hybridfree/eevblog-posts huggingface dataset:
High power Buck - Page 1
Forum section: electronics / beginners

author: InSanCen
author_rank: Newbie
timestamp: April 24, 2014, 11:05:30 pm
content: Greetings. Love the YT channel, and it's mainly what has brought me back to piddling around with electronics.While I did study electronics at GCSE and A level in the UK, it was 20+ years ago, and I have done so little with it since, I have forgotten most of it. Looking at my A level project (Glass density spectral analyser), I was disappointed to discover that I couldn't do much more than follow the basic flowchart. So, I am re-learning.I have recently stopped smoking using a "vape" as an alternative. It's worked well, and I haven't had a real cigarette in a week. The geek in me wants to tinker though, and make my own, so I suspect I need a DC-DC converter/Buck. I'll e using a 7.4v nominal input (2x 18650 or LiPo) and want a 3v-6v output. Looking around, I seem to see that I'll need around 4A current capability. Low voltage cutoff on the supply would be nice as well, but even having forgotten as much as I have, I can't see that being a problem even if I have to do it as a separate item.I am not asking to be spoonfed schematics, BOM etc. I would like some chip suggestions, (low power+high power combo?) design tips etc.I look forward to your answers, and all help is appreciated.

author: InSanCen
author_rank: Newbie
timestamp: April 26, 2014, 06:33:18 am
content: Not suitable? Would I be better posting in another section?

author: Whales
author_rank: Super Contributor
timestamp: April 26, 2014, 12:05:43 pm
content: What exactly are you trying to make? A fluid vaporiser?

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 26, 2014, 12:16:21 pm
content: are you trying to directly power the unit or to just charge its battery?
high power DC/DC converter - Page 1
Forum section: electronics / beginners

author: V_King
author_rank: Regular Contributor
timestamp: July 04, 2017, 07:28:12 am
content: Hello,My work place is decommissioning a number of 3kW UPS units.I want to reuse them as inverters to supply 230V for my boat hooked to the deep cycle leisure batteries.I did some digging, there is plenty of projects of this kind online using small UPS units. I would need to sort out a better cooling for the unit to be run for prolonged periods which is easy. I am not worried about the charging side as the batteries are charged by the solar panels and diesel generator.The problem I have is that the UPS units use 10x 12V batteries connected in series to provide the 120VDC nominal to the UPS. I do not want to use more than 5-6 batteries due to space constraints and thinking of a DC/DC converter to pretty much double the voltage from 60VDC to 120VDC.There are lots of small DC/DC integrated units up to a couple of hundred watts. but I need 3kW rated one.I wonder if I can run in parallel a number of those DC/DC converters? Or are there any other simple ways of doubling the DC voltage?Cheers

author: Fungus
author_rank: Super Contributor
timestamp: July 04, 2017, 01:15:17 pm
content: Quote from: V_King on July 04, 2017, 07:28:12 amNo. Those things monitor their output voltage closely. Even a tiny difference in tolerances means they'll fight each other over the 'correct' voltage and some of them will be overloaded.

author: Zero999
author_rank: Super Contributor
timestamp: July 04, 2017, 01:38:31 pm
content: Higher voltages mean less current and greater efficiency so reducing the voltage is counter-productive. Use ten 12V batteries with half the Ah rating and they should take up the same amount of space as 5 larger ones, everything else being equal of course.

author: Supercharged
author_rank: Regular Contributor
timestamp: July 04, 2017, 02:11:22 pm
content: Quote from: Hero999 on July 04, 2017, 01:38:31 pm,I would also add that, should you put a DC/DC converter between the UPS and its batteries you bypass the battery undervoltage protection built into the UPS. You could therefore damage the batteries by discharging them too far without noticing.

author: David Hess
author_rank: Super Contributor
timestamp: July 04, 2017, 04:02:04 pm
content: Quote from: Supercharged on July 04, 2017, 02:11:22 pmThat is not necessarily the case.Instead of trying to design a regulating 3 kilowatt switching power supply to convert 4x12V to 10x12V, it would be much simpler to design a 3 kilowatt inverter. Open loop operation means that the output voltage will track the input voltage minus losses. An inverter also places fewer demands on the input and output capacitors.Now the big problem becomes finding or building a suitable medium to high frequency transformer. If I did not wind the transformer for 20+ kHz operation, then I would use several 60Hz transformers in parallel at a slightly higher frequency if I could find the right voltage and ratio.
High Power LED Driving. - Page 1
Forum section: electronics / beginners

author: Pariston
author_rank: Contributor
timestamp: January 27, 2022, 08:12:59 pm
content: Hi,I am working on the schematic to drive high power led with failure detection system. Basic logic is to drop 24 Volt power supply voltage with switching buck converter to 12 volts, then connect it to the LED strip, which goes to linear led driver with PWM switching.ADC_4000K goes to ESP32. If ADC voltage jumps up, there is an LED in the strip which failed short. On the other hand, if voltage is floating, there is an open LED in the strip.PWM_4000K is used to dim LED strip.We have switching voltage regulator connected to switching linear led driver, which sounds a little concerning to me. I am not sure what to expect on the output side of the buck converter.*Should I increase capacitor size from 220u to 470u?*Should I increase Inductor size?Feel free to point any of your concerns regarding this circuit to me.Thanks.Buck converter: A5973ADTR (https://www.st.com/content/ccc/resource/technical/document/datasheet/cf/88/bd/ac/ba/8b/41/52/CD00172511.pdf/files/CD00172511.pdf/jcr:content/translations/en.CD00172511.pdf)Linear LED driver: BCR421UFD-7 (https://www.diodes.com/assets/Datasheets/BCR420UFD-BCR421UFD.pdf)

author: Faringdon
author_rank: Super Contributor
timestamp: January 30, 2022, 12:55:44 am
content: Yes, you are right to be concerned, to drive your led string, you just need a current regulated, switch mode buck led driver.....diodes.com do a very cheap one....so do many others.Attached is a buck led driver in the free LTspice simulator, which you can run......there are many ones easier than this.The following are an SMPS course....one of them contains a folder called "LED drivers" (or LED drivers_1?)....in there youll find loads of LED driver simulations which can get you into it.https://drive.google.com/file/d/17ij_pQLkAzzYeL_TRNci86sXHMirKHmD/view?usp=sharinghttps://drive.google.com/file/d/1WvElhDNfHI0EBei4rouSNEdWWTO1oCtJ/view?usp=sharing

author: Pariston
author_rank: Contributor
timestamp: January 30, 2022, 01:57:50 am
content: Thank you for taking your time with me.Yes, I've looked into switching led drivers before, but I couldn't find a way to identity the type of failure within the led strip (priority requirement). Switching led drivers operate with switching pin(SW) as the anode of the led strip and current sense feedback pin(CS) as the cathode of the led strip. For us to detect a type of failure, we would need to take the voltage from the switching pin (which in my case can be anywhere from 22-7 volt) and compare it with some reference voltage. This probably means adding windowed comparators for short and open circuit detection. At the same time, voltage at the SW in relation to CS pin, could be different from our reference voltage in relation to the circuit ground. Some switching led drivers can raise a flag incase of a failure, but i couldn't find an IC to differentiate between failure types.Thank you for LTspice models! I've actually had hard time finding theses.
"High Resolution" mode on the Siglent SDS1104x? - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: September 13, 2023, 06:57:44 pm
content: https://www.electronicdesign.com/technologies/test-measurement/article/21805339/whats-really-the-difference-between-a-12bit-and-8bit-oscilloscopeJust read the above article and learned that my Siglent SDS1104x appears to support a "high resolution" mode.https://siglent.com.pl/public/assets/SDS1104X-E_User_Manual_UM0101E-E02B.pdf(Page 44).If I'm measuring signals below 25mhz, should I be concerned about this? Is it fine to leave the high resolution mode always enabled?

author: bdunham7
author_rank: Super Contributor
timestamp: September 13, 2023, 07:08:07 pm
content: Quote from: LooseJunkHater on September 13, 2023, 06:57:44 pmPresumably you mean MHz. No, you wouldn't leave ERES 'on' all the time and you have to keep in mind that there are different levels. Using a larger number of bits worth of ERES may lower your bandwidth well below 25MHz. So for a specific purpose it is a useful feature, but you always have to consider its effects when you use it.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: September 13, 2023, 07:11:03 pm
content: Quote from: bdunham7 on September 13, 2023, 07:08:07 pmWoops, yeah I did mean MHz.ERES = high resolution mode?Alright thanks for the information. I guess I'll need to see where the setting is located and only turn it on during use cases when I don't need additional bits of resolution. Thanks!

author: u666sa
author_rank: Frequent Contributor
timestamp: September 13, 2023, 08:45:47 pm
content: Sounds like someone you would use for measuring power supply ripple.
High side current sensing at 56V / 3A not working - Page 1
Forum section: electronics / beginners

author: Xtal011
author_rank: Newbie
timestamp: July 27, 2020, 04:43:18 am
content: Hello everyone, newbie here.After a few months thinking about it I started to design my own power supply and after a few itherations finally got something promising, it all works fairly well until tried to implement a self made High side current sensing amplifier that could measure the current through a shunt resistor user for short circuit protection.After some research I whipped up a somewhat functional circuit based on an opamp, two voltage dividers and a few resistors nonetheless this circuit is not working as intended as the output voltage is offseted by at least 1.465V, is there any way to bring down the output level to 0V at 0V input?.Schematics and simulation results attachedEdit: Added the application note from which I based this design, te base design is in figure 2 (pages 2 and 3)

author: eblc1388
author_rank: Frequent Contributor
timestamp: July 27, 2020, 05:43:24 am
content: Quote from: Xtal011 on July 27, 2020, 04:43:18 amSure. Just provide a negative power supply of 5V or more to the LF351 pin#4.The output of the LF351 opamp cannot reach V- by a margin of two to three volts. If you connect V- to ground, then the output will not goes below 2V in general. You are lucky to get only 1.465V.

author: Xtal011
author_rank: Newbie
timestamp: September 13, 2021, 03:19:38 pm
content: Sorry for the late response.Tried the tip you gave me and it worked like a charm, although extra steps were needed, once I added the negative power rail to the opamp the offset decreased to arround 10 mV but that was fixable with a trim pot between the offset null pins with the winding tap connected to the negative power rail. Once I did that it worked perfectly.@eblc1388 : thanks for the tip
High-Side N-Channel mosfet driver question - Page 1
Forum section: electronics / beginners

author: Spike101
author_rank: Contributor
timestamp: September 09, 2014, 07:14:34 am
content: Hello,I'd like to use a n-channel mosfet in a high-side configuration for a project i'm working on.I was thinking to use the LT1161 high side n-channel driver because it would suit my application very well, but i don't know if it will work with the MOSFET i was planning to use.The datasheet of the LT1161 states, that if the input for a mosfet is high, it will drive the output of the gate driver to its supply voltage + at least 7V and up to 10V at 12V supply voltage.The mosfet I wanted to use (CSD16340Q3) specifies an absolut maximum rating of Vgs = 10V. I understand, that as soon as the channel becomes conductive, the voltage between gate and source will be 7V-10V.But at the beginning the channel will not be conducting, so doesn't that mean, that the voltage between gate and source will be 19V - 22V, which exceeds the absolute maximum rating for Vgs?Is this a problem, or does the voltage between drain and source drop so fast, that it doesn't matter?I noticed that in some of the application examples in the LT1161 datasheet there is the same situation - they drive it with a supply of 24V (at which point the gate driver will output up to 38V), but the RFD16N05 mosfet they are using specifies an absolute maximum of +/-20V for Vgs.

author: David Hess
author_rank: Super Contributor
timestamp: September 09, 2014, 09:12:54 pm
content: Quote from: Spike101 on September 09, 2014, 07:14:34 amThat is possible but pretty unlikely. By the time Vgs reaches 10 volts, the channel current will be very high so the MOSFET should be fully saturated with the source only millivolts from the drain. Either the source will be pulled up to the supply voltage or the massive short will bring the supply voltage down.QuoteThe LT1161 outputs should never get above 14 volts so I do not think there is a problem here.Driving your CSD16340Q3 to its absolute maximum rating may compromise reliability however.

author: Spike101
author_rank: Contributor
timestamp: September 10, 2014, 06:32:11 am
content: Thanks for your reply. I'm using a different mosfet now with the same size footprint, which is rated for +20V Vgs and 30V Vds, so i should be safe in any case.
High side N-MOS fried. Voltage too spiky? - Page 1
Forum section: electronics / beginners

author: step_s
author_rank: Regular Contributor
timestamp: November 24, 2016, 11:54:25 pm
content: Hi EEV'ers.So I just built a buck setup with an FDS9926Ahttps://www.fairchildsemi.com/datasheets/FD/FDS9926A.pdfThe dual N-MOS is driven by a NCP5901http://www.onsemi.com/pub_link/Collateral/NCP5901-D.PDFI tested it all, and it worked perfectly with 5V on the controller, and 5V on the buck setup, but alas, this was not the case with 12V on the buck setup. The high side N-MOS's gate is toasted, and I'm now wondering why.The controller runs on 5V and the Drain of the N-MOS was at 12V (input of the buck converter). The boost on the controller was supplied with 12V through a diode, in order to make it run at 12V plus the 5V from the controller. Since the MOSFET has a maximum rating of 10V from gate to source my guess is that the SW (connected to Source) was still climbing when the high side drive instantly went to 17V, frying the gate.So how do you deal with this? Other than keeping the gate-source rating above input + boost? Resistor to gate to introduce some sort of slew-rate?

author: EPTech
author_rank: Regular Contributor
timestamp: November 25, 2016, 03:06:40 pm
content: Hi there,A low capacitance zener diode of about 15V across gate-source will do just fine.Happy converting.
High-side vs. low-side switching with SSR - Page 1
Forum section: electronics / beginners

author: amaningd
author_rank: Contributor
timestamp: August 08, 2022, 06:32:03 pm
content: I'm using a 3.3V logic signal to control anIXYS CPC1706Y solid-state DC relay; in turn, its output switches the coil of a mechanical relay (edit: 24V DPDT relay; coil is driven by an isolated supply). I'm wondering whether it is best to place the SSR above the coil and flyback diode (closer to the positive rail) or vice versa, as shown in the attached image. IXYS doesn't show the placement of the output load in the datasheet, but I've seen other manufacturers' schematics place the load near ground (as in the "b" configuration of the attached image), such as thePanasonic AQAD551DL(pg. 5 of thedatasheet). I've also seen tutorials on driving relay coils with MOSFETs likethis one, where an n-MOSFET is placed below the coil.

author: Zero999
author_rank: Super Contributor
timestamp: August 08, 2022, 06:38:16 pm
content: Either will work, but why use an SSR to switch an ordinary relay, when a simple transistor will do?

author: amaningd
author_rank: Contributor
timestamp: August 08, 2022, 06:50:27 pm
content: Quote from: Zero999 on August 08, 2022, 06:38:16 pmThe 3V3 control signal comes from a LabJack U3's digital I/O, but the relay coil takes 24V from a separate, isolated supply (I should have mentioned that originally; I've edited my OP). In my previous tests, I "rolled my own" with an optocoupler, acting as another switch, that controlled the gate of an n-MOSFET (see attached), and I'm still debating between this and the SSR from my original post.

author: ledtester
author_rank: Super Contributor
timestamp: August 08, 2022, 09:07:22 pm
content: You might be able to use just the optoisolator to switch the relay.

author: Zero999
author_rank: Super Contributor
timestamp: August 08, 2022, 09:32:29 pm
content: Quote from: amaningd on August 08, 2022, 06:50:27 pmThat will work.How much current does the relay use? Another option is to use a BJT, with the optocoupler between the base and collector.
high speed adc board  - Page 1
Forum section: electronics / beginners

author: 5282
author_rank: Regular Contributor
timestamp: December 28, 2016, 09:10:29 pm
content: hiiii have high speed 100msps running at 100mhz adc chip and i want to make development core board for adc like this boardare this board will make problem with my adc at 100mhz speed?

author: Paul Moir
author_rank: Frequent Contributor
timestamp: December 28, 2016, 10:43:46 pm
content: Yes it will cause problems. Dealing with 100MHz digital signals on through hole devices is extremely tricky. Dealing with 33MHz is tricky enough.

author: danadak
author_rank: Super Contributor
timestamp: December 29, 2016, 12:31:46 pm
content: This might be useful -http://www.ti.com/lit/ml/slyp173/slyp173.pdfRegards, Dana.
High Speed Digital Design: a Handbook of Black Magic - editions? - Page 1
Forum section: electronics / beginners

author: jgalak
author_rank: Regular Contributor
timestamp: March 06, 2018, 02:22:21 pm
content: I got my hands on a copy of this book, the original 1993 version. While the math hasn't changed, it does feel a bit dated - lots of time is spent on chip families that aren't in much use these days (at least I don't think they are).Amazon has what appears to be a 2008 version, but I can't tell if it's just a reprint or an update. Anyone know?

author: Shock
author_rank: Super Contributor
timestamp: March 06, 2018, 02:47:40 pm
content: International printing it looks like (selling it cheap).Edit:Yuphttps://www.ebay.com/itm/161918867021
High speed displays - Page 1
Forum section: electronics / beginners

author: jimon
author_rank: Regular Contributor
timestamp: October 18, 2015, 08:58:29 pm
content: Hi everyone,I have an idea to try to build a prototype of low latency (<5ms) touch controlled user interface, so I'm trying to get grasp of what parts I need for it.Outside of everything else I'm trying to figure out what is the state of art of obtainable (<2k$) high speed LCD displays at the moment. I've found some mentions on internet about 600 fps displays, but no references whatsoever. I've also tried digikey and mouser, but obviously they don't have any information about refresh rate thereAlmost any size and resolution will do, preferably color, but b&w is also a good start. The best would be if display provided direct control over column drivers because I don't need to update whole screen every frame.Any ideas where to look for such device ? Thank you in advance

author: jimon
author_rank: Regular Contributor
timestamp: October 20, 2015, 09:01:29 am
content: Ok, after some research I figured out that I probably need OLED screen, not LCD - some refs herehttp://electronics.stackexchange.com/questions/64073/implementing-a-very-high-frame-rate-1khz-oled-display.Though I have hard time to find fast OLED displays either

author: bktemp
author_rank: Super Contributor
timestamp: October 20, 2015, 09:15:45 am
content: If low resolution (128x64) is ok, look for OLED displays with chip on board or chip on flex drivers and replace them with your own driver circuit.Maybe a DMD (digital mirror device) could also be used, because they are quite fast and need PWM to generate grayscales. Therefore the actual framerate used to drive those devices is quite high.

author: Marco
author_rank: Super Contributor
timestamp: October 20, 2015, 09:21:05 am
content: If rear projection is an option there is theTI Lightcrafter.
High-speed signal isolation - Page 1
Forum section: electronics / beginners

author: Time
author_rank: Frequent Contributor
timestamp: September 02, 2010, 04:01:44 pm
content: I am designing something where the application requires isolation of a some what high speed signal (1 MHz). It is essential to isolate the source signal from the rest of the device and preserve the waveform characteristics at the same time. The catch is that even though the frequency is only 1 MHz, the risetimes are on the sub-nanosecond (2ns to pico-seconds to be exact) order and the rise and fall times of the signal are the most crucial aspect of the signal to this application.I have spent some time online sorting through various optocouplers and have found the fastest Tphl and Tplh (time to propagate high to low and vice versa) is in the 10s of ns realm. I gave up on the notion of an optocoupler for this reason and began to search for another isolation method but have not really had much luck.I was hoping someone here had any good ideas for isolating a 5V MHz signal with sub-nanosecond to pico-second rise/fall times without impacting these times and providing atleast a few kV of isolation. The isolated signal can be TTL or CMOS, either would work just fine.

author: Zero999
author_rank: Super Contributor
timestamp: September 02, 2010, 04:37:46 pm
content: You could try a pulse transformer but finding one with a wide enough bandwidth still might be a problem.

author: jahonen
author_rank: Super Contributor
timestamp: September 02, 2010, 04:59:12 pm
content: Might be easier to decode the risetime information before isolation and then transfer it across the isolation barrier (whatever it is).Regards,Janne

author: Zad
author_rank: Super Contributor
timestamp: September 02, 2010, 06:26:22 pm
content: How about a wide band RF transformer?http://www.minicircuits.com/cgi-bin/modelsearch?model=ADT1-1WT&search_type=modelhttp://www.minicircuits.com/pdfs/ADT1-1WT.pdfAs an aside, notice the pricing breaks.Buy 1 to 9 and pay $14:95 eachBuy 10 or more and it is $2:95 each

author: Time
author_rank: Frequent Contributor
timestamp: September 02, 2010, 07:05:32 pm
content: I've been looking at those. I have previously used some minicircuits x-frmrs for matching networks. I am just not quite sure they have the few kV of isolation I need, though.

author: Unknown
author_rank: Unknown
timestamp: September 02, 2010, 10:09:49 pm
content: You might be able to find suitable parts in the AD icoupler series or similar parts from Silabs (there's a third source I can't recall). Not sure about rise times, they support signals up to 100Mhz, but I'm not sure about rise time fidelity. Isolation up to 6kV or so. If rise time is critical in an analog way, modulating it might be the best solutiom.

author: Time
author_rank: Frequent Contributor
timestamp: September 02, 2010, 10:27:12 pm
content: Those analog devices have the best specified performance I've seen so far at 3 ns rise/fall times. I will probably give those a whirl.
High Temp Glue - Page 1
Forum section: electronics / beginners

author: thefast1
author_rank: Newbie
timestamp: June 10, 2015, 02:33:38 pm
content: Hi All, new here and wanted to ask what Glue of sorts I could use to cover some resistors that get very hot.Just to explain what it is i need to do, I have some High power resistors (3) that are going to be used in conjunction with some after market rear LED car lights, so I want to house the resistors in a small plastic box but want to fill the box with some heat resisting glue or compound of some sort to stop the box melting as well as protecting the components, I have seen various electronics in plastic boxes covered with some sort of Black hard glue, what is this called and where may I get some, I did a search on here but not sure what to call the glue,thanks for your help,

author: orbiter
author_rank: Frequent Contributor
timestamp: June 10, 2015, 02:39:33 pm
content: It's called potting compound. A type of epoxy. I'm not sure if it's ALL high temperature resistant though so you may have to look fora specific high temp potting compound.Here's a link to the available compounds at Farnell.. Check the datasheets for specifics.http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000004395&sort=P_PRICE&pageSize=25&beginIndex=1&showResults=true

author: thefast1
author_rank: Newbie
timestamp: June 10, 2015, 02:55:09 pm
content: Thanks for your speedy reply

author: Ian.M
author_rank: Super Contributor
timestamp: June 10, 2015, 03:07:17 pm
content: If they already get very hot, they'll get even hotter in a sealed box and unless you keep the epoxy coating very thin, will probably overheat. If they are already getting hot enough to melt the box, they will be a fire risk if buried in potting compound.

author: SeanB
author_rank: Super Contributor
timestamp: June 10, 2015, 04:34:19 pm
content: You probably will be better off using a small diecast box, and using some aluminium cased resistors inside the box, attached to the case to heatsink them. Then you can simply use a waterproof cable gland and thermal compound between the resistors and the box, and if you want use some silicone grease on the lid to seal it.I take it you are retrofitting LED lamps to a vehicle with lamp failure detection, so you have to handle the power of the original lamps, around 30W per side. You probably will need to use 50W metal cased resistors to handle the power.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 10, 2015, 10:24:24 pm
content: What are the dimensions of the box, and what power rating are the resistors?Tim
High torque servo DS3218MG PWM signal drive current - Page 1
Forum section: electronics / beginners

author: niclatrique
author_rank: Contributor
timestamp: April 12, 2020, 12:03:47 am
content: Hi,I work on a project involving the control of "high torque" RC servo motor generally called "DS3218MG". These are all such cheap knock off products that getting technical specification about them is quite a challenge.So far I got the PIC16F1615 programmed and running fine the PWM output. Using a simple potentiometer I can play with the duty cycle from 0% to 100%. small regular servos require a 50Hz PWM signal to operate. One very interesting specification I can read on any page where those "high torque" motors are sold is the frequency. It is stated as follows : "1520uS/333Hz". Is that me or there is something strange about these numbers ? 1 / 333Hz = 3.003ms as 1/1520us = 657Hz. Also, whatever the frequency I try to control it, it does not even try to follow the duty cycle, whatever the duty cycle is... it sometmes kind of turn randomly.https://www.rcmoment.com/p-rm10488.htmlRight now, the servo signal line is directly connected to the PIC's output. I can testify the output is cycling, the scope is connected to it to whitness the frequency and duty.The circuit is powered by a good old 7805.there is no mechanical load connected to the motor, only the little 1 inch arm that came with it.I'm about to decouple the PIC output from the servo PWM line using an N-channel mosfet, just to boost the drive power a littlebit.Question 1: What is the actual frequency those "20kg high torque" servo should be operated at ? 50Hz, 333Hz, 657Hz ?Question 2: What is the needed current drive for the servo's signal line.Anyone who can light me up, I will greatly appreciate,Thanks !

author: niclatrique
author_rank: Contributor
timestamp: April 12, 2020, 03:03:22 am
content: what an idiot !The ADC value fed straight into the PWM ouput. No filtering of some sort. The ADC output so noisy that the servo would chase himself forever. After some filtering it works just fine !Thanks anyways
High Valued (100 mF) Unpolarized Capacitors - Page 1
Forum section: electronics / beginners

author: gigavolt
author_rank: Contributor
timestamp: July 13, 2020, 02:44:35 am
content: How are huge unpolarized capacitors made in practice?I am trying to implement an LCR filter from this  paper which cleans up the output of a high current power supply for electromagnets. They claim that they are using absolutely enormous single farad scale capacitors for their system and that they use it on a bipolar supply. I don't understand how they make those systems in practice though, because I typically think of unpolarized capacitors maxing out at a few hundred uF. Can you combine polarized caps together safely to get large unpolarized caps? How well does this work for a filter design? Praeg, W. F. (1970). A High-Current Low-Pass Filter for Magnet Power Supplies. IEEE Transactions on Industrial Electronics and Control Instrumentation, IECI-17(1), 16–22.https://doi.org/10.1109/TIECI.1970.229868(https://ieeexplore.ieee.org/document/1701751)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 13, 2020, 08:09:02 am
content: Take two polar electrolytics, connect series opposing, and bias up the middle node to somewhat higher than half the maximum peak voltage expected in the application.Nonpolar types are constructed symmetrically, i.e. both plates anodized, so the voltage rating is high and works either way. Tends to be much less capacity than otherwise, even given that you're effectively doubling the voltage range (it goes from -V to +V instead of 0 to +V) and halving the capacitance (effectively two capacitors in series).Tim
High Volt Gain Amplifier Blow Up Troubleshoot... - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 06, 2017, 11:43:16 am
content: i have a blow up time and still diagnosing where the problem is, it will be slow as i have to retest all the related components for damage to narrow down where the problem source is... in the mean time i would like to ask... refer to diagram below, adapted fromhttp://cds.linear.com/docs/en/application-note/an18f.pdf(page 7). i havent put any load yet, just a 1Kohm R278. its functional correctly before as a 4.8X volt gain amplifier for few minutes until the power source Vr+ and Vr- (±50V)which are BJT (not shown in another sheet) in linear mode blew up. after 2nd replacement and retest, the power source blew up almost instantly. Q45 and Q56 are also taking some heat as solder paste i put on the metal tab melted a little bit during operation, Q44 and Q57 are not installed yet as this is only a test, i will desolder and check Q45 and Q56 after this for functional integrity...in this query i would like to take attention to 4 diodes stack D46-D49,is it possible due to higher volt differential to bias the push pull bjt, both Q45 and Q56 is shorting each other?the usual setup is 2 diodes stack to bias, but i use 4 diodes due to Q45,Q56 are darlington bjt. i measured using DMM diode mode, the volt drop Vbe of both darlington is about 0.79V each making both drop is about 1.58V, and Vdrop on all 4 diodes stack is about 1.3V, this should be safe ie no shorting of push pull, but during operation,is it possible that Vbe drop on both NPN-PNP darlington reduced during temp rise and in effect shorting each other and worsen the situation?the questions are in bold, hope someone help, thanks.
high voltage across relay contacts? - Page 1
Forum section: electronics / beginners

author: electronics man
author_rank: Frequent Contributor
timestamp: May 22, 2015, 03:01:35 pm
content: i have an application where there may be a hight voltage across the contacts of a relay however it will never be switching that high voltage. most relays are only rated to switch about 30V however i won't be witching that voltage . my question is is it ok to have this voltage across contacts without switching it even though the relay is rated to switch a lower voltage and can i increase the breakdown voltage across contacts by putting relay contacts in series (increased gap = increased breakdown voltage) O0 O0 O0 O0

author: Pillager
author_rank: Unknown
timestamp: May 22, 2015, 03:32:45 pm
content: Quote from: electronics man on May 22, 2015, 03:01:35 pmI wouldn't do that. Yes, it is theoretically possible, but not recommended. Buy a suitable relay for the voltage you're expecting, it's your safest bet.BTW, how high is High Voltage?

author: electronics man
author_rank: Frequent Contributor
timestamp: May 22, 2015, 03:51:36 pm
content: Quote from: Pillager on May 22, 2015, 03:32:45 pmi meant to put in 1KV MAX

author: PSR B1257
author_rank: Frequent Contributor
timestamp: May 22, 2015, 04:18:25 pm
content: QuoteDepends on the relay.The nominal switching voltage is here not determining, since this is the voltage where the relay is able to switch it's rated nominal current.Take a closer look in the datasheet. You will find a figure calledDielectric strengthfor the contacts.Here is an (random) example:http://www.omron.com/ecb/products/pdf/en-g5le.pdf

author: Asmyldof
author_rank: Regular Contributor
timestamp: May 22, 2015, 09:01:42 pm
content: And for the general question of "Can I do this with a relay" always take the lowest dielectric withstand/strength you can find, unless you know which one to pick for your exact situation.
High voltage constant current circuit - Page 1
Forum section: electronics / beginners

author: DanioIO
author_rank: Contributor
timestamp: March 15, 2015, 02:20:39 pm
content: Hi,How can i change a standard constant current circuit so it will work with 500V supply which exceeds the maximum supply voltage of a op amp?

author: rs20
author_rank: Super Contributor
timestamp: March 15, 2015, 02:28:43 pm
content: I'm not sure if that op-amp circuit is necessarily the right way to go there, others may have other suggestions. But that aside, it seems to me that all the voltages the op-amp needs to see there are near 500V, so just use 480V or whatever as the op-amp's ground and you'll be fine. That way, the op amp has a 20V supply. Maybe a 5V supply would be more appropriate. Or, equivalently, re-draw your circuit with ground at the top, and negative 500V at the bottom, and work that way.Be careful with 500V! What are you actually doing? How much current are you hoping to deliver? Do you really need constant, regulated current, or would a resistor suffice?

author: Zero999
author_rank: Super Contributor
timestamp: March 15, 2015, 06:00:44 pm
content: That circuit uses a PNP output transistor which has a lot of gain so will need some additional frequency compensation, otherwise it'll oscillate.I was wrong. Looking at it again, the feedback is taken from the emitter, so it's an emitter follower, rather than a common emitter amplifier as I'd previously thought. A common emitter amplifier is fairly immune from oscillation and can safely included in the feedback loop of an op-amp without worrying about introducing another pole or oscillation.The sense resistor is connected to +V so the op-amp needs to float near the +V and both of the inputs must be within the common mode range.How much current do you need?

author: richard.cs
author_rank: Super Contributor
timestamp: March 15, 2015, 08:15:43 pm
content: You'll have to be really careful with the transistor selection there of you want to avoid problems with second breakdown. Scan the datasheets for the dc safe operating area.

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: March 15, 2015, 08:27:49 pm
content: how much current, accuracy, noise, Zout?there a (very) few depletion mode MOSFET made today that can be used in 2 terminal CCS to 500V, Supertex(now Microchip?) and Ixys

author: Marco
author_rank: Super Contributor
timestamp: March 16, 2015, 07:02:20 am
content: Ignoring the wisdom for a moment, the smallest change so that particular circuit can still work is to use a simple zener+resistor+PNP regulator to make another voltage rail for the opamp, 490V for instance.
High Voltage Coupling - Page 1
Forum section: electronics / beginners

author: diyfella
author_rank: Newbie
timestamp: May 06, 2025, 10:59:00 pm
content: I have a tiny hv transformer around 10 to 20 kv that i drive using a function generator and a mosfet. It works fine and generates a nice and stable arc in the output. I wanna couple the hv output to another circuit basically the same as a tig hf start circuit. In tig welders this is normally done with a flyback, a spark gap, a hv cap and coupling coil like thesebut no matter how hard i try i can't get the hv output to be inducted to another wire.also when i add a hv cap to the output in parallel it doesn't arc anymore.this guy has done the same thing but he uses a very powerful flyback transformer with a zvs driver where as mine is a tiny epoxy transformer the kind you find in a taser (without voltage multiplier or rectifier).

author: David Hess
author_rank: Super Contributor
timestamp: May 07, 2025, 04:57:34 pm
content: Quote from: diyfella on May 06, 2025, 10:59:00 pmDid you include the capacitor and spark gap? The flyback transformer output is not enough to directly drive the coupling coil.I actually did not know how the HV start on a TIG works until you listed the elements. Now it is obvious.

author: diyfella
author_rank: Newbie
timestamp: May 07, 2025, 07:40:20 pm
content: Yes, i tried all that but to no avail.

author: David Hess
author_rank: Super Contributor
timestamp: May 07, 2025, 08:56:04 pm
content: Quote from: diyfella on May 07, 2025, 07:40:20 pmIs your spark gap triggering? A lower power flyback circuit should result in the spark gap triggering at a lower frequency. If it is not triggering, then the voltage is not high enough, or the spark gap is too large.

author: diyfella
author_rank: Newbie
timestamp: May 07, 2025, 09:47:00 pm
content: Yeah the spark gap is sparking, but when i put a hv cap in parallel to the output no more arc. even with just the cap in the output it no longer arcs.
High Voltage DC Blocking - Page 1
Forum section: electronics / beginners

author: nicknails
author_rank: Regular Contributor
timestamp: October 10, 2017, 03:46:25 pm
content: I have a need to measure AC ripple on the output of high voltage DC converters (anything in the range of 1kV-20kV). My thought is to filter the DC with multiple caps, then use an op-amp to amplify the ripple to make it easier to measure on a scope. All I have is a TDS1002B that goes down to 20mV/div. On the lower voltage stuff the ripple is in the 20-40mV range and nearly impossible to see on the scope. My current setup is a 0.01uF in series with a 10M and measure across the resistor. This works but there's a transient spike on the cap. My understanding is that if I put multiple caps in series, the transient spike will be smaller and smaller on successive caps, but I have no idea how to calculate the capacitance or how many caps are needed. The ripple frequency is anywhere from 60k-300kHz.I'm assuming I'll need separate setups because of the voltage range, which isn't a problem. I have some nice AD822 op-amps that I'll be using, which can run up to +/-15V, so I'm thinking I can get the ripple in the 4-8V range.Please no rants about high voltage and killing myself. I've been doing HV DC/DC converters for many years (up to 12kV), just never had a need to measure such a small ripple.

author: ebclr
author_rank: Super Contributor
timestamp: October 10, 2017, 03:58:01 pm
content: Why not use a high voltage probe ?

author: ovnr
author_rank: Frequent Contributor
timestamp: October 10, 2017, 04:03:04 pm
content: Transient during capacitor charging: Just clamp it with a TVS or Zener or something to that effect - you've already current-limited it with the series resistor (beware maximum working voltage, etc).

author: nicknails
author_rank: Regular Contributor
timestamp: October 11, 2017, 01:03:47 pm
content: Quote from: ebclr on October 10, 2017, 03:58:01 pmThis would require the scope to be set to 1000X, making it 2V/div minimum.Quote from: ovnr on October 10, 2017, 04:03:04 pmI have no experience with TVS diodes; I'll do some research and check that option out. Thanks.
High Voltage DC Power supply  - Page 1
Forum section: electronics / beginners

author: DarkZero
author_rank: Regular Contributor
timestamp: June 05, 2015, 09:15:24 am
content: Hello All!I have been trying for some time to make my own 1kV 1A dc power supply but i got only to 265v and i seem stuck there. i used that zvs driver circuit with more transistors (circuit is in the attachment i just paralleled 4 transistors).Now i made a transformer with 6/6 turns one the primary and a 100 turns on the secondary and with 60uF capacitor this produces high pitch sound and 265v dc on 150W 220v light bulb i attached the wave forms of the primary and secondary under that load, also i noticed that by increasing capacitance i get higher voltage but at this point they become ridiculously large and i'm sure i'm doing something wrong with the transformer. I'm using transformer core from crt tv. Transistors doesn't even get to 35C under load. if someone can help im willing to spend time since i have been trying to make this for like past 2 months i don't give up that easy i find it relaxingthanks in advance
High voltage DC - Page 1
Forum section: electronics / beginners

author: abdulsamaddabu
author_rank: Contributor
timestamp: December 13, 2017, 07:17:27 am
content: Hey what the circuitry/princple is used in usb killerI mean how it boost 5v to 200vIs it by switch mode power supply or like converting to ac stepping up ac using transformer and rectifying to dc or any other method and also how this circuit is so compact

author: jonovid
author_rank: Super Contributor
timestamp: December 13, 2017, 07:24:21 am
content: usb killer, but why

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 13, 2017, 10:12:03 pm
content: https://www.eevblog.com/forum/projects/usb-killer-v3-reverse-engineering-in-progress/
High Voltage Electronnics Book Recommendations - Page 1
Forum section: electronics / beginners

author: muttyfut
author_rank: Newbie
timestamp: December 26, 2024, 03:00:55 pm
content: Hi all,I'm looking for books about the design of high voltage equipment, specifically on high voltage (1 - 100 kv), low power (<<1kw) switch mode power supplies, HV lab grade equipment, as well as other general HV design considerations. I've had a brief search but mostly what pops up is large high power industrial/grid/generation related, whereas I'm interested in HV for essentially physics and experimental applications.I've 'played' around with various HV stuff in my time, Tesla coils, neon sign transformers, TV flybacks etc. but now I’m more interested in the design of more 'proper' lab grade equipment and best practices.I'd be incredibly grateful for any recommendations with regards to books or resources!Thank you all very much!

author: Terry Bites
author_rank: Super Contributor
timestamp: December 28, 2024, 11:56:26 am
content: I doubt there is a single publication that covers your non-specific requirements. HV lab gear isn't a subject in its own right.A niche book, if it exists, will cost an arm and a leg too.You would be better off checking for designs of the actual gear you want to build.Manafacturers app notes on IGBTS, SCRS and MOSFETs, switches, isolators, connectors etc and insulators are worth reading.CERN publications (free) are a goldmine of HV ideas and techniques written by the smartest guys in the room.https://onlinebooks.library.upenn.edu/webbin/book/lookupid?key=ha011425568https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.mv.helsinki.fi/home/tpaulin/Text/hveng.pdf&ved=2ahUKEwjixNSKsMqKAxWVVUEAHSPWHNgQFnoECBcQAQ&usg=AOvVaw1mLjYPG_HxaOzlqERmb8hy
High Voltage input ac breakers - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 03, 2017, 06:30:46 am
content: 1. I am using a lithium ion battery charger.2. Its bit expensive, & in field one of it got failed. I checked its input ac side board gets burned out due to over voltage ac input3. Charger is rated at:i) Input:a) Voltage Range: 90~264Vacb) Frequency Range: 47Hz--63Hzc) Power Factor(Typical): PF?0.95/230VAC Full Loadd) Efficiency ( Typical): ?91%(220vac/Rated Load)e) AC Current (max.): ?20Af) Inrush Current (Typical): ?30A @220Vac Cold startg) Leakage Current: Input—output: ?0.25mA Input—PG: ?3.5mAii) output:a) DC Output: 48Vb) Rated Current: 21A?90-174Vac??42A?175-264Vac?4. Need a ac input overvoltage tripper for that:a) If AC line voltage ever increases to 264Vac max system should trip.b) Sometimes in field, one line falls over another line due to some breakage, this almost doubles the voltage of the line, system should trip.c) Also protection in case of lightning.5. Is there any ready made good quality device for this?

author: fourtytwo42
author_rank: Super Contributor
timestamp: July 03, 2017, 08:54:42 am
content: Several pictures would help as would the make and model

author: testian
author_rank: Regular Contributor
timestamp: July 03, 2017, 09:36:54 am
content: Maybe something like:http://uk.rs-online.com/web/p/surge-suppressor-units/3115830/(Over Voltage Protector)

author: MosherIV
author_rank: Super Contributor
timestamp: July 03, 2017, 10:31:43 am
content: Yes, I was thinking what he was describing was a surge suppressor.Bear in mind that each surge takes life out of the MOV.Good ones have a separate neon to indicate if the surge supressor is working or not and the light goes out when it is not