hybridfree/eevblog-posts huggingface dataset:
1-2mA surge current limitter for megger. Need help! - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: November 15, 2017, 09:56:47 am
content: Hi!I'm going to make simple diy megger/ insulation testerLike vintage analog: 2.5kV rectifier + galvanometerBut i see what modern meggers have safety current limiter about 1mA at zero loadCurrent limmiter is a basic thingButWhat is the adequate way to add it to hi voltage circuit?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 15, 2017, 11:29:01 am
content: A big fat resistor helps a lot.There isn't much else you can do, to limit current on microsecond time scales. Even that is difficult, because space itself holds a lot of charge at those voltages.If it's just for steady state current limiting, anything can do: a resistor, a current limit circuit, a controlled current power source, etc.Tim

author: 001
author_rank: Super Contributor
timestamp: November 15, 2017, 04:03:37 pm
content: Quote from: T3sl4co1l on November 15, 2017, 11:29:01 amNo matterOutput impedance is limited by measuring purposes

author: oldway
author_rank: Super Contributor
timestamp: November 15, 2017, 05:36:44 pm
content: You could use a very high voltage Mosfet as IXTA02N450HV made by Ixys (Vdss Max = 4500V) as current limiter.http://www.pankajelectronics.com/semiconductors/mosfets/n-channel-standard-power-mosfets/2500v-to-4500v-very-high-voltage-power-mosfets/ixta02n450hv?zenid=aldghoh59s4p8rc1b1h8huuqg5

author: 001
author_rank: Super Contributor
timestamp: November 15, 2017, 10:21:14 pm
content: Interesting mosfetWho use this circuit? Is it a part of similar project, isnt it?

author: oldway
author_rank: Super Contributor
timestamp: November 16, 2017, 10:01:54 am
content: Quote from: 001 on November 15, 2017, 10:21:14 pm

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 16, 2017, 11:20:33 am
content: It's just a "ring of two" current source circuit, made two-terminal by the bias resistor (which unfortunately spoils the CCS characteristic).If they make depletion MOSFETs with voltages that high, that would be even better -- self biasing, no need for the large value resistor.You can also stack lower voltage DMOS CCSs; the voltage will not be shared equally, with some being saturated, some avalanching (a TVS would be good, to improve ratings), and about one doing the actual regulation, but that's alright when high accuracy is not required, and when the power ratings of each transistor are designed safely.Tim
1.2V diode? - Page 1
Forum section: electronics / projects

author: ralphd
author_rank: Frequent Contributor
timestamp: July 05, 2015, 02:45:33 am
content: I'm making a circuit where I want a 1.1-1.2V drop. Obviously I could use 2 standard diodes, but I looked for a single part and have not found anything. The lowest zener I could find is 3.3V. A TL431A is 2.5V.Any suggestions?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 05, 2015, 03:32:53 am
content: Hi,have you considered using a double diode. That is two diodes in one package like the BAV99W, there are many others.http://www.diodes.com/datasheets/ds30045.pdfThis will have a temperature coefficient of about -4mV/C.You could also look at a red or IR LED. (also not very good tempco.)There are shunt references available. Look for LM385-1.2Regards,Jay_Diddy_B

author: ralphd
author_rank: Frequent Contributor
timestamp: July 05, 2015, 03:59:09 am
content: Thanks. Hadn't heard of either the bav99 or lm385.

author: Psi
author_rank: Super Contributor
timestamp: July 05, 2015, 04:29:32 am
content: It really does depend how much current you're going to be pushing through it.This one looks like ~1.25v @ 10mAhttp://www.digikey.com/product-detail/en/GI250-4-E3%2F54/GI250-4-E3%2F54GICT-ND/3711806High voltage diodes tend to have high Vf

author: Frant
author_rank: Regular Contributor
timestamp: July 05, 2015, 09:55:47 am
content: ZXRE1004, ZR431L
1.3mm Testpoints... Round vs Square? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: October 12, 2024, 01:00:01 am
content: Hi,because of a high density PCB and many testpoints, I'm thinking of using 1.3mm wide testpoints.The PCBs will be tested by ATE equipment after assembly but also manual bed of nails jig made manually (not by a company). Because of the latter, in order to maximise the area of contact and minimise any misalignment issues I am leaning towards square test points.But After a bit of research it seems that round testpoints are better recognised by ATE equipment. Is that correct? Do you see any issues that would favour round testpoints vs square ones?Thank you

author: jbb
author_rank: Super Contributor
timestamp: October 12, 2024, 02:15:20 am
content: It can be a little easier to sneak PCB traces past a round test point.Also, if you assume that, statistically speaking, your positioning uncertainty on the X and Y directions are normally distributed then there doesn’t seem to be much benefit in going from a round to a square test point.Finally, do all your test points need to be identical sizes? Maybe you can set most of the test points to be a bit larger (say 1.5mm ??) and only use the smaller 1.3mm in difficult areas? This would reduce the number of test points at higher risk of missing.

author: ricko_uk
author_rank: Super Contributor
timestamp: October 12, 2024, 03:04:11 pm
content: Thank you jbb
1-50 MHz signal generation - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: March 18, 2010, 02:50:44 pm
content: I'm looking to generate a 1-50 MHz signal, I don't neccesarily need it to be variable ov that range, I may also need to got as far as 100-150 MHz. can anyone suggest a simple diagram ? possibly uasing 2N2222 transistors as I have them available.I think I'd need it to be sinusoidal but really anything will do !

author: KTP
author_rank: Frequent Contributor
timestamp: March 18, 2010, 02:57:24 pm
content: http://upload.wikimedia.org/wikipedia/commons/f/f6/NPN_Colpitts_oscillator_collector_coil.png

author: Simon
author_rank: Unknown
timestamp: March 18, 2010, 03:37:18 pm
content: thanks, can i adapt the values for up to 150 MHz ? is it C1 or C2 that has an effect on the frequency ? or both ?
[please delete] - Page 1
Forum section: electronics / projects

author: Jaunedeau
author_rank: Regular Contributor
timestamp: November 11, 2015, 08:33:00 am
content: ok, you look for some information for 1 hour, ask question on a forum, and just see the answer to your question in the "related topics" of your new postRefer tohttps://www.eevblog.com/forum/beginners/rapid-charging/sorry,John.
1.8V H-Bridge - Page 1
Forum section: electronics / projects

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 05, 2020, 09:21:17 pm
content: Hi,I'm designing a simple h-bridge with a couple of mosfets, and my question is can I use 1.8V gate signals?What should I exactly look in the datasheet to confirm this? (I have been looking at Vgs and the values are 1V and -1.2V)The mosfets are DMN2230U (https://www.diodes.com/assets/Datasheets/ds31180.pdf) and DMG2301L (https://www.diodes.com/assets/Datasheets/DMG2301L.pdf)I'm just looking for a cheap h-bridge solution to use at 1.8V.Thanks!

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 05, 2020, 09:21:51 pm
content: Just realized that I have put both sides to be channel A

author: magic
author_rank: Super Contributor
timestamp: January 05, 2020, 09:42:47 pm
content: Look what's the guaranteed RDS(on) at Vgs=1.8V and whether it's good enough for you.Your first link says 230mV at 1.8V right at the top of the first page. In the detailed specification it further states that this is guaranteed for currents up to 1A and that the typical value should be slightly less.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 05, 2020, 10:28:17 pm
content: Quote from: mrburnzie on January 05, 2020, 09:21:51 pmAlso the transistors in the upper side of the bridge should switch their place with the ones from the lower side, and the Drain and Source terminals in the upper side must be switched between them, and some other details that won't make sense to discuss before fixing the schematic.My advice is to search for a schematic of a "H bridge with complementary MOSFET" if that's what you want to use (search for images) and start from there.About the question if an 1.8V I/O can control those MOSFET, no, it won't work, even after correcting the posted schematic. VGSmust be 1.8V or lower in order for a MOSFET to be controlled by an 1.8V signal. MOSFET transistors with low VGSare sometimes called "Digital MOSFET" or so, so that would be a good term to search for, then look in the datasheets and pick some MOSFETs with VGS1.8V or lower.Be careful with batteries and H bridges. Even when the design is OK they can still catch fire or explode, not kidding.Always put a fuse in series with the battery, NEVER skip the fuse.

author: Yansi
author_rank: Super Contributor
timestamp: January 06, 2020, 12:03:39 am
content: Not to mention the nasty cross-conduction current and that it won't work with higher than 1.8V battery voltage.

author: langwadt
author_rank: Super Contributor
timestamp: January 06, 2020, 12:33:38 am
content: http://www.ti.com/product/DRV8839

author: mikerj
author_rank: Super Contributor
timestamp: January 06, 2020, 11:24:01 am
content: What is the battery voltage range? A couple of extra transistors (could be bipolar) would allow the gates to be driven from the battery voltage which may ease the Vgs concerns. Is this for low speed on/off operation or are you wanting higher frequency PWM control? Obviously fix the transistor positions first!
1-cell NIMH charging - Page 1
Forum section: electronics / projects

author: diegop
author_rank: Contributor
timestamp: October 15, 2018, 09:43:40 pm
content: Hello everyone. I'm working on a circuit where I'm planning on using 1xAAA NIMH battery. I want to charge the battery in circuit and not have to remove it from the device.Is it ok to be constantly charging a NIMH battery or recharging a battery that has been slightly discharged?I plan on using a chip like theDS2710 from maximto charge the battery.In normal use the device will leave the charging station for say around 5-15 minutes then come back to the charging station and could stay there only a couple of minutes or a couple of hours. When the device comes back to the charging station, it will enter a low power mode to reduce current consumption (about 50uA) and during operation away from the charging station it'll consume about 15 mA.
1 Form C Relay Contact Rating question - Page 1
Forum section: electronics / projects

author: unscripted
author_rank: Contributor
timestamp: June 27, 2024, 04:26:41 pm
content: I'm going through a relay datasheet (see attached) and I'm wondering why would the Form B (NC) contact be rated way below than the NO contact if the relay is single pole? They're claiming 10A for the NO and 3A for the NC. Am I interpreting the data correctly? I'm really expecting 10A contact rating in both NC and NO setup.

author: ArdWar
author_rank: Frequent Contributor
timestamp: June 27, 2024, 05:12:05 pm
content: A bit of simplifying here, basically due to difference in contact force.NO contact is held close by solenoid force while NC contact is held close by spring force. Due to how relay works, the spring needs to be weaker than the solenoid.
1 millaVolt AC Standard? - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: August 19, 2015, 04:51:56 am
content: Does something like this exist? I would like to calibrate my pc dmm AC coupled range channel one and two measure the same voltage with a 4mv difference, it annoys me when doing emf and common mode tests. Would it be easy to buid?

author: Gyro
author_rank: Super Contributor
timestamp: August 19, 2015, 10:05:19 am
content: I think your best chance of success would be to use a higher voltage ac reference and divide it down with a close tolerance resistive divider which you can verify on DC. As long as you keep the frequency low you shouldn't need to worry about capacitive ratio compensation.Edit: Maybe use a low voltage mains transformer as the source which you can monitor with a DMM at the same time as dividing it down to feed the PC audio input (assuming your input is flat down to 50Hz)

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: August 21, 2015, 12:01:03 am
content: Hmmm thank you.. thats a good idea

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 21, 2015, 04:59:39 am
content: If you have a known accurate meter to compare to, you can use a PC's audio output.

author: robrenz
author_rank: Super Contributor
timestamp: August 22, 2015, 02:17:45 am
content: Quote from: rwgast_lowlevellogicdesin on August 21, 2015, 12:01:03 amMy setup inthis postwill probably do the trick
1 Phase 2 direction motor what would happen? - Page 1
Forum section: electronics / projects

author: Isad
author_rank: Frequent Contributor
timestamp: August 20, 2016, 02:12:59 pm
content: Hello allI have a 1 phase motor with 2 direction it has 3 contact 1 Line and 2 other connectedtogether with a cap wich determine the rotationnow my question is what would happen if you connect the both the clockwise and counterclockwisetogether do you get a big bang or is just not gona spin and were talking about 1 to 2 sec long .Thanks for all the help

author: Andy Watson
author_rank: Super Contributor
timestamp: August 20, 2016, 02:19:51 pm
content: It just hums until the magic smoke comes out.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: August 20, 2016, 02:43:20 pm
content: ACor DC?

author: Isad
author_rank: Frequent Contributor
timestamp: August 20, 2016, 04:55:33 pm
content: AC 1 phase but its for a brife time like 1-2 sec max,its a arduino starting up and it turn evry output on,i just wanted to know what happen if both go on at the same time

author: Andy Watson
author_rank: Super Contributor
timestamp: August 20, 2016, 05:04:57 pm
content: Quote from: Isad on August 20, 2016, 04:55:33 pm1-2 seconds should probably be ok - any longer and you risk cooking the windings. Make sure that you have some means of disconnecting the power - quickly!

author: Isad
author_rank: Frequent Contributor
timestamp: August 21, 2016, 08:13:31 am
content: Quote from: Andy Watson on August 20, 2016, 05:04:57 pmIts just if power faiuler ocurs and the arduino randomly restartbut if anything croses 2-3 amp the breaker comes on.Thanks for the help
1-wire iButton reader interrupt to host? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: November 17, 2024, 12:26:18 am
content: Hi,Does anybody know if there is some specific way to detect that a iButton has been connected and detected? Surely the host does not need to keep polling all the time...?I am asking because I am using this 1-wire to I2C bridge IC:https://www.analog.com/media/en/technical-documentation/data-sheets/ds2482-100.pdfI would like to use that IC but the same question applies to this other reader IC:https://www.analog.com/media/en/technical-documentation/data-sheets/ds28e17.pdfI am going to use it exclusively to read iButton fobs for people ID like they use in most bars/pubs (see attached picture).Thank you
100,000lm LED array - Page 1
Forum section: electronics / projects

author: VoidsWarranties
author_rank: Contributor
timestamp: November 29, 2017, 02:12:44 pm
content: I’m making an array of 100w leds, 10000lm each(supposedly). They run at 34-36v. They are going to be liquid cooled so the array itself could be reasonably light and portable. I have 3 750w 12v power supplies that I can put in series to run them. I’m asking for any advice or problems that you can see with this design.Sent from my iPhone using Tapatalk

author: ajb
author_rank: Super Contributor
timestamp: November 30, 2017, 03:03:42 am
content: You haven't really provided a design, more of a concept. In theory what you've described will work, but the devil is in the details. The specific power supplies you have in mind, how well matched your LEDs are to one another (cheapo high power LEDs tend to have substantial parasitic parallel resistance which affects their V/I curve beyond the normal diode parameters), how exactly you distribute the 60A from your power supplies to the LEDs, and a number of other factors will all affect how WELL it will work.10klm sounds rather hopeful for 100W LEDs, the cheap ones I see on Amazon all claim 8-9k. With cheap electronics, usually the claimed performance is inversely proportional to the quality, so beware.Generally you want to run LEDs in constant current mode, but the high power chip arrays often get away with CV due to parasitic series resistance and the fact that voltage changes are split across large series strings. Hopefully you'll at least be able to trim your PSU output voltage a bit to get your current in the right ballpark.

author: texaspyro
author_rank: Super Contributor
timestamp: November 30, 2017, 05:21:00 am
content: I have designed several very high power (50,000 - 500,000 lumen) sources. I can't go into any detail, but:Forget those Ebay arrays. They are all pretty much falsely spec'd, unreliable, inefficient turds. I used arrays from Bridgelux. They were rather overdriven, but still very reliable.Forget using CV supplies... disaster awaits. I used a separate programmable / dimable / addressable CC supply for each array. Main power input to the drivers was 48V.Liquid cooled. Over 5000 watts to get rid of. Waste heat was put to good use.
100 MIPs FPGA-based CPU in under 200 lines of Verilog - Page 1
Forum section: electronics / projects

author: jamesbowman
author_rank: Newbie
timestamp: December 04, 2010, 09:33:38 pm
content: Small CPU in Verilog, runs Forth at 100 MIPs.The J1 Forth CPUAll BSD-licensed, comes with a TCP/IP stack, and various fun pieces of demo code including VGA interface and a space invaders game.J.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 05, 2010, 12:40:12 am
content: I thought people had stopped banging on about how great Forth was years ago...!

author: CryptLordGR
author_rank: Contributor
timestamp: December 05, 2010, 12:51:13 am
content: James change your signature because it is incorrect,i dont know about FPGAs but i can tell ,even if it runs Forth, that it is very compressed code
100 volt dc to 0-24 volt dc circuit design with SCR ???????? - Page 1
Forum section: electronics / projects

author: arnould
author_rank: Newbie
timestamp: January 07, 2015, 03:21:23 am
content: Hello everyone. Thanx for reading this.I couldnt design it well and i am new at this so if you can design this circuit it will make me so happy.I wanna make a buck converter which can convert 100 volt dc to between 0-24 volt dc.and This buck converter is gonna work with SCR. is switching frequency effecting to output voltage and current? ? think yes butHow does switching frequency effect to output voltage and current?

author: Alex30
author_rank: Regular Contributor
timestamp: January 07, 2015, 03:28:02 am
content: If you could provide a quick sketch or example on what you were thinking of doing that would help us work out how to help you. Also why 100V DC? Why not 28V or 26V? Does it have to be 100V DC?

author: arnould
author_rank: Newbie
timestamp: January 07, 2015, 03:41:45 am
content: it is gonna help me so much. because it is one of my power electronics lectures final exams question.the proffesor gave us one question of exam for searching for it.I hope someone help this newbie.and oneday I hope with years of working experience ? will design it myself but its gonna be so late for now

author: c4757p
author_rank: Super Contributor
timestamp: January 07, 2015, 04:06:13 am
content: If it's an exam question, surely they taught you something about it?

author: Seekonk
author_rank: Super Contributor
timestamp: January 07, 2015, 04:55:19 am
content: If you want to take credit for another persons work, a career change to management would be appropriate.

author: oldway
author_rank: Super Contributor
timestamp: January 07, 2015, 10:14:47 am
content: This technology is almost outdated for low voltage and low power buck converter.Use Mosfet switching devices and not fast SCR's.It has great benefits:- higher switching frequencies: up to 500Khz for Mosfet's, only 6 Khz (more of less) for fast scr's.- lower dc loss: more or less 2V for fast scr's , less than 2V for Mosfet.- lower cost: need 2 scr's, switching inductor and high quality capacitor, not needed with Mosfet.- simpliest schematic.As scr's can't be turned off by gate pulse, you need provide "forced comutation" who let the anode current stay 0 for a time longer than the the Turn - off time of the scr before reapply direct voltage.Basic esquematic and explanation of scr chopper (buck converter) can be found here:https://www.pantechsolutions.net/power-electronics/introduction-of-dc-chopper-using-scrYou need to add an inductor to use it as an DC-DC converter.http://www4.hcmut.edu.vn/~nvnho/Download/EngPE/Chapter1_Switching%20Power%20Supply.pdfMore explanations about scr chopper:http://www4.hcmut.edu.vn/~nvnho/Download/EngPE/Chapter1_Switching%20Power%20Supply.pdfYou must choose fast scr with Toff between 5 and 50µs.
100 watt led flashlight build question - Page 1
Forum section: electronics / projects

author: firehopper
author_rank: Frequent Contributor
timestamp: March 18, 2017, 12:26:20 am
content: I'm building a 100 watt led running off 24 volt 7ah battery pack, using a 400 watt CC/CV driver circut, and it sparks when I connect it to the battery pack, now I'm going to be using a switch I got from radio shack(50% off) its rated for 25 amps at 24 volts. and wonder if theres something I should do to help protect the switch from the surge..

author: calexanian
author_rank: Super Contributor
timestamp: March 18, 2017, 12:39:31 am
content: The spark is most likely an inrush surge for a bulk filter capacitor somewhere. There are ways of mitigating that such as soft start electronic switches and such. You can just let it go and know the switch will only last so many activation. Most likely it will be fine, but its a messy solution. To get you pointed in the right direction i suggest you have a look at Mr Elliott's page. This article was written about power amplifiers but the idea is much the same for a 24 volt DC load.http://sound.whsites.net/project39.htm

author: firehopper
author_rank: Frequent Contributor
timestamp: March 31, 2017, 01:18:47 pm
content: nearly finished it, just little touchups now, will post some pictures soon.
100BASE-FX to PCIe? - Page 1
Forum section: electronics / projects

author: Schluug
author_rank: Newbie
timestamp: December 12, 2017, 02:22:23 pm
content: HiI am working on a project where I need to make an addon-card which communicates with an other unit over a 1310nm multimode 100BASE-FX fiber connection.The problem I have is how to interface the 100BASE-FX connections to the computers PCIe-bus..Earlier I made a design using an Intel 82575 Ethernet controller and a ML6652 media converter chip which worked OK but the media converter chip has been EOL for a few years so I need to find a new solution.The system would look something like this:|CPU-<PCIe>-"CHIP1"-<MII?>-"CHIP2"|-<100BASE-FX>-|UNIT|For "CHIP2" I have found Microchips KSZ8441 which is a PHY/MAC that supports 100BASE-FX but on the host side has a 8/16-bit MII interface. I can not find any suitable solution for "CHIP1", any one got an idea?Regards,Schluug

author: drussell
author_rank: Super Contributor
timestamp: December 12, 2017, 04:08:17 pm
content: Does this computer not have a PCIe slot? If you are you building this system from scratch, some kind of embedded thing rather than a standard PC, can't you just stick a PCIe slot on it? Then you can just buy a standard 100BASE-FX network card. They're readily available.

author: Gribo
author_rank: Frequent Contributor
timestamp: December 12, 2017, 05:48:16 pm
content: What about media converters? There are many 100Base-T to 100Base-FX converters out there.

author: Schluug
author_rank: Newbie
timestamp: December 13, 2017, 07:27:08 am
content: Quote from: drussell on December 12, 2017, 04:08:17 pmSadly no, it has a completely different form factor.So i basically need to make one of those network cards, but with a different form factor but I can not come up with a good chip solution..

author: Schluug
author_rank: Newbie
timestamp: December 13, 2017, 07:29:38 am
content: Quote from: Gribo on December 12, 2017, 05:48:16 pmYou mean on of these?Any one know what circuits they use inside by chance?

author: AndyC_772
author_rank: Super Contributor
timestamp: December 13, 2017, 07:36:47 am
content: Probably just a pair of back-to-back Ethernet PHYs linked by MII.

author: Schluug
author_rank: Newbie
timestamp: December 13, 2017, 08:00:24 am
content: Thank you for your help!I have also managed to find similar circuits,http://www.ti.com/lit/ds/symlink/dp83849if.pdfmay work for my needs but it also "only" have a MII interface so still need to "convert" MII to PCI Express preferably. For that I need an Ethernet controller or MAC, where I have mostely found Intel parts which are not industrial temped. Hmm..

author: AndyC_772
author_rank: Super Contributor
timestamp: December 13, 2017, 08:06:25 am
content: Have you thought about using a USB to Ethernet chip instead? Microchip do them.
100GEA 420FZ0S  Component.... - Page 1
Forum section: electronics / projects

author: Tony.T
author_rank: Regular Contributor
timestamp: May 20, 2024, 02:39:40 pm
content: I got a mainbord for a LG TV.This component above givs me a unstable pwr_on signal. Something is wrong and i located the signal to this chip.Anyone knowing what kind of chip it is? Some say voltage regulator? Some say it is i microcontroller. I would guess the last one is right.??!!!!That means that i can not replace it with another chip i have that sais 100GEA 728UZ03 ?? It needs to be programed first.Can someone please confirm this?I cant find proper information on the web regarding this chip 100GEA 420FZ0SThe chip looks like this one....but the markings is not the same...https://www.aliexpress.com/item/4000251963110.html

author: kundewayne
author_rank: Newbie
timestamp: May 27, 2024, 03:59:57 am
content: Quote from: Tony.T on May 20, 2024, 02:39:40 pmYou're right to exercise caution when it comes to mainboard repairs for your LG TV. We can analyze the following depending on your description:The Issue:The power-on signal on the mainboard of your LG TV is erratic.You think there may be a problem with a certain chip (designated 100GEA 420FZ0S).Problems:It is challenging to determine the precise chip function—microcontroller or voltage regulator—without a schematic or service manual for your particular LG TV model.Even if the chip is accurately identified, replacing it could be difficult.

author: Phoenix
author_rank: Frequent Contributor
timestamp: May 28, 2024, 06:05:17 am
content: 100GEA looks like a programmable gate array. Definitely need the correct configuration on it to work.https://www.worldwayelec.com/pro/renesas-electronics-corporation/100gea/2758763
100kHz frequency PWM from Arduino - Page 1
Forum section: electronics / projects

author: radhika
author_rank: Regular Contributor
timestamp: September 08, 2018, 12:15:18 pm
content: Hello,I am working on project and I need 100kHz from the Arduino. I have tried building code but I am not getting anything when I checked in proteus..Here is the code,void setup(){pinMode (5, OUTPUT);pinMode(6, OUTPUT);TCCR0A = 0;TCCR0B = 0;TCCR0A = 0b01010011;TCCR0B = 0b00001010;//WGM02= 1(Pin 5 is disconnected)OCR0A = 9; //Control value of 100kHz, N = 8}void loop(){analogWrite(6, 206)// 81% duty cycle;}I am using Proteus for checking output. As shown in the attached picture I an unable to get output at pin 6. Guide me for the circuit if I have attached to the wrong pin and the code.PS: Apologies for the late reply.https://postimg.cc/image/g84qnrsrr/
100mA (or whatever) the easy way - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: May 03, 2024, 03:00:22 pm
content: A simple circuit can make for a very precise current source (no, not a sink).You need an opamp with a CMV range to V+.I had an AD820in the drawer but any rail to rail input amp should work fine.Use a better shunt ref if required.

author: David Hess
author_rank: Super Contributor
timestamp: May 03, 2024, 05:59:05 pm
content: Replace Q1 with a JFET or MOSFET to remove the base current error.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 03, 2024, 06:02:29 pm
content: Quote from: David Hess on May 03, 2024, 05:59:05 pmThere is no base current error in this circuit. It is a classic configuration of a current source, used at least in two units on my bench - Keithley 263 and HP3245A.CheersAlexP.S. - the inputs of the opamp need reversing!

author: David Hess
author_rank: Super Contributor
timestamp: May 03, 2024, 06:23:38 pm
content: Quote from: Alex Nikitin on May 03, 2024, 06:02:29 pmAh, you are right of course. This is the circuit which I commonly see in books describing voltage and current references.

author: Terry Bites
author_rank: Super Contributor
timestamp: May 05, 2024, 09:07:30 am
content: I make no claims to originality, for a fixed and upgradable source it's simple and handy.It doesn't appear much in current source examples on the interwotzitA MOSFET could be used but it will reduce the avaiable voltage compliance.A bit more compliance can be squeezed out using a Sziklai pair instead of a Darlington.Some of stability components don't go amiss.

author: magic
author_rank: Super Contributor
timestamp: May 05, 2024, 11:18:50 am
content: I think the opamp doesn't need to work to V+, its inputs normally see over 2.5V less than the output is.OTOH, it needs to be functional down to V- if you want the circuit to work accurately with low resistance loads. And even if you don't, it must have no phase reversal or it could blow up on such loads.The value of R2 makes the reference run at a fairly high current when load voltage is high, and starves it when load voltage falls below 0.5V. An active sink would fare much better.

author: wasedadoc
author_rank: Super Contributor
timestamp: May 05, 2024, 04:57:59 pm
content: Quote from: David Hess on May 03, 2024, 06:23:38 pmBoth of those figure show a VREFdeveloped across a short circuit. Should be across RS
100ns DRAM chips in place of 150ns chips? - Page 1
Forum section: electronics / projects

author: Skyfox
author_rank: Regular Contributor
timestamp: July 14, 2018, 04:45:43 pm
content: When doing a troubleshooting/replacement/repair project on something that has DRAM chips with a 150ns response time, would it be a compatible replacement to use 100ns chips? I don't know how backward compatible they would be with a circuit made for the slower 150ns time. BTW, I'm talking about single 64Kbit x 4 DIP-18 chips, not something like a RAM card for a PC.

author: Benta
author_rank: Super Contributor
timestamp: July 14, 2018, 04:48:05 pm
content: No problem as long it's the same type. You can even replace standard DRAMs with EDO (but not the other way round).
100v DC to low voltage (under 24V) - Page 1
Forum section: electronics / projects

author: han
author_rank: Frequent Contributor
timestamp: January 10, 2014, 03:37:25 am
content: hi all,Is there any simple efficient and save way to convert 100v DC to low voltage (under 24V)?the device will be used to convert 100V DC supply in Electric power station to easy to used voltage (under 24V), and the power capacity needed is under 20VA.I familiar with common dc to dc circuit (LM2576, MC60xxx, etc..) but the none of them capable to work at more than 60V.I plan to use Industrial Switching Power supply, but aware low voltage brown out will reduce the lifespan of the power supply...any suggestion are welcomedthanks

author: digsys
author_rank: Unknown
timestamp: January 10, 2014, 03:40:49 am
content: Unless you want to make you own, or have a tight budget, these are what we use -www.vicorpower.com/dc-dc-converters-board-mount/maxi-mini-micro-dc-dc-convertersSome have 4:1 IP range as well, all power levels, good efficiency.

author: han
author_rank: Frequent Contributor
timestamp: January 10, 2014, 03:46:48 am
content: thanks for reply,yes, i have tight budget (under $100) since its only for trial and base on personal budged only...is it possible to build or modify commercial regular power supply?

author: johansen
author_rank: Super Contributor
timestamp: January 10, 2014, 04:02:24 am
content: Most laptop power supplies will have no problem operating from 100vdc, which corresponds to 71 vac, but they will not be able to deliver full rated load for various reasons (but 20 watts from a 90 watt converter should be easy). you might bypass the bridge rectifier to get 2 more volts into the device.

author: digsys
author_rank: Unknown
timestamp: January 10, 2014, 04:07:08 am
content: Quote from: hanDefinitely. Have a look at the Meanwell AC-DC units. For what you want, you can find something well under $100.Don't get Power factor correction, just plain AC in. The only thing you need to verify is the MIN AC in !!For 100VDC, you need a minimum of ~70VAC_in (ideally 60VAC), so a computer P/Supply won't work.Don't need to short out the bridge (AC>DC)Edit: oops, forgotwww.meanwell.com/webnet/search/seriessearch.html
100V Vin buck regulator options - Page 1
Forum section: electronics / projects

author: EarthLord
author_rank: Contributor
timestamp: November 26, 2022, 12:34:34 pm
content: Hello all,For a project we need a 100V Vin rated buck regulator with output voltage of 12V and current rating of at least 1A. Low Iq is preferable (<200 uA). As I can see only TI, Analog Devices and Monolithic Power have such chips.Any other company having buck regulators with such high input voltage?Thanks!

author: PartialDischarge
author_rank: Super Contributor
timestamp: November 26, 2022, 01:42:33 pm
content: Probably Power Integrations has something, the LNK3209GQ does meet the input voltage but no the output current, have a look

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 26, 2022, 06:18:13 pm
content: chingbei $1 with free inductor, trimpot and everything
103680 LEDs for fifty bucks! Some reverse-engineering required... - Page 1
Forum section: electronics / projects

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 12, 2017, 09:36:37 am
content: These are stupidly cheap compared to what they must have cost originally. Might be hard to reverse the rear-connector protocol, but might be viable to talk direct to the drivers.If anyone's tempted I'll buy one off you to play with!http://www.ebay.com/itm/Lot-of-10-Barco-NX-4-LED-HD-Indoor-Display-Panel-Tile-/232520098489

author: mikerj
author_rank: Super Contributor
timestamp: October 12, 2017, 10:54:14 am
content: That is a bargain, somemore specs here.200 panels needed for a full HD display, at 239watts (peak) per panel = ~48kW

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 12, 2017, 11:38:28 am
content: It's 'only' 1152 leds per panel if you don't count the RGB leds as 3 leds.Same seller sells 20 panels for $84 btw. (+ $276 shipping)
107 volt regulator - Page 1
Forum section: electronics / projects

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: December 23, 2017, 12:13:18 pm
content: A non-technical friend called to say that he had acquired a box of "those things that you have in your workshop" and did I want it, so I told him to bring it round. It was a huge cardboard box full of electronic components, some in ziplock bags, some loose. It has taken me all afternoon to sort them into heaps on the dining table- anything with 3 legs in one heap, ICs in another heap, caps, diodes, connectors etc. I think that it came from an electronic supplier that closed down many years ago in a town down the coast. Many of the plastic bags have flaked to bits with UV exposure, so I grabbed handfuls of loose components and sorted them roughly.One component (among many) caught my eye. It is a STR440 in a modified TO3 case (3 legs.). I cannot find any data on this, other than it is a monolithic 107V output 0.6A regulator.I don't recall seeing anything that needed 107V specifically.Any ideas for its intended use?I have seen the 3 leg TO3 case style only once before, and it was a high-voltage switching transistor by Motorola used in a vehicle ignition system.Regards, BT

author: RES
author_rank: Regular Contributor
timestamp: December 23, 2017, 12:38:31 pm
content: STR440 is a high (107V) voltage regulator to supply the picture tube coil of a tv.

author: Audioguru
author_rank: Super Contributor
timestamp: December 23, 2017, 03:28:47 pm
content: Picture tube? Don't be silly, TVs don't have a picture tube and a coil, instead they have an LCD screen.Oh, I think I remember that TVs a long time ago had a picture tube and deflection coils.

author: David Hess
author_rank: Super Contributor
timestamp: December 23, 2017, 07:28:18 pm
content: 108 volts is also common in oscilloscopes which may have something to do with being twice 54 volts.

author: jaycee
author_rank: Regular Contributor
timestamp: December 24, 2017, 12:41:12 am
content: Sanken commonly made modules like this and judging by the part number it's one of those!

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 24, 2017, 12:54:39 am
content: Quote from: Audioguru on December 23, 2017, 03:28:47 pmYou did a funny!

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: December 24, 2017, 03:23:41 am
content: Thanks everyone- I knew that someone would know!Happy New Year, BT

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 25, 2017, 04:03:08 am
content: Quote from: Audioguru on December 23, 2017, 03:28:47 pmWhat is this antique tech you call an LCD? Everybody knows TVs have OLEDs.
-10dB 14MHz source for Power Meter Calibration - Page 1
Forum section: electronics / projects

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 09, 2014, 03:05:16 pm
content: Hi,It is time to share another project.The aim of this project is to make a small signal generator that make a -10dBm signal at 14 MHz (20 metre Band) that can be used for checking RF power meters, spectrum analyzer and oscilloscopes. The signal generator can be powered from a 9V battery.Block diagramHere is the block diagram. The circuit starts by generating a regulated voltage from the 9V battery. The 5V is used to operate an oscillator set for 14 MHz.The square wave from the oscillator is resistively matched to a 50 ohm, 20 MHz LP filter. The filter extracts the fundamental from the square wave. A 6dB attenuator is used to ensure a good 50 ohm match at the output.Filter SimulationLTspice was used to model the filter characteristics. This is the frequency domain model:And the results of the modeling:SchematicThe LTspice model was converted to a 'real' schematic:Board DesignThis shows a picture of the board design:And the component locations:To be continued ...Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 09, 2014, 03:18:10 pm
content: Hi,Continuing the project...The Board assemblyThe blank Board:The assembled board:AndCalibrationThe source was adjusted for an output of 70.7mV RMS into 50 ohms using an oscilloscope:Spectral PurityA spectrum analyzer was used to check the spectral purity. The first screen shows that the second harmonic is -26dB with respect to the fundamental. The third harmonic is -50dB relative to the fundamental.A second shot shows a wider frequency span (200MHz):Regards,Jay_Diddy_B

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 09, 2014, 04:52:58 pm
content: I love your home made PC boards.Are they routed?Dick

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 09, 2014, 05:13:09 pm
content: I have just noticed from another thread that you have one of those fancy PCB routing machines.The results are indeed excellent.Dick

author: BravoV
author_rank: Super Contributor
timestamp: March 10, 2014, 02:18:45 am
content: Another nice project JDB, thanks for sharing this, its definitely very suitable for a quick & brief testing when in the progress of buying/bargaining on used T&M equipments at the seller's place.Since its so small and so light even with battery, I think its better to be installed with a male BNC connector instead of that female type, this will save the hassle of using BNC cable, just plug in directly at the test equipment's input connector, just a thought.

author: Unknown
author_rank: Unknown
timestamp: March 10, 2014, 03:49:15 am
content: Handy little things those LT oscillators, aren't they

author: calexanian
author_rank: Super Contributor
timestamp: March 10, 2014, 04:02:57 am
content: Looks good.
10Gbps PCB design - Page 1
Forum section: electronics / projects

author: gar8814
author_rank: Newbie
timestamp: July 25, 2020, 02:42:35 am
content: HiI am designing an RTM board for an ATCA crate. The rtm is for a Trigger Processor carrier board that has a couple 7 series Xilinx FPGA's with GTY transceivers that will be sending and receiving data through a fancy new EBTF samtec high density high speed zone3 connector. My RTM has 8 QSFP modules that will have a total of 31 channels that have to run 10Gbps. I am curious if there is anyone on the forum that has experience designing multi gigbit designs. Our first prototype was a flop and my BER is 10^-10 and 10^-9when I run Xilinix's IBERT project using a PRBS31 but works some what at PRBS7.Cheers

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: July 25, 2020, 06:39:41 am
content: Quote from: gar8814 on July 25, 2020, 02:42:35 amSure, I have dabbled in high-speed baseband stuff. But it's kinda hard to say without knowing more info about what you are doing where the problem lies.What is your design flow? Did you manage to simulate your connector landings? Maybe even fully simulate the connectors?
10kHz Sine wave power oscillator design - Page 1
Forum section: electronics / projects

author: mustafayilmaz
author_rank: Contributor
timestamp: November 23, 2024, 08:55:41 pm
content: Hello,I want to transfer maximum power to a coil of 1mH (d.c. 3-4ohm) at 12 Volts or +/-6 volts at 10kHz medium frequency. Current target is at least 100mA.Frequency should be adjustable with some tolerance (9.5-10.5kHz) and should have as few components as possible.What kind of circuit can you recommend to do this?Thanks.

author: moffy
author_rank: Super Contributor
timestamp: November 23, 2024, 09:19:37 pm
content: A Wein bridge oscillator driving a power amp IC.

author: Benta
author_rank: Super Contributor
timestamp: November 23, 2024, 09:42:56 pm
content: Peltz oscillator.For more info and performance evaluation, see here:https://www.eevblog.com/forum/projects/simple-sinusoidal-oscillators/

author: PCB.Wiz
author_rank: Super Contributor
timestamp: November 23, 2024, 11:16:41 pm
content: Quote from: mustafayilmaz on November 23, 2024, 08:55:41 pmHow do you want to adjust the frequency ? Single trimpot, dual-ganged pot, or variable capacitor or digital control ?Peltz oscillator is emitter coupled, with LC elements so gives a good sine wave, VBE clamped. It is tuned by varying L or C.Wein bridge is a Dual RC circuit, usually trimmed by a dual ganged pot, with some AGC for best quality sine.An inductive load is more tolerant of sine quality, so you could use a triangle wave clipped/shaped to approximate a sine.The triangle wave has a precise amplitude and can be frequency trimmed with a single trimpot.The simplest shaper is to just slightly clip the triangle wave, or you can use transistors / diodes for fancier but more complex fits, or a low pass filter, as you have a somewhat narrow range.I find some notes here that suggest each triangle flat ~16.3% of period gives lowest distortion from a 3rd order bandpass filter.

author: mustafayilmaz
author_rank: Contributor
timestamp: November 26, 2024, 07:19:03 am
content: Thanks. I will consider the suggestions.Quote from: PCB.Wiz on November 23, 2024, 11:16:41 pmI am thinking of using a potentiometer to adjust the frequency.

author: jonpaul
author_rank: Super Contributor
timestamp: November 26, 2024, 07:55:22 am
content: MOPAOsc > driver> H br or half brSee old friends (RIP) Jim Williams /Linear Tech or Bob Pease at Nat semi for osc desj
10MHz capable 1.2V to 5V logic level shifter? - Page 1
Forum section: electronics / projects

author: hlavac
author_rank: Frequent Contributor
timestamp: June 10, 2013, 07:31:54 pm
content: Does anyone have some clever design for a fast logic level (up) shifter?I'm thinking discrete transistor or something, comparators that are fast enough (<<50ns response) are insanely expensive...Minimum input impedance should be greater than ~110 Ohm, input logic levels 1.2V, output 5V into CMOS input.Any ideas?

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: June 11, 2013, 02:08:34 am
content: Quote from: hlavac on June 10, 2013, 07:31:54 pmHmm, define "insanely expensive". Last one I used - LMV7219, is $2.87 on DigiKey or half of that in 100+ quantities. 7ns propagation delay. Propagation delay is what you refer to as response time, correct?Input impedance, in my application at least was set by choice of external components, like it is 50ohm on illustration below.Am I missing the something?BTW here is a page that I usually refer to for translations. It seems that there is a special chip for every logic combination.http://www.interfacebus.com/Design_Translation.html#hYou may want to look at "bus transeivers" section for this purpose not individual comparators. Consider connecting multiple inputs/outputs of single transeiver together to get sharper edges if you have long tracks, capacitace on your 5V CMOS input side.

author: hlavac
author_rank: Frequent Contributor
timestamp: June 11, 2013, 12:55:19 pm
content: I have an idea - how about using RS-485 line receiver? They are cheap, have propagation delays <40ns, and there are multiple converters in one package!If I tie the negative input to 0.7V or so, it should work!I will try MC3486 - only problem may be it will be pulling the inputs high thru ~16k to some 2.5V, which may or may not be a problem...

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2013, 04:00:52 pm
content: Could this one be used ?http://focus.ti.com/docs/prod/folders/print/sn74lvc1t45.html/Bingo

author: hlavac
author_rank: Frequent Contributor
timestamp: June 11, 2013, 04:24:00 pm
content: I looked into that one, but its minimum voltage seems to be 1.65V,I need 1.2V... maybe if I power it from the 1.8V rail? I got some of these, will try them if plan A fails

author: nctnico
author_rank: Super Contributor
timestamp: June 11, 2013, 04:54:51 pm
content: A single LVDS receiver might work but going up to 5V may be a problem.

author: function
author_rank: Contributor
timestamp: June 11, 2013, 05:32:37 pm
content: Is this for an ad985x by any chance?

author: hlavac
author_rank: Frequent Contributor
timestamp: June 13, 2013, 10:01:33 am
content: No, its for the iPod 6 nano LCD interface I'm playing with.I'm trying to determine if the display supports LPDT and bus turnaround for frame buffer readback.