hybridfree/eevblog-posts huggingface dataset:
Correct way to create a panel and how to cut them? - Page 1
Forum section: electronics / beginners

author: Ram80
author_rank: Contributor
timestamp: August 11, 2024, 09:32:15 pm
content: This guy just creates rectangles with edge cuts between the PCBs. He's using kicad.https://youtu.be/3FGNw28xBr0?t=530Is this the correct way and if so how do you cut the PCBs apart from the panel?

author: PGPG
author_rank: Frequent Contributor
timestamp: August 12, 2024, 11:13:00 am
content: If you order PCB to being scored (word from Google translator, not sure) then you simply break out each PCB.To ensure be clear: PCB gets V shape grooves on both sides leaving only a thin connection, easy to break.The other solution is milling. To make panel for milling PCBs need be positioned in some distance (typically 2mm, I think).I let making panel to contract manufacturer or PCB manufacturer as they know how many PCBs use at one panel to be optimal for format they use.

author: tszaboo
author_rank: Super Contributor
timestamp: August 12, 2024, 11:42:26 am
content: The video is not showing a very good technique.You want V-Scoring or mouse bites. Or a combination of both. This you need to cut it yourself with a milling bit or saw or something, the other two can be disassembled without tooling at home, or using standardized tooling in production.https://www.eurocircuits.com/panel-guidelines/customer-panel-basics/

author: selcuk
author_rank: Frequent Contributor
timestamp: August 12, 2024, 11:43:12 am
content: If you are using KiCAD, I recommend you to use KiKit plugin for generating panels. Deciding for V-cut or milling depends on the board shape. You can usually use V-cuts for rectangular boards.https://github.com/yaqwsx/KiKithttps://www.eevblog.com/forum/kicad/how-to-panelize-with-kicad/
Correcting USB impedance mismatch, parallel resistors? - Page 1
Forum section: electronics / beginners

author: ankeakala
author_rank: Contributor
timestamp: September 12, 2020, 12:14:09 pm
content: If I have understood it correctly, I seem to have differential impedance of 159 ohms and single-ended impedance of roughly 80 ohms. Which is way out of spec for USB. How would I correct this? Would I simply use proper value resistor to ground to bring the impedance to correct level? If I try to calculate proper trace width and separation to do that like that, I get trace width of 70 mils..

author: Siwastaja
author_rank: Super Contributor
timestamp: September 12, 2020, 12:23:03 pm
content: Bring the ground plane closer (use thinner prepreg material) so that you don't need 70mils trace. So a 4-layer PCB is practically necessary.Or, if you don't have budget for 4-layer PCB, keep the traces very short and just accept the impedance mismatch. A few cm is OK for up to USB2.1.

author: ankeakala
author_rank: Contributor
timestamp: September 12, 2020, 01:39:23 pm
content: Quote from: Siwastaja on September 12, 2020, 12:23:03 pmYes, the design goals are such that it may not be an option. And even if it was, the calculators online don't seem to support the idea that changing those factors would make big enough difference. So, not sure how one would correct for such mismatch.But, in another thread, mikeselectricstuff worded quite strongly to the direction that no, it won't make much of a difference. And worst case, maybe I need to run it at low speed which would still be perfectly fine.

author: tszaboo
author_rank: Super Contributor
timestamp: September 12, 2020, 05:13:19 pm
content: Whats the length of the trace, and what USB speed do you want to reach?

author: ankeakala
author_rank: Contributor
timestamp: September 12, 2020, 07:38:12 pm
content: Quote from: NANDBlog on September 12, 2020, 05:13:19 pmRoughly 60mm with 1mm difference between the pair. Low speed 1.5Mbit would be plenty. ATMEGA32U4 would allow that so it would work fine, if it will.

author: tszaboo
author_rank: Super Contributor
timestamp: September 12, 2020, 10:28:23 pm
content: Quote from: ankeakala on September 12, 2020, 07:38:12 pmDont worry about the impedance, connect it with two tracks next to each other. 0.3mm wide or so.If the reference guide or the datasheet has series resistor recommended, than place 0603 or 0402 size on your board.
Correctly attach negative pole to pcb - Page 1
Forum section: electronics / beginners

author: Yannik
author_rank: Unknown
timestamp: November 12, 2017, 04:39:25 pm
content: While disassembling a megaphone to clean the residue of a leaking battery, the negative wire from the battery compartment accidently came loose and now I have no idea where to resolder it to. Looking at the pcb I could not find an obvious place to put it.Unfortunately I'm not well versed enough in electronics yet to solve this myself. I'd really appreciate any tips.This is the pcb:Mirrored picture of the bottom side:Non-mirrored bottom side:The two white wires close to each other attach to the microphone, the two black ones to the speaker. The single white one is the positive pole.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: November 12, 2017, 04:46:51 pm
content: Middle bottom on the PCB side, between the DIL legs looks to me to be -ve and have a broken wire soldered there.

author: Gyro
author_rank: Super Contributor
timestamp: November 12, 2017, 04:49:31 pm
content: Possibly the square pad, centre bottom. That looks as if it is a ground net. Look very closely with a magnifier and you should be able to confirm it from visible broken wire strands.Edit: Snap!

author: Yannik
author_rank: Unknown
timestamp: November 12, 2017, 05:04:14 pm
content: Thanks alot, you guys were right!
Corroded battery readings - Page 1
Forum section: electronics / beginners

author: Causailty
author_rank: Newbie
timestamp: October 17, 2013, 12:15:53 am
content: Another question, as you all answered my last one so efficiently.Using my multimeter to measure if non rechargeable(alkaline) batteries are 'good', which has been successful.The 'bad' ones were reading mV.But one 'bad' one was reading negative mV?And a corroded 'bad' one seems to be reading inconsistently unlike the others, i.e. not one fixed number.In the hope of learning, I am wondering if there is any technical reason for this and that?

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 17, 2013, 04:35:23 am
content: Quote from: Causailty on October 17, 2013, 12:15:53 amA common reason is reverse discharge;If the battery is in a device where the batteries are in series, the current will flow through all of them, discharging them. Some will reach 0v before others, because not every battery has the same capacity or internal resistance. When the battery becomes flat, but the batteries around it are not, the battery will have a positive charge on its negative terminal and a negative charge on its positive terminal from the other batteries, with the device completing the circuit, this causes the empty battery to begin charging in reverse.Another reason may be that the chemicals in the battery behave in unexpected ways when the cells loses charge.Quote from: Causailty on October 17, 2013, 12:15:53 amThis is likely due to a poor electrical connection between your multimeter probes and the battery or the case of the battery and the internal materials, though it depends on how much it is fluctuating. The corroded terminals may still also have corrosive chemical on them, reacting with your probes creating a slight charge.

author: Causailty
author_rank: Newbie
timestamp: October 17, 2013, 03:34:44 pm
content: Awesome thanks
Corrosion on LiPo Battery Cell Wire - Page 1
Forum section: electronics / beginners

author: MuhScopeBroke
author_rank: Contributor
timestamp: March 16, 2021, 01:32:50 pm
content: I've been using a Turnigy 1600mAh 3S 30C Lipo Pack to power an automated sailboat for a few weeks now but last night I tried to re-solder a connection to the 2nd cell's parallel wire (not sure what else to call it) and ran into something weird. It was extremely brittle and coated in a white powder, essentially rendering it useless. None of the other wires were like this which leads me to believe that it is from some corrosion of the cell.I've ditched the battery as I can no longer charge it but I would still like to understand what happened so I don't do it again. Any thoughts?

author: amyk
author_rank: Super Contributor
timestamp: March 16, 2021, 01:37:11 pm
content: Quote from: MuhScopeBroke on March 16, 2021, 01:32:50 pmIn salt water? That'll definitely cause corrosion on everything... but even moisture in general tends to do that.

author: MuhScopeBroke
author_rank: Contributor
timestamp: March 16, 2021, 02:13:53 pm
content: I haven't actually used this particular battery in a wet setting yet so I can rule that out as a factor

author: SeanB
author_rank: Super Contributor
timestamp: March 16, 2021, 02:25:05 pm
content: Going to guess the wires are CCA wire, which will do this as the aluminium corrodes.
Corsair SMPS repair. - Page 1
Forum section: electronics / beginners

author: IvoS
author_rank: Frequent Contributor
timestamp: June 14, 2016, 11:16:55 pm
content: I have TX650 Corsair desktop power supply that I am trying to repair. This is really nice power supply with all Nippon Chemi-Con capacitors inside. I found one faulty diode and the PFC/PWM control chip dead. The CM6800G integrated circuit is mounted on small separate board with lot of stuff on it. The schematic is as attached on the picture. I also found shattered C18 that is SMD and I have no idea what the value of C18 should be. By looking at the schematic, it looks like C18 and R43 form a low pass filter and also holds the reference voltage on pin6. Pin6 goes to collector of photo transistor. I don't know how critical this capacitor value is on the power supply performance as it may affect the switching response and noise? I need at least a ballpark value. Can someone experienced help? Thanks.

author: uncle_bob
author_rank: Unknown
timestamp: June 15, 2016, 01:18:14 am
content: HiWhere do the pins (1,2,3,4...) off of that board go?Bob

author: IvoS
author_rank: Frequent Contributor
timestamp: June 15, 2016, 08:40:30 pm
content: Unfortunately, I don't have a full schematic, so I don't know.

author: uncle_bob
author_rank: Unknown
timestamp: June 15, 2016, 10:47:39 pm
content: Quote from: IvoS on June 15, 2016, 08:40:30 pmHiI would suggest tracing it out. It appears to be a loop compensation filter, but maybe not.Bob

author: tautech
author_rank: Super Contributor
timestamp: June 15, 2016, 11:21:56 pm
content: Be sure to check C16, the local bulk VCC cap that is normally supplied from both a resistor dropper from the HV supply and a flyback winding on the primary side of the transformer. Check flyback diodes too.

author: IvoS
author_rank: Frequent Contributor
timestamp: June 20, 2016, 08:59:07 pm
content: I found some schematic. It is not exactly the same as the Corsair is designed, but basically using same parts and concept. So, pretty much the same.The schematic can be seen in PDF file page15. You can see more stuff on the PCF/PWM control board, there also is a LM358 opamp doing something, but everything else is basically in the same connection. There are more passives added, as the CAP for example I am trying to find out its value.

author: tautech
author_rank: Super Contributor
timestamp: June 20, 2016, 09:14:58 pm
content: C18 appears to be part of a snubber/smoothing arrangement so I'd try .1uF and larger.

author: IvoS
author_rank: Frequent Contributor
timestamp: June 20, 2016, 09:24:59 pm
content: It is in a RC network of a VDC pin6, which is parallel to feedback of optotransistors. I thought the value should be much smaller, like 1nF, just to snubber the switching peeks off. But I can be wrong.

author: tautech
author_rank: Super Contributor
timestamp: June 20, 2016, 10:14:40 pm
content: Quote from: IvoS on June 20, 2016, 09:24:59 pmTry 1nF, i thought a larger value that are usually in series with a resistor.
Cortex M0 SWD programming issue. - Page 1
Forum section: electronics / beginners

author: avc4eva
author_rank: Contributor
timestamp: March 26, 2015, 09:51:05 am
content: Hi all,To keep this short and sweet:I am programming an Cortex M0 nrf51822 MCU and has been going great on another of my projects, this project (in schematic) is causing trouble programing over swd.Currently to program i am using a Keil Ulink PRO with a tc2032 tag connect to the board, i used to use the VCC from the u link/tc2032 for programing but omitted this as I can power the device by usb or LiPo while programing, however this seems to be causing issue.If i use my previous board which allows to power via the ulink the board is recognized in keil, however if i remove the power and simply power by the usb or LiPo i get nothing.Any ideas?The schematic is attached.EDIT: The TC2032 VCC was connected before to +3v3 and thus directly to the chip and not through LDO.

author: avc4eva
author_rank: Contributor
timestamp: March 26, 2015, 12:13:37 pm
content: Solved:Was due to the ulink not sharing common ground with board, now fixed!
COS6100M & Tenma 72-760 - Page 1
Forum section: electronics / beginners

author: Gmm213
author_rank: Contributor
timestamp: October 07, 2017, 03:04:30 pm
content: Figured this question is to basic for the test equipment forum but if Im wrong please move.Does anyone have info and/or experience with these scopes? I found both on the CL next city over (about 2 hrs). The COS6100M is five channel 100mhz and the 72-760 is 60mhz. They are asking $100 and $75 respectively.

author: edavid
author_rank: Super Contributor
timestamp: October 07, 2017, 04:00:44 pm
content: Quote from: Gmm213 on October 07, 2017, 03:04:30 pmThe Kikusui COS6100M is a great analog scope, and pretty easy to work on. Sometimes it can be hard to find parts. That price is a little high unless it's in extra good condition. Most of these scopes are ex-military, so you see some that are really beat up.The Tenma might be OK too, but I would avoid it, since there's no service manual available.
cosine value of x given in radian in mikroc Problem - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: July 07, 2021, 02:26:13 pm
content: Hello guys I wanted to print cosine value of x given in radian in mikroc but after conversion, the value shown is 10 times the actual value.I can't find the problem so please help meCode:sbit LCD_RS at LATB4_bit;sbit LCD_EN at LATB5_bit;sbit LCD_D4 at LATB0_bit;sbit LCD_D5 at LATB1_bit;sbit LCD_D6 at LATB2_bit;sbit LCD_D7 at LATB3_bit;sbit LCD_RS_Direction at TRISB4_bit;sbit LCD_EN_Direction at TRISB5_bit;sbit LCD_D4_Direction at TRISB0_bit;sbit LCD_D5_Direction at TRISB1_bit;sbit LCD_D6_Direction at TRISB2_bit;sbit LCD_D7_Direction at TRISB3_bit;char text;void main(){float y,x = 1.0;y = cos(X);//X is given in radianFloatToStr(y,text);Lcd_Init(); // LCD display initializationLcd_Cmd(_LCD_CURSOR_OFF); // LCD command (cursor off)Lcd_Cmd(_LCD_CLEAR); // LCD command (clear LCD)Lcd_Out(1, 1, "Trigon. cos(x): ");Lcd_Out(2, 1, "cos(1)=");Lcd_Out(2, 10, text);while(1){}}Here is the picture of my simulation in proteus

author: hexreader
author_rank: Frequent Contributor
timestamp: July 07, 2021, 03:14:01 pm
content: Answers already given on mikroC forum
Cost-effective thermal gap pad - Page 1
Forum section: electronics / beginners

author: jram
author_rank: Contributor
timestamp: August 21, 2018, 08:33:34 am
content: Hi,I have a project where I'm using 2 solid copper busbars not only for current capacity but also to conduct heat to the aluminium case for cooling. My plan is to use nylon or insulated bolts to attach them to the case and ensure a snug fit. Clearly I'll need an appropriate layer between the busbars and the case to prevent current flow but also be a competent thermal conductor. I've looked at a bunch of products that seem to fit the bill but I'd welcome advice from those who have actually faced this problem as to configurations, thicknesses and products used.ThanksJohn

author: GadgetBoy
author_rank: Regular Contributor
timestamp: August 21, 2018, 08:45:26 am
content: Look for heat sink silicone sheets.Sent from my ONEPLUS A3000 using Tapatalk

author: Eka
author_rank: Regular Contributor
timestamp: August 21, 2018, 06:28:12 pm
content: Depends on how much you need, and how thick?This one at Amazon is 100 mm squarehttps://smile.amazon.com/gp/product/B01A9RHAH4Berquist Gap Pads, plus others manufaturers are available at Digikey.https://www.digikey.com/products/en?keywords=Berquist%20Gap%20Padmany different types and thicknesses. Some are in sheet form.I use them to transfer heat from DC to DC converters to the aluminum frames of my sculptures. The nice thing is you don't need a milled flat surface if the pad is thick enough, and the parts can handle lower heat transfer rates due to the greater gap.
costant current generator - Page 1
Forum section: electronics / beginners

author: fady232
author_rank: Contributor
timestamp: September 11, 2025, 02:24:32 pm
content: Hello all,I have made modifications u suggested me to do, now i got on the non inverting input a lower voltage as VREF and i put a resistor of 1k to set the 150uA that has to flow on the capacitor, but what i see is this: across the cap i got is 53mA, i want to have 150uA for 100us, the time there is the positive cycle of the square wave , how and why i could achieve that?

author: mikerj
author_rank: Super Contributor
timestamp: September 11, 2025, 03:07:49 pm
content: The OP-07 isn't a suitable choice for this design, you are violating the common mode range and likely causing phase reversal.

author: MariuszD
author_rank: Regular Contributor
timestamp: September 11, 2025, 04:19:31 pm
content: Don't use random transistors and random amplifiers.At the beginning of the simulation, there is a step change from 200uA to 150uA to check the stability and settling time. Overshoot in the opposite direction is the gate current, reaching 100uA at its peak.

author: fady232
author_rank: Contributor
timestamp: September 11, 2025, 04:44:14 pm
content: I didnt get the Step part, what u do? 2-- we change from 200uA tò 150uA the current on the cap, what kind of stabiliti?

author: MariuszD
author_rank: Regular Contributor
timestamp: September 12, 2025, 12:16:27 pm
content: Any circuit with feedback can become an unintentional oscillator. Therefore, it needs to be tested to see if it has a tendency to oscillate.I've observed oscillations in a current source circuit with a MOSFET and an operational amplifier.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 12, 2025, 04:34:27 pm
content: The question is, what are to trying to achieve with this set up?I cant read the microfonts on your images and I'm on a 26 inch screen!mikerj is right, pushing an input to rail will put it out of limits.The opamp could power up in an unknown state and it may not be able establish the feedback loop in time.The OP07 is a very slow opamp, its intended for use in precsion DC applications. The datasheet doesnt show a wake up time.I suspect it will be open loop for a while. This is a bad circuit and torture for the opamp.Keep the CCS on all the time and switch the capacitor in to circuit. Maybe use a low Ron analog switch or some small mosfets.I'd choose a fast single supply opamp.BTW, this text book CCS is not particularly stable. A real world circuit needs compensation components.

author: MathWizard
author_rank: Super Contributor
timestamp: September 15, 2025, 02:02:31 pm
content: One thing you usually see is some series resistor from the op-amp to the gate, and often from the gate to GND or other low impedance node. Now the op-amp will have some small output resistance too, maybe a few ohms. You usually get a faster circuit the smaller you make the series resistance, but that also usually makes it easy to oscillate too.
Could a CFL bulb erase a UV EPROM? - Page 1
Forum section: electronics / beginners

author: ali6x944
author_rank: Frequent Contributor
timestamp: April 06, 2016, 05:21:13 pm
content: Could a CFL bulb erase a UV EPROM?

author: Gyro
author_rank: Super Contributor
timestamp: April 06, 2016, 05:23:59 pm
content: Very unlikely, even though they're very bright, the wavelength is wrong. EPROM eraser tubes have quartz envelopes.

author: amyk
author_rank: Super Contributor
timestamp: April 07, 2016, 10:26:38 am
content: Yes, if left for long enough. I'm not too sure of the physics but I believe that although a specified wavelength will have the most effective erase process, there's a range of wavelengths at which photons hitting the floating gates will liberate their charge.http://electronics.stackexchange.com/questions/34607/erasing-eproms-with-sunlight

author: danadak
author_rank: Super Contributor
timestamp: April 07, 2016, 10:33:04 am
content: Look at spectral range of CCFL vs that required by part.https://www.google.com/search?q=ccfl+spectrum&espv=2&biw=1517&bih=725&tbm=isch&imgil=_bJSAPhlUWQHsM%253A%253BibjtCEx8_BLV3M%253Bhttp%25253A%25252F%25252Fwww.eizo.com%25252Flibrary%25252Fbasics%25252Feyestrain%25252F&source=iu&pf=m&fir=_bJSAPhlUWQHsM%253A%252CibjtCEx8_BLV3M%252C_&usg=__Vz-zQ7NHRkx3kjDTqI-jbKvO8-c%3D&dpr=0.9&ved=0ahUKEwiMme-JqfzLAhXE7SYKHWljCYIQyjcIJQ&ei=xTYGV8yiEcTbmwHpxqWQCA#imgrc=_bJSAPhlUWQHsM%3AA UV grow light used for plants would help but still radiant flux level wouldmake erasure take a long time.Regards, Dana.

author: bktemp
author_rank: Super Contributor
timestamp: April 07, 2016, 10:39:56 am
content: A CFL can erase a UV EPROM, but not the typical CFL used for lighting applications.There are special CFLs without the phosphor coating and being made using quartz glass. Standard glass blocks the UV-C wavelengths needed for erasing a UV EPROM.

author: ali6x944
author_rank: Frequent Contributor
timestamp: April 08, 2016, 08:44:36 am
content: thanks very much!
Could anyone tell how to design 16x32 RGB LED matrix ? - Page 1
Forum section: electronics / beginners

author: sangar
author_rank: Regular Contributor
timestamp: December 03, 2018, 04:42:11 pm
content: Hello All,I want to design 16 x 32 RGB LED matrix...I have seen some mono colour LED matrices and get to know how to drives it using LED driver likes STP16DP05...But, when you come into RG matrices, each LED has 3 pins for RGB...Here, each needs to be connected to each constant current sink channel of the STP16DP05 that have a total of 16 channels...Could anyone share your knowledge on this and give some guidance ?.Thanks,Muthu

author: mvs
author_rank: Frequent Contributor
timestamp: December 03, 2018, 06:42:18 pm
content: RGB matrix has 3x more LEDs then single color matrix, so essentialy you will need a lot of channels for driving it.You can multiplex array with shift registers like STP16DP05 or use LED matrix driver with memory, like Holtek HT1632C. It can drive 8x32 or 16x24 LED matrix.

author: tsman
author_rank: Frequent Contributor
timestamp: December 03, 2018, 07:50:56 pm
content: Urgh. Please don't makemultiple posts.

author: modernjack3
author_rank: Contributor
timestamp: December 08, 2018, 12:05:07 pm
content: I personally have designed a 48x48 RGB LED Matrix using the TLC5958 from TI. They are really nice to work with! You should take a look into them. They can drive 32 by 16 RGB LEDs with multiplexing at max, but depending on what brightness you want you might want to split your matrix up into 2 or 4 drivers.
Could I get some help with understanding Ribbon cable sizing?  - Page 1
Forum section: electronics / beginners

author: peps1
author_rank: Regular Contributor
timestamp: June 09, 2021, 06:55:01 am
content: I need to make up some 2x5 pin 2.54mm pitch female header cables to run some LCDs and really need the cables to be black, but I can't find any black 2.54mm pitch cable, but I can find 3M 1.27mm ribbon cable....So, do I need to match the pitch of the cable to the header (have both 2.54mm) or is 1.27mm the right size to fit a 2.54mm pitch header onto?Sorry if this is a really stupid question, new to the daunting world of IDC connectors

author: sleemanj
author_rank: Super Contributor
timestamp: June 09, 2021, 08:41:32 am
content: 1.27mm cable is correct for a 2x2.54mm header.

author: tooki
author_rank: Super Contributor
timestamp: June 09, 2021, 05:10:52 pm
content: Quote from: peps1 on June 09, 2021, 06:55:01 amIf you look at a data sheet of a 3M connector, it’ll be described as (for your case) ‘.100” × .100” for .050” Pitch Cable’, making it very clear what the cable pitch is.
Could I have some HELP figuring out These BMSs - Page 1
Forum section: electronics / beginners

author: Ehaze
author_rank: Contributor
timestamp: February 04, 2022, 07:39:48 am
content: Could anyone help me figure out how to hook up these two BMSsOn the molicell battery pack, do I hook up the charge port negative lead to the "C" and positive lead to the "P+".Or Does it go positive lead to the "C" and negative to ground ?Im not sure what "T" means ?On my drill battery I wanted to use it for a 4s3p but I have read I need to connect each cell or it wont balance. ( I was going to use 3 packs or 4 cells.) Im not sure what each letter means . on this one like "C+" and B-.Thanks for any help given !

author: tooki
author_rank: Super Contributor
timestamp: February 04, 2022, 07:44:44 am
content: How are we supposed to know what you’re talking about when half of the silkscreen labels are obscured by the glare in the photo?

author: jerryk
author_rank: Regular Contributor
timestamp: February 04, 2022, 09:08:38 pm
content: As a guess - T is probably a thermal monitoring circuit. C and D may connect to the charge/discharge source sides of the mosfets. Check the resistance of RT1 and RT2 then check T and positive and T and Ground and see if any resistance comes up close to some of the common NTC values.The lower circuit board looks typical of a 5 cell series pack with the outer terminals as your main battery terminals and the inner two split in to 4 inner balance terminals to the charger. I can't tell if there is a TH (temp monitor) and ID terminal in the mix.Edit: To add that my guess about the lower circuit board is not correct. I have taken too many dewalt packs apart and made assumptions. The inner terminals are not split from what see looking closer. Some part numbers would help.Jerry

author: Ehaze
author_rank: Contributor
timestamp: February 07, 2022, 05:37:47 am
content: it was upside down .

author: Ehaze
author_rank: Contributor
timestamp: February 07, 2022, 05:46:12 am
content: How should I wire the charging cable, I am unsure becuase it usualy says "C+ or -"?The drill battery BMS is from a hyper tough 12v 2ah , I am unsure of the actual parts , these are scavenged .

author: jerryk
author_rank: Regular Contributor
timestamp: February 07, 2022, 07:48:16 am
content: From what I can see charge inputs are C+ and P-. It's a 18V 5S board according to the part number silk screen. Are you sure its 12v? Understanding U1's datasheet would be wise in this kind of experiment. Baby sit it on your first try.Jerry

author: Ehaze
author_rank: Contributor
timestamp: February 08, 2022, 01:07:02 am
content: My mistake its 20v max, is there a way to lower the output to 12to 14 volts ?On my battery pack , how would I know its charging if there is no display , I wondering where I can buy a display for amps and voltage, Amazon shopping is not very helpful
Could not able to find compatible soldering handle for generic 852D+ SMD station - Page 1
Forum section: electronics / beginners

author: suryaputhra
author_rank: Regular Contributor
timestamp: August 15, 2016, 07:11:35 pm
content: HiI could not able to find compatible soldering handle for generic Max Brand(Chinese) 852D++ SMD rework station which I brought recently.ProsExcellent value for moneySurprisingly accurate temperature, measured with thermo coupleGood build qualityConsSometimes Solder station led display blinks, Working on it to troubleshoot.Coming to point I want to procure one more soldering handle for Max station I tried 936A handle, it heats up but no temp display on max unit. When I connected Max soldering handle to 936A station it heats up but no cutoff.I reversed the polarity of thermo couple of 936A handle, now Max reads temperature, cuts off at desired temperature setting but due to two dissimilar metals and their resistances the temp shoot up to 30 degrees more than desired temp setting and then stabilises at desired temp, also temp accuracy is out of 30%.How to solve this issue. Many people said 936A holder is incompatible with 852+ and its variants.I hope I can not even change ceramic core on Max 852++ because no compatible ceramic core

author: Brumby
author_rank: Unknown
timestamp: August 16, 2016, 12:51:31 am
content: This is one of the'cons'downsides of getting cheap Chinese gear - spares and support are not a strong point.However, first suggestion - ask the seller who sold this unit to you.Next - have a look (on eBay for example) for spares for a model 852D - without the 'brand'. I have a "W.E.P." brand model 852D+ (only one '+' ... yours has two - so it must be better) which has the same controls as yours and almost the same layout. I would think there is a chance you could find a compatible unit. Here's a candidate I found:http://www.ebay.com/itm/172279651907It's less than $3 - delivered, so it's not much of a risk ... but then you don't know if $3 is going to buy you something worth having.It would be a whole lot simpler if some basic specifications were available on these parts, so compatibility could be determined without such mystery, uncertainty and frustration. But that is a dream, I fear.

author: amyk
author_rank: Super Contributor
timestamp: August 16, 2016, 02:00:50 am
content: There are only two types of 4-wire 936-style heaters, thermocouple and thermistor. Genuine Hakkos use the thermistor. Search for "A1321" and "A1322" on this forum for more information.You can start here:https://www.eevblog.com/forum/reviews/genuine-vs-fake-hakko-936-ceramic-heater-a1321/

author: suryaputhra
author_rank: Regular Contributor
timestamp: August 20, 2016, 05:37:44 am
content: Solder station led display blinking problem solved, switch is faulty. Replaced switch with good quality one. Problem solved.
Could somebody please help identify the following components. - Page 1
Forum section: electronics / beginners

author: JJ_023
author_rank: Frequent Contributor
timestamp: December 27, 2023, 02:01:48 am
content: As the title says. Could somebody please help identify the following components.The 1st picture I believe is some sort of choke. The top of it reads 0057hI am assuming it's 5.7 Millihenry. It reads open across 2 connectors, and 365 ohms across the other.The other 2 pictures I have no idea what the component is.These came off of some salvaged boards so not really sure of the origin.

author: wraper
author_rank: Unknown
timestamp: December 27, 2023, 02:11:35 am
content: First one could be common mode choke for mains voltage. As of second one, I have suspicion it could be PTC thermistor for degaussing from CRT TV or monitor.

author: wraper
author_rank: Unknown
timestamp: December 27, 2023, 02:16:06 am
content: I found similar parthttps://www.globalsources.com/product/mz3-ptc-thermistor_1141132806f.htm

author: JJ_023
author_rank: Frequent Contributor
timestamp: December 27, 2023, 03:13:34 am
content: Quote from: wraper on December 27, 2023, 02:11:35 amThe 1st one I believe you are right it is a common mode choke. Thanks for helping out. PTC thermistor that you suspect reads 48 ohms at room temperature and doesn't budge.

author: wraper
author_rank: Unknown
timestamp: December 27, 2023, 03:22:11 am
content: It's supposed to operate at 120V (if it's from device for US market) and get real hot. It won't budge from slight external heating.

author: JJ_023
author_rank: Frequent Contributor
timestamp: December 31, 2023, 01:14:26 am
content: So based on the suggestion that was made I did an experiment by applying some heat to the component.At room temperature the component was 50 Ohm. After heating it considerably with a heat gun I saw the resistance dropped to 25 Ohm.Do you still think it's a thermistor?

author: wraper
author_rank: Unknown
timestamp: December 31, 2023, 08:27:01 am
content: Then it should be NTC, not PTC

author: JJ_023
author_rank: Frequent Contributor
timestamp: December 31, 2023, 04:06:29 pm
content: From 50 ohm to 25 ohm. Isn't that kind of a small range for a NTC thermistor?
Could someone explain me what happened ? - Page 1
Forum section: electronics / beginners

author: kat1337
author_rank: Contributor
timestamp: December 10, 2024, 03:17:02 pm
content: Hello I've assembled the first one and everything was okay but it was outside of the housing just for test etc.The housing arrived so I've started the assembly and this happened....

author: coromonadalix
author_rank: Super Contributor
timestamp: December 10, 2024, 03:20:00 pm
content: does your meter on the rear look like this ?http://diyprojects.eu/how-to-wire-digital-dual-display-volt-and-ammeter/https://cb-electronics.com/products/dc0-100v-10a/

author: kat1337
author_rank: Contributor
timestamp: December 10, 2024, 04:08:08 pm
content: Yes Its exactly this one. Thanks for fast reply

author: kat1337
author_rank: Contributor
timestamp: December 10, 2024, 04:26:06 pm
content: I've checked the links that you've posted and I still think my connection is correct

author: BeBuLamar
author_rank: Super Contributor
timestamp: December 10, 2024, 05:20:12 pm
content: I think the meter is rated for 10A and to damage it you have to have more than 10A going thru. The power supply is limited to 5A but the battery current isn't limited. So somehow the battery voltage is shorted thru the current measurement circuit.

author: tunk
author_rank: Super Contributor
timestamp: December 10, 2024, 05:53:59 pm
content: If the housing is metal then something may be shorted.Post some photos?

author: Poroit
author_rank: Frequent Contributor
timestamp: December 11, 2024, 04:19:44 am
content: G'day kat1337,Open up the damaged meter and have a look at the internal shunt as per coromonadalix's link.You should be able to see quickly if the shunt has been cooked.

author: Psi
author_rank: Super Contributor
timestamp: December 11, 2024, 04:32:22 am
content: Yeah, a photo showing what exactly burnt would help explain what might have happened.eg, shunt melted, or IC blew up.I prefer the panel meters that have an external CT or Hall module for the current sense (instead of in series with the negative wire) they tend to be easier to deal with because they are isolated.
Could someone help decipher this Alibaba description? - Page 1
Forum section: electronics / beginners

author: rp58
author_rank: Newbie
timestamp: November 03, 2023, 06:11:27 pm
content: https://www.aliexpress.us/item/3256805086851428.html?src=google&afSmartRedirect=y&gatewayAdapt=glo2usaIt is a DC-DC Constant Current Boost converter. You set the output current according to two resistors.*The drive current is equal to the set value of resistance 1 plus the set value of resistance 2*The driving current calculation formula is: current=0.1/resistance value (the default resistance of the board 1 and 2 are 0.25 Ω, the current is about 0.4A when the ISET is not short-circuited, and the current is about 0.4A+0.4A when the ISET is short-circuited). Note that the calculation here is only the approximate current, and the actual current will have some error according to the actual application. Please refer to the following curve for details.Are r1 and r2 in parallel, and I replace both of them? Or is r2 optional and I only use it if I can't find an r1 in the exact value I need?The description also implies I can feed it low voltage A/C. Is that right?My application is to drive a 20w LED requiring 32vdc at 700ma from 12vac landscape transformer. If I can really skip the rectifier and filter, that would be a bonus. Is it really as easy as swapping in a R047 resistor?

author: Jwillis
author_rank: Super Contributor
timestamp: November 03, 2023, 09:34:37 pm
content: From what I gather is when ISET is not shorted only one of the resistors is used . 0.1/0.25=0.4A . When ISET is shorted then both resistors are in parallel. 0.1/0.125=0.8A .The part that says "and the current is about 0.4A+0.4A when the ISET is short-circuited" confirms the current is around 0.8AAs for the AC part, I can't 100% be sure. It says it can support up to 65VAC. Get 2 and see if one blows up with AC

author: torch
author_rank: Frequent Contributor
timestamp: November 04, 2023, 12:23:23 am
content: I read it that the input voltage can be 10-100VDC or 10-65VAC.

author: rp58
author_rank: Newbie
timestamp: November 04, 2023, 12:47:01 am
content: Thanks, you've given me enough confidence to try a couple. Usually you have to take the Chinese specs with a grain of salt, but I am hopeful.

author: BillyO
author_rank: Super Contributor
timestamp: November 04, 2023, 12:57:58 am
content: I agree on the ISET jumper putting the two resistors in parallel, however, I am not sure that it will handle zero-crossing AC. I think they mean it will handle something like the input voltage swinging between 20V and 85V (example) and maintain current within spec. Not -30V to 30V.

author: rp58
author_rank: Newbie
timestamp: November 04, 2023, 03:07:29 am
content: Rats, I thought that AC implied zero crossing. So maybe it means I have to rectify the AC, but not filter it.
Could someone please explain crossover noise - Page 1
Forum section: electronics / beginners

author: Bobthecooldad
author_rank: Contributor
timestamp: October 04, 2015, 10:51:38 am
content: Could someone please explain crossover noise and where it comes from?

author: Len
author_rank: Frequent Contributor
timestamp: October 04, 2015, 12:09:12 pm
content: Someone did, just the other day:http://youtu.be/VgodYtiD_F0

author: TimFox
author_rank: Super Contributor
timestamp: October 04, 2015, 02:11:33 pm
content: Technically, it's distortion, not noise. Noise is random, but distortion is deterministic.

author: janoc
author_rank: Super Contributor
timestamp: October 04, 2015, 03:17:33 pm
content: Yes, while Alan's video is excellent (as always - I always learn something from them!), this wouldn't be the first thing I would be thinking about when someone speaks about "crossover noise". I would be more likely to think about the noise in filters for loudspeakers (those are often called "crossovers").@Bobthecooldad, could you clarify what are you exactly after?
Could someone please Help me to make this Into an Colpitts Crystal Transmitter? - Page 1
Forum section: electronics / beginners

author: Scarlett133
author_rank: Contributor
timestamp: January 21, 2025, 12:57:57 pm
content: This is an CW 27,145 MHz Transmitter

author: MathWizard
author_rank: Super Contributor
timestamp: January 22, 2025, 03:56:28 am
content: Is it just for fun, or as a replacement for something ? Does the circuit work in a simulator ? Have you ever made stuff like this before ?For something this high frequency, it probably won't work very good on a breadboard. You could always try a lower freq. version, or solder up the circuit on a protoboard or copper clad boar. But you'd probably have to try a few values to get it to work. (IDK maybe it would work right away).That circuit is missing an audio section. So what is your goal ?

author: fourfathom
author_rank: Super Contributor
timestamp: January 22, 2025, 07:04:40 am
content: You probably want to put a medium-value resistor from the base of T2 to ground. T2 is probably supposed to be a class-C amplifier, and without the base resistor the B-E rectification will bias the transistor to the point where is only conducts through an extremely narrow portion of the carrier cycle. Select the base transistor to give you the desired conduction angle. I don't know, start with 1K?Also, that series-resonant output filter (L3, C6) is tuned somewhere around 5 MHz, not 27 MHz. Even if the values were changed, a single series resonant circuit like that will probably not filter out the harmonics to be ham-legal (-43 dBc, I think). But that limit only applies to transmitters delivering 5W or more, and you will be lucky to get 100 mW with this design.

author: Scarlett133
author_rank: Contributor
timestamp: January 22, 2025, 08:39:56 am
content: It Works id just Like to Have an Version working with the Crystal from Base to Ground, and the point that it doesnt have an Audio Section is so it just makes an Carrier like in CW

author: MathWizard
author_rank: Super Contributor
timestamp: January 24, 2025, 06:36:41 pm
content: Looking up images for 'Colpitts crystal oscillator topologies' and 'common emmiter colpitts crystal oscillator' gets a few, some are common-collector, and then there's common-base, which is nice too. I've made a few crystal Osc, but just for fun, I never tried using them w/ my RF projects yet.Here's a picture of a couple of circuits, you may have to play with the feedback capacitors, or even the operating point to get it working, and at it's best.

author: Scarlett133
author_rank: Contributor
timestamp: January 25, 2025, 03:59:29 pm
content: Thank you very much
Could someone please tell me what this part is? - Page 1
Forum section: electronics / beginners

author: cpposteve
author_rank: Regular Contributor
timestamp: October 07, 2021, 03:02:56 pm
content: Hi all. Please see attached picture. Only markings are ST ELECTRONICS. and CBN Z440. Trying to work out what this part is so I can see if this is the issue my JBC soldering station. Thanks

author: Manul
author_rank: Super Contributor
timestamp: October 07, 2021, 03:27:22 pm
content: I think it is TVS.https://www.st.com/en/protection-devices/smbj36ca.html

author: Andy Watson
author_rank: Super Contributor
timestamp: October 07, 2021, 03:32:11 pm
content: Possibly SMBJ36CA - bi directional 36V transient supressor.https://www.st.com/resource/en/datasheet/smbj.pdf

author: cpposteve
author_rank: Regular Contributor
timestamp: October 07, 2021, 03:37:32 pm
content: Yes that would make sense. I’m guessing it’s used so if it sees a spike of anything over 40v in this case is shorts and absorbs the spike in voltage? Is this what they are used for? If so is it correct that it’s open circuit untill it goes over that thresh hold voltage? Thanks

author: Manul
author_rank: Super Contributor
timestamp: October 07, 2021, 03:52:03 pm
content: Quote from: cpposteve on October 07, 2021, 03:37:32 pmYes, that is correct. Open circuit with some small capacitance and leakage.

author: mayor
author_rank: Regular Contributor
timestamp: October 09, 2021, 11:04:47 am
content: Check out the topic around here about the smd markings database:https://smd.yooneed.one/Code:CBN3KSMC58CATGFagor ElectronicaDO-214ABTransient voltage supressorCBNLN61CC5102MShanghai Natlinear ElectronicsSOT-23Voltage detector ICCBNLN61CC5102NShanghai Natlinear ElectronicsSOT-343RVoltage detector ICCBNLN61CC5102PShanghai Natlinear ElectronicsSOT-89Voltage detector ICCBNRP106N101D5RicohSOT-23-5Linear voltage regulator ICCBNSMCJ16Galaxy SemiconductorDO-214ABTransient voltage supressorCBNUM1550B-39Union SemiconductorSOT-89Linear voltage regulator ICCBNXC6116B021MRTorex SemiconductorSOT-25Voltage detector IC
Could someone "sanity check" my calculations / switch selection here?  - Page 1
Forum section: electronics / beginners

author: mindcrime
author_rank: Unknown
timestamp: May 28, 2021, 06:41:52 pm
content: Hey gang, as part of thisreflow oven projectI'm working on, I wanted a rocker switch on the AC mains feed, "upstream" of everything - the heating elements, my new transformer for the low voltage rails, etc. The SSR will control the heating elements of course, but I wanted "something" I could use to "hard tun off" the entire unit (besides unplugging it from the wall outlet).Anyway... it's a 1500W oven, and being in North America, our nominal AC mains voltage is 120V. So I took 1500, divided by 120V and got 12.5 amps. With that in mind, theswitch I orderedis rated for 16A at 125VAC. This seems safe to me, but given that I'm dealing with AC mains stuff here, which I don't normally do (and haven't done much of) I thought I'd ask for somebody to sanity check my thinking here. Also, I know there is the possibility of an "inrush current" that exceeds the steady state current, but that should be brief. Right? There is also the additional power draw from the transformer I added to power the Arduino, the control signal for the SSR, and the door actuator. I just realized that thetransformer datasheetdoesn't explicitly list a current draw for the transformer primary, so maybe I should be more concerned about that than I am?Anyway... what do you all say? Does a 16A switch seem good enough here, or should I allow a little more margin for error? If so, what do you recommend?Edit: I'll probably go ahead and do the initial build with the 16A switch, unless somebody points out something blindingly obvious that I've missed, that makes it a huge NO-NO. But just to be on the safe side, I just ordered a couple of 20A switches. If it seems called for, I can change out for the 20A which gives me a little more margin for error. If not, I can keep those around for a future project.

author: mindcrime
author_rank: Unknown
timestamp: June 02, 2021, 02:44:36 am
content: Well, FWIW, that 16A switch seems to be holding up fine so far. I think I have enough headroom / margin with that, as the fuse I put inline with the heating elements is only a 13A fuse and I haven't blown it either.

author: BeBuLamar
author_rank: Super Contributor
timestamp: June 02, 2021, 10:57:20 am
content: For the heater there isn't much of an inrush current. The heater when cold does draw more current but not by much unlike a motor at start up.
could the green gnd terminal on bench psu's be used to generate negtaive voltage - Page 1
Forum section: electronics / beginners

author: amateur_25
author_rank: Regular Contributor
timestamp: May 19, 2014, 06:21:57 pm
content: HiSo I've decided to ditch my single rail tlc272 for a dual rail version. It didn't have a high enough voltage rating anyway.The bench supply we have at the lab has two outputs and separate green terminal marked GND. It has a purpose built busbar to connect the outputs together. Am assuming with this bus bar in place, I will have the dual rail supply I need?If so , is there any particular mode I need to set it in? Again am guessing with the bus bar in place I set it to series then set whatever voltage.Am I correct?

author: owiecc
author_rank: Frequent Contributor
timestamp: May 19, 2014, 06:47:43 pm
content: Yes, you are correct. You may also have a voltage tracking mode when one channel becomes master and second becomes slave. Then if you change the voltage on one channel to 15V you will automatically have +/–15V.

author: dog80
author_rank: Regular Contributor
timestamp: May 19, 2014, 06:54:16 pm
content: I believe that the green post on some bench PSUs is simply a connection to earth ground. These cannot provide a symmetrical output.

author: David_AVD
author_rank: Super Contributor
timestamp: May 19, 2014, 08:53:17 pm
content: I think some clarification on your power supply is needed. When you say "it has two outputs", do you mean two terminals (one each red and black) or two actual outputs (two red and two black) ?The green terminal is usually chassis ground and sometimes has a bar from it to the black terminal. This makes the black terminal connected to chassis (mains) ground.

author: owiecc
author_rank: Frequent Contributor
timestamp: May 20, 2014, 05:44:37 am
content: Just to clarify. You do not need to connect to green terminal. Both outputs are isolated from each other therefore you can connect them almost in any way you want.