hybridfree/eevblog-posts huggingface dataset:
Dave Jones See and Say - Page 1
Forum section: electronics / projects

author: TomS_
author_rank: Frequent Contributor
timestamp: August 08, 2016, 09:55:05 am
content: If you haven't already seen it...It's a couple of years old now, but it has to be a classic.https://youtu.be/wYo4lOuD_-YIt would be awesome if Dave could get hold of it for a (non destructive) "teardown" or some such (review?), even though we already know what's in it.Just too funny. Jealous of who ever has it now. :-D

author: TomS_
author_rank: Frequent Contributor
timestamp: August 08, 2016, 09:56:38 am
content: Oh, I *just* found the video where he did get hold of it!Episode #633!

author: LeonV
author_rank: Contributor
timestamp: August 09, 2016, 05:26:15 am
content: For the lazy
Dave your shirt just showed up on youtube - Bullet Impact Sensor - Page 1
Forum section: electronics / projects

author: Pulseit
author_rank: Contributor
timestamp: April 18, 2014, 04:01:28 pm
content: Worn by an Australian gun youtuber

author: calexanian
author_rank: Super Contributor
timestamp: April 18, 2014, 04:16:58 pm
content: Verry cool! You could use that to trigger the sweep of a scope.

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: April 19, 2014, 02:53:03 am
content: this is an amazing tutorial on teaching transistors. amazing i am going to do this
Daves Dummy Load as Current Source, and Battery charger? - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: May 05, 2013, 05:46:57 pm
content: So Last week I threw together a dummy load, via Daves schematic. I changed things a bit though. First off I added a micro/lcd/encoder to adjust the thing, then to read the current im using a touchstone current sense amp with a 1% .005ohm vishay 5 watt load resistor.I was wondering what kind of modifications I would need to make in order to use the fet/opamp set up as a constant current source? I want to throw this thing in an enclosure and think it would be a lot more usefull if it could also supply the current instead of just eating it up. When using an LM317, I can use the same circuit as a dummy load or constant current source, is this possible with the opamp/fet set up?Currently i am using an LM358 opamp, I also have the same amps dave uses (LM354 I belive) which is the same as the 358 spec wise correct? The 354 is just the quad version? Well I found some MC6043 amps and was wondering if they may be better for this project?http://ww1.microchip.com/downloads/en/DeviceDoc/21669c.pdf
Daves Power Supply (from 8 part design series) - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: April 24, 2013, 05:47:49 pm
content: So I watched all these videos twice, they are very intresting, very informative and have sparked a ton of ideas and inspired me to build a digital linear power supply.What I was wondering is what happened with this power supply, I thought he was suppose to sell a kit.... I just realized the schematics and pcb files are under projects, which is nice, but the store does not list this item. Does dave plan on selling it again, and was it available in kit form?

author: SebG
author_rank: Regular Contributor
timestamp: April 24, 2013, 09:32:08 pm
content: He mentioned somewhere that he won't do any videos on it until he finishes the design and gets a prototype and software working. He will also sell it as a product instead of a kit since most of the components are SMD. He will finish it eventually.

author: Greek0
author_rank: Newbie
timestamp: April 25, 2013, 10:32:56 am
content: But I think it might take a bit longer for Dave's PSU to be finally finished due to some problems with the LT3080 (cf.https://www.eevblog.com/forum/projects/lt3080-wierdness-dave%27s-power-supply-%28eev224%29-gone-mad/).Does anyone have a link to the recent update (new schematic)? I saw it in some thread but can't find it anymore.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: April 25, 2013, 04:23:57 pm
content: Ya I heard him talking about this on the amp hour, I hope the 3amp version does not have the same issues I just ordered some. I think he said the 3085 has been fixed but it's only 500mA, blegh
Daves Schematics - Page 1
Forum section: electronics / projects

author: jwflammia
author_rank: Newbie
timestamp: February 13, 2015, 02:16:26 pm
content: Does Dave post schematics of stuff he built in episodes.

author: zapta
author_rank: Super Contributor
timestamp: February 13, 2015, 05:36:17 pm
content: I don't think he is building anymore. The new hire is supposed to change that.
Dave's uCurrent in the UK and also Low cost precision ohmmeter  - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: January 21, 2021, 01:25:33 am
content: Hi,are there reliable micro ohmmeters which are relatively low cost? Whether kits or fully built?Also looking for a distributor in the UK for Dave's uCurrent meter? Do you know any?Thank you

author: alex-sh
author_rank: Regular Contributor
timestamp: January 24, 2021, 12:58:48 pm
content: Hi,I think Simon here on the forum used to sell uCurrent Gold in the UK:https://simonselectronics.co.uk/product/ucurrent-gold/For the milliohm meter you can take this one:https://www.barbouri.com/2016/10/09/milliohm-meter-version-1-5/very precise and works well.

author: bob91343
author_rank: Super Contributor
timestamp: January 24, 2021, 07:07:12 pm
content: There are DIY projects for low resistance measurement. I built one, only two or three parts, works well.Basically you use an LM317 to supply constant current and measure the drop on a DVM.

author: ricko_uk
author_rank: Super Contributor
timestamp: January 25, 2021, 03:54:19 pm
content: Thank you Alex and Bob

author: kripton2035
author_rank: Super Contributor
timestamp: January 25, 2021, 05:40:17 pm
content: some simple to build.I'm also modifying the shorty device to add a display, and a better adc. gets the 10µΩ resolution . I have a aop offset to solve, and then will publish.http://kripton2035.free.fr/continuity-repos.html

author: Dr.Krieger
author_rank: Contributor
timestamp: January 25, 2021, 06:23:17 pm
content: There are many circuits that use something as accurate as a LM317 as a current source (for example youtube.com/watch?v=ReHFli7gAq4) but if you want something more refined with better parts you could take a look at Scullcom's design:

author: Gyro
author_rank: Super Contributor
timestamp: January 25, 2021, 06:29:14 pm
content: This Maxim app note works well for a battery powered milliohmeter adaptor. You can chose your own reference and opamp [Edit: and Mosfet.]Adding a capacitor between the opamp output and inverting input improves stability.

author: ricko_uk
author_rank: Super Contributor
timestamp: January 25, 2021, 09:06:19 pm
content: Thank you all for the infos and links!
Daydreaming: Can SMR be used with floppies - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 06, 2022, 03:29:37 pm
content: Just wondering out loud. SMR seems to be recording the data closer together by "eating up" one of the guard bands on each side of a CMR data track, and from what I can understand even modern hard disks record essentially the same way as a 1970s floppy disk: a magnetic write gap puts down a track and two erase gaps erase the "side lobes" to create a single data track protected on each side by nothingness.The entire section of SMR data has to be recorded in one continuous operation which means somehow you need as much conventional storage in the first place to record it in SMR after.If I'm right, what's preventing a floppy drive from doing the same thing? I mean mastering a floppy disk in SMR would mean about a 50% increase in storage, I think, and as long as it's written in one go it should work, right?Ignoring writing back to the disk for now.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 06, 2022, 06:17:05 pm
content: The crosstalk between tracks is pretty bad as is, I doubt it would work with even more crosstalk.Quote from: Alex Eisenhut on November 06, 2022, 03:29:37 pmThe latest hard drives use a laser to heat up a spot which then becomes easier to magnetize.

author: bdunham7
author_rank: Super Contributor
timestamp: November 06, 2022, 06:26:21 pm
content: Quote from: Alex Eisenhut on November 06, 2022, 03:29:37 pmI believe SMR requires a much narrower read head compared to the write head. I think the whole idea is that the physical limitations on how narrow a track you can read are different (less) than the limitations on how narrow a track you can write, at least with modern technology. So maybe you could do it on a floppy, just not with existing hardware.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: November 06, 2022, 06:32:18 pm
content: Floppy disks don't have a 'servo track', so the head positioning is open-loop. I doubt you'd have sufficient accuracy to implement SMR.

author: wasedadoc
author_rank: Super Contributor
timestamp: November 06, 2022, 07:46:20 pm
content: Quote from: radar_macgyver on November 06, 2022, 06:32:18 pmFor a brief period there were 3.5 inch drives that could store 120Mbyte on special floppies. Could also read and read conventional 1.4 Mbyte floppies.I still have two of the Matsushita units. LKM-F734-1 manufactured May 1998. The discs were £10.http://www.computinghistory.org.uk/det/49387/Panasonic-LKM-F7-34-1-Super-Disk-Drive/https://en.wikipedia.org/wiki/SuperDiskhttps://goughlui.com/2013/05/02/tech-flashback-iomega-zip-100-vs-3mimation-superdisk-ls-120-showdown/There are laser warning messages in 6 languages on the casing.The internal units have the standard 40 pin PATA interface that was used for hard discs before SATA. Some motherboards had 'LS-120' as one of the boot options in the BIOS.
DB9 plugs that take a ribbon cable?? - Page 1
Forum section: electronics / projects

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 30, 2013, 07:41:37 am
content: Has anyone come across DB9 connector plugs that accept a computer type ribbon If so, where did you source them from please, and are they solderless? Many thanks.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 30, 2013, 07:47:56 am
content: You're not looking very hard - these are readily available form any component supplier - include "IDC" in you searche.gFarnell

author: Monkeh
author_rank: Super Contributor
timestamp: August 30, 2013, 07:48:43 am
content: They are easily located with the appropriate search terms (DE-9 and IDC).http://uk.farnell.com/multicomp-formerly-from-spc/spc15406/connector-d-sub-plug-9way/dp/2112364E: Damnit Mike.

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 30, 2013, 08:16:41 am
content: "IDC" was the key to success! Thanks, I see them now at Farnell and from umpteen sources ready assembled on Ebay. Thanks, soldering normal DB connectors is a PITA I findIs there a way to bring a 16 male pin PCB board header, via ribbon, to a DB style chassis socket? I see 16 pin connectors for the headers, and 16 way ribbon cable to suit, but what about the other end where i would like a DB style socket?

author: ovnr
author_rank: Frequent Contributor
timestamp: August 30, 2013, 09:42:39 am
content: So you want a DB9 in one end of the cable, and a 2x8pin header in the other?There are DB9 to 2x5p ones on eBay for <$2:http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_nkw=pc+serial+bracket&_sop=15Other than that, if you really need a 16-pin connector on the other end, just get DB9s with ribbon cable, and crimp on the 16-pin connector yourself - you can find IDC connectors cheaply enough, and all you really need to crimp 'em is a hammer or strong pair of pliers.

author: nctnico
author_rank: Super Contributor
timestamp: August 30, 2013, 10:32:13 am
content: hammer or strong pair of pliersIts better to use a small vise. You need to apply force evenly across the connector.

author: Monkeh
author_rank: Super Contributor
timestamp: August 30, 2013, 10:32:52 am
content: Honestly, a 9-pin IDC like that can be done with your fingers..

author: ovnr
author_rank: Frequent Contributor
timestamp: August 30, 2013, 10:33:19 am
content: Quote from: nctnico on August 30, 2013, 10:32:13 amWell I didn't say it was going to be a good crimp, now did I?

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 30, 2013, 10:55:46 am
content: I have plenty of vices, or so the wife tells me, and a small and large vises, so no worriesThanks for the info, parts ordered, so should be AOK now I know what to ask for, all much appreciated.
DC and LED converted candleholder =) - Page 1
Forum section: electronics / projects

author: Teljemo
author_rank: Contributor
timestamp: December 20, 2014, 09:59:17 pm
content: I did a little project tonight (late evening in sweden)A diode bridge do get DC for my LEDSOf course im using the colour of christmas... blue..The whole project is on my site:http://www.workshopprojects.net/how-to-led-convert-a-electric-candleholder/merry Christmas!!!

author: Zero999
author_rank: Super Contributor
timestamp: December 21, 2014, 01:07:55 am
content: Nice project.I have to disagree with you about blue being the colour of Christmas: red yes, so it yellow but not blue!

author: rdl
author_rank: Super Contributor
timestamp: December 21, 2014, 08:14:51 pm
content: I would probably go with an orange color, but maybe you are an Elvis fan?

author: Teljemo
author_rank: Contributor
timestamp: December 22, 2014, 10:03:47 am
content: hehe..I just got a shipment of blue led's so they were close to hand..but as you can see in the project post on my site, I made it so I can easily change the Led's to any kind around 3V
DC arc fault interrupter for solar install. - Page 1
Forum section: electronics / projects

author: wemme
author_rank: Regular Contributor
timestamp: March 10, 2014, 10:11:51 pm
content: Hello.I am looking for a supplier of DC arc fault interrupters in New Zealand / Australia. I may consider else where depending on how my luck goes.Can Anyone recommend someone?These are for 3 PV solar sites 1-3Kw driving off grid resistive loads.They will be upgraded later with a MPPT load controllers.RegardsBart

author: wemme
author_rank: Regular Contributor
timestamp: March 11, 2014, 02:32:53 am
content: I finally found this place.Australian Solar Manufacturing Pty Ltd139 Atlantic Drive, Keysborough, VIC 3173P: 61 3 9798 3895F: 61 3 9798 3847www.australiansolarmanufacturing.com.au
DC backup - 19V 4A - Page 1
Forum section: electronics / projects

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 02, 2010, 09:27:54 pm
content: HelloI would like to build a power supply that delivers 19VDC and 4A. This power supply will be fed from a 120VAC input at 60Hz. When there's an AC interruption, the power supply should continue feeding its output by using 2x12V lead-acid batteries. It should also have the battery recharging circuit.Can you please recommend me a circuit or application note to follow? I've looked in google but I can only find laptop power supplies.Thanks!!

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 02, 2010, 09:34:11 pm
content: 27.6v power supply for float charging along with a buck converter to convert it to 19v.

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 02, 2010, 10:43:10 pm
content: Hello NiHaoMikeIf I use the 27.6V for float charging, should I add a recharge current controller or just let the battery draw all the current it needs? I've seen some recharging supplies which feature PWM to control the amount of current been supplied to the battery, but, is it really necessary?

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 02, 2010, 10:48:23 pm
content: Put a shunt in series with the battery in order to limit charge current.

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 03, 2010, 02:11:04 am
content: Quote from: NiHaoMike on July 02, 2010, 10:48:23 pmOK, I'll study how to calculate that shunt according to the Ah rating of the battery. Thanks.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 03, 2010, 03:59:37 am
content: Quote from: migsantiago on July 03, 2010, 02:11:04 amSimply put it in series with the negative side and use an opamp circuit to create a feedback loop.

author: migsantiago
author_rank: Frequent Contributor
timestamp: July 03, 2010, 12:52:45 pm
content: Yes, I know thatBut I want to know how much current will flow, depending on the Ah rating of the battery and its actual charge value in Volts.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 03, 2010, 01:04:00 pm
content: Quote from: migsantiago on July 03, 2010, 12:52:45 pmYou first pick a shunt as small as possible while still getting a large enough voltage drop to measure, then compare it to a reference voltage. It's usually something small, on the order of 50mv or less.

author: Pyr0Beast
author_rank: Contributor
timestamp: July 08, 2010, 10:57:11 am
content: Diode to discharge and shunt to recharge.Use Schottky diode.Tho I would rather go with boost design. You don't need additional higher voltage to drive the upper mosfet.
DC bias in symmetric linear power supply? - Page 1
Forum section: electronics / projects

author: Freesurfer
author_rank: Regular Contributor
timestamp: April 14, 2025, 10:40:39 am
content: I'm designing some circuit with a "textbook" symmetric linear power supply. It uses a PCB mount 50Hz transformer, which has one primary and 2 isolated secondaries. The 2 secondary windings are connected in series to create a center point for GND and rectified for a positive and negative rail.However the system that will be powered, will mostly only draw power from the positive rail between V+ and GND (100-200mA perhaps). There are only a few opamps connected to V- drawing a few mA at most. (5-10mA or so)This means that for every cycle of the input sinewave, each secondary winding will mostly conduct current only for the positive half of the cycle and see a DC component. But each secondary winding will alternate, so that from the primary winding's point of view, the current draw balances out with no DC component.But I am wondering, can I run into some DC bias saturation problems with this config? This symmetric design is very common, but I don't know if it also assumes a symmetrical load to work correctly?I rarely build the PSU part myself, but in this case I had to because I need access to both symmetric DC, and the low voltage AC pre rectification for the system. So an off the shelf DC supply won't do.

author: PGPG
author_rank: Frequent Contributor
timestamp: April 14, 2025, 11:50:48 am
content: Quote from: Freesurfer on April 14, 2025, 10:40:39 amDon't worry.DC bias is not a problem for winding, but for core and in core you don't have DC bias (like primary winding).This circuit with only 2 diodes and only V+ output was frequently used in times when two diodes were more expensive than addintional winding.

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 14, 2025, 12:50:50 pm
content: It will work fine as is.As for me, if I have a transformer with isolated secondaries and non-symmetric load then I would use two rectifiers.
DC Brushed Motor - Page 1
Forum section: electronics / projects

author: Tnixsw
author_rank: Contributor
timestamp: March 11, 2024, 10:10:00 pm
content: Hi,I haven't had any experience with small DC brushed motor control, and I am looking at using a DRV8251 DC motor driver in a small battery driven project. I am not quite sure I understand what is required for controlling a motor at constant speed. The motor is used to drive a small printhead on some old equipment I want to get going again, so the load should not vary too much.The IC has a motor current sense output (not the motor current path) that can be used with a resistor to give a voltage for a processor to use as feedback to control the motor with PWM.With my lack of knowledge, I'm not sure how battery voltage and load changes interact with each other, they seem contradictory.Battery voltage goes up, motor current goes up, sense voltage goes up, PWM needs to slow motor down.Load goes up, motor current goes up, sense voltage goes up, PWM needs to speed motor up.If this is the case, then I am not sure how to proceed.I am getting on these days, so reading complicated papers on DC motors is getting the better of me, so I was hoping there would be a reasonably simple solution. I did get the motor controlled with battery variations, but I wasn't using the current feedback.cheersTony

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 11, 2024, 10:18:12 pm
content: For a Brushed DC motor, voltage results in RPM, while torque results in current. If there is a high voltage over the motor, but it runs freely, it will spin fast, but the current will be low. If the motor is blocked, then current will be high, even with a very low voltage over the motor.How much detail do you want?https://en.wikipedia.org/wiki/Brushed_DC_electric_motorYou can do some experiments with an adjustable / current limited power supply. Combine it with some theory until you understand it's behavior.If you really need a constant RPM, then you will need some kind of feedback and a control loop (such as PID).
DC Brushless Motor - Built-in Thermistor control - Questions - Page 1
Forum section: electronics / projects

author: rfdes
author_rank: Regular Contributor
timestamp: December 08, 2021, 07:36:01 pm
content: HiI have zero experience with Brushless DC fans and how they are built. I have a DC PC fan with a extra pair of wires which allows connection to a thermistor for controlling the speed of the fan. I would like to make use of this fan for a project and want to know whether there is a typical schematic that explains the method used to control the fan's speed. Are most of these fans similar in topology where a somewhat universal schematic exists? My search efforts have not been fruitful, so if someone has any pointers as to the method of speed control operation, it would be appreciated.Thanks

author: strawberry
author_rank: Super Contributor
timestamp: December 08, 2021, 07:45:55 pm
content: some have PWM speed control input, some have tachometer output ... need datasheet of particular fan

author: rfdes
author_rank: Regular Contributor
timestamp: December 08, 2021, 08:38:15 pm
content: Thanks for the response.The part number of the fan isDFB802512Hmade by Younglin Tech. All of the datasheets that I found only show a 2 wire version. The one I have is a 4 wire version. 1 red/1 black/2 yellow.The 2 yellow are for a 2 wire thermistor. There is no PWM input or Tachometer output on this model.I've been unable to find any schematics, etc.

author: strawberry
author_rank: Super Contributor
timestamp: December 08, 2021, 09:47:19 pm
content: to get thermistor slope and estimate shematic components. take thermistor and measure resistance at room temperature for first point then put in fridge with thermometer and then measure resistance for second point.. can skip and do try and error method and add adjustment pots for trimminguse 555 timer to generate PWM or just comparator to turn on/off fan at specific tempeature and power MOSFET to switch fan power on or offor code mcu
dc clamp meter design with 10mA resolution - Page 1
Forum section: electronics / projects

author: justarandomelectron
author_rank: Newbie
timestamp: April 19, 2024, 04:25:19 am
content: hello gang,I wanted to design a dc clamp for measuring current with a resolution of 10mA. I am just measuring stuff upto 5A with 10mA resolution. I have some 49e laying around and a iron core. Now I have 2 choices, either make a open loop design or a closed loop with compensation winding. I think that open loop design will be worse since the resolution will be worse, and the core will be magnetize after measurement even though slightly. Though I searched online but I couldn't find a detailed design guide on closed loop design. Can anyone help me? Also will the 49e be sufficient for measuring flux near zero point in closed loop design?Also I found out another method called self oscillating fluxgate sensor with a single coil using a simple op amp . Anyone has any ideas about it too?
DC controlled current source correct study with Ltspice - Page 1
Forum section: electronics / projects

author: Gonzy78
author_rank: Contributor
timestamp: January 30, 2018, 10:26:21 am
content: Hello everyone hereI am looking to study in open loop a current source. However the path to do it, is not clear to me. I have seen a topic similar, but a bit different schematic on the forum.I choose to inspire my schematic with the AN90 from Linear tech. (Page 5)http://cds.linear.com/docs/en/application-note/an90f.pdfin the attachement, the schematic, I tried to place the AC source in different places, however the result of the simulation don't looks right.I never found any theorical study on this kind of circuit, in small signal, (and nmos versions of it). That doesn't help to set poles and zeros.The simulation looks right in transient, I would like to be sure to set right compensation, and know how to improve it.The 10 gain in the loop for the shunt is used to reduce power loss in the shunt.Maybe someone has an idea.

author: moffy
author_rank: Super Contributor
timestamp: January 31, 2018, 11:02:19 pm
content: Your voltage source should be connected to Vin with a DC offset, you can then monitor the current coming out of the collector over frequency. Make sure it is suitably biased.
DC converters configuration options  - Page 1
Forum section: electronics / projects

author: davelectronic
author_rank: Frequent Contributor
timestamp: February 18, 2019, 12:03:33 pm
content: I've been looking for high current DC to DC converters, buck in particular.High current units seem hard to find, just a couple of questions really. I'm looking to drop 19.5 Volts to 12.5 Volts, the source being relatively high current IT plug pack adaptors. Tried lower currents up to 4 Amps with good results. So just wandering is there a way to parallel converters to increase load current, and get the units to share evenly.The other question was, can voltage droppers the 24 to 12 volts types be adjusted internally so it's dropping 19.5 down to 12 Volts.If I could get buck converters to share load current, that would be great.Thanks for reading.thoughts and ideas appreciated.

author: Psi
author_rank: Super Contributor
timestamp: February 18, 2019, 12:14:32 pm
content: I dunno what the quality of these is like, but..https://www.aliexpress.com/item/Adjustable-Voltage-Reducer-DC-DC-20A-300W-Power-Supply-12V-55V-to-1-25V-53V-Step/32817410116.htmlhttps://www.aliexpress.com/item/300W-20A-DC-Buck-Module-Constant-Current-Adjustable-Step-Down-Converter-Voltage/32864475232.htmlhttps://www.aliexpress.com/item/1Pc-DC-24V-To-12V-10A-15A-20A-25A-30A-Reducer-Voltage-Step-Down-Power-Supply/32839756029.htmlQuote from: davelectronic on February 18, 2019, 12:03:33 pmYes, if you can find the low voltage shutdown circuit and change some resistor values then should be possible to make a 24V->12 run from 19V.19V is close enough to 24 that the rest of the circuit should work ok.Most of the 24-12V converters you see for sale are for getting 12V from a 24V lead acid battery and will shutdown at 21V.Hence the need to tweak the low voltage shutdown circuit to keep them operating at 19V

author: davelectronic
author_rank: Frequent Contributor
timestamp: February 18, 2019, 08:24:41 pm
content: Thank you for your reply, and thanks for the link. Might attempt looking into a dropper, with the intention of adjusting the input voltage range.
Looking for DC coupled transconductance class D amplifier IC - Page 1
Forum section: electronics / projects

author: Molenaar
author_rank: Regular Contributor
timestamp: March 29, 2016, 09:46:31 am
content: To drive an inductive load (speaker-like, frequency range DC - ~20 kHz, preferably >4 watt) with a battery powered appliance I want to use a class D amplifier for efficiency reasons. There are so many amplifier chips available, while selection filters at farnell, digikey etc do not allow to filter on dc-coupling and transconductance (i.e. current feedback). Could anyone recommend an IC for this purpose?

author: danadak
author_rank: Super Contributor
timestamp: March 29, 2016, 02:10:53 pm
content: Pick a vendor and call up their FAE (Field Application Engineer), with dialogyou will have a productive set of recommendations, whats current, whats new,etc..Regards, Dana.
DC current hall effect sensors in CT form factor - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 11, 2024, 12:37:34 pm
content: I'm working on a new PV String Level Monitoring Device, Do you know or guess the Type of sensors they have used? See the attached picture and catalogue, do you know or recognize some Chinese manufacturer of the sensors?

author: TizianoHV
author_rank: Regular Contributor
timestamp: November 11, 2024, 05:46:01 pm
content: By searching "50A pcb hall" in google images i found:"SCK19D " ->https://www.directindustry.de/prod/shenzhen-socan-technologies-co-ltd/product-132598-1607978.html.On aliexpress, same research, i found:"QNHC3" ->https://it.aliexpress.com/item/1005007046909862.html"HCS-LSP 50A" ->https://it.aliexpress.com/item/4000048955032.html

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 12, 2024, 12:15:54 pm
content: Thanks for the findings Could you find datasheets for them too?, I think we should have something way cheaper, Because i asked the manufacture the price and they told me it's around 48$ for 24 input model,See some internal pictures

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 12, 2024, 12:56:45 pm
content: Some more picturesAny Idea what the core materials would be? or if we could find something very cheap like these ones

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 12, 2024, 01:08:34 pm
content: A closer look at the chip? what do you guess?

author: ajb
author_rank: Super Contributor
timestamp: November 12, 2024, 04:00:39 pm
content: That's a common package for hall effect sensors, unless someone recognizes the marking it will be hard to say more than that from the picture. Clearly it needs to be an analog output for measuring current, possibly bipolar if you need to measure current in both directions. From there you will need to do some design work based on the geometry and current range you need. I imagine calibration could be challenging, depending on how consistent and stable the individual sensors are and how accurate you need the measurements to be.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 13, 2024, 10:49:57 am
content: The real question is if we can find a Chinese manufacturer that could build these or similar single CT shape lied sensors for real cheap.
DC current rating N connector? - Page 1
Forum section: electronics / projects

author: nctnico
author_rank: Super Contributor
timestamp: January 20, 2015, 08:36:18 pm
content: Does anyone know the DC current rating of an N connector (HF connector)? I looked in several datasheets but the DC current rating isn't specified.

author: penfold
author_rank: Frequent Contributor
timestamp: January 20, 2015, 11:51:05 pm
content: I'm not sure you'll get a recommended figure published. The voltage limit (depending on manufacturer) is in the region of 1 kV for frequencies that there won't be too much heating in the dielectric... so in a 50 ohm system this will be a current of 20 A. So the answer will be somewhere in excess of that.

author: nctnico
author_rank: Super Contributor
timestamp: January 21, 2015, 12:32:20 pm
content: That is an interesting approach. The reason I'm asking is because I'm toying with the idea of making a power amplifier capable of outputing DC to around 10MHz at currents up to 10A. Banana leads or a BNC are not going to cut it. Frequency wise an N connector is sheer overkill but the large pin would definitely be able to carry some current.

author: tszaboo
author_rank: Super Contributor
timestamp: January 21, 2015, 01:29:33 pm
content: I dont think that the connector will be the limiting factor. TE Connctivity specifies milliohm DC resistance on their N connectors, so technically, they could carry 40-50A with some heat-up. Check the cables. The ones I've seen specify power rating for sub 1Ghz region, say 900W for this one:http://www.farnell.com/datasheets/1763482.pdfFor a 50 Ohm load, that would compute to 4 Amps only.

author: qwaarjet
author_rank: Regular Contributor
timestamp: January 21, 2015, 05:19:48 pm
content: I have a system that performs similar to what you are describing except I run RF with DC bias on it. I run a N connector and it handled 20A DC +500W of 13.5Mhz no problem.

author: nctnico
author_rank: Super Contributor
timestamp: January 21, 2015, 06:42:42 pm
content: OK. Thanks for confirming!
DC DC boost controller. BL8530. Trouble getting it work - Page 1
Forum section: electronics / projects

author: jorgemef
author_rank: Regular Contributor
timestamp: September 03, 2023, 08:08:13 pm
content: Hello,I purchased some BL8530-3.3v in aliexpress. I used one in a shaver booster and it seems to work but minimum consumption is 6mA while it should be in the order of micro ampers.I tryed to prototype in a board but it is not working well. With large capacitors in output if pulls hundred of mA. Only works with capacitors in output in the order of 100nF while the datasheet recomends 100uF.Am I doing something wrong? Do the size of the inductor matters? I tried 4.7uH, 47uH and 100uH. No big changes.Shaver had 100uH and 100uF of cap output. It was a very small inductor with 2.5mm diameter.Tried also SMD cap of 22uF on the output but no luck. Anything bigger then 330nF pulls hundred mA of current.BR,Jorge

author: jorgemef
author_rank: Regular Contributor
timestamp: September 03, 2023, 08:14:27 pm
content: Big inductor in the image is 100uH. Small inductor is 4.7uH. Adding wave output when COut is 100uF (consuption of 600mA unloaded)

author: Wolfram
author_rank: Frequent Contributor
timestamp: September 04, 2023, 12:19:59 am
content: Double check your circuit. It's hard to tell definitively from the photos, but it does look like you have the output cap (and the load) in the wrong position, across the boost diode instead of between the cathode and GND.

author: jorgemef
author_rank: Regular Contributor
timestamp: September 04, 2023, 06:46:45 am
content: Quote from: Wolfram on September 04, 2023, 12:19:59 amIt is OK. There is a cut separating the GND layer from the anode. The GND goes from the back. This is a dual layer board.

author: jorgemef
author_rank: Regular Contributor
timestamp: September 04, 2023, 08:01:42 pm
content: Well, it seems it works well but the datasheet is not correct for the RM version. Pin 3 is Vout and Pin 2 is SWitch. Pin 1 is ground.I revised my shaver as well and realised that the layout is correct in the shaver, the 6mA where due to me reversing the input cap polarity. The markings where very thin and while soldering/desoldering some time in the past I left it in reverse. Now the shaver consumes 250-300uA while not in use.So now all is well and I only destroyed 2 chips to find out the pinout is wrong in the datasheet I have.
DC-DC boost regulator for a negative supply - Page 1
Forum section: electronics / projects

author: Synthtech
author_rank: Regular Contributor
timestamp: August 04, 2020, 11:05:20 am
content: I have been looking at the plethora of DC to DC buck and boost switching regulators that can be found on EBay as I have a need for a dual rail solution to provide me with +/- 20V output from a +/- 12V dual rail DC source at around 1A for the positive rail and 300mA for the negative rail. There doesn’t seem to be anything designed to act as a boost in the negative polarity and I am wondering why? Would anyone have any suggestions as to where I could look for an off-the shelf solution? I don’t mind designing linear supplies but I don’t have enough experience with switchers to design something from scratch. Am I barking up the wrong tree trying to use boost converters for this application?

author: thm_w
author_rank: Super Contributor
timestamp: August 04, 2020, 10:20:23 pm
content: Inverting boost regulators exist, so it could all be run off of a single +12V rail. +/- boost modules are available as well, that have one boost and one boost inverter on there.
DC-DC converter connection question - Page 1
Forum section: electronics / projects

author: xrunner
author_rank: Super Contributor
timestamp: August 10, 2016, 03:39:03 pm
content: Maybe this is a dumb question but ...I want to power a DC-DC converter from a +13.8V supply. The output of it will be adjusted to about 7V to 8V, but - the output will be used as anegativevoltage to bias a circuit in a radio, the radio being powered from the same +13.8V supply. So, to have a negative V to the bias circuit, I'll have to ground thepositiveoutput of the DC-DC converter, which will obviously then be connected to the inputnegativesupply to the converter, again the same supply the radio is using. I am assuming that won't damage theconverter- am I correct?

author: jeroen79
author_rank: Frequent Contributor
timestamp: August 10, 2016, 05:38:48 pm
content: It depends. Will you be buying or DIYing?If you are buying an existing design you have to check how it is designed.Some will have a floating output, others will have one of the inputs tied to one of the outputs. (often a common negative)If you are building something yourself then you make the outputs floating or tie positive out to negative in.

author: ovnr
author_rank: Frequent Contributor
timestamp: August 10, 2016, 05:56:25 pm
content: A simple buck converter will die. You need an inverting converter which already gives a negative output voltage by default, or an isolated DC/DC converter.It sounds like you want a ready-made brick, in which casehereare some negative-output converters, andhereare some isolated converters where you can safely ground the positive output.

author: xrunner
author_rank: Super Contributor
timestamp: August 10, 2016, 06:12:14 pm
content: Good info thanks guys. Exactly what I needed to know.

author: Someone
author_rank: Super Contributor
timestamp: August 11, 2016, 05:27:54 am
content: Quote from: xrunner on August 10, 2016, 03:39:03 pmYou can use an inverting or isolated output power supply which will directly create the negative supply, or use a buck regulator with some trickery by connecting its output to the GND as you describe:http://www.vishay.com/docs/76946/creatingnegativeoutputvoltage.pdfhttp://www.ti.com/lit/an/snva022e/snva022e.pdf
dc-dc converter help a noob   AMS1117 and other stepdown ... - Page 1
Forum section: electronics / projects

author: voidptr
author_rank: Contributor
timestamp: January 09, 2017, 03:51:35 am
content: hello,here few questions for people used to use dcdc,I used in the past dcdc stepdown like the bottom module on the picture without problem, it can produce 5V with 1A and be not even too warm.So for another thing I decide to buy the top module base on AMS1117 output 5V, I read the spec and it should be good from max around 800mA,this is fine I need 200mA, the problem tho is if I try to draw more than 90mA the module get really hot and the chip turn off (temp protection).Well Im puzzle, do I got really crappy parts or those AMS1117 are junk I thought I would I have be able to get 250mA without heatsink...What do you think ?any good suggestions I need to power a small 5 volt arduino clone from 12v ...

author: DaveHardy
author_rank: Regular Contributor
timestamp: January 09, 2017, 04:03:04 am
content: You probably blew it up. DC to DC converters are quite easy to damage. You need a stable source and load.

author: voidptr
author_rank: Contributor
timestamp: January 09, 2017, 04:27:01 am
content: I tried with the same results from 2 different "new' one.source is converted PC power supply, kind of stable 12Vlaod a big fat 25 watt ceramic resistor ....humm I thought AMS1117 was a step down , is it more like a linear regulator so maybe it doesn't like to convert 12v to 5V without heat sink ...Quote from: DaveHardy on January 09, 2017, 04:03:04 am

author: sleemanj
author_rank: Super Contributor
timestamp: January 09, 2017, 05:23:36 am
content: The AMS1117 is a LINEAR regulator, not a DC-DC converter.MASSIVE difference.

author: DBecker
author_rank: Frequent Contributor
timestamp: January 09, 2017, 05:53:24 am
content: Quote from: sleemanj on January 09, 2017, 05:23:36 amLinear regulators are often sold on eBay as "DC-DC converters".In a broad sense they are, but not by the commonly accepted meaning of the phrase.

author: voidptr
author_rank: Contributor
timestamp: January 09, 2017, 07:01:37 am
content: Ya I guess Im a noobIt was in the description sold has a dc-dc ...and @sleemanj I also found your datasheet about the Chinese version who max out at 10V.(I read 12V and Max 15 on the none Chinese one)so I will have to design this differently, Im gonna put a step down in frontsomething like this who will give me 5Vhttp://www.ebay.com/itm/DC-DC-9V-12V-24V-to-5V-3A-Step-Down-Power-Module-Vehicle-Charger-Module-/142053321439?hash=item211309aadf:g:08cAAOSw5cNYbv3Xwith noise like 300mV, (I got an output variable here that I just measure)Question tho is that stable enough to be seen like USB power for my arduino clone ?or do I need filtering ?or a step down variable with output like 7V plus ams1117 - 5V filtering ?...Quote from: DBecker on January 09, 2017, 05:53:24 am
DC DC converter with TPS562242  - Page 1
Forum section: electronics / projects

author: drewle
author_rank: Newbie
timestamp: August 15, 2024, 07:48:24 pm
content: Hello,I just came across this: TPS562242 (link see below)This is a DC DC converter for a very low price and it meets my expectation in terms of input voltage and current.The problem I see is that the switching frequency is very high: 1400 kHz!According to the data sheet, an inductance of 3.3 uH is recommended for 5V output.When I search for an inductor, I only find iron-based ones. If I have informed myself correctly, iron is not suitable for such high frequencies.The data sheet for “L-1616FPS 3.3µ” (link see below) states: flL (kHz) 100/1.0V. (What is that supposed to tell me?)Which inductance can I use here?Is the “L-1616FPS 3.3µ” suitable?Thank you in advance,DrewleDatasheet ofTPS562242:https://www.ti.com/product/de-de/TPS562242/part-details/TPS562242DRLR?bm-verify=AAQAAAAJ_____4xv3lV9imjWuVzsP-Zy0CthW4zo82EXVLia5XxSWmbYISHYmdb9Ac5d4aZopyfrMjTOQTzoUstKuq2U6w7H-VAVDGHJ8E_rlPpA53ftG9S1HSY4QxfqZYId-eAd754lT-rT2eWfZpzVnCxnbdix5FcJHm133N-wLnUvDnuFFga_t1UQLHxeXIeDgwR-hbQqABX3Sl0CB2tWRgyh3-8znw1Ofy_iJKv-rjVh_AA2NBo21JGGV3n6yY0hhtvjq6WC4GHi-ast0i6CRsY4OFODrGcfZxsyfIuics1RvJFWFab73vPfJ5dFQl6_bI8OCnrrsc6nGkSiiv80trk5k4Z-bslNndulWVb6DSQL-1616FPS 3.3µ:https://cdn-reichelt.de/documents/datenblatt/B400/DS_1616FPS.pdf

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 15, 2024, 08:16:07 pm
content: Alloy powder composite cores are pretty good these days; they have improved greatly over plain powdered-iron cores of earlier times. That, and losses are generally more acceptable in small converters -- maybe the Q factor is only 20 or so, but 1/20 of the reactive (switched) power might be 100s mW.As a result, there isn't a whole lot of pressure around optimizing inductors for small converters like this. If you need really low losses, you can go down that route and try a few. As you may've noticed, Q factor isn't often measured, or rated at the exact frequency you'll be using, so your only recourse is to buy a lot and try them all.The main thing to beware of is the layout; switching edges are regularly near or below 10ns, and when they say the loop between VIN (or VOUT if boost), GND, and SW and diode when applicable (non-synchronous converters) must be kept small and use low-ESL capacitors (usually ceramic)... they mean it. Start with the recommended layout, position components as close as you're comfortable with soldering, use wide traces and pours on power connections where possible.Tim
DC-DC Power Supply Design? - Page 1
Forum section: electronics / projects

author: ibnul7
author_rank: Newbie
timestamp: August 18, 2013, 07:12:24 am
content: Hey guysThis is my first post, so here goes...I am looking for descent circuit designs for a DC-DC power supply that uses something like a 12-32volt input with variable output. However, it would be nice if it was designed without transformers or ICs, such as the LM317 linear voltage regulator. It is just for a summer project and it may serve as a bench power supply.Thanks guys

author: Skimask
author_rank: Super Contributor
timestamp: August 18, 2013, 05:50:32 pm
content: Google must be down again.

author: eurofox
author_rank: Unknown
timestamp: August 18, 2013, 06:07:56 pm
content: Quote from: ibnul7 on August 18, 2013, 07:12:24 amYou cannot build it for the price you can buy it on ebay, just check it, depending what you are looking for, start at a less than 1 $ or €http://www.benl.ebay.be/itm/DC-Converter-150W-10-32V-to-12-35V-Boost-Step-up-Module-Adjustable-Power-Supply-/161087964252?pt=LH_DefaultDomain_0&hash=item258197445c&_uhb=1Eurofox
dc-dc power supply  - Page 1
Forum section: electronics / projects

author: classified
author_rank: Contributor
timestamp: January 11, 2024, 06:09:16 pm
content: hi all i was wondering how to builda dc-dc boost converter for some led stripsi have seen some around that do what i want but they are all digital controle i want good old potentiomiter controlethe input will be from 48v dc battery and i need a minimum of 115.3v dc out at a max current of 10Ai would like the voltage and current to be continuasuly adjustable

author: coromonadalix
author_rank: Super Contributor
timestamp: January 11, 2024, 06:44:14 pm
content: and the current ?

author: classified
author_rank: Contributor
timestamp: January 11, 2024, 07:01:51 pm
content: sorry dident notice i forgot that parta max of 10A but as stated i would like it to be continusly variable

author: Terry Bites
author_rank: Super Contributor
timestamp: January 12, 2024, 10:28:49 am
content: There are plenty of voltage controlled driver ics out there. Get onto Mouser.com and put in your specs.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: January 12, 2024, 03:00:18 pm
content: Your total power is over 1KW. A little bit of high threshold, it should not be the first DC/DC converter you build. Or the specs are off.

author: Marco
author_rank: Super Contributor
timestamp: January 12, 2024, 03:33:49 pm
content: Why do you want 110V led strip? Even if it's sealed I wouldn't trust it.

author: Andy Chee
author_rank: Super Contributor
timestamp: January 12, 2024, 03:47:38 pm
content: Quote from: classified on January 11, 2024, 06:09:16 pmHow many LEDs are you controlling??? It might be easier to construct a continuously adjustable variable "knob" interface for the existing digital controller.(and before the pedants jump in, yes, I know Clark Griswold probably wasn't using LEDs!)

author: coromonadalix
author_rank: Super Contributor
timestamp: January 14, 2024, 03:51:35 am
content: you miss the current conversion to boost up 48vdc into 115.3 volts at 10 amp = 1150 watts of needed powerbut from 48 to 115volts, you have a ratio of 2.39, it means you'll consume at leats 24 amps to do the conversionun-realistic and tons of lossesyou have 24vdc rgb led strips, but going higher than 48 volts is considered dangerous, and if your project blows up or create fire, you're toastedits not a battery, it's many batteries or a huge one and wont last longjust buy the right stuff and dont play godhttps://www.superlightingled.com/high-voltage-rgb-led-strips-c-3_35.htmlhttps://www.superlightingled.com/high-voltage-led-dimmer-controllers-c-7_50.html