hybridfree/eevblog-posts huggingface dataset:
SMD Tantalum capacitor or SMD diode, resistor...?! - Page 1
Forum section: electronics / beginners

author: JPBAPT
author_rank: Newbie
timestamp: December 01, 2022, 11:49:29 am
content: Hello everyone.I have a question about the component in the foto.Is that a Tantalum cap, or a diode, or maybe a resistor...?!And the values, how can i no them?They are almost the same...Thank you

author: jpanhalt
author_rank: Super Contributor
timestamp: December 01, 2022, 12:05:18 pm
content: Can you power up the circuit? If so, what's the voltage across it?Welcome to EEVBlog.

author: JPBAPT
author_rank: Newbie
timestamp: December 01, 2022, 12:11:40 pm
content: Quote from: jpanhalt on December 01, 2022, 12:05:18 pmThis is from a Car ECU... and i can not power the circuit.I measure it, and the values are from both sides the ones at the foto.

author: DavidKo
author_rank: Frequent Contributor
timestamp: December 01, 2022, 01:02:41 pm
content: Usually there is a lot of ESD protection. It can be TVS diode or something similar.

author: JPBAPT
author_rank: Newbie
timestamp: December 01, 2022, 02:48:40 pm
content: Thanks friend.I think you right, its a disse.But i canto find nowhere watt the reference 10-10 mesma.I search the NET, no match.

author: Manul
author_rank: Super Contributor
timestamp: December 01, 2022, 04:01:17 pm
content: That's a capacitor. Should be 10V 10uF. If it is not shorted, I doubt there is a problem with it.

author: gamalot
author_rank: Super Contributor
timestamp: December 01, 2022, 04:57:05 pm
content: Quote from: Manul on December 01, 2022, 04:01:17 pmI second.It's obviously a 10uF/10V tantalum electrolytic capacitor.https://www.vishay.com/docs/40002/293d.pdf

author: JPBAPT
author_rank: Newbie
timestamp: December 01, 2022, 10:23:37 pm
content: Thanks for your help.I have another question.I send a photo for 2 caps, can i use the one on the left, the Sanyo 10UF 25V, if the other 10V 10UF is not in good use?One is tantalum, the other is what we call a "normal" electrolyte cap.I read a lot about this, and many people do this.I watch, that sometimes the use of tantalum caps is only because of the space, is that true?Thantas in advance.

author: Manul
author_rank: Super Contributor
timestamp: December 01, 2022, 11:19:22 pm
content: Electrically speaking most likely everything would be fine, but I would not use it. This is a car ECU, exposed to high vibrations, possibly high temperatures. Don't underestimate that, do a solid repair, grow good habbits.

author: caius
author_rank: Regular Contributor
timestamp: December 02, 2022, 06:01:39 pm
content: It's a tantalum capacitor, 10uF 10V.Keep attention that the white band denotes the positive terminal unlike all other SMD capacitors where the band (usually black) is the negative terminal.

author: JPBAPT
author_rank: Newbie
timestamp: December 02, 2022, 06:07:47 pm
content: Quote from: caius on December 02, 2022, 06:01:39 pmYes, true.I already install it. Its all ok
SMD thermistor and resistor - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: October 19, 2023, 07:52:35 pm
content: What is a marking (colour) of SMD thermistor? How can I distinguish thermistor and resistor?

author: alligatorblues
author_rank: Regular Contributor
timestamp: October 20, 2023, 03:12:20 am
content: I don't know if there are any markings. But I would connect a DMM to the terminals on it, and put a soldering tip about 1/4" away. If the resistance changes a lot, it's a thermistor.

author: Konkedout
author_rank: Frequent Contributor
timestamp: October 22, 2023, 03:00:22 am
content: Yes unfortunately marking of small SMT passive components is very "iffy." And if it is a thermistor: While NTC thermistors are probably more common, PTC thermistors also exist.
SMD Transistor Identification  - Page 1
Forum section: electronics / beginners

author: Bskitter
author_rank: Regular Contributor
timestamp: August 08, 2017, 11:43:44 am
content: Hey Guys I am doing some work on a Computer Power Supply and I need to identify the control transistor for the relay circuit.Can anyone please help me out ?Byron

author: Kjelt
author_rank: Super Contributor
timestamp: August 08, 2017, 11:53:16 am
content: According to the smd code book (google) it is probably a FMMT-A42R high voltage transistor.

author: perieanuo
author_rank: Frequent Contributor
timestamp: August 09, 2017, 07:58:42 pm
content: No way, it's nfet or pnp/npn just verify relay wiring. If it's just relay bobbin any nfet or bipolar with Vcc/Ic respect will doEnvoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk

author: floobydust
author_rank: Super Contributor
timestamp: August 09, 2017, 09:01:58 pm
content: I got SMD marking code 7E as PNPMMBTA92I got SMD marking code 3E as NPNFMMTA42OP should check if the emitter goes to GND, I expect that and an NPN.

author: Kjelt
author_rank: Super Contributor
timestamp: August 10, 2017, 05:46:23 am
content: What is the coil voltage of the relay?
SMD tweezers are great for everything !! - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: February 08, 2021, 12:17:18 am
content: Last year I ordered a set of tweezers for SMD work, but I've mainly used just the curved ones for breadboarding and picking parts out of cans/containers/bins/etc.I find them GREAT at placing/removing parts on a breadboard, including prying up DIP's.I use them to hold stuff when soldering too, but they are not meant for prying on PCBs, but they work great at holding a wire something small that needs no real force.I'd like a version for food, I think I would anyways. Also multi-purpose, upgradable, retractable versions built into my finger tips.If you don't have any, get yourself a pair, in some cases magnetic ones might help, but they are typically non-magnetic.I swear, they make breadboarding way easier sometimes, and picking parts out of bins, they are so much more needle like than our fingers. You can feel all the extra precision, and you don't want to put them down.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: February 08, 2021, 12:23:07 am
content: Like this?
SMD Voltage stabilizer SY8009B / BX6L / SOT23-6, help id on mouser. - Page 1
Forum section: electronics / beginners

author: popclone
author_rank: Newbie
timestamp: September 13, 2021, 08:44:33 pm
content: So text changed with Mouser.com and asked them to ID this chip Voltage stabilizer SY8009B / BX6L / SOT23-6, they said they don't have it and if I want to request a quantitation, I asked if any of the once that come up when you search "SOT23-6" are compatible with what I'm looking for, I didn't get an answer other then that they have to call there supplies and find out. My questions as a noob if are the lying or am I dumb and don't know how to filter this SMD chip on there site ?I can get this chip on other sites like ebay and Ali but I was looking to order more stuff at the same time from mouser.As a beginner it feels suspicious that one of the once on there site its not compatible to what I need.

author: neuschs
author_rank: Contributor
timestamp: September 14, 2021, 05:31:08 pm
content: Hello,seems like the DIO6012CST6 is pin compatible with same input voltage range and output current.

author: wraper
author_rank: Unknown
timestamp: September 14, 2021, 06:02:09 pm
content: QuoteYou cannot reasonably expect them to do this for you. They would need to look into tons of datasheets and compare them thoroughly to give you an answer. Not to say it would require an actual engineer to do this, not sales person. The only case when I would probably expect them to do this if it was a huge customer which has a huge turnaround with them.

author: popclone
author_rank: Newbie
timestamp: September 14, 2021, 08:07:54 pm
content: 1st; I didn't get any notification even though I checked the box to e-mail me when people reply to my post, and my junk box dose not contain anything.2nd; As a beginner I'm suspicious of some people trying to "quote" you something for 10x the price, that was my problem, didn't know these chips are all different in the end, I tough that they have most stuff (standard chips) that's needed out-there for repairing electronics. O am I wrong LOL. It's my learning curve in this field.3rd; the board that I'm trying to repair is a Android TV-Box MXQ (Amlogic S805), the buck/ this SMC Voltage stabilizer SY8009B is blown, I'm trying to salvage it and learn at the same time, its not worth more then $35 and a quotation for a chip should not be more then they charge on the site, but I had to ask others to be sure that I'm just paranoid and not everyone is looking to scam you for a part that its worth $2.To be honest I didn't even let the Mouser guy quote me, I just said "thank you but I'll pass" ...thinking that being locked into a contract for overpriced chip is not what I wanted when I was dealing with a cheap product aka Android Box, which in the end might not resolved the problem. I have to start small LOL.Thank you to all who replied and I will try DIO6012CST6 , nothing to lose , it will be a lesson. I can get the "proper named SMD" from China but I can't wait that long since I can also get other caps from them for other repair projects.We all fear the unknown till we know what that is, then the fear goes away. Learning curve...
SMD with 43 printed on it need help identifying  - Page 1
Forum section: electronics / beginners

author: DarkZero
author_rank: Regular Contributor
timestamp: March 15, 2016, 12:39:46 pm
content: Hello all!i think this part is transistor with built in resistors but i cant seem to find data sheet and i have few questions about this kind of transistors mainly hop to decide on replacement of such and how to test them.in circuit base of the transistor goes to micro controller and what i think is collector goes to Z3M triac, triac is in short circuit but before i change it i measured base to gnd and +5v no shorts there so i guess micro is alive. now i need to make sure transistor is working and if its not what replacement to use if anyone could help my friend would be one happy person if we fix it.

author: fra.gherard
author_rank: Contributor
timestamp: March 15, 2016, 07:39:33 pm
content: hi, look here:http://www.s-manuals.com/smd/43it's a SOT23 package, all results for SOT23 are BAS40 schottky diodes.put your DMM in diode test and try to measure the component how indicated in page 2, pin 1 anode-pin 3 katode. pin 2 not connected. if you read about 0.2 - 0.3V maybe is a BAS40

author: Brumby
author_rank: Unknown
timestamp: March 16, 2016, 12:39:54 am
content: If you're right about the BAS40 - then all you then need to do is figure out which configuration is inside:I couldn't see it, but I didn't checkallthe datasheets.

author: Back2Volts
author_rank: Unknown
timestamp: March 16, 2016, 03:12:10 am
content: That list of 43s has a digital transistor in UMT3F package, which I wonder how close it is to the SOT23. The transistor is a DTC143XUB from ROHM.But the Z3M TRIAC has a 3mA sensitivity, so it could possibly be driven directly by the MCU.

author: Brumby
author_rank: Unknown
timestamp: March 16, 2016, 06:08:13 am
content: Quote from: Back2Volts on March 16, 2016, 03:12:10 amThe UMT3F package body is 2.0mm long, the SOT23 is 3.0mm.

author: fra.gherard
author_rank: Contributor
timestamp: March 16, 2016, 10:54:34 am
content: if it is a BAS40, is only a BAS40, the other types haven't 43 marking (44-45-46).but can be a npn digital transistor DTC143 series. here's datasheethttp://rohmfs.rohm.com/en/products/databook/datasheet/discrete/transistor/digital/dtc143x.pdftry to take the measures of the component and compare it with the dimensions indicated in datasheet. so, you will find how package it is, and which inner circuit do you have
SMD work - Page 1
Forum section: electronics / beginners

author: akis
author_rank: Frequent Contributor
timestamp: October 07, 2014, 09:20:42 am
content: I have watched a few youtube tutorials on how to work/solder SMD components.Do I understand it correctly that the PCB must have a solder mask otherwise the solder paste will bridge ? On the youtube tutorials they use professionally made PCBs but for home made ones, I do not have solder mask equipment.

author: Kjelt
author_rank: Super Contributor
timestamp: October 07, 2014, 10:35:29 am
content: This might be an issue on components with small distances between the legs <0.8mm so or you can use a lot of flux and hope for the best or as I sometimes do with rework, is solder each leg seperately with a small smd solder pencil and a tiny amount of solderpaste (not solderwire but paste) that you have put on with a syringe with needle and solder paste dispenser.EDIT: I assumed you manually soldered, for reflowing the amount of paste is crucial, too much paste and small pitch even the pro pcb's won't stop bridging.

author: sleemanj
author_rank: Super Contributor
timestamp: October 07, 2014, 10:38:39 am
content: Quote from: akis on October 07, 2014, 09:20:42 amOnly if you were using really tight pitchpackages, or were sloppy with the paste I expect.I don't reflow, but don't have problems with drag-ish soldering SOIC etc on home etched boards without mask, easy as pie.
Smith Chart Basics - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: January 17, 2023, 03:08:57 pm
content: Liked this videos, maybe a bit overlap between them...

author: Terry Bites
author_rank: Super Contributor
timestamp: January 17, 2023, 07:46:02 pm
content: Yep.Once you've seen it in use it no longer looks like the map of a terrifying black hole.

author: pdenisowski
author_rank: Super Contributor
timestamp: January 18, 2023, 09:34:39 am
content: The most popular video on the Rohde & Schwarz YouTube channel(And BTW, I absolutely love Alan's videos - they're outstanding)

author: bidrohini
author_rank: Regular Contributor
timestamp: January 23, 2023, 10:14:21 am
content: You can watch this too:
Smith chart of λ/4 Transmission Line - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: March 19, 2019, 04:58:29 am
content: I came across thefollowing slide on power combiner circuitand I have questions about it.1. Why traverse across the upper half circle ? In other words, why is Zin located at the right side of Zout ?2. Why when translating an impedance towards the generator we move clockwise around the chart ?3. Why "ZT-line is the geometric mean of Zout and Zin." ?4. Why overlay the Smith chart scaled for ZT on top of the Z0 Smith chart ?5. Why is L=λ/4 located directly opposite to L=0 ?
Smoke release! - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: December 31, 2017, 12:36:08 pm
content: Thought I'd share this. You buy cheap chinese stuff and 9 times out of 10 it works fine. Then there is the one.https://www.ebay.co.uk/itm/USB-Power-Breakout-DC-to-DC-Power-Module-Micro-USB-5V-to-1-8V-3-3V-5V-9V-12V/311932552254?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648Powered it up, fine.1.8V was 1.801V3.3V was 3.26V5V was 4.99V9V was 8.89VSwitched it to 12VGlow, sparks, smoke. The little 6 leg chip just up and right of the 9V/12V switch lit up orange, then yellow, then white and smoked. I pulled the plug after glancing to see it drawing 1.5A current on the USB analyser. So a 1.5A short circuit current through that poor little chip.Plugged it back in and now:1.8V was 1.801V3.3V was 3.26V5V was 4.69V9V was 4.5V12V was 0VSo I figure the chip is (was) part of some form of boost circuit and is now no more. It looks like it was boosting whatever regulates the 5V, 9V and 12V outputs as 5V also dropped.Still, I only bought it as a gimmick to play with. Thought it was a nice way to get low current range of different voltages from USB.So my score for yesterday is 1:1 evens. I killed a power supply gimmick module, but I also fixed an old Innokin CoolFire IV eCigarette mod which my ex dropped and while it powered on it flashed fault lights when you attempted to use it. Took it apart and found the sense register had a cracked solder joint as it looks like the 18650 cell slammed into it when dropped. Quick resolder and it now works again. Win!

author: WaveyDipole
author_rank: Frequent Contributor
timestamp: December 31, 2017, 03:04:02 pm
content: I recently had one of these meters go up in smoke:ttps://www.ebay.co.uk/itm/10A-0-100V-voltage-meter-and-LED-DC-dual-display-digital-current-home-garden/391849081750?hash=item5b3c067b96:m:mIzVQQemqxMhdUnk8vVwc6QIt worked just fine but one day when I powered it on (using a supply voltage that was well within the specified range) an IC just let out the magic smoke and the thing died. No fizz bang and no obvious reason. Once faild, an excessive current draw was evident.Most of these far east modules do seem to work OK but given how cheap they are I have learned not to expect too much from them. These meters, for example, are rather inaccurate and can serve only as an indicator at best. It seems that every now and then one of these cheap modules will just fail unexpectedly for no apparent reason. I guess that's what you get when something is made to a price point, there is a lack of any kind of quality control, and the sources of components are questionable at best. Its a bit pot luck.
Smoothing VCC with cap - conceptual question - Page 1
Forum section: electronics / beginners

author: Erwin Ried
author_rank: Regular Contributor
timestamp: July 07, 2017, 06:42:58 am
content: Hi everybody, I need some theorical tips about my issue. I am making a simple dock for a raspberry pi zero. The usb of the zero is quite simple, directly connected to almost everything so when I hot plug a load in the usb (100mA) it reboots the Pi 1 of every 10 tries.What can I do to prevent this?Should adding a 10uF cap between vcc and gnd be enough? Will adding a bigger cap bring some undesired counter effect?Thanks

author: OiD
author_rank: Regular Contributor
timestamp: July 07, 2017, 02:53:02 pm
content: IS it always the same device that causes this to fail? What device is it? If its not one single device is there anything in common that does not cause this effect? Maybe a very low value resistor in series with the power line for the specific device

author: Erwin Ried
author_rank: Regular Contributor
timestamp: July 07, 2017, 11:39:37 pm
content: Yes it is the same. I discovered that the inductor in the pi had a crack so maybe that is the cause of the reboot.How do I put the resistor by the way?

author: OiD
author_rank: Regular Contributor
timestamp: July 08, 2017, 11:28:16 am
content: Maybe the inductor has something to do with it, maybe not. If you can fix it you'll knowThe resistor Idea was if it only happened with one device. But if it happens with all then its on the raspy side or the power supply... or the Kernel?

author: Erwin Ried
author_rank: Regular Contributor
timestamp: July 09, 2017, 11:22:43 pm
content: Well, I only want to use that device. Could adding 1 ohm resistor in vcc between the device and the pi do something bad at the long run?

author: OiD
author_rank: Regular Contributor
timestamp: July 11, 2017, 05:11:10 pm
content: That would depend on the device, it's current rating and voltage tolerance. Maybe your devices has a large capacitance and no power control IC so all it does is draw as much current as possible. Try with a lower or higher value resistor, maybe an NTC if you can find one rated at the current required.If you have acces to a scope you could also probe the pi and see if there are current spikes when you plug the device in. Or you could also try a dummy conector, one with only the power pins and no data to make sure it's not a communication issue/bug.
SMPS acting strange under heavy load - Page 1
Forum section: electronics / beginners

author: SnipTheCat
author_rank: Unknown
timestamp: October 22, 2016, 01:16:20 pm
content: Hi,I have a 18V/30A switching power supply that is acting strange ("standard" chinese SMPS). It can be adjusted from 11.5V to 20.5V, and I'm using it to power an induction heating circuit. I usually start at minimum voltage and crank it up.I have made a new induction circuit which is power powerful, with larger coil and crucible. It starts as 11.5V/16A under load. I noticed that when I reached ~15V the voltmeter module connected to the supply showed decreasing voltage... I didn't pay much attention and thought it might be the voltemeter's wiring that has some issues, and as the cooling fan of the induction circuit kept having higher pitch. I ran like that for a while, wihtout any problem (ammeter reading 23-24A), melted some aluminium, no apparent problem.Today I took a closer look at highest setting (20.5V)... verified the voltmeter... same problem, I connected my multimeter to the supply, above 15V it started to have crazy readings... I switched to AC and it read a good stable 3V, brought the oscilloscope... see the picture attached... huge 3Vpp ripples at 100Hz (nothing visible < 15V/20A appears after that)I naturally suspect the power supply (100Hz is the frequency of rectified AC mains), and some kind of protection circuit kicking in and out.I tried connecting 2 10000µF caps to the supply output... voltmeter then had a nice clean 15V reading and ammeter didn't go higher than 20A, also the cooling fan didn't seem to run faster as I tried to go above 15V.Any idea what to look for, is this fixable? Supply is supposed to be 540W not 300David.

author: bktemp
author_rank: Super Contributor
timestamp: October 22, 2016, 01:44:09 pm
content: Maybe some caps inside the power supply have failed (large caps after the mains rectifier) or the power supply is overrated and goes into some current limit mode when the input voltage drops.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 22, 2016, 02:13:36 pm
content: Probably you have reached what the input capacitor or the main transformer can supply at that volt level...

author: SnipTheCat
author_rank: Unknown
timestamp: October 22, 2016, 03:43:10 pm
content: Quote from: bktemp on October 22, 2016, 01:44:09 pmJust tested the input caps... they don't look good... 4x 330µF / 200V : capacitance from 120 to 135µF ESR of ~0.4ohm for 3 of them 0.7 for the 4th.... I think that's a good lead...

author: SeanB
author_rank: Super Contributor
timestamp: October 23, 2016, 05:53:57 pm
content: Do they look too small to be 330uF caps, and is the PCB layout where they are set up with space for larger ones? If so then they are relabelled 100uF caps, and should be replaced, along with the ones in the secondary side, as they likely are relabelled ones as well.
SMPS and Transformer Design Help - Page 1
Forum section: electronics / beginners

author: ajukarandikar11
author_rank: Newbie
timestamp: June 07, 2018, 05:22:24 am
content: I am looking for a consolidated design cook-book for:1. Linear supply2. Flyback3. Forward4. Half/full Bridge5. LLCCan anyone suggest a e-book/link that has everything conceptually explained with design examples?

author: strawberry
author_rank: Super Contributor
timestamp: June 07, 2018, 06:51:32 pm
content: Good question, I would like to know as well ..1. LM3172. works alike boost converter. important primary and secondary windings polarity3. works alike isolated buck converter.4. works alike isolated buck converter5. hardDIY or EDU

author: ajukarandikar11
author_rank: Newbie
timestamp: June 08, 2018, 04:29:28 am
content: Thank you.It is indeed a good collection of equations.Is there any book/link that explains how the equations are derived?

author: ajukarandikar11
author_rank: Newbie
timestamp: June 08, 2018, 08:33:39 am
content: Great Book. Thank you.
SMPS and two power voltages output using N channel mosfet - Page 1
Forum section: electronics / beginners

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 05, 2025, 09:42:22 pm
content: Taking the attached schematic from a STM SMPS design which is supposed to provide selectable voltages using an n-channel mosfet with a third resistor added in parallel that controls the voltage ratio. Under "normal" operation, the output voltage is 0.81V, otherwise, when controlled by the MOSFET, the output voltage is 0.89V.I understand that when the mosfet is off, the circuit acts as a traditional resistor divider network so the output voltage becomes 0.81V using the formula from the SMPS IC datasheet R1=R2((Vout/Fb)-1), where R2 is chosen to be 56K. After solving, R1 becomes 160K.What I do not understand is how the value for R3 is calculated such that the output voltage becomes 0.89V when R3 is turned on by the mosfet.

author: PGPG
author_rank: Frequent Contributor
timestamp: March 06, 2025, 12:54:01 pm
content: Quote from: newtekuser on March 05, 2025, 09:42:22 pmSince you did not provide Fb value, I try to find it.R1=R2((Vout/Fb)-1), soR1=R2(Vout/Fb)-R2, soR1+R2=R2(Vout/Fb), so(R1+R2)/R2=Vout/Fb or R2/(R1+R2)=Fb/VoutQuote from: newtekuser on March 05, 2025, 09:42:22 pmFrom equation I got, it looks that not R2 but R1 was chosen to be 56k.So, in contrast to what you wrote I assume R1=56k, R2=160k and I can find Fb to be 0.81*160/216 = 0.6V.Now we need to find R2 for 0.89V.From your first equation R2=R1/((Vout/Fb)-1) so R2=56/(0.89/0.6 -1)=56/0.483333=116k.One of first things I have learned about electronic was how to calculate resistance of connected in parallel resistors R=R1*R2/(R1+R2). Later, when I learned how to transform equations I found that when we know the paralel result and one of resistors than the lacking one we can get from R2=R*R1/(R1-R). So to get 116 from 160 || with something we need 116*160/(160-116)=422k.You have to be very young as these calculations are at primary school level. If you seriously plan to play with electronic assume math is the most important subject at school.

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 06, 2025, 06:38:08 pm
content: Quote from: PGPG on March 06, 2025, 12:54:01 pmThank you my friend!
SMPS basic formula's - Page 1
Forum section: electronics / beginners

author: Simon
author_rank: Unknown
timestamp: July 09, 2014, 01:07:27 pm
content: I'm looking for the basic formula's to use to calculate L and C in a stepdown switchmode converter. If there somewhere that gives these without trying to teach me to use a specific chip ?Can the ones on the MC34063 datasheet be considered generic ?
SMPS behaving oddly - Page 1
Forum section: electronics / beginners

author: Chryseus
author_rank: Regular Contributor
timestamp: July 04, 2011, 06:24:23 pm
content: Recently I accidentally blew up my 12V AC transformer so I had to find a new one, I found a ET60T-2 low voltagelighting transformer just laying around, I tried connecting it to my linear regulator circuit and it seems to be oscillating for some reason.My linear regulator just consists of bridge rectifier, 160uF cap, BJT power transistor and an op-amp.The SMPS works fine powering a lamp or similar and I know the regulator circuit works.Also is it normal for a SMPS to show high voltage to earth ?

author: Zero999
author_rank: Super Contributor
timestamp: July 04, 2011, 07:51:52 pm
content: That's because it's a high frequency transformer not a standard low frequency transformer or a switched mode power supply. The mains is rectified and connected to an oscillator driving a ferrite core transformer. The output is a 20kHz to 100kHz squarewave modulated by the mains frequency.The standard low frequency diodes in your bridge rectifier will struggle to rectifiy the high frequency waveform, will have high losses and might overheat. The linear regulator will have virtually no ripple rejection at higher frequencies so the output will be noisy.There will be a relatively high voltage between the secondary relative to earth because there will be a lot of leakage, both through the transformer itself and the Y capacitors, assuming the latter are fitted.I've never tried to use such a transformer to power anything but a light bulb and I suspect it's more trouble than it's worth. You'll need to replace the low frequency diodes with Schottky diodes, add lots of low ESR ceramic capacitors , ferrite beads and a choke to the DC side but I don't know if it'll be enough to get rid of all of the noise.Here are a couple of links:http://sound.westhost.com/lamps/dimmers.htmlhttp://skyline-bg.com/ref/13707.pdf

author: Chryseus
author_rank: Regular Contributor
timestamp: July 04, 2011, 08:52:42 pm
content: I thought it might be something like that, thanks for the info.As for noise I know exactly what you mean, I originally powered my projects from an old ATX supply but as soon as I tried to build a high gain amplifier... well you can guess the result.
SMPS books - Page 1
Forum section: electronics / beginners

author: slashguitar
author_rank: Contributor
timestamp: December 16, 2011, 11:49:51 am
content: Does anyone know any good books/courses about SMPS?thanks

author: Slobodan
author_rank: Regular Contributor
timestamp: December 16, 2011, 12:35:20 pm
content: I don't know about books, but here is one reference manual from ON semi:http://www.onsemi.com/pub_link/Collateral/SMPSRM-D.PDF

author: Neilm
author_rank: Super Contributor
timestamp: December 16, 2011, 04:14:36 pm
content: The big problem I have with all these is that they tend to assume things about your application. I have been caught out by effects that were not mentioned at all in the textbooks as I was not doing a standard application.Neil

author: mkissin
author_rank: Regular Contributor
timestamp: December 16, 2011, 08:11:29 pm
content: Depending on what you want, there are some reference books that I found very good:Switchmode power supply handbook, by Kieth BillingsSwitching power supply design, by Abraham PressmanSwitch-mode power supplies; SPICE simulations and practical designs, by Christoph BassoEach covers different aspects of the supply, with the handbook being more about the small, often forgotten details like inrush limiting, auxilliary power, and transistor drive circuits. The SPICE book is obviously skewed more towards getting a supply simulating and the design aspects.Of course, no book is likely to ever deal directly with the application you're trying to design for!

author: bfritz
author_rank: Regular Contributor
timestamp: December 17, 2011, 05:19:06 am
content: I have and use this book:http://www.amazon.com/Supply-Cookbook-Second-Design-Engineers/dp/075067329XI know the author, so he gave me a signed copy. It covers both linear and switch-mode supplies, and covers most topologies.

author: slashguitar
author_rank: Contributor
timestamp: December 18, 2011, 11:50:16 pm
content: thanks...now it's time to study

author: melrel
author_rank: Contributor
timestamp: January 16, 2012, 03:13:12 am
content: If you want a superb book on SMPS theory/repair then take a look at the website of Jestine Yong.www.jestineyong.comHe's Malaysian but was trained in UK in electronics. The book is an ebook and you can have it in your hands within seconds - fantastic. Hope it helps you.

author: mobbarley
author_rank: Regular Contributor
timestamp: January 16, 2012, 08:50:41 am
content: This is a good resource too:http://www.powersystemsdesign.com/power-supply-development-diary---part-i?a=1&c=1142Goes from part 1 -> 16, and there are other power related articles in the design tips section.
SMPS - buck converter PCB layout - PLS review - Page 1
Forum section: electronics / beginners

author: Tom199
author_rank: Newbie
timestamp: September 08, 2020, 01:34:00 pm
content: Hi everyone, can someone pls review my SMPS PCB layout? I am not sure about grounding and Vcc pin controller distance... Let me please know if there are more things to rework in this layout.- Used controller is NCP3020A- Vin is 12V, Vout should be 7V/10AThx in advance.

author: KT88
author_rank: Frequent Contributor
timestamp: September 08, 2020, 03:16:28 pm
content: I won't use a controller with external TO220 at low frequency for that buck...You get very large magnetic loop areas and large areas for the switch node.You should try something like the ADP2389https://www.analog.com/en/products/adp2389.html#product-overviewwhich gives you a much more compact design. If you don't need the highest possible efficiency operating the regulator at the upper end of it's frequency range to get a smaller inductor and smaller caps. This seems to be counterintuitive but small size is your friend.The step response benefits as well.
SMPS compensation does not match simulation - Page 1
Forum section: electronics / beginners

author: zmaster
author_rank: Contributor
timestamp: August 14, 2023, 07:02:39 pm
content: Hello everyone,I'm a bit lost and I could use some advice.I've designed a board which is essentially a SMPS that takes the voltage from a 1-cell Li-ion battery and boosts it up to 24V to drive some LED strips.I figured it wouldn't be too difficult as the LED strips don't need a perfectly regulated output, however I didn't consider that driving those LEDs with a PWM I would be constantly unsettling the regulator due to the load switching, so a good control loop was going to be important.I started by designing the circuit with TI's Power Designer and I got this schematic:When I made my board, I used that same design, but I made a couple of mistakes:I used the available ceramic caps from JLC-PCB, assuming they would derate to 50% of nominal capacity due to DC bias like the ones picked by TI's designer. I later discovered they actually derate by 90%.To simplify the BOM, in the compensation network I re-used some existing values for Rcompand Ccomp, aiming to keep a similar RC constant. I later realised that's not how it works.The 24V output was fine with a 100% PWM, but it would not regulate well at all with a 50% PWM.I then addressed the points above by adding a 10uF electrolytic in parallel to Cout and bringing Rcompto 1.5k and Ccompto 200n.Still, the regulation is terrible, drops to 17V and overshoots to 35V:I've found a tool from TI to calculate the compensation loop and with these values it should be stable:(cells in yellow are the relevant ones, the ones on the top left come from previous calculations)I've played a bit with different components and got to something that kind of works (Cout=220uF, Ccomp=100n, Rcomp=22k), but it's still not great and I don't know if it will be stable. I suppose I could try all possible conditions (Vin, DC, etc).In conclusion, my questions would be:Why does the circuit behave so different than the simulation? What am I missing?If it's normal for the simulation to be so unreliable, how can I tune the compensation and ensure it will be stable under all conditions?Edit: Sorry, I don't know why pictures are not showing inline...
SMPS controller for a non isolated PSU design - Page 1
Forum section: electronics / beginners

author: tomicode
author_rank: Newbie
timestamp: December 08, 2018, 05:13:04 pm
content: Hello,I am designing an ATmega based wireless light switch. For my test layouts I used the HLK-PM01 PSU, but having it completely enclosed I think it is time to design a SMPS, but a non-isolated one. First of all, I know the risks of non-isolated power supplies.So my project requires a 5V 100mA rail and my question is related to choosing a controller chip. For example I found atti.coma buck converter circuithttp://www.ti.com/lit/ug/tidt015/tidt015.pdfand seems fine, but the typical application schematic for theUCC28710D:http://www.ti.com/lit/ds/symlink/ucc28710.pdfsupplies only an isolated power supply reference and many other controllers seems to do the same. Now to my question, probably a silly one: How can I adopt other controller chips from an isolated layout to a non-isolated?Best regards,TomiCode

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 08, 2018, 07:02:28 pm
content: Even if you don't need isolation, it can be worth using a normal isolation transformer because they're off-the-shelf.The price is awful though. You can buy a ready-made module for $10, or all the parts you need for this for a little more than $10.Not that single-quantity pricing is at all meaningful.You may be interested in a high voltage buck, like these things,https://www.monolithicpower.com/en/mp163c.htmlTim
SMPS course for you - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: January 13, 2019, 12:25:05 pm
content: Hello,Please email me if you want me to send you my free SMPS course.It uses the advantageous method of "annotated simulatons" to teach the principles of SMPS.andymassey22@gmail.comThe sims are in the free download LTspice by linear.comit is some 1.2GB in size so its on a google drive link, so i can only send it to you by email.

author: anishkgt
author_rank: Frequent Contributor
timestamp: January 13, 2019, 12:26:16 pm
content: Better, just share the link if it’s free of cost.Www.Georgehobby.wordpress.comEquipments: DSO104z, Hakko FX888D, Brymen BM869sSent from my iPhone using Tapatalk

author: Fred27
author_rank: Unknown
timestamp: January 13, 2019, 04:54:56 pm
content: I suspect even at this price it won't be good value for money.

author: ocset
author_rank: Super Contributor
timestamp: January 13, 2019, 06:38:12 pm
content: QuoteThanks...oh, you mean there is some way of sharing a google drive link without having to email someone from your gmail account?The course is superb in explaining smps principles to the newcomer, and has content for the more experienced.Try and explain to someone in writing what is the difference between voltage mode control of an smps, and current mode control of an smps......it will take pages and be hard to understand....now go to my course and run the annotated sims of the voltage mode and current mode smps's and you will see exactly how they both operate and what is the difference between them.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 13, 2019, 07:16:37 pm
content: Quote from: treez on January 13, 2019, 06:38:12 pmi clicked and downloaded files before from public google drive sharing. never done it but this is maybe it...https://www.techrepublic.com/article/how-to-share-a-google-drive-document-with-the-public/

author: Zero999
author_rank: Super Contributor
timestamp: January 13, 2019, 07:18:09 pm
content: Quote from: treez on January 13, 2019, 06:38:12 pmWho wrote the tutorial you're referring to?If you wrote it yourself, please don't be offended if yoy're met with some level of scepticism, as you've asked some very beginner questions here, in the past.

author: Cliff Matthews
author_rank: Unknown
timestamp: January 15, 2019, 01:11:43 am
content: A similar courseseems offered here, is this a work-in-progress? or something already published?

author: ocset
author_rank: Super Contributor
timestamp: January 15, 2019, 06:09:05 am
content: There is a lot of finished work in there, annotated sims for people to run.But i do update it regularly.
SMPS has blown the current sense resistor - Page 1
Forum section: electronics / beginners

author: gck303
author_rank: Newbie
timestamp: July 11, 2025, 08:09:16 pm
content: I have a SMPS and an trying to get it back up and running. Attached is the schematic.I blew up the IC by accident when a probe slipped. yeah, I won't ever be making THAT mistake again.After replacing the IC I then made another rooky error by not using a series limiting bulb when powering it up for the first time. Ditto.It then blew up the 0.5ohm resistor connected to the CS pin of the IC. Why did it do that?I can't see, or find, any obvious fault... but obviously there is!

author: chilternview
author_rank: Frequent Contributor
timestamp: July 11, 2025, 10:15:09 pm
content: Replacement IC a fake or faulty? Or maybe a bridged solder joint betwween pins?

author: gck303
author_rank: Newbie
timestamp: July 11, 2025, 10:57:42 pm
content: I had not though that it was not original , until you asked the question.I bought from eBay (local seller)…. So it might well be fake.

author: floobydust
author_rank: Super Contributor
timestamp: July 11, 2025, 11:20:54 pm
content: You need a new IC and likely the opto-coupler is damaged as well.

author: gck303
author_rank: Newbie
timestamp: July 11, 2025, 11:32:44 pm
content: I will check the optic outlets, there are two.I am assuming that the blower resistor has been caused by a duff IC. And it could not be anything else?

author: floobydust
author_rank: Super Contributor
timestamp: July 12, 2025, 12:16:15 am
content: You slipped with a probe so anything could have been killed that was touched by it. Hard to guess what parts are dead- but for sure the IC, current-sense resistor, opto are the predicted. Oh, and use a dim bulb to power it up....

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 12, 2025, 03:04:43 pm
content: Considering your other brilliant movesyou probably soldered in the IC upside down.A solder bridge between pins 3 and 4 would also get you pretty close to an exploding shunt resistor.
SMPS in series for 60vdc? - Page 1
Forum section: electronics / beginners

author: usagi
author_rank: Frequent Contributor
timestamp: March 24, 2017, 08:39:12 am
content: I have a device which wants ~1500W max at 60vdc.Rather difficult to come by a single 1500W 60vdc psu for any reasonable price.I'd like to run several 500W 20vdc smps in series to achieve this. They are relatively inexpensive and plentiful.Aside from grounding issues, anything else I should be aware of?

author: Rerouter
author_rank: Super Contributor
timestamp: March 24, 2017, 08:51:17 am
content: fit a fuse between each supply connection,use floating output supplies, and make sure they are all powered from the same power source, so when you go to turn things off you only need to flick 1 switch,other than that, perhaps a 18k resistor between your outputs to bleed off any capacitance.

author: Zero999
author_rank: Super Contributor
timestamp: March 24, 2017, 08:58:29 am
content: As long as the output is isolated, then it should be fine. I've done a similar thing myself to get a +90V -70V supply from 24V and 48V power supplies. I picked units with voltage adjustment so I could fine tune the output.

author: Benta
author_rank: Super Contributor
timestamp: March 24, 2017, 09:14:05 am
content: There is a small risk of beat frequencies at the combined output, as all three will not be switching at exactly the same frequency.Built-in power supplies are usually synchronized, which isn't an option here.Be prepared that you may need extra filtering if the issue arises.

author: samofab
author_rank: Regular Contributor
timestamp: March 24, 2017, 08:23:53 pm
content: HP ESP-120 48V server power supply can be modified to go to (almost?) 60V. They can be found for relatively little money. Slightly off topic but perhaps it helps.

author: Seekonk
author_rank: Super Contributor
timestamp: March 24, 2017, 08:49:05 pm
content: Not knowing the supplies chosen, I would put a diode in parallel with each output in case one of the supplies should turn off for some reason.

author: james_s
author_rank: Super Contributor
timestamp: March 24, 2017, 08:59:14 pm
content: I run a pair of 675W hot swap server PSUs in series to power a large RC LiPo charger, there are a lot of people doing this. I had to perform a minor modification to the power supplies to isolate the DC ground from the earth ground. It should be possible to connect more of them in series, the highest I've tried was 3 and that worked fine.

author: usagi
author_rank: Frequent Contributor
timestamp: April 12, 2017, 08:01:33 am
content: picked up two sorensen dcs33-33em47 PSUs for $35/ea. i think i'm set now
SMPS in series function - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 08, 2017, 07:46:26 am
content: 1. I need to make 200Vdc/5Adc SMPS from 220Vac/50Hz.2. Its very high dc voltage. But I have 50Vdc/5A SMPS which has internal current limiting i.e if load ever tries to draw more than 5A from it, SMPS will go to CC mode.3. can I connect 4 smps in series to make 200vdc/5A?4. Can it work? What could be pitfalls? havent tried it myself as I dont know if something can went wrong?

author: oldway
author_rank: Super Contributor
timestamp: July 08, 2017, 09:53:52 am
content: First of all, it is, as you say, a high tension with high risks.Should the 200Vdc voltage have to be adjustable? If yes, how much?What is the ripple allowed to 5A?What is the requested regulation?What is the grounding scheme? Should the 200Vdc be grounded? If yes, the + or -?To answer your question,"Can I connect 4 smps in series to make 200vdc / 5A?"No, because the last power supply will have a potential of 150V with respect to earth, this is not acceptable with respect to the case that must be earthed, or with respect to the insulation of the ferrite transformer.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 08, 2017, 10:45:25 am
content: found this, on page5, it explains.https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwja0fbWuPnUAhVIKpQKHVO_AfYQFghCMAQ&url=http://www.nextys.com/files/sito/application_notes/AN004_Parallel_and_Series_Connection_of_Power_Supplies_V1-0.pdf&usg=AFQjCNFvBIW2cYzsVKNrubM_SFPHYDjIFg

author: b_force
author_rank: Super Contributor
timestamp: July 08, 2017, 11:48:09 am
content: In depends on the topology they are using.If they are floating (insulated), I think it's possible.For example, you can use Meanwell power supplies in series and symmetric mode (a plus and minus voltage).Meanwell is also pretty affordable, so I would just write them an e-mail with this question.

author: Avacee
author_rank: Unknown
timestamp: July 08, 2017, 12:32:36 pm
content: I'm ignorant of putting supplies in series but wouldn't the first SMPS in the series have to provide 20A at 50V to equal the 1000W wanted overall? - which is above the 5A current limit.Then the second at 100V provides 10A.. the third 6.66A.. the fourth 5A at 200V.And that's assuming 100% efficiency...

author: b_force
author_rank: Super Contributor
timestamp: July 08, 2017, 12:41:16 pm
content: Quote from: Avacee on July 08, 2017, 12:32:36 pmNo, They just need to be the same current (power) rating.Of course you can use a power supply with an higher rating if you need other voltages as well.
SMPS LED bulbs dying running off dimmer switch - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 30, 2018, 09:56:29 am
content: In a rental house someone has a dimmer switch for some of the mains 120V lights. And were using LED bulbs, and 1/2 of them stopped working. IDK if they used the dimmer or not.I opened 1 up figuring a series LED fried, but they all work. There's some type of buck converter in there. I mapped it all out but to me the design seems very strange so far. There's 1 inductor that must be open, so maybe I found the problem.In general tho none of the "eco" bulbs with a SMPS in the socket should ever be used with a dimmer switch right ?I should tell the landlord either use incandescent's or take out the dimmer (since tenants can't be trusted with simple instructions like don't use the dimmer)

author: Zero999
author_rank: Super Contributor
timestamp: July 30, 2018, 10:30:22 am
content: As a general rule, LED lamps cannot be used with a standard dimmer circuit. It can cause problems with flicker, damage to the lamps or dimmer circuit.Special LED lamps which are designed to work with a standard dimmer circuit can be purchased, but they're more expensive and are slightly less efficient.

author: JS
author_rank: Frequent Contributor
timestamp: July 31, 2018, 03:25:56 pm
content: Yes, put a switch, incandescent or dimmerable lamps.JS

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2018, 04:40:06 pm
content: My observation is that about 80% of the LED bulbs from reputable brands can be used on dimmers. Special LED rated dimmers are preferable but most will work to some degree on a standard dimmer. If in doubt, look at the package, it will say. I have lots of Philips, Cree and Feit LED bulbs that are dimmable.