provide a 13-63V DC input to power it myself. Right now I'm just using another cheapy 0-30V power supply to test it and it seems to work fine. There's a few bugs in the firmware in operating with the memory settings but otherwise it seems to be doing its job okay.So my question is what kind of AC (220V) to DC (I'm thinking around 48V 5-10A, as I won't need 60V 10A output anyway) module should I get? A beefy transformer with some basic rectifying circuitry? Or anther 220V to 48V switch mode power supply? A quick look at my sources suggests that cost-wise there's not much of a difference there. What are the pros and cons?

author: Monkeh
author_rank: Super Contributor
timestamp: November 21, 2012, 04:26:47 am
content: A 5A 48V PSU is a fairly beefy item whichever way you go. I've got a unit like this kicking around:http://cpc.farnell.com/stontronics/rs-150-48/psu-enclosed-48v-150w/dp/PW01592They can be had pretty cheaply.

author: T4P
author_rank: Super Contributor
timestamp: November 21, 2012, 08:31:47 am
content: It's advertised as ZXY6005 right? It's a stepdown DC-DC converter and you could just head out and buy a 48V 5Amp meanwell PSU from a shop near youWait it actually looks more like a ZXY6020, the 20amp version!

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: November 21, 2012, 08:42:04 am
content: No it's the ZXY6010D, D for digital, 60V 10A version. It's new, they just released it in October. Besides being digital, it also differs from the original versions with the easily accessible breakout pins, for easy button/LED/encoder/etc. mounting on the housing.

author: T4P
author_rank: Super Contributor
timestamp: November 21, 2012, 09:27:59 am
content: I see. And a larger back mounted heatsink the original ones had hardly any heatsinking

author: zagnut
author_rank: Newbie
timestamp: March 29, 2015, 02:53:05 pm
content: sorry for the necropost but info on these modules is just a bit hard to come by...anyways, i'm interested in the 20 amp version and wondering if current and/or voltage can be adjusted while the output is on? all i see in any of the manuals is setting the limits and then turning the output on.thanks.