hybridfree/eevblog-posts huggingface dataset:
Unknown IC  - Page 1
Forum section: electronics / beginners

author: shobo
author_rank: Regular Contributor
timestamp: December 21, 2016, 10:08:53 pm
content: Hi all,Can someone help me identify this IC?https://scontent.fotp1-1.fna.fbcdn.net/v/t34.0-12/15666404_1269153669815864_296832328_n.jpg?oh=66b49957ac1bcf49715707cdb4c0aa4f&oe=585DB1EEIt is from a Tamura HBL-0353 laptop dual CCFL that i want to hack into a desk lamp.

author: Productions0Red
author_rank: Newbie
timestamp: December 21, 2016, 10:20:22 pm
content: That's one heck of a generic chip you got there! Google couldn't find it neither most datasheet databases. I would guess it would be some sort of an inverter, voltage controller or an over voltage/current chip. It could also be a voltage booster since those lamps are quite beefy!

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: December 26, 2016, 05:44:41 am
content: The link is dead....

author: shobo
author_rank: Regular Contributor
timestamp: December 29, 2016, 03:02:34 pm
content: Quote from: kiran_shrestha on December 26, 2016, 05:44:41 amhttps://scontent.fotp1-2.fna.fbcdn.net/v/t34.0-12/15666404_1269153669815864_296832328_n.jpg?oh=7325529a6e4f29640dd6f6d182f07ccb&oe=58683DEEhope this one works

author: elecman14
author_rank: Unknown
timestamp: December 29, 2016, 03:41:34 pm
content: Not the IC but it looks like you can get a datasheet for the entire module:http://www.tamuracorp.com/clientuploads/pdfs/engineeringdocs/HBL-0335.pdfMy hunt also turned up with nothing

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: January 02, 2017, 01:09:34 am
content: Dont know why I always get "URL signature expired" so sorry .. keep banging ur head

author: shobo
author_rank: Regular Contributor
timestamp: January 03, 2017, 08:41:57 pm
content: Quote from: kiran_shrestha on January 02, 2017, 01:09:34 am

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: January 04, 2017, 01:58:54 am
content: Sorry man no luck , might be some copied IC by Chinese manufacturer.
Unknown ICs? - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: November 04, 2017, 09:06:16 pm
content: I got a grab-bag with about 100 ICs in it, and after some difficulties I identified all but a few Motorola chips. You can see the chips in the image - here's what written on them. Google comes up pretty empty when I search on the only part that changes between each chip:All:WP-90409L610116Then each chip have a slightly different text on the bottom:1: CPMJ99062: CPPF99053: CPDG9905I expected the bag to consist of basic 7400/CMOS 4000 series chips - all everything else but these fit that.I have a few other chips all Motorola with MC14556B followed by different CPD numbers on them.USUALLY I have no problems finding component datasheets using basic search engines. But these come up empty. So maybe there's a better way to find (obsure?) ICs than just googling what's printed on them?

author: Andy Watson
author_rank: Super Contributor
timestamp: November 04, 2017, 09:16:41 pm
content: Could they be MC 10116 ?http://pdf.datasheetcatalog.com/datasheet/motorola/MC10116FN.pdf

author: bitman
author_rank: Unknown
timestamp: November 05, 2017, 01:36:54 am
content: Quote from: Andy Watson on November 04, 2017, 09:16:41 pmNot that I claim to know - but that would make them very very different from the 7400/4000 series which are usually "gates" of some kind.

author: jmelson
author_rank: Super Contributor
timestamp: November 05, 2017, 02:50:48 am
content: Quote from: Andy Watson on November 04, 2017, 09:16:41 pmYUP, very likely to be 10116, triple differential-in, differential-out line receiver, part of the MECL 10K series. The 990x numbers are likely the date code, preceded by a lot or factory ID.Jon

author: amyk
author_rank: Super Contributor
timestamp: November 05, 2017, 03:29:27 am
content: Quote from: jmelson on November 05, 2017, 02:50:48 amThe package and code matches, but the one thing that would make me refuse a 100% ID is the fact that all the other pictures of MC10116 I can find online have onlytwolines of marking, explicitly saying "MC10116" on them.

author: SeanB
author_rank: Super Contributor
timestamp: November 05, 2017, 05:57:31 am
content: Motorola was very easy to get a custom part number out of, they would happily mark any large lot purchase with a customer supplied part number if asked, it was part of the standard order info if you were buying in bulk. That there are 3 different batch number means this was either a regular IC marked as such, or a custom interconnect mask for some customer who wanted a slight variant on some die they made, and who ordered enough of them.The usual DMM diode check things will at least get you info as to what are inputs, outputs and power and ground pins, so you can class the IC into an appropriate logic or analogue family and further class it if logic or linear into a rough type category ( if a logic then TTL x input y output and rough pinouts) and from there a breadboard, some resistors and a current limited supply will give a logic map to tell you what it is.
Unknown ID of TO-18 transistor - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: May 20, 2019, 12:01:23 am
content: Scored a bag of 100 NOS gold lead TO-18 PNP transistors for 50-cents, but can't find the specs anywhere. Sorted them on the transistor tester all are fine (they're SI and HFE's score from 100 to 250). Any hunches on aMotorola 3-093 026??

author: bob91343
author_rank: Super Contributor
timestamp: May 20, 2019, 02:00:34 am
content: I have no definitive information but I would guess they are silicon high frequency units, perhaps 25 to 40 Volt rating. You can use them for casual, uncritical purposes. With that many of them you can have some fun building circuits. In fact if you build a high frequency oscillator you can discover if it's a high frequency transistor. Failing that, you can simply drive it with a fast pulse and see how much it degrades the rise time.I have many drawers full of unmarked transistors and others with strange markings. I use them here and there as general purpose units. Some are extremely high gain Darlington types. Lots of PNP and NPN. Most are the little plastic half round, I think TO-92 or something.I scavenge parts from defunct equipment such as monitors and computers and so on. It's amazing how useful those parts can be. Great rectifiers as well, capacitors, flame proof resistors, relays, LEDs, the list is long and my storehouse overflowing. Most of them are numbered and I can look them up on the web but not all.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: May 21, 2019, 02:09:02 am
content: That number is not necessarely a Motorola designation. Even if the number does not produce any hits, compare the number structure with known number systems, such as ECG, Tektronix, HP, IBM..That might give you an idea whose part that really is.
unknown LCD - usable? if so, how? - Page 1
Forum section: electronics / beginners

author: dont even trip dawg
author_rank: Newbie
timestamp: March 11, 2017, 01:28:20 pm
content: So, i took apart a broken printer (brother DCP 375CW) and among other nice stuff found an LCD. It has 16 characters in one line and 6 pins. Although there are no markings or numbers on the unit itself i found the model number using some spare parts website but no datasheet.

author: macboy
author_rank: Super Contributor
timestamp: March 11, 2017, 01:43:54 pm
content: Don't bother. You can buy a comparable new LCD with known interface for a couple dollars.

author: sentry7
author_rank: Regular Contributor
timestamp: March 11, 2017, 01:55:28 pm
content: I'd have to agree with macboy.Adafruit has a nice high-contrast display, and it's even got a backlight with brightness control.

author: dont even trip dawg
author_rank: Newbie
timestamp: March 11, 2017, 02:10:32 pm
content: whoops post wasn't even complete and sent by accidentbut thank you, was expecting it to not be feasible either way

author: amyk
author_rank: Super Contributor
timestamp: March 11, 2017, 05:05:00 pm
content: There is aservice manual (ignore the filename, this is apparently a family of models)for that printer, containing schematics, which labels the pins as:1 DATA (serial data)2 SCK (serial clock)3 STB (strobe)4 VREF (contrast reference voltage)5 VSS (power)6 VDD (power)If you have the board that drives it, a logic analyser will be sufficient to determine the protocol/controller it uses. But a preliminary Googling of the signal names leads me to some NEC LCD controllers, so you could continue down that route.I think it's always better to reuse existing parts even if you have to figure out how, plus the analysis will give you a good learning experience.

author: james_s
author_rank: Super Contributor
timestamp: March 12, 2017, 05:37:18 am
content: Not to mention it's fun. If you still have the board for the printer and can power it up, you could use a logic analyzer or DSO to capture the communications to the display and work out how to drive it.
Unknown meter movement testing. Soon to be calibration... - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 11, 2012, 10:31:37 pm
content: I bought two ostensibly the same D'Arsonval meter movements marked 0 to 500uA FSD.Turns out they are not the same. I did the following test, which I THINK is the correct method. I connected two 1.5 volt batteries in series (as they were conveniently laying around with wires soldered to them) and a decade resistance box in series with them, and a meter. I started with a very high resistance and lowered it until I achieved FSD on one of the meters. I measured the voltage drop across the decade resistance box. I noted the resistance I had to set the box to in order to achieve FSD. Here are the figures for the two meters:Meter 1: 2.939 volts and 6K resistance. Meter 1 appears to be a 50uA, I think? Or have I got the decimal point wrong, and it's 500uA?Meter 2 : 2.910 volts and 14.3k resistance. Meter 2 appears to be a 20uA, I think? Or decimal point wrong again, and it's 200uA?Oh dear, I should have listened to the nice man in the gown better....I am hopeless at maths, really HOPELESSThanks!

author: vk6zgo
author_rank: Super Contributor
timestamp: November 12, 2012, 12:19:15 am
content: Well,if your other figures are correct one is 500uA,& the other one is 200uA.More quality control problems in the dear old PRC?
Unknown mistery SMD component marked VAH5; What is it ? - Page 1
Forum section: electronics / beginners

author: brainport
author_rank: Newbie
timestamp: February 29, 2024, 01:15:07 pm
content: I searched various sites from NXP and Seiko and general ones but have no clue what it is." alt="" class="bbc_img" />Known : SOT-23 case, measured high Ohmic values between the terminals.I expect it is not a simple diode or transistor, or some defective since I received it unused.Where to search next ?I tried to insert an image, but I don't see the attached uploaded image when I post the message.Quote : "Attached:Uncheck the attachments you no longer want attached:VAH5.png [Insert Attachment 1 in the message]"

author: Terry Bites
author_rank: Super Contributor
timestamp: March 04, 2024, 09:14:12 am
content: https://smd.yooneed.one/code5648.html
unknown part: DP5321 2248F 40 pin QFN - lowercase d and p in a square logo - Page 1
Forum section: electronics / beginners

author: jpyeron
author_rank: Regular Contributor
timestamp: May 12, 2023, 02:42:44 am
content: Anyone have a lead on the manufacturer or even better a datasheet?It is from RF side of a NFC circuit.

author: ataradov
author_rank: Super Contributor
timestamp: May 12, 2023, 03:27:04 am
content: No idea on the logo, but it is pretty searchable. Here is one resulthttps://blog.csdn.net/yolanda97/article/details/117086266The page says that is is pin to pin compatible with thishttps://www.nxp.com/docs/en/nxp/data-sheets/PN532_C1.pdf

author: jpyeron
author_rank: Regular Contributor
timestamp: May 12, 2023, 11:29:50 am
content: Quote from: ataradov on May 12, 2023, 03:27:04 amYou are Super Contributor, thanks. Ug my google prefs excluded Chinese - fixed.I was looking at the NXP suspecting the same.
Unknown serial communication protocol - Page 1
Forum section: electronics / beginners

author: BSYS
author_rank: Newbie
timestamp: January 12, 2022, 01:46:42 pm
content: Thanks

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 12, 2022, 02:12:23 pm
content: i looked to me like it is a IR remote control code. i think they just reused the code, minus the modulation.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 13, 2022, 01:42:14 pm
content: You are correct. It is the NEC IR coding scheme:https://exploreembedded.com/wiki/NEC_IR_Remote_Control_Interface_with_8051
Unknown Solder Tips - Page 1
Forum section: electronics / beginners

author: SharkyMoto
author_rank: Newbie
timestamp: October 03, 2018, 05:36:03 pm
content: Hello guys,i got a CFH soldering station wich i pretty like (better than nothing) but i dont know what tips i can use with it - nobody seems to have "original" ones and those i can find have the wrong dimensions for the most part. it would be nice if anyone knows what brand should fit, see the pictures for measurements.thanks a lot!

author: nanofrog
author_rank: Super Contributor
timestamp: October 03, 2018, 05:55:37 pm
content: Those look like Weller ET series tips.It appears they cloned the iron, and possibly even the electronics (different enclosure), as the original design has been around long enough the patents have almost certainly expired around the world.
Unknown symbol in Electronics Schematics - Page 1
Forum section: electronics / beginners

author: LukasElectronics
author_rank: Newbie
timestamp: February 18, 2020, 01:03:27 pm
content: I have encountered the following symbol in an electronic schematic and I do not know what it means. It is in a schematic for a PCB and I believe it might have something to do with filtering or isolating a line from noise.

author: Yansi
author_rank: Super Contributor
timestamp: February 18, 2020, 01:08:32 pm
content: Likely symbol saying that signal is a differential pair.Probably symbol from Altium.

author: tggzzz
author_rank: Super Contributor
timestamp: February 18, 2020, 01:39:02 pm
content: Show the context!

author: LukasElectronics
author_rank: Newbie
timestamp: February 18, 2020, 01:42:34 pm
content: Seems very likely that it is differential pair. I can't supply the context unfortunately.Edit: It is a differential pair made in altiumhttps://www.altium.com/documentation/altium-designer/differential-pair-routing-ad?version=18.1Thank you guys for the quick help!

author: wraper
author_rank: Unknown
timestamp: February 18, 2020, 01:44:47 pm
content: Differential pair, seems to be from Altium.
Unknown Through Hole Solder Joint - Page 1
Forum section: electronics / beginners

author: GM_Schwartz
author_rank: Newbie
timestamp: March 23, 2018, 02:33:01 am
content: Hello all,I have been desoldering some components from an old CRT TV recently, and I ran into a type of solder joint I've never seen before. You will notice a "flower pedal" pattern on the joint. This was revealed after removing most of the solder from the joint. I have been unable to find a reference to this type of connection online.The following is total speculation.I think this could be some sort of riveted connection that was added for support or to prevent easy removal of the component. What I'm imagining is something similar to the "copper rivet" image I attached, except that it's small enough to fit inside the component hole, and is slotted at the bottom. The manufacturer would flatten out the rivet on the bottom side of the circuit board during construction of the board. This could explain the "flower pedal" pattern observed on the "unknown solder joint" image.I have attached images of the type of joint from above and below. Also, I have included an image of a copper rivet, which I am imagining being inserted in the component hole.Thanks in advance to anyone who corrects me or has any more information on this.

author: drussell
author_rank: Super Contributor
timestamp: March 23, 2018, 02:47:07 am
content: Yes, it is relatively common to find those various styles of "riveted" tie-points for additional physical structure.

author: TheDane
author_rank: Regular Contributor
timestamp: March 23, 2018, 08:08:59 am
content: It seems close to a high power circuit, so it might also be used to prevent PCB damage/fire.If/when a solder joint goes bad, the resistence will go up. This will heat up the board, eventually burning it - making the fiberglass conductive carbon = bad situation.

author: TassiloH
author_rank: Regular Contributor
timestamp: March 23, 2018, 09:27:38 am
content: I would guess that is a method to protect the solder joint from mechanical stress on single sided boards. On a single sided board, a regular solder joint will take pulling on the component leads pretty well, but a pushing force will act on the glue between copper and board. That glue bond is not very strong, especially on the FR2 board you are showing. So for power semiconductors (thermal cycling/expansion) or switches/pots the rivets make sense.

author: GM_Schwartz
author_rank: Newbie
timestamp: March 23, 2018, 08:18:02 pm
content: Thanks to all for the responses. Time to work on removing them now... =)
Unknown trace origin - Page 1
Forum section: electronics / beginners

author: irondemigod
author_rank: Newbie
timestamp: June 23, 2024, 07:47:08 am
content: Hello!I am currently making a schematic from an audio board I found somewhere.During this, I found a trace coming from a capacitor, to the input of a potentiometer.The other pole of the cap is connected to ground via 1kOhm resistor.I found a cap similar to this, connected to the other pot input.(attached image of circuit board part)I need help figuring out where the trace comes from/ if and why it starts from the capacitor poleThanks!(attached image of corresponding part in my schematic)

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 23, 2024, 07:58:22 am
content: Are you sure that it is a potentiometer and not a rotary encoder. It looks like the capacitors are for de-bouncing. The way I reverse engineer this kind of boards is with a DMM and use the connectivity check to look for where a connection is going to.

author: irondemigod
author_rank: Newbie
timestamp: June 23, 2024, 08:39:48 am
content: Yes, it is a potentiometer. a thumbwheel dual-pothttps://components101.com/resistors/thumbwheel-potentiometer-5-terminalalso, the traces in question leads to the positive audio inputs of the amp IC (IN1+ and IN2+)isn't debouncing used for buttons?i have attached more pictures in the original post. please check them out

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 23, 2024, 08:50:55 am
content: Quote from: irondemigod on June 23, 2024, 08:39:48 amCorrect, and that is what more or less is inside a rotary encoder.But for a potentiometer filtering can also be useful, and that is what capacitors in combination with resistors do. Filter.I will check your added pictures.Edit1: Pin 1 of the potentiometer is connected to ground, and my guess is that the left and right inputs are connected to the pins 4 and 5. On the backside of the board it might be that the signals are lead to the other side with vias, but I'm not sure about that.Edit2: After a better look it seems the signals are connected at the other side of the capacitors and come from the two transistors below near R157 and R172, and the capacitors are for decoupling to get rid of a DC component.
Unknown wire to board connector - Page 1
Forum section: electronics / beginners

author: matkar
author_rank: Regular Contributor
timestamp: January 26, 2015, 11:46:02 pm
content: Does anybody recognise the connector type/manufacturer from the picture?I've been searching at all major sellers and producers, but had no luck.The pitch is 2,54 or 2,5mm. I can't tell.Any help much appreciated!
Unmarked surface mount "tantalum capacitor," what is it really? - Page 1
Forum section: electronics / beginners

author: grenert
author_rank: Frequent Contributor
timestamp: March 01, 2015, 12:12:05 am
content: I bought several of these components in a grab bag of tantalum capacitors purchased from a surplus seller. However, despite its yellow color, it does not appear to be a capacitor. It essentially measures as a short circuit in both directions across the terminals. It conducts in both directions. Obviously, there is no capacitance.My guess is that it's some kind of fuse, but I really don't know.I broke open a couple, and there's a black compound on the inside.Any idea what it is?

author: John Coloccia
author_rank: Super Contributor
timestamp: March 01, 2015, 12:34:18 am
content: At a minimum, a tantalum capacitor would have the polarity marked somehow, so that's probably not a tantalum cap.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 01, 2015, 01:25:27 am
content: There should also be a hard slug of sintered tantalum inside, not just black stuff (black or brown stuff is, however, a key component of regular dry slug tantalums!).Perhaps they were incorrectly manufactured and are little more than resistors anymore?Tim

author: sleemanj
author_rank: Super Contributor
timestamp: March 01, 2015, 04:02:22 am
content: My guess, inductor.Usually grey-black, but no reason they couldn't be yellow-tan.http://www.vishay.com/inductors/

author: Zero999
author_rank: Super Contributor
timestamp: March 01, 2015, 10:18:19 am
content: Either way it's not what you asked for so put the seller on your blacklist.

author: JuKu
author_rank: Frequent Contributor
timestamp: March 01, 2015, 10:33:15 am
content: Yes, looks like a Vishay inductor, that has been taken off from a scrap board. Those are not a surplus (meaning unsold stock) parts, those are salvaged parts, that have been soldered at least once already. Clearly, the workers that take off parts from boards (and eventually die from the toxic fumes) sort the part by a criteria "yellow box= tantalum cap".

author: grenert
author_rank: Frequent Contributor
timestamp: March 01, 2015, 03:08:13 pm
content: Quote from: sleemanj on March 01, 2015, 04:02:22 amDing-ding-ding, that's the winner! They test out as 4.7uH inductors. Thanks!I think these actually are new/surplus, rather than salvaged. I was the one who tinned the leads on a couple of parts in the photo. Thought I was going to test them out in a simple circuit, but then thought the better of that idea. The seller is still on my blacklist, though

author: SeanB
author_rank: Super Contributor
timestamp: March 01, 2015, 05:15:44 pm
content: If surplus and "new" they probably are the sweepings out of a PNP machine factory, swept up at the end of shift and then sorted by size and colour. wonder if they do resistors and transistor assorted packs as well.
unpopulated circuits - Page 1
Forum section: electronics / beginners

author: guygibbs
author_rank: Newbie
timestamp: February 20, 2015, 09:52:03 pm
content: I'm sorry for the newbie question but I've noticed a few boards ex. Power supply 5v has unpopulated capacitors and resistors going to a +12v -12v terminal . I've noticed this in a other types of boards and I'm curious if they have the board labeled well can I add in those unpopulated components to get the extra features rather than only the +5v and 0v? Thanks in advance for taking time to help a newbie

author: Simon
author_rank: Unknown
timestamp: February 20, 2015, 09:53:20 pm
content: The simple answer is no idea, other parts that are there may need to be different.

author: guygibbs
author_rank: Newbie
timestamp: February 20, 2015, 10:01:12 pm
content: Ah I see! I didn't think of that and I did notice one cap on the 5v. Side labeled incorrectly so that sounds like what you have said . Thanks so much for the time to reply.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 21, 2015, 07:09:43 am
content: There's kind of three reasons for DNP's (Do-Not-Populate):- Some parts were removed in production (or considered for addition, but ended up not needed), often for EMC (electromagnetic compliance -- electrical noise) purposes,- Using the same PCB to market different models (in the case of the power supply, different voltages, currents and combinations),- Enhanced/improved/stripped down versions, variants, stuff like that; a cell phone without the accelerometer to save cost or whatever.If you had the BOM (Bill Of Materials) for the variants... you absolutely could stuff the parts, and play with it. But unless you know exactly what it was intended for... it's just a bunch of traces connecting pads, no? You could build any circuit that uses the same topology with the same size components!Tim

author: John Coloccia
author_rank: Super Contributor
timestamp: February 21, 2015, 12:18:06 pm
content: I often have unpopulated components on my boards, and they're marked as "TBD" on my schematic. What happens is something like this:-I have some section I'm unsure about, such as wondering if I need to stick a capacitor in a gain stage to keep from picking up radio stations...things like that. So I design it in, and worry about it later.-Some time later, after I've spun the board once or twice and finalized the design, I decide the cap is unnecessary. Well, at this point I'm not going to redo the artwork to update it because that would require doing yet another prototype run to insure that I haven't messed something else up in the process. When you order hundreds of boards at a time, you simply can't afford to take a chance, even on a trivial change.So the boards get incorporated into my product, and there are inevitably a couple of components that don't get populated.
Unregulated dc-dc isolated converters - Page 1
Forum section: electronics / beginners

author: Asim
author_rank: Regular Contributor
timestamp: November 20, 2014, 06:43:27 am
content: Hello everyone,I am making a project that needs +5v,+12v,-12v supplies. I need it to be portable and small so I had the idea of using a power bank that will give me the 5v. I will also use a DC-DC isolated converter that will take the 5v and give an output of +15&-15 isolated with 1 watts for each rail. These high rails will only power a dual op amp.My question is:Can i get away without regulating the rails?Expected current is less than 40 mA for the high rails

author: Asim
author_rank: Regular Contributor
timestamp: November 20, 2014, 06:57:27 am
content: The op amp will be the front end of a simple function generator

author: kizzap
author_rank: Unknown
timestamp: November 20, 2014, 09:03:04 am
content: It depends on the op-amp. Also it depends on the noise that the DC-DC converter puts out.

author: Seekonk
author_rank: Super Contributor
timestamp: November 20, 2014, 12:44:54 pm
content: It is likely that it can, but do you REALLY need two rails?.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 20, 2014, 02:03:18 pm
content: Does it have to be isolated? Can you not stack 3V above and below the 12V rails?Also, why does it require 12V rails if you obviously require 15V rails?Tim

author: macboy
author_rank: Super Contributor
timestamp: November 20, 2014, 02:04:02 pm
content: Does it really need to be isolated, that is, floating with respect to the +5V supply? Do they really not share a common ground?Old thin net (10Base-2) ethernet cards often had an isolated 5 V to 9 V (or 12) converter. This converter powered the 10Base-2 Phy, which could not be ground referenced to the computer, otherwise there would be a huge ground loop created by the ethernet cable. With 10Base-T and other twisted pair ethernet, the isolation uses a transformer on the ethernet signal instead. If you can find one of these old ethenet cards, you could salvage the converter. You can of course buy these too.After you have one 9 V supply, getting the other is easy. There are common small ICs to provide a negative rail from a positive one, like MAX1044, TC0144, LT1054, etc.If you don't need an isolated supply, and if you can operate from +/-5V, then just use the converter IC above to create the -5 V rail. Using XR-2206? Try it this way.

author: Asim
author_rank: Regular Contributor
timestamp: November 20, 2014, 05:55:17 pm
content: Actually it is DDS, the 5 v for the microcontroller. The other rails for the op amp so i can have a signal that i can vary its amplitude and bias

author: Jeroen3
author_rank: Super Contributor
timestamp: November 20, 2014, 06:03:34 pm
content: You might get away with an inverting supply.+12V input, LDO to +5V, and than you invert some to -12V.An isolated supply (such as recom RB-0505S) makes it flexible, since they don't care if they are boosting or inverting, or just isolating.Those isolated recom modules aren't regulated very strictly, but you can get very efficiënt LDO supply IC's for a little bit of power.
Unspecified units in schematic - Page 1
Forum section: electronics / beginners

author: joeyjoejoe
author_rank: Frequent Contributor
timestamp: November 26, 2018, 01:50:18 am
content: Any chance of knowing what the values for C1, C15, etc are? C16 has units, the rest however, do not. Is that normal?

author: ataradov
author_rank: Super Contributor
timestamp: November 26, 2018, 02:03:35 am
content: They are specified in a way they are labeled on the capacitors.104 == 0.1 uF, 475 = 4.7 uF.Here is the referencehttp://www.robotoid.com/appnotes/electronics-capacitor-markings.html

author: joeyjoejoe
author_rank: Frequent Contributor
timestamp: November 26, 2018, 02:11:00 am
content: Thank you. Didn't even think of that. Seems a bit odd in a schematic to mix and match these things?

author: ataradov
author_rank: Super Contributor
timestamp: November 26, 2018, 02:11:57 am
content: Quote from: joeyjoejoe on November 26, 2018, 02:11:00 amIt is strange, but it looks like a random Chinese schematic, so be thankful you have at least that.
unstable sawtooth at 60khz. - Page 1
Forum section: electronics / beginners

author: drm
author_rank: Contributor
timestamp: August 19, 2014, 02:39:07 am
content: hi ppl.Need help to make this pwm circuit works at 60khz.It works ok at low frequency, but sawtooth looks unstable running at 16 useg, which makes pwm out, miss some pulses or last more than it should.Attached is msim model n circuit diagram.Video showing fault:http://goo.gl/qH6NON

author: dentaku
author_rank: Frequent Contributor
timestamp: August 19, 2014, 03:49:11 pm
content: From what I see in the video it's just the software not being capable of displaying this accurately using the default settings.Change your Maximum time step (TMAX) to 1e-006 or 1e-007.Search in the HELP for the word timestep.

author: drm
author_rank: Contributor
timestamp: August 20, 2014, 01:14:31 pm
content: Already tried that with no luck, may be lm339 is a lil slow for that frequency.

author: dentaku
author_rank: Frequent Contributor
timestamp: August 20, 2014, 05:54:39 pm
content: Quote from: drm on August 20, 2014, 01:14:31 pmStrange. You should be seeing an improvement between 1e-005, 1e-006, 1e-007 .Have you tried it in LTSpice?

author: dentaku
author_rank: Frequent Contributor
timestamp: August 20, 2014, 09:08:36 pm
content: By the way, this circuit works in real life tooHere's two videos of me adjusting the PW pot.with 0.1uF cap -http://1drv.ms/1tirTSJwith 100pF cap -http://1drv.ms/1q16pHKAs you can see, it's not square anymore at high frequencies but the pulsewidth adjustment still works.

author: drm
author_rank: Contributor
timestamp: August 21, 2014, 05:30:02 pm
content: That´s right, it works.I did a mistake setting timestep.Will try with another comparator, thanks!http://goo.gl/KYSCW4

author: dentaku
author_rank: Frequent Contributor
timestamp: August 21, 2014, 09:35:53 pm
content: Quote from: drm on August 21, 2014, 05:30:02 pmNice.I'm used to Circuit Wizard and it sometimes warns you when you have your simulation settings set too fast.
Unstable Signal from JDS6600 Signal Generator? - Page 1
Forum section: electronics / beginners

author: RTKurek
author_rank: Newbie
timestamp: June 28, 2020, 09:36:55 pm
content: Hey folks!First off, apologies if this is a dumb question or I'm missing something obvious. I'm a total EE newbie!I recently picked up an oscilloscope and a cheap JDS6600-based signal generator (from Koolertron). I was hoping to create some low-voltage signals for use in learning about amplifiers. However, when I hook the generator up to the oscilloscope, it seems to have trouble locking onto the signal. It seems to do a decent job with higher frequencies and voltages, but the signal still pumps around somewhat regardless of what I do with the trigger settings. Anything below 0.5 V peak-to-peak just becomes a total mess - the scope can't determine the frequency at all.Any thoughts on what the issue could be? Bad cheapo signal generator? Bad cables? User error?Thanks!

author: Kleinstein
author_rank: Super Contributor
timestamp: June 29, 2020, 09:00:08 am
content: The waveform looks rather noisy. This could be a weakness of the generator. If really small amplitudes are needed one would better use an external attenuator (divider).The rather noisy signal is tricky to trigger. So it may need some extra function on the scope or more experience to find a good trigger setting. So there could also be some weakness with the scope. Using single trigger may work to get at least a stable picture.

author: cliffyk
author_rank: Frequent Contributor
timestamp: June 29, 2020, 12:49:50 pm
content: Could be a bad cable and/or connectors also--have you tried another?
Unsure about interpreting  - Page 1
Forum section: electronics / beginners

author: BurnedResistor
author_rank: Regular Contributor
timestamp: May 22, 2017, 08:10:13 am
content: I was looking at the SST39SF010A-55-4C-WHE Flash Memory chip for an electronics project:http://www.mouser.com.tr/ProductDetail/Microchip-Technology/SST39SF010A-55-4C-WHE/?qs=sGAEpiMZZMtLtwjrIQVJ5poS20IhCHQRvTU3jikDu7Y%3dhttp://www.mouser.com/ds/2/268/20005022C-708779.pdfAnd I am a little confused by the datasheet's explaination of the two means of detecting the completion of a write. If, because of other limitations of my system, I can ensure a write and read will always be held for the minimum amount of time, can I simply disregards this?In this case, is writing simply a case of putting the data and addresses on the bus, and pulling write enable low? Similarly, is reading a case of putting the address on the bus and pulling output enable low?

author: bktemp
author_rank: Super Contributor
timestamp: May 22, 2017, 08:57:18 am
content: Reading is simply putting the address on the bus an pulling CE and OE low.For starting a program operation you need to perform a sequence of writes, see Figure 16 on page 19.For checking write complete you have 3 options, see Figure 17 on page 20:- You can wait for 20us- You can read the programmed byte multiple times and wait until DQ6 stopps toggling every read- You can read the programmed byte wait until DQ7 contains the valid state and not inverted

author: BurnedResistor
author_rank: Regular Contributor
timestamp: May 22, 2017, 11:23:26 am
content: So If I wanted to perform a single write to a single address, I put the data and address on the bus, and pull the WE pin?

author: bktemp
author_rank: Super Contributor
timestamp: May 22, 2017, 11:58:04 am
content: Yes, but you need to perform the byte write sequence:First you put data 0xAA and address 0x5555 on the bus (the upper addessbits don't care) and pulse WR low.The you put data 0x55 and address 0x2AAA on the bus (the upper addessbits don't care) and pulse WR low.The you put data 0xA0 and address 0x5555 on the bus (the upper addessbits don't care) and pulse WR low.And finally you put the data you want to write and address where you want to write on the bus and pulse WR low.After that you wait until write is done.This sequence is used to prevent accidental writes, because this sequence with its alternating values is highly unlikely to happen unintentionally.Before you can write data, the address location needs to be erased.Erasing works similar to writing, but uses a slighty different sequence.
Unused D+ D- on USB - Page 1
Forum section: electronics / beginners

author: uprightsquire
author_rank: Contributor
timestamp: April 07, 2013, 04:22:38 am
content: If i use USB as a source of 5v, can I just leave the D+ and D- floating? What happens if this is connected to a computer?

author: c4757p
author_rank: Super Contributor
timestamp: April 07, 2013, 04:45:28 am
content: Short answer: Yes, you can, and nothing happens.Long answer: Read the USB spec if you're not just doing this on your own computer.

author: digsys
author_rank: Unknown
timestamp: April 07, 2013, 05:24:31 am
content: I always leave provision for a terminating / id# resistor. Never had to use it and most systems don't bother checking for it,but you need to be aware of it !! The specs explain what the values mean.

author: amyk
author_rank: Super Contributor
timestamp: April 07, 2013, 10:44:25 am
content: The USB specs are actually quite readable. Much better than ISO's standards at least...
Unused oscillator - Page 1
Forum section: electronics / beginners

author: Alex
author_rank: Regular Contributor
timestamp: September 12, 2014, 10:03:01 am
content: I've got a PIC MCU that has RTC functionality programmed into it and uses a typical external 32kHz crystal. The core is clocked using the internal RC oscillator.In the application I will be using it I do not require the RTC functionality. What is the optimum (electrically) way to disable the internal part of the oscillator? I do not have access to the firmware.I have attached a schematic of the Pierce-type oscillator.How about a pulldown resistor to ground at the input of the inverter? 100k?A

author: fcb
author_rank: Super Contributor
timestamp: September 13, 2014, 08:18:29 am
content: A pull-down will work fine on the input - are you removing the xtal as well? If not, then you need to make sure your pull-down is low enough to stop it oscillating.
Unusual old german PSU transformers stage - Page 1
Forum section: electronics / beginners

author: Francenthusiast
author_rank: Contributor
timestamp: October 01, 2016, 03:58:58 pm
content: Hi !A friend gave me that old german power supply and I try to understand the hot stage before the bridge rectifier.Why the two transformers are that big ? (I mean T1 is only powering the relay, why is it the same size as T2 ?)How the relay is acting on them ? I guess that the relay is here as a short circuit protection, but I can't decipher the schematic with the centred taps... Any good soul to help me ?Here is the schematic I found on internet and the list of components :Thank you very much !

author: oldway
author_rank: Super Contributor
timestamp: October 01, 2016, 04:51:49 pm
content: QuoteThe two transformers are in parallel, they both are used the same way.

author: Francenthusiast
author_rank: Contributor
timestamp: October 01, 2016, 05:26:07 pm
content: Ok, so I may understand: the voltage divider composed of R34 R35 & R36 bias the V12 zener at a certain voltage, then bias the base of the NPN V11, it shorts to ground the PNP V9 that activates the relay. And I guess that, as the relay controls the center taps of both transformers, it doubles the output transformer voltage when the voltage divider reach the V12 bias voltage. Maybe to lower the voltage drop in the power transistors ?Am I correct ?

author: SeanB
author_rank: Super Contributor
timestamp: October 01, 2016, 08:22:24 pm
content: Yes, it allows full power at low voltage settings by dropping input voltage to the regulator stage. More modern ones will use a single transformer with more tap points, but use the same principle of trying to keep the voltage across the pass transistors as low as possible.

author: Francenthusiast
author_rank: Contributor
timestamp: October 01, 2016, 10:48:10 pm
content: Thank you for the confirmation SeanB, I'm kind of proud of myself deciphering this even if it's very simple !
Unwanted negative spike on the output of resetable charge amplifier - Page 1
Forum section: electronics / beginners

author: rgawron
author_rank: Contributor
timestamp: August 08, 2020, 02:49:00 pm
content: I try to simulate charge amplifier, it will be used as a first stage for photomultiplier tube. It doesn't have resistor in parallel to feedback capacitor (C1), instead, when output voltage is close to supply voltage, feedback capacitor is discharged by a transistor (J4).I found this idea somewhere on the internet, but it was just briefly described, the idea was to avoid noise created by (high value) resistor in feedback loop.I came with circuit presented below, it kind of works, but when the capacitor is discharged, a rellativelly huge voltage spike is visible on the output.How can I improve my design to remove this spike?Does below circuit contains other errors?Here is link to the LTSpice simulation file:https://github.com/RobertGawron/PhotomultiplierRadioactivityDetector/tree/master/Simulation/ChargeAmplifierWithAutomaticalReset

author: StillTrying
author_rank: Super Contributor
timestamp: August 09, 2020, 11:37:14 am
content: "relatively huge voltage spike is visible on the output."Maybe the junction capacitances of the J4 transistor, you could try highering that 5 miliohm resistor quite a bit to reduce the spike current and add a low-ish resistance in series with the J4's gate.The LTC6268/LTC6269 supplies are 5V max. total. I couldn't get the github .asc to load.

author: rgawron
author_rank: Contributor
timestamp: August 09, 2020, 07:07:19 pm
content: @StillTrying: thanks, I will play with it. Why gate resistor would be useful here?Here is a direct link to .asc file, GitHub adds extra .txt in filename after downloading:https://raw.githubusercontent.com/RobertGawron/PhotomultiplierRadioactivityDetector/master/Simulation/ChargeAmplifierWithAutomaticalReset/ChargeAmplifierWithAutomaticalReset.ascIt's still GitHub link, just when linking directly to a content of a file, hostname change from github.com to raw.githubusercontent.com
uP for beginner - Page 1
Forum section: electronics / beginners

author: RFTECH
author_rank: Newbie
timestamp: October 13, 2012, 12:40:15 pm
content: I'm technician in RF Communication but now i'm interresting to learn for programming uP or PIC or?. I had no base in programming.What is the best product to start!PIC or something other. My application is making board for control. What you best and easy way!- I need the type of programming- model of starting kitetc.thank you and sorry for my bad english. I'm french!

author: aluck
author_rank: Regular Contributor
timestamp: October 13, 2012, 02:23:54 pm
content: As a beginner, you have two choices - it's either PIC or Atmel. Does not really matter, which one. Pick a demo board with a programmer on ebay and go on...You did not mention if you have any programming experience. If not, then take some basic course on C programming on PC first.

author: PedroDiogo
author_rank: Regular Contributor
timestamp: October 13, 2012, 02:51:40 pm
content: I really think the best way to start is with an Arduino. You have great documentation online which will prove to be a great time saver.You can also save a few dollars buying a TI Launchpad (either the new Stellaris ones or the MSP430) which are almost free ( < 5$ ) but are a little harder to learn than the Arduino.

author: RFTECH
author_rank: Newbie
timestamp: October 13, 2012, 09:36:17 pm
content: talk me about Arduino. What type of programming you use C or something other.

author: Unknown
author_rank: Unknown
timestamp: October 13, 2012, 10:01:24 pm
content: Plenty of material for you to read:http://arduino.cc/The first paragraph mentions that the Arduino is programmed in Wiring, which is translated to C++ behind the scenes. If you find the Arduino environment limiting, you can also use the Arduino as a generic AVR development board and program it directly in C.

author: PedroDiogo
author_rank: Regular Contributor
timestamp: October 13, 2012, 10:42:36 pm
content: Quote from: RFTECH on October 13, 2012, 09:36:17 pmJeremy Blum released some nice Arduino Tutorials, you should check them:http://www.jeremyblum.com/category/arduino-tutorials

author: johnboxall
author_rank: Unknown
timestamp: October 14, 2012, 02:07:16 am
content: Quote from: RFTECH on October 13, 2012, 12:40:15 pmgreat PIC tutorial system, I have one for review at the moment. Includes assembler and C tutorials, very well done:http://www.gooligum.com.au/devboards/base-mid/base-mid.html
Upcoming Contest on the EEVBlog Forum for Beginners - Page 1
Forum section: electronics / beginners

author: xrunner
author_rank: Super Contributor
timestamp: June 17, 2017, 11:22:40 pm
content: It's been two years so it's time for another giveaway contest for beginners. No details yet other than this heads up.Remain calm - all the details will be coming in a few days ...In the meantime you can check out the first contest, this one will be very similar I think but with a few changes.2015 ContestIf you are a beginner and just reading the forum without an account, you might want to join - hint hint.No need to take any action in this thread unless you have an urge to up your post count.

author: kalel
author_rank: Frequent Contributor
timestamp: June 17, 2017, 11:56:02 pm
content: Good luck with your contest and thanks for making it. Good luck to all participants.
Upcoming Webcast - Intro to Opamps - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: July 21, 2011, 08:32:37 pm
content: This post is not intended to be an advertisement, nor am I affiliated with Element-14 or Analog Devices, I just thought that folks in this forum might find some value in this upcoming webcast on the basics of opamps.http://www.newark.com/jsp/bespoke/bespoke7.jsp?bespokepage=newark/en_US/landing/webinar/adi/adi.jsp&CMP=OAD-SOM-Twitter-Analogwebinar

author: Vertigo
author_rank: Regular Contributor
timestamp: July 25, 2011, 07:38:54 am
content: i ami hope they upload to youtube or something though, i prolly won't be awake when its on...
Update count values on the fly, PWM , STM8S003F3 - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 29, 2016, 12:57:48 pm
content: 1. I have made a PWM duty cycle generation code for STM8S00F3. I have interface dc motor using L293D. TO control the speed, I am giving PWM via a pin as in code.2. Is it ok, to change the count value of timer on the fly as in while(1) loop? TIM2_SetCompare1(cnt);3. I have checked on CRO with L293d attached, PWM works fine.Code:void all_tasks_manager(void){/* Time base configuration */TIM2_TimeBaseInit(TIM2_PRESCALER_1, 999);/* PWM1 Mode configuration: Channel1 */TIM2_OC1Init(TIM2_OCMODE_PWM1, TIM2_OUTPUTSTATE_ENABLE,CCR1_Val, TIM2_OCPOLARITY_HIGH);TIM2_OC1PreloadConfig(ENABLE);/* PWM1 Mode configuration: Channel2 */TIM2_OC2Init(TIM2_OCMODE_PWM1, TIM2_OUTPUTSTATE_ENABLE,CCR2_Val, TIM2_OCPOLARITY_HIGH);TIM2_OC2PreloadConfig(ENABLE);/* PWM1 Mode configuration: Channel3 */TIM2_OC3Init(TIM2_OCMODE_PWM1, TIM2_OUTPUTSTATE_ENABLE,CCR3_Val, TIM2_OCPOLARITY_HIGH);TIM2_OC3PreloadConfig(ENABLE);TIM2_ARRPreloadConfig(ENABLE);/* TIM2 enable counter */TIM2_Cmd(ENABLE);while(1){uint16_t cnt;for(cnt = 998U; cnt > 0U ; cnt--){TIM2_SetCompare1(cnt);}}} /* function ends here */void TIM2_SetCompare1(uint16_t Compare1){/* Set the Capture Compare1 Register value */TIM2->CCR1H = (uint8_t)(Compare1 >> 8);TIM2->CCR1L = (uint8_t)(Compare1);}
update firmware gm328B - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: May 07, 2020, 06:46:42 pm
content: I want to update a gm328b like thishttps://www.ebay.com/itm/ESR-Meter-GM328B-LCD-Transistor-Tester-Diode-PWM-Square-Wave-Generator/263884863075?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649,using an "arduino uno" as ISP, my question is.1- where do I download the latest firmware, the version that recognizes IR, rotery encoder?2- to record the new firmware I am going to use avrdude v3.3in spanishYo quiero actualizar un gm328b como estehttps://www.ebay.com/itm/ESR-Meter-GM328B-LCD-Transistor-Tester-Diode-PWM-Square-Wave-Generator/263884863075?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649usando un "arduino uno" como ISP, mi pregunta es.1- de donde descargo el ultimo firmware, la version que reconoce IR, rotery encoder?2- para grabar el nuevo firmware yo voy a usar el avrdude v3.3