hybridfree/eevblog-posts huggingface dataset:
Can amplifier output impedance or highpass cutoff change by loading? - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: November 29, 2018, 09:30:09 am
content: I have two questions,can capacitor coupled amplifier -3db point,I mean how high does the high pass filter cut off,change depending on impedance of the load? And same question,just this time if the amplifier output impedance can change depending on impedance of load.I dont see how any of this would change,but I am not so sure anymore when its highly complex circuit with bunch of feedback or feedforward loops.I ask becose I read some specifications that gave the capacitor coupled amplifier lowerfrequency cut off with added number of impedance of load that was tested with,that made me think,what if this cut off change depending on impedance of load.

author: The Soulman
author_rank: Super Contributor
timestamp: November 29, 2018, 12:47:49 pm
content: The first question is simple, substitute load for R and calculate for R-C filter.If load impedance (R) changes with frequency or temperature or..... you havea lot more points to calculate.Second question, it shouldn't, but there are way to meany variables here to give a use full answer.Do you have specific application and schematic?

author: fonograph
author_rank: Frequent Contributor
timestamp: November 29, 2018, 06:46:13 pm
content: I dont have anything specific.
Can an Earth Ground Clamp Meter be used to measure normal AC current draw?  - Page 1
Forum section: electronics / beginners

author: tigerstyle
author_rank: Contributor
timestamp: May 29, 2018, 12:22:18 am
content: Question as title reallyOnly have a Megger Earth Clamp Meter 0-35Amp capacity, can it be sued on any single phase AC circuit up to 35Amps?I believe so but wanted to check, from a quick google it is only the resistance side of the emter that is 'special' the current side is the same as any other clamp meter?Potential Meter at hand:Thanks!
Can anybody identify this SMD component? - Page 1
Forum section: electronics / beginners

author: Biggerruss
author_rank: Newbie
timestamp: December 03, 2023, 09:43:07 am
content: Hello, can anyone assist with the identification of the SMD component marked with "GF" in the picture?The component is on a 12v DC remote relay receiver board.

author: u666sa
author_rank: Frequent Contributor
timestamp: December 03, 2023, 11:05:52 am
content: If you measure it, is it resistance or diode?

author: Neilm
author_rank: Super Contributor
timestamp: December 03, 2023, 11:17:13 am
content: Looking at it, my first thought is a SMD fuse / polyswitch. Little fuse do them - it looks like a 1.5 A polyswitch part number 1206L075/16

author: MarkT
author_rank: Frequent Contributor
timestamp: December 03, 2023, 11:21:53 am
content: Possibly 10V zener, I found several devices with GF, MAZD100 being one, with that marking.

author: tooki
author_rank: Super Contributor
timestamp: December 03, 2023, 03:41:55 pm
content: Quote from: MarkT on December 03, 2023, 11:21:53 amObviously not that, since the MAZD100 is in a different package (namely, a diode package). Diodes don’t come as chip components with no cathode marking.

author: liaifat85
author_rank: Regular Contributor
timestamp: December 03, 2023, 05:41:02 pm
content: To me, it looks like an SMD resistor.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: December 03, 2023, 06:24:01 pm
content: Most probably an SMD fuse, by the letter F. And G used to indicate 0.75A rating.

author: Biggerruss
author_rank: Newbie
timestamp: December 05, 2023, 09:10:01 am
content: Thank you all for your input, it was very helpful!
Can anybody recognize this connector? - Page 1
Forum section: electronics / beginners

author: saronno
author_rank: Regular Contributor
timestamp: November 29, 2017, 11:09:44 pm
content: Some time ago I bought on ebay a little job lot ... amid other things,there are some cables I can't recognize.They are like ..unknown connector (UC)UC <-> serialUC <-> parallelUC <-> printer portUC <-> USBAnyone?They look like thunderbolt but they are not (thunderbolt has more pin and the connector is smaller).

author: Cerebus
author_rank: Super Contributor
timestamp: November 30, 2017, 12:19:29 am
content: Something in the picture to give scale would help (like a ruler/measure*) and a couple of views from other angles might help.*Not coins or other things that aren't internationally universal, I have no idea what size a US penny is, or a 10 Yen piece, just as I'm sure the people who put those into pictures for scale haven't a clue how big a UK 5p piece or a threepenny bit is.

author: saronno
author_rank: Regular Contributor
timestamp: November 30, 2017, 02:43:23 am
content: the shield of the connector is 9,5 mm x 4,3 mm
Can anyone assist in identifying a SMD diode? - Page 1
Forum section: electronics / beginners

author: poor_red_neck
author_rank: Newbie
timestamp: April 23, 2014, 03:33:35 am
content: Hello all,Novice electronics diagnostician... trying to repair a body control module from my vehicle. Long story short I goofed up and fed battery+ (12V) into the ground side switch of the BCM.The diode reads open in both directions, so looks like this is my culprit after tracing the PCB traces. Here's what I know:The markings on the diode are:A4V2G (or V26 can't tell)In the attached picture, the diode in question is D22 (same as D21-D26)Can't find my micrometer so don't have a measurement, but approximately 2.5-2.75mm long by 1.0mm wide.This part of the circuit drives an automotive relay, 95mA draw on the relay. It its ground side switched by a N channel MOSFET. The drain of the MOSFET goes to the anode. The cathode goes through a 5.1kohm resitor, then to a 47uf cap, then to GND. The relay's (-) side (what is being switched) is also tied into the cathode of the diode.I hope that information helps. Any other information I might be able to provide please let me know.THANK YOU ahead of time for your assistance,Jon, AKA poor_red_neck

author: poor_red_neck
author_rank: Newbie
timestamp: April 23, 2014, 03:34:10 am
content: Here is the best pic I could take:

author: Kremmen
author_rank: Super Contributor
timestamp: April 23, 2014, 05:13:17 am
content: Any ordinary diode will work in that position as long as you can solder it in place. There are no stringent requirements on a freewheeling diode, it only provides a path for the relay coil current to circulate when the switch turns off.

author: marabut
author_rank: Contributor
timestamp: April 23, 2014, 08:39:31 am
content: As Kremmen wrote - any small package diode will work. As a reference you can look at online SMD code book:http://www.marsport.org.uk/smd/mainframe.htmProbably it's a 1N4150W, anyway.
can anyone change a bxl library file to an Eagle library file? - Page 1
Forum section: electronics / beginners

author: krappleby
author_rank: Contributor
timestamp: January 08, 2017, 09:44:04 pm
content: Hey guys,http://www.nxp.com/assets/downloads/data/en/symbols-footprints/MK66FX1M0VMD18.bxlthe above url is to a BXL file from the manufacturer, who suggests using ultra library to transfer this to a Library file for Eagle, unfortuantely i dont have the software, and the free version does not support exporting..is someone able to change this file into an eagle library file for me please..and the chip is not already available on eagle..cheerskeith

author: ebclr
author_rank: Super Contributor
timestamp: January 09, 2017, 04:49:39 am
content: Ultra Librarian LiteExport to 1 CAD/CAE Tool (footprints only) yesFor all users who are currently running the Lite version of the Ultra Librarian: We have gotten feedback from some users that they were unable to save with their software. This bug has been fixed. If you are currently running Lite and are experiencing this problem, please download the newest version of the software in order to fix the issue. You can find this at:http://www.accelerated-designs.com/beta/ULADI_6_4_23.exeThank you for your patience!
Can anyone confirm if this ZVS driver is worth purchasing ? - Page 1
Forum section: electronics / beginners

author: zeal422
author_rank: Contributor
timestamp: June 17, 2023, 07:00:06 pm
content: Hey!I want to know if this ZVS is worth purchasing for experiments. For example driving a flyback transformer.https://www.aliexpress.com/item/32847826581.html?pdp_npi=2%40dis%21RON%21RON20.67%21RON19.65%21%21%21%21%21%402103246c16870282947508380e34a8%2165269268827%21btf&_t=pvid:fd4b3931-06fd-40e7-ac41-508a53629221&afTraceInfo=32847826581__pc__pcBridgePPC__xxxxxx__1687028295&spm=a2g0o.ppclist.product.mainProductThanks!

author: james_s
author_rank: Super Contributor
timestamp: June 17, 2023, 07:53:02 pm
content: I bought a very similar one a few years ago to play with, it blew up the first time I tried it. On the other hand I built several of them myself based on circuits I found online and those work perfectly.

author: zeal422
author_rank: Contributor
timestamp: June 18, 2023, 05:34:07 am
content: May I ask how did you manage to blow it up ? I'm guessing you blew the mosfets ?Did you power it correctly ? And did you have a load attached ?

author: james_s
author_rank: Super Contributor
timestamp: June 19, 2023, 05:22:19 pm
content: I powered it from my bench PSU with a modified flyback transformer connected and it failed instantly, I went back to my self-built board and that worked fine. I didn't bother to diagnose it because it was so cheap but I suspect counterfeit mosfets failed.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 19, 2023, 06:49:54 pm
content: A common way for these very simple circuits to destroy themselves is when there is not enough input voltage.In such a case one of the MOS fet's start operating in their linear region and this heats it up very quickly and then destroys it.Also, when you use a bench top power supply, it can deliver a limited amount of current, and it's voltage sags when you go over that, and this again results in the MOSfet's not fully opening and getting heated beyond their capabilities. A 3A power supply is usually not enough for these things.At any time the input voltage sags below around 8V, you risk blowing up the FET's.The best way to prevent that is to add comparators and real gate drivers for the FET's, and then preferably from a separate low power powersupply (12V 100mA should be enough). If you separate the gate drive from the power circuit in this way, the circuit is much more robust and much better fit for experiments.Also note that with Ali, you just need the base URL. You can omit all the tracking info and other garbage they add to the link. The link below works just fine:https://www.aliexpress.com/item/32847826581.html

author: james_s
author_rank: Super Contributor
timestamp: June 19, 2023, 07:01:19 pm
content: Well the fact remains that the one I built from scratch never failed under the same conditions the one I bought blew up. But it's cheap, if you want to play with it then buy one and try it out, maybe my case was a fluke and yours will work fine. I only responded based on my own limited experience.
Can anyone cross reference these zeners please? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: July 05, 2013, 08:22:41 pm
content: Circuit is for a small (missing) board for a huge Farnell 60 volt, 50 Amp linear power supply. I have a smaller version that is complete and working, but the schematics are a bit different, although somewhat similar. I have got together most of the bits to build a new board, and will have it remote and not plugged into an edge connector strip, to keep board manufacture simple. There should be a small schematic attached, but I have the full size one athttp://www.gatesgarth.com/supplies.jpgThe diodes in question are the three zeners. I can't find any data on these numbers. Maybe someone with a deeper understanding of the circuit can suggest equivalents? Thanks!

author: Paul Price
author_rank: Super Contributor
timestamp: July 05, 2013, 08:34:06 pm
content: The part numbers give away their voltage identity, but the M56, but from the more complete schematic it is a 5.6V zener rather than a 56V zener the designation implies, but the two on the right are surely about 5W and 15V and need to be matched.

author: Chris Wilson
author_rank: Super Contributor
timestamp: July 05, 2013, 08:38:17 pm
content: Thanks Paul, is that enough info to source suitable substitutes? How can you tell the IZM15 is a 1 watt device? It may be a 1ZM15, the schematic is not that clear. Any way to ascertain the wattage of the 56 volt device? Or should I just choose something beefy? Cheers.

author: Paul Price
author_rank: Super Contributor
timestamp: July 05, 2013, 10:03:58 pm
content: Now that I see the rest of the schematic, the MR56 is actually a 5.6V zener, 1W and setts the bias for the two 15V in series zeners.For the 5.6V zener 1W would be fine, 10% tolerance.The 15V zeners should also be at least 5% precise voltage tolerance and they may have to be closely matched in voltage at 150mA of test current from a collection of them. Since the 15V zeners are also part of a crowbar protection circuit, this is another reason the 15V voltages here might need to be precisely set. The 15V zeners may have to be 5 Watt zeners mounted on a heatsink. Be advised, the 82 ohm at the collectors of the 2N3053's, needs to handle up 3 watts of power under overload conditions,and the pair of 39 ohms at the emitters (at least 1W) and the 2N3053s will require a heatsink.

author: Chris Wilson
author_rank: Super Contributor
timestamp: July 05, 2013, 10:28:48 pm
content: That's great Paul, thanks again. If you want to see the rest it's athttp://www.gatesgarth.com/farnell/farnell.htmlThe scans aren't great, but should be readable. Have a good weekend

author: Paul Price
author_rank: Super Contributor
timestamp: July 05, 2013, 10:43:48 pm
content: I looked at the pictures, rough as they are, and I can see there are still some lights missing from this Christmas tree.
Can anyone explain to me how this 1 chip circuit work? - Page 1
Forum section: electronics / beginners

author: Azhar
author_rank: Regular Contributor
timestamp: November 15, 2013, 09:13:06 am
content: This is a variable frequency function generator, with sinusoidal output using the LM324 Op-Amp!can anyone explain to me how the circuit work? how do we get the sinusoidal output? how the wave get generated?thank you in advance

author: Kremmen
author_rank: Super Contributor
timestamp: November 15, 2013, 12:29:12 pm
content: This is a double integrator where the op amp outputs get attracted to a quadrature phase with each other. The integrals and derivatives of sines and cosines are other sines and cosines, possibly with sign change. So that is what happens here - the integrators naturally converge into a sine/cosine relation i.e. quadrature.The trimmer is to set amplitude and/or frequency but otherwise i have not checked the circuit in any way. I don't know if it will be stable or whether it will start oscillating. When it does, you don't need any initial kick, the system will start naturally.
Can anyone help me choose an amplifier? - Page 1
Forum section: electronics / beginners

author: Yurii
author_rank: Newbie
timestamp: May 28, 2023, 12:21:58 pm
content: Hello everyone, can anyone help me find an amplifier for a bridge bridge? As far as I understand, the output should have the following data frequency of generated oscillations f0 1000 Hz- relative frequency instability f 2%;- load voltage U (U output) 10V- load resistance RH 100 Ohm- harmonic coefficient Kg 5%; temperaturetemperature Tns -10/ +60I will be very grateful

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 28, 2023, 02:00:06 pm
content: 10 V (DC or RMS?) into 100 R doesn't seem as hard work. Even some opamps could do in parallel, LM3886/TDA7294 too (You haven't stated required input/output DC bias).Why it has to be a bridge? Do you mean it's load is some bridge?And, what do you mean by "frequency instability"?

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 28, 2023, 07:25:04 pm
content: Nolo comprenday voo

author: radiolistener
author_rank: Super Contributor
timestamp: May 28, 2023, 07:35:02 pm
content: Yuriiyou need to do it yourself, if you don't then your study in university will be a waste of time and money

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 28, 2023, 09:46:51 pm
content: Quote from: BILLPOD on May 28, 2023, 07:25:04 pmThat's a university home task.

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 28, 2023, 09:54:23 pm
content: Quote from: Yurii on May 28, 2023, 03:10:37 pmSorry man. It's not really interesting to do university homework (that's too boring). I had it enough. You better ask any of your classmates, I'm sure somebody will definitely help you. I don't want to investigate why LT1013 in your calculations is unacceptable for your oscillator/amplifier. In real life that's quite a decent opamp, it'll definitely work either as an oscillator or as an amplifier at 1 kHz (that is pretty low).

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 28, 2023, 09:55:29 pm
content: Quote from: Yurii on May 28, 2023, 03:10:37 pmHow do we get what is R2 and R4?

author: Simon
author_rank: Unknown
timestamp: May 29, 2023, 09:21:14 am
content: Don't bring us your homework or design requests. You are doing the design, we are here to help and guide you. You have just listed some parameters, any supplier has this thing called a parametric search. See the similarity in the words parameter and parametric? the clue to your solution is there.
Can anyone help? - Page 1
Forum section: electronics / beginners

author: Usat1987
author_rank: Newbie
timestamp: October 22, 2024, 09:03:37 am
content: Hello AllI just purchased the Signet stb3 demo oscilloscope training board. The reason I purchased it was to learn more about how to use the oscilloscope. Unfortunately, I need more hope than just a manual with pictures. I also looked on YouTube for training videos.I need step by step help or at least a better training manual that goes into more detail and pictures of set-ups. Can anyone help?

author: BILLPOD
author_rank: Frequent Contributor
timestamp: October 22, 2024, 12:24:58 pm
content: Good Morning Usat1987, Welcome to the forum. Near the top of this page is a thread titled:Oscilloscope training class (long). Lots of good information there and a good place to start. Also TONS of information on the internet if you just Google the word Oscilloscope, including lots of instructional videos. And since you don't have an actual scope yet, there are many, many threads here on the forum, about choosing one when you are ready. Have fun,and enjoy the journey.

author: Simon
author_rank: Unknown
timestamp: October 22, 2024, 06:01:33 pm
content: Is it that time of year again?https://www.eevblog.com/forum/beginners/signet-oscilloscope-stb3-demo-board/msg5078530/#msg5078530
Can anyone ID these connectors? - Page 1
Forum section: electronics / beginners

author: cvriv
author_rank: Frequent Contributor
timestamp: September 26, 2022, 10:04:04 pm
content: These connectors on a 24V laser driver board used by XTool with their 20W laser. I believe the pitch is 2mm. I tried searching a pic of them and still faolrd to find the exact type. Theres so many.Thanks.

author: Infraviolet
author_rank: Super Contributor
timestamp: September 26, 2022, 10:47:34 pm
content: Might be one of the types molex does? Microclasp with a 2mm pitch? JST also does some 2mm pitch types.If you can be sure of the 2mm pitch, double check with good calipers, then searching RS/farnell/digikey for 2mm pitch connectors and seeing if anything similar looking shows up might be a starting point.

author: cvriv
author_rank: Frequent Contributor
timestamp: September 27, 2022, 04:42:37 am
content: Yea im sure of the 2mm pitch. Ill try digikey and see if i can find something exact. I felt like ibwas getting close with the pic search but there are so many different types.

author: AnasMalas
author_rank: Regular Contributor
timestamp: September 27, 2022, 05:37:40 am
content: Take a photo from the back, and of the plug, sometimes you find the manufacturer's logo there

author: tooki
author_rank: Super Contributor
timestamp: September 27, 2022, 11:24:19 am
content: The one on the right looks like the HY connectors from China. (Search for HY2.0 on AliExpress.)The one on the left looks like a Mini-SPOX, but that’s a 2.5mm pitch connector.
Can anyone please explain how RT6575C/D works? - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: January 18, 2024, 01:45:16 pm
content: I would like to understand how RT6575C/D Dual-Channel Synchronous DC/DC Step-Down Controllerwith 5V/3.3V LDOs works. I browsed the datasheet yet still lost. The datasheet is enclosed.Can anyone please explain (in a simple way) the function? Why must be there Mosfets and how they work?If LDO3 and LDO5 are 3.3V and 5 volts ,respectively, but FB1 and FB2 are 0V. Where should I search for an error?I already replaced RT6575C/D also Mosfets, yet no success.That IC used in a laptop - I enclosed a schematicThanks a lot for help

author: jwet
author_rank: Frequent Contributor
timestamp: January 18, 2024, 02:58:38 pm
content: The main IC isn't an LDO, its a dual synchronous buck converter. (it does have a 3.3 and 5v linear regulator internally but these are not the main function- they are for making a low current supply for RAM/RTC backup, etc.) The top of each mosfet is used to control the current into the output inductor and the lower switch is used to keep current flowing when the upper FET is off. This lower FET is called a synchronous rectifier, its functioning as an efficient (zero drop) diode. In less efficiency minded circuits, a diode is used in this position. The discrete charge pump output (CPO) driven by the CLK output is an auxiliary 14v supply used to provide bias for high side load switches in the end system- its optional and not required for operation.The MAXIM MAX786 was one of the first of these IC's and has a great data sheet that might explain things better. These types of supplies have been used in notebooks since the early 90's and though refined trace their roots to the MAX786. If you've replaced the FETs and the Controller, I might look at output capacitors. These need to be very low ESR to work in this circuit- see data sheet. Probe voltages and make sure there are no internal fuses or polyswitches, etc.
Can anyone tell me why is this stage causing distortion? - Page 1
Forum section: electronics / beginners

author: slow_rider
author_rank: Regular Contributor
timestamp: October 07, 2015, 10:11:23 am
content: So I have this circuit on a board and when I set the gain of the 2nd stage to anything but ~1 I start getting distortion. I've hooked up a signal generator with a 0.4Vppk 1KHz signal and could see it goes in clean and is still clean before entering the 2nd stage, as I increase the value of the feedback the resistor the Sine wave starts looking like it has a bunch of added harmonics (I can take pictures from my scope if needed). Why is that? The headroom on the supplies is almost 18V and the max. amplitude amplified by a factor of 3 would give a signal very small compared to that. On the simulation everything works as should.Any thoughts?* Voltage rails where checked.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 07, 2015, 10:22:03 am
content: There's no resistor to U1A +in.Resistor values are also rather large for a 5532. A JFET amp like TL072, LF412, etc. would be better suited here.Tim

author: mij59
author_rank: Frequent Contributor
timestamp: October 07, 2015, 10:22:24 am
content: Pin 3 of the U1A is floating for dc, no bias current can flow, connect a resistor between pin 3 and gnd.

author: slow_rider
author_rank: Regular Contributor
timestamp: October 07, 2015, 10:41:00 am
content: That is true! Thanks!I'll see if I have a 1M resistor somewhere...

author: rjeberhardt
author_rank: Regular Contributor
timestamp: October 07, 2015, 01:31:53 pm
content: Your 400 mH inductor combined with the two 0.1 uF capacitors is giving you a series resonant circuit, resonant at about 1 kHz. So, when the two variable resistors are at or near zero you will get a much magnified signal at the input of the second OPamp and overload it.Russell.
Can anyone translate these Chinese jumper settings on a freq counter display - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: April 21, 2012, 12:49:23 pm
content: It's the 4 jumpers to the left of the "1045".I think this is an older or newer version of this displayhttp://www.pcstore.com.tw/dashop/M10079850.htmas the part numbers are the same.Google translate doesn't reveal much.Mike

author: aaronwan
author_rank: Newbie
timestamp: April 21, 2012, 03:26:40 pm
content: Frequency counterTachometer(low speed)0.1 ratioHope it helps!Aaron

author: e100
author_rank: Frequent Contributor
timestamp: April 22, 2012, 02:20:37 am
content: Thanks for that.It now makes sense as it looks mine only has the tachometer option enabled.Mike
Can battery simultaneously provide positive and negative voltage? - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: October 17, 2017, 10:03:00 am
content: This is probably stupid question,have patience I am noob.Lets say I have single 3V battery,and I need to power two devices at the same time.One device needs +3V and other -3V,can I power them both at same time from single battery?

author: 8086
author_rank: Super Contributor
timestamp: October 17, 2017, 10:05:08 am
content: Depends, do they need a common ground? If not, you can just connect one backwards.

author: fonograph
author_rank: Frequent Contributor
timestamp: October 17, 2017, 10:07:22 am
content: Quote from: 8086 on October 17, 2017, 10:05:08 amCommon ground means that the current flows in same direction in both devices,so after it exit from them it goes to the similiar place on battery,like a negative side for example? I mean common ground is when they both share same return path for current in the electronic circuit?

author: Brumby
author_rank: Unknown
timestamp: October 17, 2017, 11:24:57 am
content: First mistake is to think there is any difference between what you describe as "positive voltage" and "negative voltage".There is only voltage.The concept of positive or negative relates to the potential of one point in relation to areference point.If you take the negative terminal of a battery as your reference point, then the voltage you measure at the positive terminal will be positive. Likewise, if you take the positive terminal of a battery as your reference point, then the voltage you measure at the negative terminal will be negative.Same battery. Same voltage. It's how you measure it that makes the difference.

author: Brumby
author_rank: Unknown
timestamp: October 17, 2017, 11:30:08 am
content: These 3 circuits are identical. The voltage measurements only differ in the point which was used as the reference point.The reference point, by the way, is 0V - by definition.

author: danadak
author_rank: Super Contributor
timestamp: October 17, 2017, 11:30:30 am
content: Yes, you can use a single battery, to power positive (or negative) rail,and a charge pump or isolated switcher to power the opposite rail runningoff the same battery.Regards, Dana.

author: Brumby
author_rank: Unknown
timestamp: October 17, 2017, 11:41:10 am
content: Quote from: fonograph on October 17, 2017, 10:03:00 amIf the two circuits operatecompletelyindependentlyfrom each other - then yes.If there is any connection between the two or with other circuits, then the specific topology would need to be shown in order to answer this.

author: Zero999
author_rank: Super Contributor
timestamp: October 17, 2017, 01:13:46 pm
content: Quote from: fonograph on October 17, 2017, 10:03:00 amWhat are the two devices in question? Do you have schematics for them?

author: peter-h
author_rank: Super Contributor
timestamp: October 17, 2017, 01:14:10 pm
content: If you need to generate the positive and negative rails at the same time, the simplest way is an inverter like an ICL7660.
can bus timing - Page 1
Forum section: electronics / beginners

author: electrolust
author_rank: Unknown
timestamp: September 24, 2015, 09:20:26 pm
content: I was wondering what scope bandwidth (probe and scope) are reasonable for CAN FD?My spotty understanding is that 1Mbps CAN has a 1uS bit time. So that means a frequency of 1MHz, yes? So that calls for a scope frequency of ... 5MHz? Pretty low.CAN FD increases the data rate x8 (yes?) within the same overall time window, so that's 8MHz -> scope frequency 40MHz? Still pretty low.However just looking through Agilent's summary of differential probe options, they recommend the N2818A for CAN bus. That's a 200MHz probe. The probes they have at lower frequencies are all "high voltage", with very high attenuation factors.Do folks think that the high voltage capabilities of the "lesser" probes are the reason for recommending the 200MHz probe, or are there some other considerations besides pure bandwidth specs. (And could you explain fairly succinctly.)

author: electrolust
author_rank: Unknown
timestamp: September 25, 2015, 06:58:51 am
content: Maybe answering my own question, maybe just adding to my uncertainty.I guess the CAN bus is a digital signal, and therefore rise time, not the digital frequency, determines required bandwidth.As far as I can determine (hard to google for this, and the spec isn't enlightening to the extent of my reading ability), a 1Mbit CAN signal has a rise time of 30ns (best case). The rise time can be slower but I suppose we should be able to see the fastest signal. Would I take 80% of this time to determine the 10-90% rise time? That's 24ns. f_knee = .5/24ns = 21MHz. CAN FD is 8 times faster and therefore 168MHz.I am not highly confident of this reasoning, or even my calculations, but at least it's consistent with the recommendation for a 200MHz probe.

author: uChip
author_rank: Contributor
timestamp: September 25, 2015, 01:38:33 pm
content: You are correct. If you take a square wave signal and put it through a low pass filter of the signal's fundamental frequency you will get more of a sine wave out. The low bandwidth scope will behave like that filter so what you see on the screen will not be an accurate representation of the signal you are trying to view.To get the scope to show the signal accurately the scope has to have enough bandwidth for the highest frequencycomponentof the signal. For a digital signal, those square edges have components that are much higher than the bit rate.- Chip

author: electrolust
author_rank: Unknown
timestamp: September 26, 2015, 08:19:57 am
content: Is it the same case for digital channels?
Can DC-DC buck regulator ICs sink current? - Page 1
Forum section: electronics / beginners

author: alexthe5th
author_rank: Contributor
timestamp: March 20, 2021, 10:42:55 pm
content: I'm looking to use an adjustable DC-DC buck regulator IC to create a 25.5V voltage rail from a 28V power supply. There will be loads connected between the 28V supply and the output of the regulator, meaning that the regulator will be sinking, not sourcing current. Is this possible? I see almost no reference to this in any of the regulator datasheets I've been looking at - they typically just specify a "maximum output current" in amps.

author: langwadt
author_rank: Super Contributor
timestamp: March 20, 2021, 10:47:53 pm
content: Quote from: alexthe5th on March 20, 2021, 10:42:55 pma synchronous buck can sink current, think of it as a boost converter boosting the output to dump it in the input

author: David Hess
author_rank: Super Contributor
timestamp: March 21, 2021, 07:04:59 pm
content: That is what I was going to say. A synchronous buck converter can sink current by operating as a synchronous boost regulator in reverse and they are sometimes used for exactly this reason. One old application for this was SCSI termination (Boulay termination) as shown below:https://www.maximintegrated.com/en/design/technical-documents/app-notes/9/930.html

author: ogden
author_rank: Super Contributor
timestamp: March 21, 2021, 07:29:13 pm
content: I would rather separate loads and introduce -2.5V switching converter. Easier fault protection and diagnostics.
Can HC-05 be linked directly to Shift Register? - Page 1
Forum section: electronics / beginners

author: sheonbanks
author_rank: Newbie
timestamp: February 03, 2021, 09:36:31 pm
content: Hi All,Is it possible for the HC-05 Bluetooth module to be connected directly to a shift register(74hc595) to light leds?

author: mvs
author_rank: Frequent Contributor
timestamp: February 04, 2021, 10:56:38 am
content: With default firmware you will not be able to do this.If you can write your own, then you may use GPIOs to drive a shift register.You will need CSR BlueSuite and CSR programmer.
Can / How - to run two MP2307 (3A step down converters) in parrallel to get 6A - Page 1
Forum section: electronics / beginners

author: timgiles
author_rank: Regular Contributor
timestamp: March 05, 2016, 09:21:21 pm
content: Hi,I would like up to 6A of 5V from a 12v supply. I found the datasheet for Monolithics MP2307 and wondered if I had two of these, connecting the outputs in parallel, it would be a workable solution:1. Doing this, do I get 6A?2. Would there be an issue driving them in this configuration?The load will range from almost 0A up to 5.5A.Thanks for your timeTim

author: Simon
author_rank: Unknown
timestamp: March 05, 2016, 09:24:42 pm
content: It may well work, if in doubt put a diode from each output to a further capacitor and take the feedback network off that but It's worth just putting two of them in parallel so they each have their own inductor and share the capacitors (twice the value of capacitors). If they have peak current limiting I can't see it being a problem.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 06, 2016, 11:11:39 am
content: Having switched mode regulator in parallel can be tricky, as they can influence each other and cause strange things, like sound at the difference in frequency. There is a good reason regulators made to work in parallel usually have a synchronized clock.As the regulators are current mode, it might work. I would prefer using two LC filters behind the regulators and combine the signal only after the inductors. So the inductors can improve current sharing a little and reduce interference, both between the regulators and from the regulators to the outside.If the 12 V are from a car, there can be higher voltage spikes and extra protection or more robust regulators may be required.So I would prefer to use one regulator that is good for the job.

author: station240
author_rank: Unknown
timestamp: March 07, 2016, 12:27:11 am
content: Options:A. Have a two 5V rails with a common ground.B. Find another IC that has an external current sense resistor so you can use an external mosfet for higher current output.

author: Alex Trofimov
author_rank: Contributor
timestamp: March 09, 2016, 10:42:45 am
content: I think if use the two of those in parallel, there's so much things that can go wrong... Or, in another case, it may just work.If you want to do experimentation, it's cool, it's a good bet, that this would work. But if you want solution that will just work, I'd better use another IC. In such current rating it would most possibly have an external switch.

author: Monkeh
author_rank: Super Contributor
timestamp: March 09, 2016, 10:50:39 am
content: There arelotsof 6A+ capable buck regs on the market. One of those with supporting components will be smaller and cheaper than trying to parallel two 3A regs.
Can I? (Stepper motor:HDD with Optical mouse) - Page 1
Forum section: electronics / beginners

author: adythewolf
author_rank: Newbie
timestamp: August 21, 2013, 01:46:14 pm
content: Hello!I am new to this forum but I am an avid watcher of all EEV videos.Anyway, my question is probably a dumb one (I am young with no relevant education in electronics).Can I use astepper motorfrom an old HDD in conjunction with the circuit inside anoptical mouseand my own drivers (for the mouse) to create something resembling ananalog controller?P.S. I do not really care for it's accuracy or the amount of work.P.P.S. I am a hobbyist, not a professional.Thank you!

author: hlavac
author_rank: Frequent Contributor
timestamp: August 21, 2013, 04:42:03 pm
content: I don't think hdds use stepper motors, unless you have some 20+ years old...Its matter of number of tracks vs seek time...There are some weird steppers with built in screws in floppy disk drives and cdroms.As for optical mice, if you mean those with camera and LED light they are mostly USB, that is pretty complex to interface to.Maybe if you had the ball mice, with the little slotted wheels, it would be more usable...Unfortunately most of computer peripherals have evolved away from the simple, easy to understand and free to use interfaces of the old into more complex, too fast to do without special equipment interfaces that are parent encumbered and guarded by extortion organizations demanding exorbitant "membership fees" for the equivalent of simple assignment of unique number...This artificial scarcity serves only to stop hobbyists, open source hardware contributors and other possible future competition from gaining any traction.End of rant.

author: adythewolf
author_rank: Newbie
timestamp: August 22, 2013, 07:31:01 am
content: Thank you.I've expected it to be a long shot...I will try to make it though, if I have the time; and I'll let you all know if it works.Cheers.
Can I Chang my User Name? - Page 1
Forum section: electronics / beginners

author: Frankentronics
author_rank: Regular Contributor
timestamp: April 11, 2020, 10:51:22 pm
content: Greetings,I've been posting under this user name, Adinol, but I just came up with a better name.I can't see that it's possible to edit my user name.Is that in fact not possible?Thanks...

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: April 11, 2020, 11:20:22 pm
content: Yes, Simple Machines Forum has a "display name", which can be set by an admin ... although on many forums they don't honour such requests. You would still log in as Adinol, but everyone else would see the new name.Any admin want toChangAdinol's username?

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 12, 2020, 01:13:14 am
content: PM dave with a good excuse

author: Frankentronics
author_rank: Regular Contributor
timestamp: April 12, 2020, 01:17:14 am
content: Hello,Thank you both.I want my new name to be Frankentronics.I'm always picking up discarded electronics from the trash and making stuff out of them. Kind of like electronics art projects. So, I'm Frankensteining stuff and it seems appropriate, especially since I want to post project photos.

author: Frankentronics
author_rank: Regular Contributor
timestamp: June 09, 2020, 04:49:17 pm
content: Hello again,I did PM Dave with a request to change my "display name" to Frankentronics but I did not hear back.I would really like to make this change.Since Dave is probably super busy, could another admin do this?Thanks...
can i change max and min output of dc/dc step up? - Page 1
Forum section: electronics / beginners

author: gatoulisss
author_rank: Contributor
timestamp: January 04, 2021, 01:43:02 pm
content: hello to everybody and happy new year!im having a question, i have a dc-dc step up module witch can provide me with input of 3v output of 3-28vthe thing is that i want to limit this output between 3-15vis there any way to do it?the step up module is this one 2 24V to 2 28V 2A DC DC SX1308 Step UP Adjustable Power Module Step Up Boost Converter|Voltage Regulators/Stabilizers| - AliExpressthank you very much!

author: Manul
author_rank: Super Contributor
timestamp: January 04, 2021, 02:10:00 pm
content: Yes, you can do it by modifiying feedback network. Usually, by changing or adding a single resistor. You need to look into the circuit of the converter for more details.
Can I combine 2 output transformers? - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: October 24, 2019, 09:43:55 pm
content: so I have 2 identical single-ended tube amp output transformers and I want to make a push-pull type amp. can I put the 2 transformers in series, use the center tap for B+ input and use a higher impedance speaker?and yes I have posted this question before but I think the 'begginner' topic is better suited and I couldn't delete that post.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: October 25, 2019, 09:31:33 am
content: I tried that, but the results are.... well, not very good. which is to be expected since the magnetic coupling of the transformers is way worse than with one transformer hosting both windings.This experiment was made quite some time back, I can't exactly recall WHAT was "not good" anymore, but my personal conclusion was, that it isn't worth the hassle, just use an apropriate PP output tranny.

author: andy3055
author_rank: Super Contributor
timestamp: October 26, 2019, 02:03:03 am
content: Here is a good explanation:"An output transformer designed for push-pull operation has a center (sic) tap. The HT is applied to the center (sic) tap and either end of the primary winding is connected to the anode of a power valve. In this way, current flows in opposite directions through the output transformer. If these currents are equal they will cancel out and this is why push-pull output transformers can be made much smaller than single ended ones with the same power rating- there is (almost) no standing current in the transformer so no air gap and less iron is required.The valves are driven with identical but out-of-phase grid signals. When one grid goes positive, the other goes negative. When one valves conducts more, the other conducts less: one pushes, the other pulls. The output signal developed in the transformer is the difference between the two AC currents."Courtesy of:http://www.valvewizard.co.uk/pp.html
Can I combine differant power supplys? - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 12, 2019, 08:52:48 am
content: I have two PSU with 15V-60A and a 30V-5A but I need 25V-7A. Can I combine the two power supply's and if yes, how, in what order?Would I be able to make 30V-75A or 45V-60A?

author: capt bullshot
author_rank: Super Contributor
timestamp: April 12, 2019, 08:58:52 am
content: In your particular case, the answer is: No, you can't.One can parallel supplies, then the maximum voltage is set by the supply having the lowest voltage, and the current ratings can be added. One has to take some precautions, e.g. diode decoupling the supplies.One can serial connect supplies, then the maximum current is set by the supply having the lowest current rating and the voltage can be added. One has to take some precautions, e.g. reverse protection using diodes.One cannot simply average the output ratings. Of course, in your particular case, on can build a switching mode step-up converter to make 25V / 7A from the 15V/60A supply. The other one isn't needed then anymore.

author: Psi
author_rank: Super Contributor
timestamp: April 12, 2019, 09:05:21 am
content: Even if you look for a 25V @ 7A PSU to purchase you will have issues finding anything, 25V is an odd voltage.My suggestion is to look for a 24V 10A psu which has a little voltage adjust pot on it. Those are very common.The adj pot allows for a little over-voltage. So you should be able to set one to do 25V pretty easy.There's lots of 24V psus out there, it's a very common voltage and that makes them pretty cheap.

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 12, 2019, 09:50:31 am
content: Thanks for your great reply, that helped a lot:-)

author: Psi
author_rank: Super Contributor
timestamp: April 12, 2019, 12:04:00 pm
content: If you buy an open frame psu, play it safe and mount it in a box so the mains terminals are not exposed.
Can I common the negative of two CC LED drivers? - Page 1
Forum section: electronics / beginners

author: beelzebozo
author_rank: Newbie
timestamp: February 19, 2020, 06:23:12 am
content: Hi,I want to connect together the black wires of twoAPC-8 Meanwellpower supplies. I want to run the DC side for a bit and would prefer to have three wires( two reds and one for the blacks) instead of four.Do you foresee any issues that may arise from this configuration?
Can i connect middle of splited transformer to Pe ?  - Page 1
Forum section: electronics / beginners

author: Matthew98
author_rank: Regular Contributor
timestamp: February 17, 2017, 11:59:10 pm
content: Hey guisIm making simple mono audio amplifier and i dont really know, if I can connect the middle - zero - to earth. I suppose, that as its symbol on circuits is earth, i can...but im not sure...Also, will make connecting or not connecting it any change to the audio quality ?Thanks for answer

author: Brumby
author_rank: Unknown
timestamp: February 18, 2017, 12:01:52 am
content: No problem at all.You have laid out a very basic - and classic - split rail power supply.As for audio quality - the only time that red link might cause problems is if you have a ground loop.

author: Matthew98
author_rank: Regular Contributor
timestamp: February 18, 2017, 12:06:52 am
content: ThanksIm glad i dont have to isolate cinch connector from case... that would be pain in the assWhen its done (probably tomorrow) i ll post it here ,so you can see what Ive been working on all day

author: goldfinger
author_rank: Regular Contributor
timestamp: February 18, 2017, 12:07:00 am
content: Hi Matthew your pic is little hard to see but I'll assuming the caps are connected +/- in the middle and then you have a positive and negative rail.You would split out the centre point 0 to feed your amp modules but also tie this back to your iEC earth chassis point. Ensure you use a clamp tooth washer to make sure you have a solid connection that won't come lose and connect with wire with an approved earth lug or O ring connectorSent from my 486 IBM WIN 3.1x Desktop...

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2017, 12:22:28 am
content: Quote from: Brumby on February 18, 2017, 12:01:52 amAnother option is to connect the 0V to chassis via a small (1nF to 100nF) capacitor. Sometimes I've found AC coupling the supply to the chassis reduces hum.

author: Matthew98
author_rank: Regular Contributor
timestamp: February 18, 2017, 12:35:01 am
content: Sorry, already draw the lines ...(Im making a pcb with pernament marker and all screw holes are now connected to 0)Its not the best amp anyways .... the transformer is too week for it i bet. Im just making it because it liiks cute and will output something..I will use the next amp, i will be making, which is TDA7293 2x100W amp. Just waiting for components to arrivePs. : It will take longer, after 2 hours of finding whats wrong with the circuit, i found out that 2 leads broke from IcJust waiting for new one to arrive...