hybridfree/eevblog-posts huggingface dataset:
Need MOSFET recommendations for TPS53114 based SMPS - Page 1
Forum section: electronics / projects

author: Circuitous
author_rank: Unknown
timestamp: August 26, 2013, 01:55:28 pm
content: I'm looking at using the TI TPS53114 to build a SMPS, with an input of around 12V, and an output of 3.3V @ 5A.Any recommendations on the N-channel and P-Channel mosfets?Given that it's 16.5W output, I'm thinking of using TO-220 devices to allow for heatsinks.I'm not dead-set on using the TPS53114, but it seems to fit the bill. Recommendations for similar devices are welcome.

author: Marco
author_rank: Super Contributor
timestamp: August 26, 2013, 03:58:11 pm
content: It's a buck transformer with a synchronous rectifier, both implemented with N channel MOSFETs. Where does the P channel MOSFET come in?I have no experience with these parts, but I can tell you that there areplenty of partswhich claim to be able to handle 5A output without external MOSFETs BTW.

author: Circuitous
author_rank: Unknown
timestamp: August 26, 2013, 05:55:13 pm
content: The application notes showed two different devices on the sample application:FDS8678FDS8690 N-Channel MosfetI had found a reference to the FDS8678 being a P-Channel, but I can't find a datasheet for it anywhere.http://www.ti.com/lit/ds/symlink/tps53114.pdfMy initial thought that it would be just 2 N-Channel devices.I've used the Simple Switcher ones, but didn't like the amount of heat dissipated through the schottky diode. My understanding is that using two mosfets would improve that. I'm new to SMPS design (surprise). So, to some extent this is a learning exercise, and I will apply the new knowledge to the final design.If I do continue the separate MOSFET approach, any recommendations for the transistors?

author: Corporate666
author_rank: Unknown
timestamp: August 26, 2013, 06:42:03 pm
content: Quote from: Circuitous on August 26, 2013, 01:55:28 pmTI bought National Semi and integrated National's (IMO, awesome) WebBench tools into their website. If you are not familiar with it, you create an account and then it downloads and installs a Java app. You select your regulator, then there is a dial where you can set the compromise between board size, electrical efficiency and cost. It also gives you a list of recommended parts and updates the board size and efficiency in real time as you change the them. There are multiples of each recommended part so you can swap them out and try others. And you can enter your own part specs and it will calculate the efficiency and such.Probably the best way to short list some FT's that will work in your design.

author: Circuitous
author_rank: Unknown
timestamp: August 27, 2013, 01:06:41 am
content: @marco - thanks for the link, I didn't realize I should have included the term "synchronous" in my searches. That returned a much better list of devices to review.@corporate666 - I have spent this evening on the WebBench site, and came up with a couple of additional candidates and components.The digikey order is placed... should arrive by Thursday, and will give me something to work on over the Labor Day weekend.Thanks for your input.
Need multiconductor cable with soft and flexible insulation - what to look for? - Page 1
Forum section: electronics / projects

author: ttodorov
author_rank: Regular Contributor
timestamp: April 26, 2016, 05:16:13 am
content: Hi everyone,For one of my hobby projects, I need 5-to-10 conductor cable with soft insulation, which is also flexible as in multimeter test leads or the cables of soldering iron pens. A cable with the actual high-temp silicone jacket would be actually very nice. Problem is, when I went on Mouser and DigiKey to look for something like that, I got lost in the selection filters... EPDM, ETFE, FEP, FDPE, LLPE, PTFE, and so on, and so forth. Unfortunately I am not very strong in the materials science side of all things hobby electronics...So if someone has some suggestion what to look for, or has any URI where I could by cable by the foot, of similar type to the one used in my soldering iron (hakko ripoff, in case you are wondering) - I would appreciate the pointer.Thanks!Best regards,Todor
need of carrier supression when locking to cavity resonator - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: June 13, 2025, 09:25:06 am
content: Hello ,I am building a system that needs to tune the YIG into cavity resonator resonance as shown below and in the attached article.I want to build a basic lock to my cavity resonator.Why do I need this carrier supression?Can I make it work basickly without doing the carrier supression?Thanks.
Need Oscillatek 8032 OCXO pinout/specs - Page 1
Forum section: electronics / projects

author: Eliminateur
author_rank: Regular Contributor
timestamp: May 09, 2020, 10:12:41 pm
content: Hello,i have a vintage bit of kit that i'd love to test out but i can't find the pinout or specs:An Oscillatek 10.000MHz OCXOP/N 282376Bmodel 8032My unit also has a Scientific-Atlanta PN: 285603It has the 10Mhz coax output and a 7-pin connector, 2 of those have soldered and shrink-wrapped cables that are cut, i guess those are the power supply but i have no idea the voltage needed either(i could start cranking up until i get an output)This OCXO was pulled from scientific-atlanta satcom datalink systems (the ooold ones that worked at RS232 speeds and were 3U high rack units, plus big 2m diameter antennas with ORUs)All i can find is ebay listings of it and it appears the company changed names as well to VI-OLATHE, but absolutely no info on its performance or pinout(and i don't have the gear to really characterize the stability/phase noise/phase stability of this)

author: edpalmer42
author_rank: Super Contributor
timestamp: May 09, 2020, 10:46:55 pm
content: Did you see the one on ebay that includes a photo of the spec sheet?https://www.ebay.com/itm/302937785558

author: Eliminateur
author_rank: Regular Contributor
timestamp: May 10, 2020, 12:10:32 am
content: Quote from: edpalmer42 on May 09, 2020, 10:46:55 pmoh wow i did not see that!.excellent!so it's 12vdc, goodphase noise:-128dbC/hz @100Hz-135dbC/hz @300Hz-145dbC/hz @1 to 10Khzstability: +-1 x10^-9/day (i guess that's Hz) and +-3x10^-8/monthtemp stab: +-2x10^-8 0 to 60°Cto supply: +-10x10^-10/1% supply changesettability: +-1x10^-8 (what's settability?)but the subharmonics are not visible due to a crease in teh papernow, ¿are those values good for modern standards?
Need Part ID or Name - Page 1
Forum section: electronics / projects

author: Felicitus
author_rank: Regular Contributor
timestamp: November 05, 2016, 10:31:17 am
content: I found these ceramic standoffs with 2 connectors, however, I was not able to find any datasheet or technical data. Any clue what the part is called?

author: Fortran
author_rank: Regular Contributor
timestamp: November 05, 2016, 12:39:55 pm
content: I found something like this that seems pretty close. Only called ceramic standoff.I also found these.https://www.ettinger.de/en/product/search#53/ART_GRUPPE=61&ART_BAUART=DIRUNDWhich might work together with these.https://www.ettinger.de/en/product/search#163/ART_GRUPPE=25&ART_BAUART=MEHRFA
Need photo of agilent E3615 PCB assembly photo - Page 1
Forum section: electronics / projects

author: jtronix
author_rank: Regular Contributor
timestamp: October 16, 2012, 11:01:10 am
content: can any body have E3615 PCB photo. i want to see component on the board.any body try to design this power supply from service manual schematic?

author: nukie
author_rank: Frequent Contributor
timestamp: October 16, 2012, 01:21:23 pm
content: If you tell me how you are going to make the 2 or 3 custom transformers in the E3615A then I shall support you with all the pictures.

author: jtronix
author_rank: Regular Contributor
timestamp: October 18, 2012, 12:04:03 pm
content: i'm not going to use SCR and that custom transformer.first i will test constant voltage and current source.
need pinout of tcxo - Page 1
Forum section: electronics / projects

author: MickM
author_rank: Regular Contributor
timestamp: January 21, 2016, 06:36:59 pm
content: Hi;I have a module (PM9678B), from a Philips freq counter.I cannot find any info on it.I think it came from a PM667x unit.The can has a row 0f 3 pins opposite 2.Thanks

author: miguelvp
author_rank: Super Contributor
timestamp: January 22, 2016, 05:00:02 am
content: Page 40 on this manual:http://bama.edebris.com/download/philips/pm6673-76/Philips%20PM6673-76%20Universal%20Frequency%20Counter%20-%20Servicemanual_2.pdffrom here:http://bama.edebris.com/manuals/philips/pm6673-76/Page in question:

author: MickM
author_rank: Regular Contributor
timestamp: January 22, 2016, 05:20:22 am
content: Thank you miguelvp.

author: miguelvp
author_rank: Super Contributor
timestamp: January 22, 2016, 05:31:05 am
content: You are welcome, I knew where to look at.I posted the main link to "The Boat Anchor Manual Archive Mirror" in the sticky repair post:https://www.eevblog.com/forum/repair/repair-documents-and-links-sticky-me-please-mods/There are many links in there to find a lot of vintage equipment information.Edit: Nice TCXO module btw
Need projects to understand transistor circuit and discrete power supply design. - Page 1
Forum section: electronics / projects

author: audio
author_rank: Regular Contributor
timestamp: August 21, 2021, 06:07:16 pm
content: Greeting to all,Need some project link to understand1) transistor application and2) discrete power supply design.Atleast 10 practical Application to understand the circuit operations.So that it help me to understand circuit with more complexity.Thank you all

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 21, 2021, 07:11:52 pm
content: https://duckduckgo.com/?q=dc+power+supply+schematic+transistor&t=hx&va=g&iax=images&ia=images

author: armandine2
author_rank: Frequent Contributor
timestamp: August 21, 2021, 08:23:25 pm
content: Seymour Schwartz (Ed)(1961) Selected Semiconductor Circuits Handbook - pub WileyThe above book has a "Small Lab Supply with Current Limiting", the circuit description includes schematic drawing, by P.N. Sherrill of the Hewlett-Packard Company.The author says "the circuit is a good example of a common-emitter type of series regulator.https://archive.org/details/selectedsemicond00tran
Need Recomendation: Best Goop to Buy on Digikey - Page 1
Forum section: electronics / projects

author: TheRuler8510
author_rank: Regular Contributor
timestamp: August 25, 2013, 03:30:16 am
content: Hello Group,Can someone make a recommendation for the best Goop to Buy on Digikey for strain relief and tacking down big capacitors on a PCB?The epoxy potting compound I bought is too thin and runny to be useful. Of course it should be non-corrosive, so plain silicone is bad, right?The search tool doesn't reveal any solutions.Regards,Tom

author: robrenz
author_rank: Super Contributor
timestamp: August 25, 2013, 04:13:41 am
content: Home Depot or Lowes GE silicone II, way cheaper and just as effective as anything from the electronic supply houses.It must be a neutral cure silicone or it will cause corrosion of most exposed metal surfaces on electronicsFrom the GE site:GE Silicone II* caulk is what's called a "neutral cure" silicone, which means no acids are released during the curing process (as there are in GE Silicone I*). This enables GE Silicone II* to adhere to a broader range of substrates such as plastics, concrete, and metals. Also, the odor of a neutral cure silicone such as GE Silicone II* is much less offensive than an acid or acetoxy cure silicone such as GE Silicone I*.Silicone is tough to beat as an long term adhesive and its resiliency enables it to endure shock loadings better than just about any adhesive.

author: TheRuler8510
author_rank: Regular Contributor
timestamp: August 25, 2013, 04:45:35 am
content: robrenz,Kitchen and Bath Silicone II sound like it will work perfect.Thanks for the tip.Tom

author: SeanB
author_rank: Super Contributor
timestamp: August 25, 2013, 05:06:59 am
content: I used to use a blob of very thick cyanacuralate glue as a hold down to boards for capacitors, along with a lacing cord as originally used.

author: peter.mitchell
author_rank: Super Contributor
timestamp: August 25, 2013, 07:55:36 am
content: for strain relieving cables I use liquid electrical tape over silicone, no particular reason as to why though *shrugs*
Need review and advice - First project - Board with Heltec Wireless Shell - Page 1
Forum section: electronics / projects

author: MercadoNegro
author_rank: Newbie
timestamp: July 03, 2021, 06:08:31 pm
content: Hello all,I started this idea thinking on a weather station connected to TTN using Lorawan. It worked with standard ESP32 dev modules, then I decided to use this Heltec because it`s something I already had and I thought that was better to use it in a small board. All my I2C and the anemometer (based on a hall sensor) can be connected to 5V, for that reason I have the logic level converters.This schematic and the PCB probably have lot of rookie mistakes that I need to fix before trying to put any order with JLC.My idea was to use 4 layer PCB, with a power plane divided in two, mostly 3.3v and an L shaped section for 5v. I don`t know if this is a good practice, and this is one of the items where I need some advice.The general schematic is based mostly on the corresponding IC datasheets and some other stuff I learned reading technical docs, forum posts and videos, like the reverse polarity protection. I`m not an electronic engineer and have some basic knowledge on electronics, for that reason lot of stuff could be wrong, but I tried to do my best here.I used EasyEDA because is easy to use for a newbie and have the chance to check parts availability in JLCPCB, but I`m already learning Kicad for future projects. The post was initially posted in the beginner section, but I updated the schematic and the PCB and decided to move it here.Please, can you help me with this and tell me what things are wrong and what should I correct?Thanks!Gustavo
need sam help. - Page 1
Forum section: electronics / projects

author: Aigars
author_rank: Regular Contributor
timestamp: May 29, 2014, 09:10:01 pm
content: i have this soldering handle.1. i need make contoler.2. i need make power suplay.whu can help me about this?there its a images.

author: Sam__
author_rank: Regular Contributor
timestamp: May 29, 2014, 11:01:31 pm
content: I would assume the best thing to do would be to look at the schematic for the controller it's supposed to be used with. From there you can work on developing your own controller. This is if I'm getting the right end of the stick in that you want to make your own temperature controlled power source.

author: M4trix
author_rank: Frequent Contributor
timestamp: May 29, 2014, 11:16:29 pm
content: Well, WTA-50 is compatible with WD 1, WD 1M, PUD 81, PUD 151, PU 81, WR 3M, WR 2 and WAD 101. You can find some details about the PU-81 unit here ->http://remotesmart.wikidot.com/weller-wecp-20

author: Aigars
author_rank: Regular Contributor
timestamp: May 30, 2014, 08:42:13 am
content: Quote from: M4trix on May 29, 2014, 11:16:29 pmOK. BUT WHERE I CAN GET DOWNLOAD FILES FOR MAKING THIS ALL? I AM NOT SHOR, IF I CAN MAKE DAN THIS FROM ZERO.

author: Monkeh
author_rank: Super Contributor
timestamp: May 30, 2014, 08:47:42 am
content: You've been handed a schematic for free, now go ahead and make use of it.Good grief.

author: grumpydoc
author_rank: Super Contributor
timestamp: May 30, 2014, 09:29:48 am
content: QuoteMore than one, in fact.Yet another very useful link was posted, I wonder whether we should try to collate and index these given thet searching the forum, even with google, isn't great.

author: Aigars
author_rank: Regular Contributor
timestamp: May 30, 2014, 10:35:57 am
content: PEOBEBLY YA.

author: Aigars
author_rank: Regular Contributor
timestamp: May 30, 2014, 05:46:10 pm
content: i find samething like this. how i can use this scheme?

author: SL4P
author_rank: Super Contributor
timestamp: June 01, 2014, 12:53:43 am
content: Why do you need to copy their PCB design (which is also provided in the link from M4trix)You need the schematic - then build it - (relatively) easy.

author: nanofrog
author_rank: Super Contributor
timestamp: June 01, 2014, 06:52:13 pm
content: FWIW, here's theWD1 schematicas well (.pdf attachments).
Need Samsung LCD tv main board help!!! - Page 1
Forum section: electronics / projects

author: Napalm2002
author_rank: Regular Contributor
timestamp: December 11, 2013, 03:59:15 am
content: I have a Samsung LCD tv ln52a530p1f tv In need of a main board. All that I can find is one used board on eBay for new price. I'm in the USA. All of the sites that I have found are out of stock.can anyone tell me what breaks on the board? And if I can buy the little parts and fix the board? Or do the proprietary Samsung parts fail that are unobtanium? I just hate to buy a used board out of am old tv and have it go bad soon. When I could have paid the same price for a new one if someone had it in stock. Btw the main board number is bn96-08252b.Thanks in advance my fellow eevblog friends!Mike

author: retiredcaps
author_rank: Super Contributor
timestamp: December 11, 2013, 07:32:16 am
content: Check out badcaps.net particularlyhttp://www.badcaps.net/forum/forumdisplay.php?f=31Tom66, a member here, and budm are the regulars that help others with TVs.I used to participate there frequently, but now I have another area of interest.

author: Napalm2002
author_rank: Regular Contributor
timestamp: December 11, 2013, 03:35:00 pm
content: Thank you. I am going to check it out!Mike
Need scan from Silicon Chip March 1992 for TV pattern generator NTSC mod - Page 1
Forum section: electronics / projects

author: anderoo
author_rank: Contributor
timestamp: November 04, 2017, 08:07:52 am
content: Could someone please help me out by posting a scan of a Circuit Notebook entry fromSilicon Chip magazine of March 1992?The entry I need is called "Converting the pattern generator for NTSC" by John Clarke.Reason being is that I have resuscitated an old kit of the TV pattern generator described in the Nov/Dec 1991 issues.It seems to be working well but is limited by being PAL/50Hz only. I was hoping that the Circuit Notebook entry shows an easy mod to get NTSC/60Hz as well.Thank you.
Need simple PLL to get 73Mhz by 6 x - Page 1
Forum section: electronics / projects

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: September 09, 2025, 11:18:49 am
content: I need to multiply by 6 12,226Mhz. I need simple low cost PLL. A cheap MB1501 looks too complicated.Any advice?

author: LaserSteve
author_rank: Super Contributor
timestamp: September 09, 2025, 02:00:24 pm
content: TI's CDC5801A clock multiplier has a x6 mode. Many other clock multiplier chips exist. The cdc5801 was just the first Google search that found a x6 model.How much phase noise can your application withstand?If you only need a one-off you can do something like this, which I have used for my Ham Radio habit:https://www.w1ghz.org/small_proj/A_Flexible_VCXO_Locking_Board.pdfThe above may not do exactly what you want, but it gives you a way to be inspired.Steve

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: September 09, 2025, 02:18:05 pm
content: Thanks for suggestions.The CDC5801 unfortunately for x6, minimum input frequency is 25Mhz. I have 12Mhz.

author: LaserSteve
author_rank: Super Contributor
timestamp: September 09, 2025, 02:29:45 pm
content: Take a look here:https://www.changpuak.ch/electronics/XCO-100.phpHis online chip selector / calculator says you need NB3N511He has other designs in the menu.Steve

author: Ian.M
author_rank: Super Contributor
timestamp: September 09, 2025, 04:01:51 pm
content: If that's a fixed 12.226 Mhz consider an injection locked oscillator.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: September 09, 2025, 08:06:15 pm
content: Quote from: Kokoriantz on September 09, 2025, 11:18:49 amThe MCU Stc8h1k08t has a PLL that can do that, but not sure what 72MHz on a pin will look like ?If you have a local MCU, the si5351 could also manage 72MHz from 12MHz once configured.

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: September 09, 2025, 08:26:41 pm
content: Thank you for information, The affordable one is ICS501, replacing NB3N501.From Aliexpress, 10p cost $1.6 free ship.

author: Andree Henkel
author_rank: Regular Contributor
timestamp: September 10, 2025, 12:39:10 pm
content: caution: while still available, ICS501 is obsolete

author: radiolistener
author_rank: Super Contributor
timestamp: September 10, 2025, 05:34:44 pm
content: Quote from: PCB.Wiz on September 09, 2025, 08:06:15 pmThe si5351 is also available preprogrammed at the factory with a specific register configuration, so it does not require an external MCU for setup. For larger production runs, it can be ordered with the desired frequency already configured.
Need some advice on this video output circuit - Page 1
Forum section: electronics / projects

author: furntree
author_rank: Newbie
timestamp: July 20, 2016, 04:44:44 am
content: Hello all!I am basically tapping R/G/B + Video Sync signals from a Playstation 2. Sadly there not a lot of information online on tapping video signals for this particular system with a lot of it being very dated and brief.In researching how other people were tapping into RGB signals on their game consoles I noticed a lot of people recommended capacitors inline with each RGB line. However, this does not always seem to be the case depending on the system.Looking at the PS2 service manual where we would be getting RGB signals from. It looks like these outputs are rather well filtered (AV Multi out pins 1/2/4) with a strong signal coming from the AV Encoder (IC206). In this case adding additional capacitors seems superfluous! -Just wanted to make sure I have the correct train of thought. Plus it would save me a Digi-Key order! Any info to further understand this circuit would also be appreciated! Thanks in advance!

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 20, 2016, 04:54:23 am
content: Since the output of your source gadget clearly has capacitor coupling, you would need a good reason to add any more capacitance in line with those video signal paths.Since you revealed nothing about the destination circuit, we have not the slightest clue whether you might need DC blocking in your input circuits (or not).
Need Some Help Finding the Right Crystal Load Capacitors  - Page 1
Forum section: electronics / projects

author: XenonFlash54
author_rank: Contributor
timestamp: February 04, 2015, 01:10:14 pm
content: Hello Everyone!Well this is my first time trying to use a crystal with a PIC so I have a few questions. In thePIC18F67K22 data sheet, page 50, under the HS table it has some recommended capacitor values for C1 and C2. Unfortunately, I want to use a 16MHz crystal, and they don't have C1 and C2 values for that frequency. So I did some googling and it appears that I can calculate the value of C1 and C2 with the rated load capacitance of the crystal and this formula: CL=(C1*C2/C1+C2) + 5pF. So with a 27pF value for C1 and C2:CL=(27pF*27pF/27pF+27pF) + 5pFCL=13.5pF + 5pFCL=18.5pFAnd the crystalI'm planning on usinghas a 18pF load capacitance. So would that be about right for C1 and C2?Thanks very much!!!Dan

author: dannyf
author_rank: Super Contributor
timestamp: February 04, 2015, 01:49:50 pm
content: Crystal oscillators have very low pullability so even if the CL is off by a large margin, the frequency isn't that far off for most applications - to give you an example, I typically do NOT use any load capacitors for high frequency crystals.Now, that would be wrong if you really want to hit the frequency. In those cases, you may need to play with the capacitors, or to use a trimmer = you can make a low pf trimmer by winding one insulated wire on another.

author: void_error
author_rank: Frequent Contributor
timestamp: February 04, 2015, 02:02:32 pm
content: Putting a 100-330 ohm resistor between the crystal driving output and the crystal with the associated capacitors worked for me. I used 22pF caps with a 16MHz crystal.

author: Pjotr
author_rank: Frequent Contributor
timestamp: February 04, 2015, 03:01:57 pm
content: Quote from: XenonFlash54 on February 04, 2015, 01:10:14 pmThis is correct. For the actual load capacitance C1 and C2 are in series. The 5pF extra is the (guessed) circuit stray capacitance. Note that C1 an C2 should be equal. They form a kind of transformer so that the output of the crystal is 180 deg out of phase (inverted) to the driving voltage at resonance.

author: XenonFlash54
author_rank: Contributor
timestamp: February 04, 2015, 11:06:03 pm
content: Okay, awesome! Thanks everyone!!Dan
Need some help from an Opamp expert! - Page 1
Forum section: electronics / projects

author: rjmusto
author_rank: Contributor
timestamp: February 23, 2022, 04:45:25 pm
content: Hi all,I am trying to fix a Siemens Multizet analogue multimeter and am a bit stuck ....The unit looks like it has never been used, not a mark on it, but the meter winding has been zapped. I have been trying it out with another movement (seems to need something around 20uA meter) hooked up to it and for the most pasrt it all works. However, on the resistance ranges, it works by running the meter over to full scale for open circuit and working back from there as you measure resistance.But I am concerned that it fair whacks the meter over on open circuit - which might explain why the original was burnt out. Full scale needs aroung 80mV across the meter connection, but it applies 190mV to it on these resistance open settings, so way too much. It does though make correct resistance measurements, so it seems like it is only when open circuit that things go awry.The circuit uses a bunch of opamps to handle all this and I have been unable to get my head round it all and work out why this is happening. So could somebody smarter than me help with the challenge?Attached are two extracts from the schematic; one shows the amp for the resistance readings and the other the amp chain driving the meter. I've checked all the diodes and zeners and not found a fault.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 23, 2022, 07:00:11 pm
content: The circuit is relatively straiight forward:IS2 works as a non inverting amplifier with 2 possible gain settings depending on the range.IS3 works as a kind of voltage to current converter an precision rectifier. depending on the polarity the current flows either through D11 or D10 and than a bit like 40% through the meter movement and the rest though just a resistor (R49, R50).IS4a seems to indicate the polarity. IS4b works as a differential amplifier for the voltage over the meter movement part. What is done with this signal is ouside the picture.The usualy meter movements are OK with a somewhat high than nominal current. So 2 or 5 times the norminal value will usually no to harm to the movement.

author: rjmusto
author_rank: Contributor
timestamp: February 23, 2022, 07:22:19 pm
content: That’s very helpful. Thanks.So I guess I’m being over cautious and haven’t found a fault because there isn’t one!This meter seems to auto-sense polarity and has an LCD window to indicate it, so I think the rest of the circuit out of shot is that bit. It also auto-shifts the scale between x1 and x3.It’s a nice meter so will be good to get it back into use…..
Need some help identifying connector - Page 1
Forum section: electronics / projects

author: fozzyvis
author_rank: Regular Contributor
timestamp: July 13, 2013, 10:13:53 am
content: Hi all,I am currently working on a wireless tally control system for a client of mine.The cameras are JVC GY-HM790E models.While the electrical side of the control is working, I can't seem to find the correct connector.I've gone through numerous catalogues and websites, but no luck so far.-10 pins-circular design, no center pins-mating plug inside diameter about 8.1mm, OD about 9.8mm-three positioning tabs dividing the connector in 2X 3pins and one time 4 pins-marked on the top is "qqq DO-111" the q's are italic, not sure whether it's D0 or D1Anyone any clues?Regards,dieter

author: amyk
author_rank: Super Contributor
timestamp: July 13, 2013, 12:16:32 pm
content: The company seems to have beenhttp://www.qqq.co.jp/and is nowhttp://www.technical-e.co.jp/Here is a reference to the part number to show that they once made them:http://web.archive.org/web/20000620191706/http://www.qqq.co.jp/hp/component/qqqhomepage01b.htmStumbling around their new website with an automatic translator shows that theystillmake them:http://www.technical-e.co.jp/cgi-bin/business/elec_precision/detail.cgi?id=D0111N100Ahttp://www.technical-e.co.jp/cgi-bin/business/elec_precision/detail.cgi?id=D0111N200Ahttp://www.technical-e.co.jp/pdf/parts/catalog_10.pdf(I have no idea where to buy one though.)

author: fozzyvis
author_rank: Regular Contributor
timestamp: July 13, 2013, 12:28:18 pm
content: @Amyk: That's a great start, thanks!May I ask how you found these? I really tried looking and searching for a lot of different search strings and sites, but nothing came up.Wonder how you found this...

author: amyk
author_rank: Super Contributor
timestamp: July 14, 2013, 01:22:55 pm
content: Quote from: fozzyvis on July 13, 2013, 12:28:18 pm* Googled "qqq connector" and found their old website, then followed it to their new one and started poking around their products.
Need some help selecting a connector - Page 1
Forum section: electronics / projects

author: dimkasta
author_rank: Regular Contributor
timestamp: April 20, 2017, 07:21:48 pm
content: I am building an external psu for an audio device that delivers 30V DC @400mA with 1A peaksWhat I am looking for is a locking connector pair (panel-cable) that can supply that without issues. The restriction that I have is that the panel side has to fit in a 10mm holeUnfortunately din connectors are too big for that, and I could not locate any locking mini dins.I have some mini xlrs that fit and are rated for that, but they feel a bit flimsy.Any suggestions?Thanks for your time

author: Ian.M
author_rank: Super Contributor
timestamp: April 20, 2017, 07:30:46 pm
content: Switchcraft have got some standard 2.1mm center pin DC plugs and jacks with a screwdown locking ring.http://www.switchcraft.com/productsummary.aspx?Parent=479

author: dimkasta
author_rank: Regular Contributor
timestamp: April 20, 2017, 09:33:24 pm
content: Quote from: Ian.M on April 20, 2017, 07:30:46 pmThanks a lot. Those seem to be a perfect fit for the purpose.Any idea what is the external diameter of the threaded part of the sockets?Their mechanical diagrams are awful

author: Ian.M
author_rank: Super Contributor
timestamp: April 20, 2017, 10:07:44 pm
content: The one I looked at said "5/16 x 32 NEF-2A" for the thread. Assuming that's actually UNEF-2A, its a standardised thread.http://f-m-s.dk/3.03.7.pdfhas dimensions.

author: dimkasta
author_rank: Regular Contributor
timestamp: April 20, 2017, 11:41:44 pm
content: Quote from: Ian.M on April 20, 2017, 10:07:44 pmOh niceAgain thanks a lotIt seems it will fit nicely. I 'll get some samples on my next order
Need some help with 12v to 20v - Page 1
Forum section: electronics / projects

author: gotofbi
author_rank: Contributor
timestamp: September 16, 2022, 08:04:22 am
content: Hi,I need some help with converting from 12v to 20vThe goal is to run 8x of Tiny Computer (Lenovo M900) and it came with 90W or 135W power supplyI dont think the system will require 135W but I am going to assume its possibleSince I need to power 8x of them, I do not want to have 8x power bricks to run it but want to run it with 1 power supplyAnd I also happen to have 1200fb power supply which is 1200W 12V power supplySo even at worst case, of all 8 system consumes 135W, it will be 1080W which is still under rated usuage.Now, my main problem is to safely step up from 12v to 20vI saw some aliexpress items and found this10-30V to 12-35V Step Up CV CC 150W 10A DC DC Boost Converter(https://www.aliexpress.com/item/1886880830.html)The item description says input 16A and output 10AIs that mean this device can use up to 192W(16a x 12v) of input and 200W(10a x 20v) of output?If so, can I connect 8x of them into the 1200W power supply and use those computers safely?Or do I have better solution to power those computers with 1200fb?Thanks for reading it!

author: tinfever
author_rank: Regular Contributor
timestamp: September 17, 2022, 05:02:01 am
content: The item description you link says there is a max power output of 100W with no additional cooling or 150W with extra cooling. So assuming 100% efficiency and assuming you added some fans over the DC-DC converter, each one of those might be able to do 20V 7.5A output for 12V 12.5A input. However, keep in mind these Chinese products have been known to exaggerate their ratings, so who knows how it would work in real life. So theoretically that *might* work?Unless this is a project you're doing for your own education, but I'd suggest using the stock power bricks, although I know it isn't nearly as fun. Surplus computer power bricks are cheap in volume on eBay, and it'll probably work out cheaper and less painful to have 8 power bricks in the long run. It might be about the same efficiency too after you have the losses from the AC-DC 1200W supply and then the losses from the DC-DC 12V to 20V boost converter.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 17, 2022, 06:30:47 pm
content: So when the single 1.2kW psu fails (as if) it kills all your Tinys?
Need some help with a camera wifi connection - Page 1
Forum section: electronics / projects

author: larrybl
author_rank: Regular Contributor
timestamp: January 19, 2016, 01:26:01 am
content: Hello all, I am coming here as I really messed up and Dave said that this is the best place to find help. I purchased a "Sky Viper Video Streaming drone" (around $100 US) so not a real loss. We had fun with it, but the problem I have is it requires a smart phone or tablet to download the app and capture videos. Only my Wife and Daughter have these devices, I only have a laptop. So every time I wanted to "play" I had to enlist one f them, and they don't want to come out in the cold. I got to looking on the internet about connecting a go-pro camera to a laptop and capturing video to VLC player. Great! I found I could connect to the camera with the laptop via (192.168.1.1) and get in with a login of "admin". I was able to see the video but had a 1 second refresh rate, not streaming. Now for the oops, It was complaining about ActiveX and I thought I was adjusting those settings, but I received a message that the camera was re-setting and not to power-down, so I didn't. I then lost the wifi connection and now nothing. I tried removing power for 30 minuets and powering up, nothing. So my question here, am I screwed? I have already committed to purchasing another one of these as they are fun, even without the camera, but I would like to try and get this one back.I am able to open it up if needed, I already have but not much inside (was hopeing for a re-set button)Yea I'm a nube, but I think I got close, but no dice. Here are some pictures.

author: larrybl
author_rank: Regular Contributor
timestamp: January 19, 2016, 06:00:39 pm
content: Guess I'll go get a new quad copter, no hope for resurrecting the wifi in this. Here are a couple internal pictures for those interested.

author: Nside411
author_rank: Newbie
timestamp: December 28, 2016, 06:15:28 am
content: If you are still having issues with the wifi on the camera is be glad to take a look at it for you.
Need some help with a Power Mosfet part - Page 1
Forum section: electronics / projects

author: rvmeush
author_rank: Contributor
timestamp: April 27, 2013, 07:09:14 pm
content: I'm working on the repair of a power supply for a tube amp. There is a Supertex N-channel mosfet in the circuit with part number VN0660N3, and it's in a TO-92 case. I wasn't able to find an exact replacement, but Digikey told me that an ST Micro part STQ2LN60K3-AP would work. There are a couple odd things about this replacement. First is that the Source, Drain, and Gate are on different pins so that the new part will have to be twisted to get it in the board properly. The second thing is that the marking on the new part says "2LN62K 3" - which looks odd since the part was supposed to be a 2LN60K3. I looked up 2LN62K on the ST Micro website and couldn't find anything.Perhaps I'm being a too paranoid, but these discrepancies have me a little worried. Can anyone shed light on this to ease my mind?Thanks.

author: SebG
author_rank: Regular Contributor
timestamp: April 27, 2013, 08:33:55 pm
content: I looked at the data sheet of the STQ2LN60K3-AP part and it states the marking on the package should be 2LN60K3. It is possible that the 2 instead of 0 is some form of identifying revisions of the device. Since you can't find any other devices with the marking it should be ok to use as expected. If you want first verify it is a n-channel transistor. Put a resistor between Vcc and Drain and connect Source to GND then apply V to gate and see what the voltage is at Drain. This will be an inverter and should confirm it is a transistor.
Need some help with rf transformer design - Page 1
Forum section: electronics / projects

author: _rushin_or_draggin_
author_rank: Regular Contributor
timestamp: January 27, 2025, 04:05:58 am
content: Hey all,I am currently in the process of designing a very,verysmall scale rf amplifier to better understand how they work. My plan is to use the IRF510 MOSFET (not really an RF mosfet but readily available and used in the ham radio community a fair bit) in a common source push/pull topography to amplify a 4W signal to about 50 or so watts for the 20 meter band. Again, nothing really crazy, just to prove the concept. Anyway, I am kinda stuck on how to design the input and output transformers.From simulation (and comparing to a few other very similar designs) I see that my input transformer should be close enough to a 1:1 for 50 ohms (I have seen others use bias tees to test input impedance but I would appreciate hearing other methods), but I can't decide on how to go about making it. I'll admit, I do not have much experience at all with making transformers. One issue I'm facing is multiple types of cores of the same material. For example, when looking at fair-rite's line of ferrites, such as mat 43 or 61, they have quite a few choices of say Mat 43, but they all have difference impedances and response curves shown in the datasheet. My question is what exactly do you look for in these cores.Is there a recommended method to choosing a few to order and then once they arrive another method of testing them for your design? I attached a datasheet for one of the cores in hopes someone could better explain what exactly I am looking at.Thanks in advance!

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: January 27, 2025, 08:42:15 am
content: There is a good design using those transistors here:https://www.qrp-labs.com/linear.htmlThere is a pdf construction manual with transformer core and winding details. I think you expect too much in terms of power, 10W is more reliable.73 SJ
Need some help/advice with select-able and stable voltage divider in the mV/uV  - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: May 14, 2014, 12:22:59 am
content: Ive been working on a dummy load for quite some time now, im trying to make a piece of quality gear. My issue is this, I need to select between different voltage dividers on the output of my DAC. The first issue im having is stability, when I stick a voltage divider on the out put of my DAC the voltage doesn't seem to stay stable, im working in the nv/mv range. The 1 mv from the DAC stays stable, but the 100nv out the divider drifts around. I thought this may just be an isssue with noise/ripple in the uv range, but Im still experiencing drift well up to 1 volt in 100mv out.I would also like to select different ranges by changing the resistor divider, my fist thought was to use a digital pot on the output of the dac, this could also help me trim out any INL/DNL issues. The problem is most digital pots dont have enough resolution to set up perfect divide by 1, divide by 10, divide by 100, ranges.. let alone trim the DACs INL/DNL.I found this article about using a DAC itself as a resistor divider but it seems a bit over my head im not sure how to select the resistors,http://edn.com/design/analog/4326864/CMOS-DACs-act-as-digitally-controlled-voltage-dividers.Im hopping someone can give me a bit of advice here.

author: David Hess
author_rank: Super Contributor
timestamp: May 14, 2014, 10:44:35 am
content: Which DAC are you using and how is it configured?

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: May 14, 2014, 12:39:14 pm
content: Right now I am using an mcp4922 12 bit DAC and a 4.096 voltage reference. Although I plan on switching to a 16 bit dac (ltc2602) in the future. Right now I'm just expermenting with what I have on hand.

author: David Hess
author_rank: Super Contributor
timestamp: May 14, 2014, 08:57:07 pm
content: It is not real clear if you are talking about nanovolts or microvolts but in either case, grounding and decoupling of the DAC will be critical to getting good performance.The measurement itself can be non-trivial and some voltmeters are going to have problems. I would try connecting the divider to the reference instead of the DAC output as a test.
Need some jellybean DCDC controller chip, any recommendations? - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: January 03, 2022, 07:12:53 am
content: I need a couple of jelly bean switching regulators or controller chip.The primary requirement is that it's available and unlikely to go out of stock due to the number of suppliers with compatible versionsAny recommendations?It will probably have to be a controller chip with external fet/diode to be considered jellybean, but integrated would be better.- Application 1.Type = BoostInput = 1.8-3.3V ( 2x 1.5V AAA)Output = 3.3V at max 50mA- Application 2.Type = Buck or Boost (SEPIC would be ideal, but I could use two of them for boost then buck if needed)Input = 9-30V DCOutput = 14V 3A

author: Psi
author_rank: Super Contributor
timestamp: January 03, 2022, 07:20:08 am
content: Also,For application 1.How feasible is a MCU driven voltage doubler with 3.3v LDO to get 3.3V 50mA from two AAA's ?3.3V out + 0.2V for regulation = 3.5VTo generate 3.5V it's going to need + 0.5V to compensate for loss of voltage double diode, so 4VSo voltage doubler input minimum would be 2V, which sounds ok for 2x AAA's ?I guess the question is if 50mA is doable with this sort of voltage doubler? Probably going to need two GPIO outputs to drive a pfet and nfet to get enough switching current, but that is probably ok.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2022, 09:57:14 am
content: A capacitive voltage doubler is not really feasable for such a high current. It also needs more power.The more realistic case with a µC from 2 x AAA or similar would be a µC that can run down to 2.4 V and than a LDO to go down to some 2.5 V.Low voltage Buck converters are plents to choose from. It helps to get at least a common pinout / footprint. For the low power this would likely be a SOT23-5 or so. As an example the LM3670 / TPS6220x / XC92xx or similar. There seem to be auite a few pin compatible ones, as the pins needed are kind of fixed.A single sepic converter would be better than 2 separate ones. 14 V and 3 A is already quite some power.

author: Psi
author_rank: Super Contributor
timestamp: January 03, 2022, 10:12:03 am
content: Quote from: Kleinstein on January 03, 2022, 09:57:14 amyeah, i kind of expected the current might be a bit high.Quote from: Kleinstein on January 03, 2022, 09:57:14 amThanks, will check them out.Quote from: Kleinstein on January 03, 2022, 09:57:14 amAgreed, only reason I was considering 2 separate ones was if helped part availability due to more buck/boost controller available than sepic controllers.
Need some wires from dead Cesium tubes! - Page 1
Forum section: electronics / projects

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 31, 2021, 05:24:10 pm
content: Hi!I'm Working on a project and need the following.The HP high stability tubes have a pair of violet and violet/white wires exiting the potting that have the nylon push on connections that go the chassis.These were for the degaussing connection.I'm looking for 3 more sets of these wires.I do have a big pile of dead tubes but only managed to find a few of these wire sets.Anyone have some dud tubes laying around they could cut them from?I'd pay $5.00 + the shipping for each pair.Thanks for your help!Corby Dawson
Need suggestion for an aviation project - Page 1
Forum section: electronics / projects

author: masster
author_rank: Regular Contributor
timestamp: February 15, 2018, 10:52:33 am
content: Hello everyoneI would like to bring to your attention a project that I am starting to work at. It is about CAWS (CentralAdvisory andWarningSystem) that is a data acquisition, logic processing and display system. It indicates the system status and alerts the crew in the event of an aircraft system malfunction. I could use an already made one like in the photo below. There are a few problems though.1) The available space I have on the dashboard can not accommodate the size and shape of the display unit. The company that manufactures the CAWS does not customize the display.2) I would prefer to use a programmable LED display instead of 48 SMD LEDs and a printable foil.My idea is to use a microcontroller solution for the data acquisition and logic processing. For the display part I would use a LED display driver and a suitable display. By "suitable" I mean a display that is certified to work in an airplane under specific accelerations, vibrations, and temperatures.I'm having two problems.I can't find a display that meets aviation requirements.I can't decide what microcontroller is best for this job. There are 48 discrete inputs (0 or 28 V DC).I would like to have your feedback on this project.Thank you.

author: dmills
author_rank: Super Contributor
timestamp: February 15, 2018, 11:05:16 am
content: How are you going to get it certified for flight use (This is the reason these things cost what they do)?These things are generally certified as a system, so you will not likely find a naked display that is already certified, and this even before we come to the elephant in the room, demonstrating that your software has been developed under a suitable quality management process, you will not believe the paperwork requirements.Personally I think there is a lot to be said for a bank of LEDs and labels, it is simple and unlikely to fail in a catastrophic manner (But even then notice that that panel has some built in test and verification and a system failed indicator, bad information can be more dangerous then no information).Superficially fairly simple, but a paperwork and software reliability nightmare.Regards, Dan.