hybridfree/eevblog-posts huggingface dataset:
5MHz vacuum tube true RMS detector schematic - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: November 30, 2016, 01:10:14 pm
content: This is industrial true RMS millivoltmeter schematic (this unit in actual State Register now)See the multigrid tube connected as a diode.What oldtimers can say?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 30, 2016, 02:09:42 pm
content: Not sure why multigrid, but I suspect perhaps the whole left half of the circuit is an overly elaborate wideband amplifier (which could be perhaps three transistors with today's parts, and covering ten times the bandwidth..?), capable of driving the tube filament (which guess what, is a resistive heater), and measuring the total emission (hence, all grids diode-strapped) as a means of measuring its temperature.Emission doesn't start until a threshold temperature, and saturates at higher temperatures. And they're not dropping enough plate voltage to saturate the cathode, so it's also in space charge limited conduction. Probably, it needs to be biased on the edge of that threshold, and is quadratic over a small range, then saturates above and below that range.I would think it's not very linear (i.e., narrow dynamic range over which it can properly measure TRMS), and doesn't have much crest factor capability.But all this should be in the operator's manual, if that's any help.Tim

author: 001
author_rank: Super Contributor
timestamp: November 30, 2016, 02:15:22 pm
content: Thank for Your message!Operator manual is empty. Do You know any analogs of this circuits? Is it good idea to substitute detector?Maybe You can also say few words here:https://www.eevblog.com/forum/projects/few-mhz-true-rms-detector-schematic/https://www.eevblog.com/forum/projects/looking-for-actual-ideas-for-millivoltmeter-upgrade/

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 30, 2016, 02:21:24 pm
content: Ooh, no wonder, 1uV, quite sensitive. Was that a full 5MHz bandwidth on the 1uV range still? If so, that's quite impressive for the day!As for converters, nowadays, why not buy a proper DMM? Or, the heart of one, I think there's LT and MAX parts that apply?Tim

author: 001
author_rank: Super Contributor
timestamp: November 30, 2016, 02:26:26 pm
content: Yes. it is goodwidebandmeter. Cheap but not common and I can`t see one to substitute my stuffWhat DDM have few MHz wideband and uV range?Absolute tolerance is not nesessary, I use it to compare dB levels

author: Kleinstein
author_rank: Super Contributor
timestamp: November 30, 2016, 04:20:25 pm
content: Modern DMMs are usually not that wide band. You might get such things with an DSO and software measurements.The crest factor might not be so bad, as this about heating the filament - only the diodes might limit an extreme signal rather fast. The converter is just a kind of thermal voltage converter. So much of the averaging is done thermal. Any output curve might be corrected on the analog scale - no need to have a special form. The analog meter has a limited dynamic range anyway - so the converter may not be the problem here.
5V 60 Amp Power supply design  - Page 1
Forum section: electronics / projects

author: piyushpandey
author_rank: Newbie
timestamp: September 28, 2015, 08:36:44 am
content: Hi guysfor the past few weeks I am wandering all over the internet in search of the good article for my design of SMPS based power supply which could operate at 230V AC and can output 60 Amp of current at 5V DC voltage at full load.But what I am not able to get is how to start with.Please guys help me out with some hints and if any good articles or stuffRegardsPiyush Pandey

author: godFather89
author_rank: Contributor
timestamp: September 28, 2015, 09:28:31 am
content: Here's a good starting point:http://danyk.cz/reg60v_en.html

author: eneuro
author_rank: Super Contributor
timestamp: September 28, 2015, 10:35:19 am
content: Quote from: godFather89 on September 28, 2015, 09:28:31 amI thought that my workbench is a little bit too messy sometimes, but after watching those linked videos on this page...probably mine is fineHowever, yep a lot of usefull practical information and this PSU seams to workAnyway, no synchronized rectifiers on transformer secondary in such quite powerfull PSU?I've found during teardown on my failed Assus mATX motherboard three synchronous rectifier drivers close to CPU at 3.3V power rails
5v and 24v Power Supply - Page 1
Forum section: electronics / projects

author: Joshua
author_rank: Regular Contributor
timestamp: May 16, 2013, 03:57:35 pm
content: Hey everybody. For my latest project, I require both a 24 VDC and a 5 VDC power supply. They do not need to have common ground; a configuration of +5V, +12V, -12V, and GND would be acceptable. The 24V supply needs to be able to supply about 1A as it will only be used to power 3 solenoid valves at about 250mA each. I think 1A would be sufficient for this, but if anybody disagrees, let me know. The 5v supply will be used just to power a micro, lcd, a couple LEDs, EEPROM,etc... so I think a 500mA supply would be sufficient there.My question is, what would the group recommend as the best option for something like this? I don't want to take the time to custom design a dc/dc converter for this, but am open to using an off-the-shelf one. Some of the thoughts I had was to use a 24V CT transformer. Then I could use either a lm317 or lm7812 and their negative counterparts to get +12 and -12 for my 24V. I could then put a 7805 on the 12v line to get 5v. I am open to using a heatsink, but I want to avoid the need of having a fan.Another option is I could get a 24v transformer and use a lm7824 or a lm317 to regulate to +24v and use something like thishttp://www.mouser.com/Search/ProductDetail.aspx?R=R-78E5.0-0.5virtualkey56830000virtualkey919-R-78E5.0-0.5to get 5v.Are either of these options viable, or is there something I've overlooked?Thanks.Joshua

author: SeanB
author_rank: Super Contributor
timestamp: May 16, 2013, 04:04:55 pm
content: 24V industrial power supply in a DIN mounting case and the 24-5V switching regulator.Otherwise look up arcade machine power supplies, these give 5V and +-12V rails with reasonable regulation on the 12V rails but good regulation on the 5V rails. Often adjustable from 4-6V and the 12v from 10-15V, and each of the 12V rails can do 1A and the 5V supply can do 5A. Sef contained in a metal module that just needs mounting. Some even have the required 24V and 5V rails you want as standard.I have a few of these that are quick and dirty power units for checking, they came from dead arcade machines.

author: lewis
author_rank: Frequent Contributor
timestamp: May 17, 2013, 12:09:39 pm
content: The 24V supply probably doesn't need to be regulated if it's just driving solenoids, an 18V transformer will give you about 24V once rectified and smoothed. Then, just simply connect a 7805 to the unregulated 24V line for your regulated 5V.
5V ARGB LED controller - Non-Limiting - Page 1
Forum section: electronics / projects

author: DW1961
author_rank: Frequent Contributor
timestamp: June 15, 2021, 08:28:31 pm
content: I need a 5V ARGB controller to test amperage of 5V ARGB computer LED lights.Interestingly, I have one, but I think it is limiting current. Maybe not, but can I test it for limiting current by hooking lights up in a series and watching current increase? It's just a cheapo controller, but it says it's good for 3A @ 5V. If it actually isn't limiting current, then the strip lights are - which I confirmed by one manufacturer.I asked why by my calculations the lights should be consuming more power, and he said they limit it on the strips to make the lights last longer. If I can test the controller I have now for limiting current, and it's not, then I can just use it.One strip I tested using the 5V controller had all colors using the same power. So if I went to blue or red or green, they wold all read out the same amperage. That's not the way it is for 12V. On RGB 12V "white means R, G, and B are all on 100%, and the current jumps way up over any individual color. On these 5V ARGB strips, it was the same as all other colors. That is, all white was the same as all green, blue, or red. Anyway, I thought that was interesting. I guess the colors will put out the same lumens that way, including white. 12V RGB (non-addressable) don't do that, I guess because there is no IC in them.Any input would be appreciated. I'm just going more on deduction here, and less on concrete facts. Anyway, if there is a way can test the 5V controller I have for limiting current, I'll do it, and alternatively, is there a 5V ARGB controller I can use that does not limit current?
5V Audio Op amp - Page 1
Forum section: electronics / projects

author: paul_g_787
author_rank: Frequent Contributor
timestamp: November 12, 2019, 04:49:29 pm
content: Hi.I am planning on making a pre-amp for my computer to go into my hifi amp as the output volume of the PC is not that loud. I was thinking of a dual op-amp like the TL072, but this would require an extra power supply to get the required voltage.Can anyone reccomend a good dual op-amp IC, preferably DIP that I can run from USB (+5V and GND)..Thanks

author: Yansi
author_rank: Super Contributor
timestamp: November 12, 2019, 04:56:57 pm
content: For example:LME49721: Single 5V RRIO audio, but weak output drive,OPA342: Single 5V RRIO, worse distortionetc.. Just google for RRIO audio opamps. There are a lot of them, but mostly they are sort of a compromise and must be well chosen for the application specifically. For example, probably can't use LME49721 as an output cable buffer, and so.Also there are those that are not RRIO, so beware of the maximum signal levels with these:LM4562: Single 5V capable, small THD, small noise and great GBW, 600ohm driveThing is with these, when price considered, if it wouldn't be better to get a cheaper opamp and give it more V supply. There are lot more choices I guess for +-5V supply. (TLE206x, even OPA1632 fully differential opamp, etc..)

author: magic
author_rank: Super Contributor
timestamp: November 13, 2019, 12:59:45 pm
content: No amplifier powered from 0/5V rails will amplify AC signal centered around ground. You will need to generate a virtual ground at 2.5V or so and shift the signal back and forth with coupling capacitors. Also, deal with possible noise injection from USB.Alternatively, get a transformer wall wart and build a dual PSU using two half-wave rectifiers and 78Lxx/79Lxx regulators.
5V Boost Regulator outputs low voltage (AP2007) - Page 1
Forum section: electronics / projects

author: waymond91
author_rank: Regular Contributor
timestamp: March 15, 2024, 11:17:05 pm
content: I am using an AP2007 from LCSC to convert a single cell 18650 to 5V for use with a pi zero:https://www.lcsc.com/product-detail/DC-DC-Converters_Wuxi-Chipown-Micro-electronics-AP2007SPER_C130338.htmlHowever, my circuit only seems to be outputting around 3.3v instead of the expected 5v. Ive checked all of the connections and it seems that the power is arriving without an issue, the enable pin is pulled high, etc.There is a quite a bit of circuitry in front of this regulator (an INA219 for monitoring the battery power, a mosfet for switching power on & off, etc). However, this all seems to be functioning about as expected.One obvious issue I realize now is that I did not connect to the exposed pad on the ic, however the datasheet says the pad is connected internally to ground and I havent put it under any load yet.The IC in question is U4 above.Am I missing anything obvious? Let me know if you questions, comments, ideas, etc

author: Peabody
author_rank: Super Contributor
timestamp: March 16, 2024, 03:08:03 am
content: Have you measured the feedback resistors, R9 and R10? Also, where is L1? It doesn't appear to be populated.

author: waymond91
author_rank: Regular Contributor
timestamp: March 16, 2024, 01:10:49 pm
content: You get a raise!The inductor is populated, but it seems I put the wrong value feedback resistors in the BOM even though they are correct on the datasheet!I have ordered replacements, if you dont hear back from you can safely assume you've cracked the case!
5V Buck converter, TPS54821 - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 23, 2020, 09:09:14 am
content: Hi,I want to drive a spartan 6 device with TPS54821, I need to be able to get 3.3V @ 6A with 5V input, also the upper input limit is 12V, I came across this TPS54821 using TI webench, I want to make sure it can generate 3.3V @ 6A with 5V input, has anyone used this puppy before? Vin - Vout headroom enough?

author: capacitor_explosion
author_rank: Contributor
timestamp: April 24, 2020, 12:29:44 pm
content: Hello , i dont know about the Ic you have mentioned but i have used LM61460 its a wide input voltage automotive buck regulator . Im happy with the performance . I have attached efficiency measurements and schematic . I think it will be fine for your application .

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 24, 2020, 01:41:35 pm
content: Aparently made for 100% Duty Cycle operation so it should be fine.
5V design what do you use for i2c pullup resistors? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: June 15, 2020, 07:25:41 pm
content: It seems like I've used 1K or 2K, but not sure which is best, or something else - what do you use?

author: oPossum
author_rank: Super Contributor
timestamp: June 15, 2020, 07:45:24 pm
content: Best is going to be application dependent. My default values for 400 kHz or less on a PCB are 4k7 for 5V and 2k2 for 3V3.

author: alank2
author_rank: Super Contributor
timestamp: June 15, 2020, 08:00:26 pm
content: Sorry, I'm thinking 1MHz.
5V from 5V USB using tps63002drct - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 30, 2020, 09:01:13 am
content: I came across the TPS63002 from TI and thought I would add one to my latest gadget which requires a nice and stable 5V at up to 300mAI designed the circuit using WebBench and opted for a rather small inductor MLP2012V2R2MT but theoretically it should work.My layout isn't great but not terrible but I am having issues getting it working at all (took 5 attempts at soldering the QFN until I got a combo that worked... not sure if it is the assembly or the design with the problem) and now I am getting one output on one board the regulation is terrible (4.9 to 5.2 under differing loads)I tried adding some output capacitance but it didn't seem to change anything.So... Anyone had any experience with TPS63002? Should I seek an alternative... or possibly just let the USB source (PC) do the regulation?Thanks in advance
5V MP150GJ Power Supply  - Page 1
Forum section: electronics / projects

author: Am0rph
author_rank: Newbie
timestamp: June 21, 2021, 12:58:46 pm
content: [img = ""]I am following the reference design but it doesnt work. Apart from the wrong placement of the varistor which I have removed in the actual circuit, is there anything else I am doing wrong here?Any help will be very much appreciated!

author: Wolfram
author_rank: Frequent Contributor
timestamp: June 21, 2021, 01:17:22 pm
content: You're missing a connection between the source pin of the chip (3) and the output diode D3. Also, an 1N4007 is not fast enough to use in a buck converter like this, an UF4007 or ES1J or similar is more appropriate.

author: Am0rph
author_rank: Newbie
timestamp: June 21, 2021, 01:22:16 pm
content: Thank you so much! Such a stupid mistakeI will also try changing the diodes.Thanks you again for your help!!
5V switchable power supply for LEDs - Page 1
Forum section: electronics / projects

author: Dom324
author_rank: Newbie
timestamp: May 01, 2022, 09:36:14 am
content: Hi all,I'm looking for a 5V PSU for powering LEDs, but I would like to be able to turn on/off the power supply with a 5V signal.My current setup is a standard PC PSU, from which I use a 5V standby rail to power ESP32, which is controlled wirelessly. When ESP32 receives a wireless command to turn on LEDs, it sends 5V PS_ON signal to the PC PSU, which turns on and powers LEDs.The problem with the current setup is that the PC PSU is an old and cheap unit, and it (probably) cannot deliver/sustain enough power and it shut downs after a while. Also it coil whines.The obvious solution is to buy a better PC PSU, but I feel like that's not ideal and would rather replicate a similar setup but with a normal 5V PSU.My idea is a phone charger as a 5V standby for ESP32 (it would be awesome to have a 5V PSU with standby rail, but I don't think those exist?), and 2x 5V PSUs (rougly 40W each?), but I need them to be switchable on/off via a similar 5V PS_ON signal.One idea was to switch the PSUs with relays, but I would rather have an integrated solution within the PSU. Is something like this on the market?Why am I doing this? I don't feel comfortable having the PSU running 24/7 and LEDs being constantly under voltage, especially when I'm away.Thanks for all suggestions

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 01, 2022, 10:34:50 am
content: A brand-new basic 500W ATX psu is $13, can deliver >25A in the 12V rail, so why not just get a new one?Or are you using that PSU for only the 5V supply?Then better user as you say, small, low power phone changer or similar, and a beefier 5V PSU enabled by a relay.
5v system, li-ion single cell, 5v charging - Page 1
Forum section: electronics / projects

author: verrochio
author_rank: Newbie
timestamp: July 28, 2013, 10:45:42 pm
content: Hi, I'm designing a power supply for an embedded linux board.It needs 5v to power it's usb.I need to make this mobile so therefore it needs a battery. I was thinking about a 3.7V li Ion battery.The hole system takes about 750mA at max load. Including battery charging. Battery can supply 1450mAh.My problem:How would you do the Battery Charging from 5V and the step up from 3.7 to 5v?The scenario being: Battery is discharged, 5V DC from power plug is attached, the system should know to:1. Charge the battery at 4.2V (using a battery charging IC)2. Supply power to the system at 5VAfter the DC 5 volt is removed, the system should automatically switch on battery and step it up to 5v from 4.2v - 3.5v.I've looked into power path IC's but they only use 3.7v from the battery.What do you guys think i should do?

author: Kremmen
author_rank: Super Contributor
timestamp: July 29, 2013, 05:20:30 am
content: Why not make it simple and use a USB compatible charging controller such as MCP73831http://ww1.microchip.com/downloads/en/DeviceDoc/21984E.pdfcombined with a suitable booster SMPS chip? No need to "switch over" from charging - if outside power is available the battery is charged until full. In the meantime the circuit is powered from the same source, either from battery or external power if available and battery is full.

author: verrochio
author_rank: Newbie
timestamp: July 29, 2013, 09:29:17 pm
content: I was thinking about that and it was one of those... this is too simple to work question! I was afraid that there is something that I was missing.Thanks.
5V to 24V Step-up Advice - Page 1
Forum section: electronics / projects

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 20, 2010, 09:58:59 pm
content: Hello!I want to convert a 5V USB supply to a 24V @ 30mA supply. I will use it for audio signals so I would like it to have a switching frequency of 100kHz or more.Is there any simple IC that can step-up this voltage with low noise? The 24V load is just 15mA or so, but I am giving it a little extra window of 30mA just to be on the safe side.Thanks for your tips!!

author: tecman
author_rank: Frequent Contributor
timestamp: July 20, 2010, 10:53:18 pm
content: There are quite a few chips that can do this. Personally I like the 34063A for doing a variety of SMPS jobs. It has an internal switch transistor, reference, and error amp. As far as the noise issue, it will be more a function of the layout, grounding, proper caps and perhaps some additional L on the output as a filter.Paul

author: Zero999
author_rank: Super Contributor
timestamp: July 20, 2010, 10:59:11 pm
content: Does it need to be regulated?If not you could use a charge pump which needs no inductor, just capacitors and if you make the frequency high, the capacitors can be small ceramic disc.

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 21, 2010, 01:49:12 am
content: Hi guys!Tecman, that's a great IC, I checked its formula and you just have to calculate R1 and R2 in order to obtain the Vout you want. I think I will use it just in case nobody else posts a better one.http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=mc34063a&fileType=pdfHero999, it has to be regulated because it will feed a microphone and the bias voltage may oscillate if the 24V supply is not regulated.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2010, 05:12:34 am
content: There are plenty of boost converter chips out there. Look through the selection menus of Maxim, TI, or Linear, just to name a few.

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 21, 2010, 01:00:45 pm
content: Quote from: NiHaoMike on July 21, 2010, 05:12:34 amHi Nihaomike!I was looking for them yesterday in TI.com but I could only find 2. I'd better use one that has been tested and approved by someone else.
5V to 3.3V SPI with a second device... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: March 07, 2018, 02:03:14 am
content: I'm going to have a 5V AVR with 2 SPI devices. One will be a SD card (3.3V) and the other will be a SPI RTC (1.8V-5.5V).There seem to be a million ways to level convert with various IC's!Would you put both devices on the 3.3V side, or level convert for the SD only?Would you level convert what is coming back FROM the SPI device (MISO)? I would think that would be the proper way to do it even thought 3.3V would probably drive the 5V input ok.

author: jbb
author_rank: Super Contributor
timestamp: March 07, 2018, 04:41:29 am
content: This looks like a 50/50 question.First up, can you just make everything 3.3V and avoid the problem?If not, I thoroughly recommend you use a level converter for MISO so that you get reliable signalling. It could be a dedicated chip or just a MOSFET and pull-up resistor.If you have the RTC on 5V, the advantage is that you can test the RTC before fitting the level converter chip and SD card. The disadvantage is that the level converter must release the MISO line so the RTC can talk.If you have 3.3V on the RTC it may be easier to find a replacement RTC if necessary, and the level converter won’t have to release MISO.

author: alank2
author_rank: Super Contributor
timestamp: March 07, 2018, 04:47:40 am
content: Must stick with 5V.Ok, what about:74LVC125 for driving the MOSI, SCK, SD_SS, and possibly RTC_SS in the outgoing direction. It tolerates 5.5V and can have its VCC connected to 3.3V.Then in the other direction, I found a single SN74AHCT1G125DBVR for MISO. It is a TTL part so it should go high at 2V and can be powered at 5V.The SN74AHCT1G125DBVR also has an OE that could be connected to SD_SS from the AVR so it would only have its output active when the SD is selected with SD_SS.Then I could put the RTC on the 5V side. Or it could be put on the 3.3V side if that OE was just tied low all the time. Any benefit either way?
5v voltage reg output cap sufficient value? - Page 1
Forum section: electronics / projects

author: brg
author_rank: Newbie
timestamp: October 19, 2017, 09:06:03 am
content: Hello,I would like to use LM2931 to regulate from a 32v to 5v, using up to 20mA at most. the feeding wires to the regulator are lees than 1 meter (5v output needed is on the pcb next to the lm2931). on its data sheet as the bellow link on page 3 fig #12 for Fixed, it is noted to use an output capacitor for at least 100uf, my intention is to use instead of 100uF A 1uF or 4.7uF ceramics at the most.Can you please advice if these values of 1uF or 4.7Uf are good enough?http://www.ti.com/lit/ds/symlink/lm2931-n.pdfThank you in advance,Barg

author: danadak
author_rank: Super Contributor
timestamp: October 19, 2017, 09:22:02 am
content: Figure 34 shows the esr needed to keep the regulatorstable. You must meet that or it will oscillate. Thatincludes over temp, bulk capacitors performance verymuch subject to temperature.So I would say no to your question, follow the datasheetguidelines. However page 12 goes into depth on stabilityconsiderations. So depending on caps esr performanceyou may use smaller C value.Regards, Dana.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: October 19, 2017, 04:47:48 pm
content: 32V is outside the TI part's recommended operating range for input voltage. The data sheet specifies 26V maximum. You might be able to get away with it if you can keep it cool enough, though.The ON Semi version of the LM2931 is rated for 40V input, so I don't know whether TI are being overly conservative, or ON Semi are exaggerating.I have used the 5V SO-8 ON Semi version with 30V input, albeit only drawing 10mA, and it only got slightly warm.

author: Audioguru
author_rank: Super Contributor
timestamp: October 19, 2017, 05:40:13 pm
content: You don't say which package your LM2931 is, it might be too small then melt with the 0.5W of heating.An LM2931 is "low dropout" so it works when the input is only 5.5V. Low dropout regulators need a high value output capacitor to prevent oscillation. You don't need low dropout so why not use an ordinary 5V regulator with a low value output capacitor?
5V Wall Warts in quantity Source? - Page 1
Forum section: electronics / projects

author: Veramacor
author_rank: Regular Contributor
timestamp: February 24, 2011, 02:48:35 pm
content: Hi all,Whats the cheapest 5V, 500ma- 1A power supplies people have seen out there? I'm looking for maybe a 100 count for a project if the price is right I've seen them as low in Marlin P. Jones for $1.50 for 100+I can get USB 5v wall warts for $.99, but then I have to source USB cablessomething like this, but I can go as low as 500ma...http://cgi.ebay.com/DC-5V-1-5A-Power-Supply-AC-DC-Adapter-3-5mm-1-35mm-US-/220738395503?pt=LH_DefaultDomain_0&hash=item3365089d6fV

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 25, 2011, 10:50:32 pm
content: Is there an easy way to take apart the USB wall warts? If so, do just that and solder a length of wire to it.

author: Zero999
author_rank: Super Contributor
timestamp: February 25, 2011, 11:16:55 pm
content: Quote from: NiHaoMike on February 25, 2011, 10:50:32 pmIt sounds like he wants to mass produce it so modifying an existing product is costly.

author: OhmEye
author_rank: Contributor
timestamp: February 25, 2011, 11:25:04 pm
content: Perhaps something like this?http://www.aliexpress.com/product-gs/326925283-Free-Shipping-50pcs-lot-AC-Adapter-For-Sony-PSP-wholesalers.html
6.3v ac from 12v transformer  - Page 1
Forum section: electronics / projects

author: darkness_electro
author_rank: Contributor
timestamp: August 22, 2015, 04:59:30 pm
content: Hello, i have 2 6n2p tubes with 6v heaters and a 12v transformer. Should i put the tubes in series at 12v or half wave rectifiy the ac for each one of them? Which one would yeld a better result? I do not plan on running them off dc beacuse it would stress the transformer too much.

author: SeanB
author_rank: Super Contributor
timestamp: August 22, 2015, 05:06:01 pm
content: Put the tubes in series, as otherwise just half wave rectifying will lead to a bad case of hum as you run the heaters with very dirty DC. Common on a lot of designs, especially those meant for car radio use. You might want to place a series NTC inrush limiter as well to keep the thermal stress on the cold heaters low. It will drop a little voltage when hot, but will slowly heat the cathodes at power on.

author: darkness_electro
author_rank: Contributor
timestamp: August 22, 2015, 05:34:19 pm
content: how would i implement the thermistor? where do i put it?

author: SeanB
author_rank: Super Contributor
timestamp: August 22, 2015, 05:49:24 pm
content: In series with the heaters. RS stock no. 216-1393 is something I would use, 15R when cold and quite cheap. will heat up to operating temperaturehttp://docs-europe.electrocomponents.com/webdocs/13c0/0900766b813c0d2d.pdfDepends on the hot heater current as to which device to choose for the use.

author: Gyro
author_rank: Super Contributor
timestamp: August 22, 2015, 05:54:45 pm
content: Yhis is your " 250V DC Power supply" again, Yes?It's far better to keep all your feedback in one place, otherwise people waste their time duplicating.https://www.eevblog.com/forum/projects/250v-dc-power-supply/15/

author: darkness_electro
author_rank: Contributor
timestamp: August 22, 2015, 06:08:51 pm
content: thank you very much. is there any particular place to put the thermistor? (near the tubes, to heat up, or away?)

author: SeanB
author_rank: Super Contributor
timestamp: August 22, 2015, 06:10:46 pm
content: Somewhere where it can run hot safely, as it can go up to 250C in operation. Does not have to be near the tubes at all, just left with long leads so it can cool itself naturally.

author: darkness_electro
author_rank: Contributor
timestamp: August 22, 2015, 10:30:07 pm
content: This is one of the few shops that have a variety of parts and a website. Can you reccomend a specific thermistor?http://www.conexelectronic.ro/produse.php?id=151It't not in english, but electronics is electronics.
6 axis IMU - Complementary filter - Page 1
Forum section: electronics / projects

author: matb
author_rank: Regular Contributor
timestamp: February 12, 2024, 10:33:49 am
content: Hi everyone,I had time to work on my 6 axis IMU project and I'm having a couple of problems...I have watched Phils Lab videos a couple of timehttps://www.youtube.com/watch?v=BUW2OdAtzBw&ab_channel=Phil%E2%80%99sLabI also have the BMI088 accelerometer & gyroscope.I have a project that goes and read accelerometer data every 100ms. I verified on my scope that I have the correct frequency by toggling a pin.Capture.JPG(119.6 kB. 1299x988 - viewed 50 times.)tek00001.png(109.81 kB. 1920x1080 - viewed 42 times.)So I have a 10Hz signal. I think ?Code:while (1){BSP_PICs_Watchdog_Management(); /* Watchdog */if(Process_elapsed_ulong_time(u32_time, ul_internal_timer_never_reset_that) > 1000) // every 100ms{u32_time = ul_internal_timer_never_reset_that; // 0.1ms interruptTP4_LAT = ~TP4_LAT;Accelerometer_X_Axis_BMI = Read_X_Axis_Accelero_BMI088();Accelerometer_Y_Axis_BMI = Read_Y_Axis_Accelero_BMI088();Accelerometer_Z_Axis_BMI = Read_Z_Axis_Accelero_BMI088();Gyroscope_X_Axis_BMI = Read_X_Axis_Gyro_BMI088();Gyroscope_Y_Axis_BMI = Read_Y_Axis_Gyro_BMI088();Gyroscope_Z_Axis_BMI = Read_Z_Axis_Gyro_BMI088();}}That code gives me a fixed sample rate of 100ms.I record values in an excel file.Then I go to Matlab (actually Octave) to compute my results usinghttps://github.com/jshoga/IMU-ProcessingfromHe doesn't give the units of the file but from my guesses accelerometer datas are in m/s² and gyroscopic datas are in rad/s.I have a 0° → 45°→ 0°→-45°→0° record.All I get are strange results am I missing something here ? Could someone try that I'm very confused by these results ?Attached are the exemple files I am working on with my record of datas.accel3d_matlab.zip(1135.25 kB - downloaded 33 times.)
6 Channel RF Power Switch System Schematics - Page 1
Forum section: electronics / projects

author: dellsam34
author_rank: Regular Contributor
timestamp: July 11, 2021, 07:55:56 pm
content: I needed to control 6 12V DC lights individually using an RF switch module with 6 button remote control, The lights are powered by a 4S pack of Li-Ion 18650 batteries, Offcourse all the pieces needed to make the system are readilly available online and I have them already, The only problem is that I have a circular shaped enclosure of about 12cm in diameter and 3cm in depth (4 3/4" by 1 1/4") and I needed to fit all those pieces in the attached illustration inside the enclosure (excluding the batteries), Unfortunatly I couldn't so I needed to go plan B which is designing a circular PCB and fit all the components in it minimizing the space needed.The question is, Are there any free available schematics out there with no patent attached that I can use to design my customized circular PCB? The maximum current protection is 40A for the system and the components used will be all SMD were possible, No screw terminals will be used all soldering pads.

author: dellsam34
author_rank: Regular Contributor
timestamp: July 12, 2021, 06:36:25 am
content: One schematic down and 2 more to go:

author: dellsam34
author_rank: Regular Contributor
timestamp: July 13, 2021, 12:59:11 am
content: The schematic above is too old and I can't find most of the transistors, The V 2.3 I have in the attached picture seem to have different components but I can go of of that one because the schematic layout seem to have changed a bit, Any thoughts?
6 layer make up for USB 3 hub (small) - Page 1
Forum section: electronics / projects

author: timgiles
author_rank: Regular Contributor
timestamp: September 30, 2018, 09:14:00 am
content: Hi all,Over the last couple of years I have been, on and off, trying to design a replacement USB (3) hub, in Eagle, for my telescope mount, that is currently unpowered USB 2. The size of the PCB is 88x23mm, 4 ports plus an incoming port. The PCB has notches out of the corners so the working area is smaller (72mmx23mm). Below is a picture of the finished PCB. This is my 3rd version, which did work but there were signal integrity issues on the high speed diff pairs. In terms of routing, I had all the diff signals on the top, then a ground, layer 3 as supplies (5V, 3.3 and 1.1V) and then the bottom layer as everything else.Seeing that the price of 6 layer boards has dropped to the point where I might consider redoing this with 6 layers - I was thinking that it would help to use the additional two layers for the 3.3 and 1.1V supplies. Thus, Top-Diff pairs, Ground, 1.1V, 3.3V, 5V, Bottom everything else. Any other advice? I was using 9mil track width, 5mil spacing - and again I hope with AllPCBs service I can pull that down to 6 mil tracks and 4mil spacing. It would help greatly with the layout.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 30, 2018, 02:03:26 pm
content: How many USB3 ports do you really need? If it's just one, it can be implemented as a pass through, with a USB 2 lines going through a hub.

author: timgiles
author_rank: Regular Contributor
timestamp: September 30, 2018, 04:49:19 pm
content: Ah ok I see what you mean, only implement the high speed diff pairs for 1 or 2 ports. I had not thought of that! Camera - USB 3 preferred, guidescope - USB 3 preferred, filter wheel USB 2 is fine. So I suppose only two really need to be USB 3 connected.
6 Layers and Buried/Blind vias service advice - Page 1
Forum section: electronics / projects

author: Yaro
author_rank: Contributor
timestamp: August 03, 2016, 05:10:30 pm
content: Hi all,I need to design a PCB for "wearable" purposes. My constraints are thin and light PCB with high component density. To accomplish this I'd like to use a 0.8-0.9mm thickness size PCB and to use buried or blind vias to increase component density on each side.Since I've never done something like this before, what drawbacks I can find with such thin and 6 layer PCB(inductance, noises ecc.)?Also, can someone advice me a "cheap" prototype service that can accomplish this?Thank you!

author: alex.m
author_rank: Contributor
timestamp: August 03, 2016, 05:51:15 pm
content: Hi Yaro,I do not believe there is any drawback in using multilayer board, excepting manufacturability issues, which are translated into prices and mechanical properties of the PCB. It is also harder to troubleshoot.The more layers you have it is easier to route appropriately all the signals and guaranteed that you have solid planes for both ground and power. Also, the thinner the dielectric more the signal and return path are close together. This minimizes inductance, therefore minimizing cross-talk.As far as I know there is none cheap prototype service exceeding 4 layers. My advice is contacting or experimenting with online calculators of several manufacturers. For example in Europe, Multicircuits, Eurocircuits, Wurth Elektronik, PCB-POOL and try to find the cheapest possible technology selection that fulfils your requirements.Alex

author: Yaro
author_rank: Contributor
timestamp: August 03, 2016, 06:00:11 pm
content: Thanks for your answer. I've checked now some services and found that 4 layer have suitable price with all thickness sizes(from 30$ to 60$). But when I switch to 6 layers prices start from 160-200$, with blind or buried vias up to 300-400$ and more.This is becouse there is low demand on this type of PCB? There is possibilities that this prices drop a lot with batch pcb orders?
6 Series LED circuit by Fredzislaw100 - Page 1
Forum section: electronics / projects

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2012, 01:32:59 pm
content: He has a new series LED circuit puzzler:Dave.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 02:31:18 pm
content: Naah...just simple magicor something based on standing waves with oscillator (or noise source) hidden in the battery and L-C components hidden inside the switches.

author: McMonster
author_rank: Frequent Contributor
timestamp: May 02, 2012, 09:10:12 pm
content: It's not that interesting since he revealed how the first circuit really worked. But I think this video is also made to troll people. But this time by the way he solders those LEDs.

author: bogdan546
author_rank: Contributor
timestamp: May 04, 2012, 11:58:05 am
content: Something like this

author: Psi
author_rank: Super Contributor
timestamp: May 04, 2012, 12:14:40 pm
content: If i was going to make it i'd probably put one of those 2x2mm Atmel microcontrollers under each led and inside each switch. Switch --> led communication could be done with led pulses too short to be visible.In fact, a tiny micro doing software definition radio transmission could make some interesting layout possible
60 pin D-SUB connector - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 21, 2020, 12:46:14 pm
content: Hi,I'm searching for a 60-70 Pin Right angle D-sub connector that has good shock and vibration specs, also I want it to have some sort of lock mechanism, I prefer Molex, But It seems there is nothing on stock in Digikey or other places, do you recommend any part number or series that has rugged design and can be sourced easily,I need around 20 for now.

author: Benta
author_rank: Super Contributor
timestamp: April 21, 2020, 03:22:03 pm
content: TE Connectivity AMPLIMITE comes to mind.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 21, 2020, 07:50:39 pm
content: QuoteThanks, do you recommend any part number,say for 62 pin version? I need a right angle for the PCB.

author: Wendy_Preston
author_rank: Contributor
timestamp: April 24, 2020, 07:44:53 am
content: Hi Ali, does it have to be D-sub shape? We have an alternative in our Datamate 3-row series - which comes with jackscrews and good vibration / shock specs. Here is the catalog section for this range:https://cdn.harwin.com/pdfs/Harwin_PC_Datamate.pdf- 3-row is on pages 130 to 135.Here is the specification for the range:https://cdn.harwin.com/pdfs/C005XX_M80_and_M83_Datamate_Series_Connectors.pdfIf you want further assistance, our Experts would love to help youhttps://www.harwin.com/contact/ask-an-expert/Hope that helps!

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 24, 2020, 08:08:48 am
content: Thanks Wendy for the info,I want to put this connector in a PCIexpress card along an Ethernet connector,so I prefer D-SUB, But your connectors seems good to me too, and I have used them before,Does these ones also protected for humidity too? they need to have good shock and vibration and humidity specsmy Total space for this connector is around 70mm, and I need at least 62 connections, so which part number do you suggest? also what sort of prices should I expect.

author: Wendy_Preston
author_rank: Contributor
timestamp: May 01, 2020, 07:26:20 am
content: Ali, best thing to do would be to emailtechnical-us@harwin.com- my colleagues Dwayne and Zach are well versed in the Datamate range, and can work out which options are the best match to your needs. Please do let them know all the details you've put in this post about your needs, any specific values you have for the humidity and vibration/shock, what orientation of mating pair connectors you need, what volumes you will require, and timescales - they can work out the best matches and availability. Thanks!
600 V electronic load - Page 1
Forum section: electronics / projects

author: Martinn
author_rank: Frequent Contributor
timestamp: November 20, 2022, 05:17:03 pm
content: Hi all, just showing this little electronic load modification. Like most designers, at some point I realized the significance of the term "DC SOA" and consequentely came across the IXYS linear FET rangehttps://www.littelfuse.com/products/power-semiconductors/discrete-mosfets/n-channel-linear.aspxTheir product list has "Sample" buttons which actually work - so some time later I had a IXTN30N100L to play with. It is a 1000 V, 30 A, 800 W N channel FET. Even better, at case=90°C it has a DC SOA of 600 V, 0.5 A. Impressive!I implanted this little monster in a "100W electronic load" module from ebay and changed shunt and voltage sense resistors for a 1 kV/1A full scale range. I also replaced the potentiometer with a 10 turn, as I intend to stay away from lethal power levels and more in the mA range.Still usable current starts at about 5 mA with this setup, I'd have to change the shunt but would lose the 1A range. Anything else would need more complicated modifications and I'd be probably faster designing the whole thing from scratch.Isolation is of course not sufficient for 1 kV operation, but I tested it with a (current limited) 400 V supply and it did not fall apart. I guess this thing will be fine for testing my nixie and scope clock power supplies.- Martin

author: JohanH
author_rank: Frequent Contributor
timestamp: November 20, 2022, 07:35:20 pm
content: Quote from: Martinn on November 20, 2022, 05:17:03 pmThat's generous of them, it seems to be an expensive part! I was looking at Onsemi FCH041N60E and FGH60N60SMD with similar DC SOA as the IXYS, but much cheaper (ordered the FGH60N60SMD IGBT and planning to test it).
60Hz transformer cores - Page 1
Forum section: electronics / projects

author: uer166
author_rank: Super Contributor
timestamp: February 21, 2022, 09:28:56 am
content: Anyone know where to source low frequency cores+bobbins or toroids? I want to wind some custom 60Hz, and audio frequency transformers but having a hard time with existing parametric searches on digikey etc.

author: jonpaul
author_rank: Super Contributor
timestamp: February 21, 2022, 09:55:12 am
content: Bonjour:Ure66 seeks "low frequency cores+bobbins or toroids?.....custom 60Hz, ...audio frequency transformers ...1/50/60 Hz mains transformers are assembled from die cut laminations to reduce cost and eddy current losses. Tapewound silicon steel toroid's are also available at very high cost and long lead tiem.Seach "transformer laminations" in EE and EI shapes.2/ "audio transformers" implies 20..300 Hz LF BW and 3k..20K HF BW, totally different windings and cores. Very thin tapes and lams needed.3/ Ferrite is used for power and pulse trafos at high freq, the Bmax is much lower than steel.Avail in many shapes.4/ Toroid is most difficult to wind and insulate for safety.Suggest to read the many texts and sites on transformer design and learn a bit first. Our friend Steve Smith, wrote Magnetic Components a nice mix of theory and practiceKind Regards,Jon

author: uer166
author_rank: Super Contributor
timestamp: February 21, 2022, 09:07:51 pm
content: Jon, I'm not trying to attack here, but I find your replies are rarely useful, since they are more often than not asking the OP to read books and papers which is off-topic. If anyone knows of suppliers much like Dexter Magnetics, Digikey/Mouser, etc, that have a selection of laminate cores, that would be very appreciated..

author: Benta
author_rank: Super Contributor
timestamp: February 21, 2022, 09:18:22 pm
content: For 50/60 Hz transformers, getting some custom wound is not that expensive, perhaps a premium of 30% vs. a standard type of the same power.Now the audio ones are more tricky...

author: bob91343
author_rank: Super Contributor
timestamp: February 21, 2022, 09:51:37 pm
content: Perhaps an internet search for companies who make laminations. I remember old line companies that may no longer exist, such as Driver-Harris and Arnold and I think US Steel.https://www.thomasnet.com/products/magnetic-laminations-43020403-1.html
60V+ Output Charge Pump Selection/Design - Page 1
Forum section: electronics / projects

author: Matt Coates
author_rank: Contributor
timestamp: September 11, 2023, 11:22:12 am
content: I'm looking for some help in selecting a charge pump or other device for a project.I have an input voltage VIN which can range from 17V to 52V, and from that I am generating a 12V rail using a COTS DC-DC module.I also need to generate a voltage at VIN + 10V (or VIN + 12V would also work) which is then used to drive a HV op amp and FET gate. The current requirement is only 10mA or so.I have been looking at the LTC3290https://www.analog.com/en/products/ltc3290.html#product-overviewwhich can happily generate VIN + 10V but my voltage input range is slightly too big. To keep within spec (VIN + VAUX < 55V) I would need to keep VIN below 43V. You can push it slightly whilst keeping below the Abs Max ratings, but this isn't ideal.Does anyone have any suggestions for alternative approaches or parts? Any help would be much appreciated!Thanks!

author: Ian.M
author_rank: Super Contributor
timestamp: September 11, 2023, 11:43:03 am
content: If you don't need the boosted Vin rail to come up before the 12V rail, simply use a 0.5W or 1W 12V output isolated DC-DC converter, powered from the 12V rail and stack its output on top of Vin.
6181A current source mod - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: October 14, 2024, 08:36:41 pm
content: I found a mod for the 6181A current source where you can add a 250uA range by adding another shunt.I am wondering if you can go further then this, i.e. add a 25uA range.https://xdevs.com/doc/HP_Agilent_Keysight/HP%206177C%2C%2081C%20Operating%20%26%20Service.pdfSchematic on page 51I see they put the current signal into a 2N4045Am I correct in thinking that eventually the problem is that the input impedance of the feedback amplifier is too low to work with such a high shunt resistance? For a 25uA source it would be 90kOhm.What other problems are there?

author: enut11
author_rank: Super Contributor
timestamp: October 15, 2024, 09:09:42 am
content: I have a HP 6177C and modified it with a 500uA range using a 1800R precision resistor. I tested it down to 1uA and it is surprisingly stable. The test involved running the current through a 10K 0.01% resistor and recording the voltage. The biggest problem I had was lack of resolution on the current pot. I solved this with an additional pot in series with a value of 1/40th the original pot effectively creating a fine divider over a small range.For your purpose I would suggest you try the 250uA mod first and characterise that before going down to 25 uA. You can easily do a temporary mod without changing the range switch.enut11

author: coppercone2
author_rank: Super Contributor
timestamp: October 15, 2024, 09:07:51 pm
content: Hmm yeah I got the special switch from that mod.I thought someone might have some insight that saves me work doing characterizations of equipment.I also found like all the other similar HP supplies, the capacitors buzz, I traced down the noise using a silicone tube. I had success replacing them with foil caps. I know its not the ceramic itself, because I bought fresh disk caps and replaced them, and they buzz too on all the harrison stuff, the ones on the little rectifier PCB. Our grid is really noisy.