hybridfree/eevblog-posts huggingface dataset:
16 bit adc voltage measuring circuit with range switching - Page 1
Forum section: electronics / beginners

author: teslinius
author_rank: Regular Contributor
timestamp: August 19, 2021, 10:39:43 pm
content: It's my first time dealing with a 16 bit adc and higher resolution.I am currently designing a circuit for measuring input voltage from an electronic load (max. 150V), firstly i planned to use a 24 bit adc, but it seemed like an overkill after some thought so i decided on the 16 bit one. Since it has a resolution of approximately 38555 this means at max 150V it has approx. 4mV resolution, because i would like a 1mV resolution i thought i could have 2 voltage dividers and then switch them so up to 35V it has a resolution 1mV and above that 5mV (or 10mV haven't decided yet), will this circuit work as i intend to?, i used mosfets instead of the relays because it's just measuring dc voltage and not signals which the transistor could attentuate. Also thought instead of using 2 mosfets i could just connect the second voltage divider to the second adc input, but then i would need another opamp for filter, which makes the pcb more expensive. Also does the active low pass filter circuit look ok?, i designed it based on a pdf about adc filters i foundWould really appreciate if you would give me some additional reccomendations for improving the circuit.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 20, 2021, 11:06:51 am
content: The filter circuit will be effected by the source impedance and thus the switch choice. So ideally there would be an extra sereis resistor with the lower impedance divider.However the OP07 does not like a 3 V supply. AFAIR it needs some 8 V min and than it still has a limited input range (not including ground). So it would be better to use a low voltage Rail to Rail precision OP. This could be an auto zero OP, like MCP6V76, OPA335, max4238 or similar (many to chose from).With the divider there may be a problem switching the 1:7 divider. It probably still works, as there is no need to turn it on when the voltage is too high.There is still some possible leakage from one FET effecting the other divider. With the relatively low resistance dividers this is likely still OK, but could add some error that may need correction in the calibration.It may still be easier to use a 24 or 18 bit ADC and skip the switchable divider.But keep in mind that the actuall resolution of the ADCs is often lower, especially with the 24 bit ones.With sigma delta ADC one may not even need much filtering at the input. These ADCs are essentially contineous sampling the input and show little aliasing.

author: teslinius
author_rank: Regular Contributor
timestamp: August 22, 2021, 10:21:41 pm
content: Thnaks for the reply, yeah i forgot to check minimum supply voltage for the opamp, i replaced it with MCP606T-I/OT also aded a breaker so if this filter isn't needed i can just bypass it.I have another question how does for example electronic load sense when to switch to vsense voltage measurement instead of the internal, do you usually have to do that manually in software or does it do automatically when you connect vsense to voltage?
16 bit ADC  - Page 1
Forum section: electronics / beginners

author: Dreamer1
author_rank: Contributor
timestamp: December 11, 2017, 09:15:14 am
content: Hi guys,I have been looking for a 16bit , 20ksps+, 2.7v, single-endes, SPI adc for a while. I have found a bunch but all of them have such small footprints!I was wondering if anyone knows a good non obsolete 16bit ADC in the 5-10 dollar range I can hand solder. Or maybe some tips on how to narrow down my search. I have spent some time here and no luck.I don't care about the package, just want to maximize footprint size. Hopefully in the 1mm range.

author: danadak
author_rank: Super Contributor
timestamp: December 11, 2017, 11:21:22 am
content: What is the A/D being connected to ? Do you need a processoras well, one with 20 bit A/D onboard and an onboard reference ?Regards, Dana.

author: Dreamer1
author_rank: Contributor
timestamp: December 11, 2017, 05:06:46 pm
content: Connected to a buffered signal, I lreadt have an MCU.

author: danadak
author_rank: Super Contributor
timestamp: December 11, 2017, 06:22:35 pm
content: QuoteCan you rephrase, I cannot understand that part of post.Regards, Dana.

author: Seral1981
author_rank: Newbie
timestamp: December 11, 2017, 08:08:00 pm
content: Quote from: Dreamer1 on December 11, 2017, 05:06:46 pmthank you man for you advice. will try out and will come back sharing if it worked.

author: pigrew
author_rank: Frequent Contributor
timestamp: December 11, 2017, 08:56:00 pm
content: I'm in the middle of a project using a LTC2641. I'm using the 12-bit version, but I think the 16-bit version would fit your requirements. The pin pitch is .65mm, so less than your 1mm suggestion, but I find it easy to solder.I can't read. I suggested a DAC, not ADC.

author: MasterT
author_rank: Frequent Contributor
timestamp: December 11, 2017, 09:28:55 pm
content: AMC1203. Easy to search on digikey, just select packages SOIC-8/16/.... - 1.27 mm. Adapter boards SOIC to DIP a few cents on aliexpress.
16 electromagnetic motors for robot - Page 1
Forum section: electronics / beginners

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 21, 2022, 02:28:16 am
content: I need a robot as strong as a man.I have 16 hinges on it.The motors I was looking at were $100-$400 each!! for $400 motors, that comes to $6400. That seems like a waste of money.https://www.google.com/search?q=dc+motor+buy&rlz=1C1JJTC_en-GBAU953AU953&sxsrf=AOaemvIRRbB3w0yiOzpcdSM69zkCMtxGDw:1642732031789&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj10NzZ5cH1AhVISmwGHcmHCn4Q_AUoAnoECAEQBA&biw=1600&bih=757&dpr=1If I want a robot approximately as strong as ur average man, is there some cheaper option?The other problem is, I need to make sure its coupled for its strength as well. and all I have now, is just some 3d printed plastic couplers, but I'm thinking they are going to break really easily.I dont need gears, or encoders. Just a dc motor, but still its so expensive!

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 21, 2022, 02:51:04 am
content: this one looks better.https://www.alibaba.com/product-detail/Motor-Brushless-Brushless-Hollow-Shaft-2_1600435815720.html?spm=a2700.7724857.normal_offer.d_image.452267a4J9rlGN&s=p$28 USD. that would $640 AUD, for the whole thing, it says its 400kg payload - is that strong?

author: rpiloverbd
author_rank: Regular Contributor
timestamp: January 31, 2022, 02:19:32 pm
content: You may find something here too:https://www.electrocraft.com/motors-for/robotics/humanoid-robots/

author: langwadt
author_rank: Super Contributor
timestamp: January 31, 2022, 02:29:11 pm
content: Quote from: Capernicus on January 21, 2022, 02:51:04 amI supect the 400kg is what the bearing will hold, 2.5Nm isn't that much

author: rstofer
author_rank: Super Contributor
timestamp: January 31, 2022, 08:14:42 pm
content: A person can generate 1.2 HP briefly and sustain 0.1 HP indefinitely. Or so sayeth Google - search string 'hp equivalent of one person'1 HP = 746 Watts so given motor current and voltage, work from there. You may need to consider efficiency and 1 HP may need to equal something closer to 1 kW.

author: viperidae
author_rank: Frequent Contributor
timestamp: January 31, 2022, 08:44:48 pm
content: You're not going to get the torque required from an electric motor along. You'll need gear reduction or to go hydraulic.Just imagine an outstretched arm, that's about 1m, how much weight do you expect to hold? Including the weight of the arm.Just to hold a 10kg weight, you're looking at 100Nm for the weight alone, plus a portion of the arm as well.

author: rstofer
author_rank: Super Contributor
timestamp: January 31, 2022, 09:56:33 pm
content: Quote from: viperidae on January 31, 2022, 08:44:48 pmPhysics does tend to get in the way.

author: rob77
author_rank: Super Contributor
timestamp: January 31, 2022, 10:01:22 pm
content: Quote from: langwadt on January 31, 2022, 02:29:11 pmyep, 2.5Nm is a equivalent of lifting 250grams with a 1meter long arm. average toddler is much stronger than that
1602 v 2.0 Can't understand it - Page 1
Forum section: electronics / beginners

author: 0x007
author_rank: Contributor
timestamp: June 03, 2016, 08:30:48 pm
content: Hi, I bought a 1602 LCD and I can't figure it out.I have this Data sheet :https://www.crystalfontz.com/products/document/964/CFAH1602XYYHJP_v2.0.pdfI looked at it several times and couldn't find a satisfying description of how the thing communicates,I found that there is an example on page 35 tried it but no luck.I understand the general idea but it looks a bit weird, It doesn't have a clock input only 8 pin data and 3 pin control.If it just scans for data changes why it is not working?it is probably a timing problem but I don't know the operating concept ...do someone have experience with this LCD ? (but no arduino please)

author: LukeW
author_rank: Frequent Contributor
timestamp: June 03, 2016, 09:12:47 pm
content: It's a bog standard LCD module with HD44780-equivalent controller.https://en.wikipedia.org/wiki/Hitachi_HD44780_LCD_controllerYou can easily find heaps of software examples, books, reference designs etc for using these with whatever type of microprocessor platform floats your boat. 8051, PIC, PC parallel port, whatever. Or Arduino.

author: hammy
author_rank: Unknown
timestamp: June 03, 2016, 09:34:17 pm
content: Quote from: 0x007 on June 03, 2016, 08:30:48 pmPlease describe your (circuit) setup and what you had done so far.

author: 0x007
author_rank: Contributor
timestamp: June 03, 2016, 09:49:31 pm
content: Ahhh sorry to every one who tried to help, I figured it out on my own , sorry

author: 0x007
author_rank: Contributor
timestamp: June 03, 2016, 09:51:03 pm
content: I missed the E pin in the description, its the Clock
'161 vs '163 binary counters - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: April 27, 2021, 08:53:31 am
content: Hi,it's as simple as that: I have both '161 and '163 4bit synchronous counters (they were gifted to me by an electronics shop owner who retired, alongside a bunch of other stuff). I can't tell the difference though, they seem kinda the same. Can someone please explain?Thanks!

author: tggzzz
author_rank: Super Contributor
timestamp: April 27, 2021, 09:34:06 am
content: They are kinda the same.The differences are stated in the datasheets. Look at the control signals.

author: Moriambar
author_rank: Unknown
timestamp: April 27, 2021, 09:44:17 am
content: Quote from: tggzzz on April 27, 2021, 09:34:06 amhm looking at the waveforms it seems it's just the async clear, right? I had to compare printed sheets side-to-side lolThanks

author: tggzzz
author_rank: Super Contributor
timestamp: April 27, 2021, 10:24:19 am
content: You're welcome.Training yourself to spot differences is a useful skillYou might like to have a look at the two titles, text descriptions, and pin descriptions in order to cement your ability to spot the keywords and concepts.

author: ledtester
author_rank: Super Contributor
timestamp: April 27, 2021, 11:53:11 am
content: This datasheet (which is for both chips) has the following to say about the two counters:https://eater.net/datasheets/74ls161.pdfQuote
16x2 lcd backlight going dim - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 08, 2014, 02:36:31 am
content: 1. I had made a project in which 16x2 lcd is interfaced with couple of other functions.2. After some hours(varies) of functions correctly i had seen that lcd backlight starts going bit dim. Ten it fluctuates. It goes high & low repeatedly.However text on it is printed correctly.i assume:1. Since text is printed correctly so my lcd code is fine. & it has nothing to do with lcd backlight going dim.2. I checked 15 pin of lcd on CRO it shows correct +5V all the time.What could be problem??

author: miguelvp
author_rank: Super Contributor
timestamp: December 08, 2014, 03:05:13 am
content: What do you have connected to pin 3?A picture or diagram might help

author: sleemanj
author_rank: Super Contributor
timestamp: December 08, 2014, 05:05:23 am
content: Quote from: Vindhyachal.takniki on December 08, 2014, 02:36:31 amPin 15 is the Anode of the backlight LED, pin 16 is the Cathode, if you have connected 5v and gnd directly there, you're shoving 5v through that LED without any current limiting.The backlight led in these usually has fairly high forward voltage (4.2v or some such) and current capability (120mA or some such) which will be why it has survived thus far, but the added heating and current will be killing it swiftly, which is what you're seeing with it coming-and-going.Like any LED, you need to current limit it.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 08, 2014, 05:03:23 pm
content: yes I haven't connected any current limitor.My ckt is attached

author: void_error
author_rank: Frequent Contributor
timestamp: December 08, 2014, 08:26:30 pm
content: You need a resistor between +5V and backlight anone (+), anything between 100-330ohms should do. I usually go with 220ohm regardless of the backlight color for testing purposes.
180MHz clock generator - Page 1
Forum section: electronics / beginners

author: DanioIO
author_rank: Contributor
timestamp: March 28, 2014, 04:32:39 pm
content: Hi,I'm looking for 180MHz clock for my DDS project, i didnt find any crystal oscillators at that frequency so how is it generated?

author: woodchips
author_rank: Frequent Contributor
timestamp: March 28, 2014, 06:53:20 pm
content: Overtones. Use a 20MHz oscillator (or whatever) and a 180MHz filter.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: March 28, 2014, 08:34:09 pm
content: Is your DDS project based on FPGA? like maybe Cyclone III or Spartan? You can configure internal PLL to generate clock signal that you need up to ~300 MHz usually. If not look at DDS IC from Analog Devices AD9851 - that one is probably exactly what you need.http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad9851/products/product.html
18650!! - Page 1
Forum section: electronics / beginners

author: isaacsong23
author_rank: Contributor
timestamp: April 13, 2017, 06:25:09 pm
content: Hi!!Quick question!!If my power supply is putting out 5V 4A for my four tp4056 modules in parallel, and lets say i wish to only use one of the four tp4056 module to charge a single 18650 battery , i am seeing two scenarios, first Will the tp4056 still put out 1A for the 18650? Second, Or will the battery try to pull.more current causing the TP4056 Module to exceed its current rating of 3A and than boom. Thank you!! If you are curious my batteries are LG H2 18650 batteries Thank you!!:)Sent from my SM-G935F using Tapatalk

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: April 13, 2017, 06:42:23 pm
content: First: Please put a descriptive title if you want descriptive answersSecond: Take a look at the datasheet. I don’t know about the specific part, but looks like a constant current linear charger with constant finishing charge voltage so it puts out what current you program it to until finishing charge voltage is reached.Regards,Frederik

author: isaacsong23
author_rank: Contributor
timestamp: April 13, 2017, 06:45:47 pm
content: Haha sorry!!New to this will definetly put a more descriptive title in the future!!thanks for yhr advice:)) cheers!Sent from my SM-G935F using Tapatalk
18650 battery charger - Page 1
Forum section: electronics / beginners

author: tomtenberge
author_rank: Newbie
timestamp: November 20, 2016, 10:57:27 am
content: hello everyone,i have been working on my own 4v 18650 li-ion battery charger based on a MAX1555.the charging is working.. however i have a probem with the indication.you see, the MAX1555 has a sink pin for when it is charging... for connecting a LED, however, i wanted to have 2 LED's to tell if it is charging or not.now, i drew it out, even tested it in yenka (i donno if any of you know that... it's basic but it works).however, connected it doesn't work, anything i did wrong? please help, it is driving me nuts.at first the red LED staid on, and now only the green one... thats no good.added info:schematic:https://gyazo.com/4c29436a43964905e518dc1380c75f5dSoldering:https://gyazo.com/036ab77533a5e60f2cecc8009c8f0a9dcomponents:https://gyazo.com/e24e8853d6974b87ecf934ed44fdc0edMAX1555 datasheet:https://www.sparkfun.com/datasheets/Components/MAX1551-MAX1555-1.pdf

author: jeroen79
author_rank: Frequent Contributor
timestamp: November 20, 2016, 07:42:07 pm
content: The schematic doesn't say which LED is red and which is green.I suppose then when it is charging D2 should be on and D1 should be off.And once complete D2 should be off and D1 should be on.If I do a quick simulation it will show that there will always be a small current through D1 so it would be lit up a bit.(http://tinyurl.com/zyxwq86)Why Q2?It sinks current away from Q1 but the MAX1555's CHG output is already sinking current.Q2 would just raise the base of Q1 by .6VTo turn off D1 you want to turn off Q1 and therefore pull it's base as low as possible.Put Q1 between VCC and D1/R3.What are you measuring in the circuit?

author: tomtenberge
author_rank: Newbie
timestamp: November 20, 2016, 10:18:08 pm
content: sooo, basicly what your saying... is i am using the NPN wrong?

author: jeroen79
author_rank: Frequent Contributor
timestamp: November 21, 2016, 12:15:50 am
content: The NPN will conduct when the base is .6V (one diode) higher than the emitter.If you tie the emitter to ground then any Vb-gnd above 1 diode will make it conduct.If you tie the base to a current sinking transistor that is also connected to ground then the Vb-gnd will never get lower then 1 diode so it will conduct a tiny bit.If you place the NPN on top of a 2V diode then you need a Vb-gnd of 2.7V to make it conduct.The current sinking transistor can easily pull the base below that.

author: tomtenberge
author_rank: Newbie
timestamp: November 21, 2016, 09:28:03 pm
content: sooooooo, i build the circuit as it said in your simulator... an the green led (the one with the NPN) won't go off...

author: jeroen79
author_rank: Frequent Contributor
timestamp: November 22, 2016, 12:11:01 am
content: What if you leave out the MAX1555 and simulate it's CHG current sink with a switch directly to GND?
18650 battery charging / chargers - Page 1
Forum section: electronics / beginners

author: Liteace
author_rank: Regular Contributor
timestamp: February 01, 2020, 05:12:51 pm
content: Ive got a few battery powered tools , lamps that I want to convert to use a few 18650 batteries, One thing that is confusing me is the charging, Ive see these little charging / management PCB but none have any meter or LED to indicate what state the battery/ies are in.I have a few pieces of equipment, lamps, phone, laptop and even the cheapest lamp has a green/red charging-charged LED indicatorIs there anything I can add to these charging / management PCB ?

author: aix
author_rank: Regular Contributor
timestamp: February 01, 2020, 05:53:10 pm
content: It's pretty easy to find charging boards that have status LEDs. For example (first hit on Aliexpress for "TP5100"):https://www.aliexpress.com/item/4000130857356.html

author: aix
author_rank: Regular Contributor
timestamp: February 01, 2020, 07:56:55 pm
content: For completeness, TP4056 charging modules also seem to routinely include status LEDs. The first two hits on Aliexpress (sorted by sales):https://www.aliexpress.com/item/32797834680.htmlhttps://www.aliexpress.com/item/32986135934.html

author: Liteace
author_rank: Regular Contributor
timestamp: February 02, 2020, 08:10:40 pm
content: Thanks is the TP5100 just for a single 18650 ?Thanks again

author: aix
author_rank: Regular Contributor
timestamp: February 02, 2020, 08:27:33 pm
content: 1S or 2S (you can of course connect multiple cells in parallel).

author: Liteace
author_rank: Regular Contributor
timestamp: February 22, 2020, 05:06:25 pm
content: Thanks for the info. Im still a bit lost as to how to wire up these chargers, is the charge input the same connections as the power output from the batteries and if the charger has not got any type of indicator how do you know when the batteries are fully chargedThanks

author: mvs
author_rank: Frequent Contributor
timestamp: February 23, 2020, 10:44:38 am
content: Quote from: Liteace on February 22, 2020, 05:06:25 pmDo you talk about Li-Ion charger or battery protection board/BMS?
18650 Battery Charging Question - Page 1
Forum section: electronics / beginners

author: Electro Fan
author_rank: Super Contributor
timestamp: March 29, 2020, 06:38:23 pm
content: In section 3 of this spec sheet there are numbers for Standard charge (1A) and Rated charge (4A).Does this mean that the Standard charge of 1A is the recommended charge, and the Rated charge of 4A is the maximum safe charge? Or does Rated charge mean something else?If 1A is the recommended charge but up to 4A is the safe maximum charge, is the tradeoff that the battery life will be longest using 1A charges, but at 4A the battery will charge faster at the expense of battery life (ie, fewer charging cycles possible over the life of the battery when using higher current for faster charges)?Thankshttps://www.imrbatteries.com/content/samsung_20S.pdf

author: doobedoobedo
author_rank: Regular Contributor
timestamp: March 29, 2020, 07:28:03 pm
content: Quote from: Electro Fan on March 29, 2020, 06:38:23 pmI think that's a pretty safe assumption.Quote from: Electro Fan on March 29, 2020, 06:38:23 pmIf you look further down it states that if you charge and discharge at the max rated rates the cells lose up to 60% of their capacity in only 250 charge cycles. As with most things be gentle and it'll increase life. If you need the max for either charge or discharge then that comes at a cost.
18650 Capacity Testing with B6AC - Page 1
Forum section: electronics / beginners

author: codysmith105
author_rank: Contributor
timestamp: May 20, 2016, 03:09:34 am
content: Hello EEVBlog community,I'm getting into Lithium Ion cell recycling / reuse. This is basically pulling apart laptop battery packs and harvesting the 18650 cells for projects.I bought an imax B6AC v2 charger and have started charging / discharging cells.The first cell I put on the charger was already charged so I discharged it at 1A and I got 2096 mAh out of it (that's according to the charger and was a discharge from 4.1v to 3.1v).I then charged the battery and only measured (again according to the charger) 1560 mAh.These numbers are wildly different.How can 2096 mAh go out and only 1560 go in?Also, what procedure should I use to test cells with this charger / in general.Thanks so much in advance guys.-Cody
18650 Charger  - Page 1
Forum section: electronics / beginners

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: December 25, 2015, 03:48:32 pm
content: I have a couple projects that use a 18650 cells and does anyone know a good charging circuit for these ??Thanks

author: Rick Law
author_rank: Super Contributor
timestamp: December 25, 2015, 06:48:36 pm
content: Quote from: TorqueRanger on December 25, 2015, 03:48:32 pmI personally like the TP4056 for random applications and do implement the temperature monitoring. You can roll-your-own or get one of those $2 boards online. Most of the TP4056 boards do not implement the temperature monitoring but some has it. For the most part, you wont need temperature monitoring. But when you do have a bad cell, that could save your house from burning down.For day-to-day charging, I use a consumer grade charger.

author: Stonent
author_rank: Super Contributor
timestamp: December 25, 2015, 07:08:07 pm
content: The store Five Below in the US has a number of cheap power banks for under $5. The small ones that are 18650 sized have one inside. You could just desolder it and put in a 18650 battery holder. I believe it has that exact chip mentioned previously in it.One of them that I got looks like a Lego brick and has 1 cell inside but molded for 2 cells.If you just want a lot of power on demand, they do have a 6600mAH pack for $5 has 3 cells inside it. Since it came out, the other single cell ones have dropped in price.Here's a teardown video that someone else did on that one.

author: doobedoobedo
author_rank: Regular Contributor
timestamp: December 25, 2015, 07:18:09 pm
content: Another vote for the TP4056https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdfthey're ubiquitous in chinese stuff. Cheap as chips and do the job.
18650 pack for 12v with buck - Page 1
Forum section: electronics / beginners

author: geo999
author_rank: Contributor
timestamp: September 08, 2021, 10:14:52 am
content: Hi all,I need your advice for the following situation:In order to power a camera surveillance system over nigh I've built an 18650 pack in the 7S10P configuration.from that a DPS3005 (30V max input, 5A max output) buck converter is used to get the voltage down to 12-13v or so.the DPS3005 needs a minimum of about 13.76v to give 13v output.for 3.5V min and 4V max per cell we have the following voltages:- 7S : 24.5V discharged, 28V charged- 6S : 21V discharged, 24V charged- 5S : 17.5V discharged, 20V charged- 4S : 14V discharged, 16V charged - minimum configuration for 13v output of buck.the question is:what is the configuration that gives the smallest buck converter loses but still have decent Wh from the pack ?asking this because the 7S at 28V buck input gives about 5W of loses for 13V @35W of consumption.Have not yet tested the other configurations, thus the question.Thank you,George

author: Jwillis
author_rank: Super Contributor
timestamp: September 09, 2021, 03:31:52 pm
content: Best efficiency is when the power supply voltage is closest value to the load voltage . The 18650 Li ion battery has an optimal voltage of 3.7V so the best would be 4Series or 14.8V . Each parallel increases Amp hours . An amp hour (Ah) is the amount of current that can be drawn for one hour from 100% charge to 80% charge . So depending on the mAh of each cell in parallel added together will give total milliamp hours of the series at 14.8V . Do not mix cells with different mAh ratings . This can led to damage of individual cells .
18650 parallel sanity check - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: December 30, 2017, 02:01:32 pm
content: So I just want to check in case I've lost the plot, but...I have some 18650 cells out of a brand new laptop pack. They are factory paired in parallel. I have put them into a 3 series 2 parallel configuration in an 18650 battery holder.The cells are 3.7V 2600mAh each, so 3S2P creates a 11.1V (12.6V) 5200mAh pack (which was the rating on the laptop battery before I dismantled it).This means to charge it at 0.5C I supply 2600mAh and charge to 12.6V. For 1C fast charge I supply 5.2Amps, although I think I'll keep that to 5 Amp max.Note, I have a standard balance lead wired to 0V, 3.7V, 7.4V, 11.1V and will be using a dedicated LiIo balance charger.
18650 powerstation  - Page 1
Forum section: electronics / beginners

author: albach
author_rank: Newbie
timestamp: June 16, 2018, 07:18:18 pm
content: Hi guys i recently found my old Energie Station (german brand name form Einhell) which was a 50 Ah sealed Pb gel battery with a charger and some cigarette lighter outlets. I want to do a little water camping trip in the summer and wanted a small reliable energy source for charging my phone and cameras. the Pb battery is dead and now the question arose to replace it witch 18650 cells. I have a few 2p4s packs and 3 of them have the exactly same size a the pb battery.My question is if i use the 2p4s cells and connect them in parallel i get 10v if they are completely (2,5v) per cell empty and 16,8 completely charged (4,2V per cell).For a cigarette lighter output both is wrong. I also want to be able to charge everything off a 12v outlet at camp stations or my car.My idea is to use one stepup converter so get 16,8V for charging to the bms and one boost buck converter to get 12 v to the outlets maybe also two one for each outlet.is there an easier option or are my thoughts correct. I will put fuses in front of the outlets so hopefully only the will blow up in case of an overload or short. Charging is no problem because the cells already have a bms fitted to themthanks for your helpAlbach
18650 spot welder advice needed please - Page 1
Forum section: electronics / beginners

author: luddite
author_rank: Newbie
timestamp: March 19, 2021, 01:47:03 am
content: I have a Rockseed 305p power supply.I am looking at this spot welder and need to know if purchasing it will let me spot weld or am I missing something?https://tinyurl.com/pkwuuyxj(link to it)I am hoping to drop a couple of decent amperage cables on it and connect to the power supply.Will that be ok, help would be appreciated thanks

author: Cliff Matthews
author_rank: Unknown
timestamp: March 19, 2021, 02:39:23 am
content: For spot welding you will need more current. Maybe get a lightly used car battery and a circuit like this?https://youtu.be/p6XTPPBLiYg

author: james_s
author_rank: Super Contributor
timestamp: March 19, 2021, 04:46:38 am
content: I use a capacitive discharge spot welder I built years ago, it's little more than a bank of about 1F worth of capacitors, the biggest stud mount SCR I could find on ebay and a current limited variable power supply built around a LM317. I got a good deal on a bunch of surplus capacitors, otherwise it might be easier to just buy something like a K-weld these days.

author: tautech
author_rank: Super Contributor
timestamp: March 20, 2021, 02:01:12 am
content: https://www.eevblog.com/forum/projects/guesses-on-what-i-am-attempting-here/msg1232857/#msg1232857
18w amplifier using tda2030 - Page 1
Forum section: electronics / beginners

author: iitsanup
author_rank: Newbie
timestamp: February 05, 2014, 11:47:24 am
content: hi ,i have build an amplifier circuit using tda2030 as in the attachment , but i have done only stereo part and not the sub woofer.now the thing is the amplifier is working fine only if i increase/ decrease the volume of one side(LHS/RHs) if i do the both a craking noise comes. pls help me. i want to listen in both speakers.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 05, 2014, 12:03:15 pm
content: I'm not sure what your problem is.Do you have a dual-gang potentiometer for the volume control or two single-gang ones?Do you mean that you get a crackling sound as you turn the volume control (which then stops when you stop turning the volume control?If so then a dry joint on the pot might be the cause. Or a DC potential across the track although if you have built the circuit correctly this should not happen as there is a capacitor to block any DC.Do you mean that you hear crackling distortion when both channels are in operation but not if only one has the volume turned up?If so then I'd look at the power supply - a single 7812/7912 is a bit marginal for a TDA2030 and I think inadequate for two or three as it is a 1A regulator. You might find the supply voltage is dropping low and you are getting clipping when that happens.Or do you mean something else?

author: dr_p
author_rank: Frequent Contributor
timestamp: February 05, 2014, 12:16:58 pm
content: If both channels work at low volume, but not at full power, check the power supply. I suspect that as the current consumption increases, the ripple is getting higher, reaching too low of a voltage for the TDA2030 to output the required power. Measure AC voltage on the filter caps or put a scope on it. If it's the case, increase the size of the filter caps.BTW, do you need regulated +/- 12V for the op-amps? Where did this schematic come from? I'm just curious.@grumpydoc: only the op-amps are regulated(V+ and V-), the TDA2030s get the VDD ans VSS

author: grumpydoc
author_rank: Super Contributor
timestamp: February 05, 2014, 12:25:41 pm
content: QuoteMissed that, thanks.We both agree it sounds like the PSU is the probem. I think it's worth the OP making sure that he's not feeding the TDA2030 from the regulated supply and that his transformer is adequately rated.
1946 Mason 45-4 - Progress Made - Page 1
Forum section: electronics / beginners

author: Wil_Bloodworth
author_rank: Regular Contributor
timestamp: November 26, 2023, 11:29:08 pm
content: Well, all of the components have been (poorly) replaced. I started at one end and worked toward the other and it was very apparent that my soldering abilities leave ample room for improvement. However, I did notice that I got better as I went along and I found myself in a slightly different mindset where I would mentally remind myself of certain things to not forget about. I tried using heat shrink tubing in a few places; mostly because I wanted to experiment. Mr. Carlson recommended the white sheathing that is seen in a couple of places in the image below. I very much prefer the white tubing to the heat shrink but I can see different purposes for each.The new polarized plug looks nice I think. Next, I need to put the IF 1 transformer back in and then figure out the antenna wires and how they're supposed to be wired up. That is a different educational journey that I will explore tomorrow.She will be soon ready to turn on (via the isolation transformer/variac/dim-bulb rig) and do some measuring and, with any luck, attempt to get a new speaker hooked up. I think I can do the IF alignment with a dummy load but honestly, I think that is a bit above my pay grade at the moment so I'll just take it slow and go the easiest route for now.Enjoy!- Wil
1975 TMK Electronic Tester model 117 - Page 1
Forum section: electronics / beginners

author: Hammer_651
author_rank: Newbie
timestamp: September 23, 2024, 02:13:25 am
content: Hi all. I have this older multi-meter a TMK Electronic Tester Model-117 (see pic) as it's called and i have now found a burnt rotary switch PCB. I would like to find another one but I don't like my chances as I think it may have been a kit project. Maybe someone out there may have an old one or a damaged one for parts. Does anyone know if these PCB's can be repaired or should I just get a new PCB made?I do know about electronics and a student in the same. This is a restore project for me so if anyone can help it would be appreciated.Thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 23, 2024, 02:08:03 pm
content: internals pictures and close ups would help

author: Hammer_651
author_rank: Newbie
timestamp: September 26, 2024, 04:26:58 am
content: Hi. I think a polite g/day would also help when replying. Attached is a pic of the rotary switch PCB. The previous owner did some work on it and I would like to restore it to a better state.Hammer_651

author: squadchannel
author_rank: Frequent Contributor
timestamp: September 26, 2024, 05:08:29 am
content: The image appears to be corrupted, but I was able to view it in GIMP.does not need to be made a circuit board. It is completely repairable.Just repair the red-penned area with tinned copper wire.

author: Hammer_651
author_rank: Newbie
timestamp: September 26, 2024, 06:47:52 am
content: Hello. Thanks for5 the reply I'll give it a go with the help of youtube.H.

author: squadchannel
author_rank: Frequent Contributor
timestamp: September 26, 2024, 06:52:07 am
content: mark's video would be helpful.

author: Poroit
author_rank: Frequent Contributor
timestamp: September 26, 2024, 08:43:31 am
content: G'day Hammer,Check the meter movement is OK first up before you start any other repairs.Heaps of videos on Youtube which show you how.
1990 Olypmus Video Light Source - Noxious Smell - Page 1
Forum section: electronics / beginners

author: K1JOS
author_rank: Regular Contributor
timestamp: March 22, 2014, 03:51:51 am
content: I came upon a new appearing Olympus video-endoscope lightsource that I would like to use as a bore-scope. Only problem is after a few minutes a really nauseating stink comes from the PSU fan. Not your classic burn resistor, plastic but something I would expect (though never experienced) from that described for selenium rectifers that have become zapped. I have looked over the chassis and it looks virtually new, no dust, no dead bugs, and no bulging or leaking lytics but it is definitely coming from the power supply PCB. Should I just replace the 6 or so lytics or is there some other 1990 vintage culprit known to smell this bad?thanksjerry

author: Shock
author_rank: Super Contributor
timestamp: March 22, 2014, 05:18:41 am
content: If not caps, transistor, rotting rubber or plastic, or perhaps mice used to read the newspaper in there.

author: lapm
author_rank: Frequent Contributor
timestamp: March 22, 2014, 08:11:30 am
content: 1990 electrolytics? I would change them to new ones. Thats 24 years of service life all ready. Very respectfull for any electrolytics.While capacitors are out, you might consider use some sort of electronics cleaning spray or something, just in case of above mentioned reason...

author: Yago
author_rank: Frequent Contributor
timestamp: March 22, 2014, 08:18:17 am
content: Quote from: Shock on March 22, 2014, 05:18:41 amHehe good one Shock
19th century spectrum analyzer and oscilloscope - Page 1
Forum section: electronics / beginners

author: pplaninsky
author_rank: Regular Contributor
timestamp: October 03, 2015, 10:28:56 am
content: when you see this - you can really grasp the ideas of harmonics, time base, volts per division, dc offsetall done with mechanics and gears, so you actually see it.rest of the series

author: Vgkid
author_rank: Super Contributor
timestamp: October 03, 2015, 05:53:20 pm
content: That is very cool, just started watching them.

author: Tom45
author_rank: Frequent Contributor
timestamp: October 03, 2015, 11:17:48 pm
content: The science museum in London has an extensive display of 19th century mechanical devices like this. When I visited, I only had time to marvel at them, but not understand their working principles.This series of videos does a great job of showing the theory and practice of one such class of mechanical marvel that I saw at the museum.Thanks for finding this.

author: pplaninsky
author_rank: Regular Contributor
timestamp: October 09, 2015, 02:38:58 pm
content: You are most welcome!I enjoyed these videos very much as well.

author: TimFox
author_rank: Super Contributor
timestamp: October 09, 2015, 04:18:35 pm
content: Also check out the classic "On the sensations of tone..." by Hermann Helmholtz (1863), still available in a classic English translation on Dover:http://www.amazon.com/Sensations-Tone-Dover-Books-Music/dp/0486607534.He synthesized musical notes with an ensemble of tuning forks (at integer harmonics of the fundamental fork), synchronized to a master fork (with a needle dipping into a mercury cup) that drove electromagnets at each fork. In turn, each fork had its own Helmholtz resonator with a variable aperture to adjust the amplitude. By detuning the resonators, he was able to demonstrate that the audible result was not sensitive to relative phase of the harmonics.He was able to synthesize German vowels, which was more than my college German teacher could get me to do accurately.
1F capacitors discharge rate - Page 1
Forum section: electronics / beginners

author: Salmannm94
author_rank: Newbie
timestamp: August 03, 2016, 12:44:18 am
content: I have been experimenting with different capacitors to test their charge/discharge rate. While doing that I noticed something weird. I have a 1F 5.5V capacitor that I charged to about 4.4V and then connected it directly to a LED to discharge it. I was expecting that capacitor to discharge quickly since the LED has negligible resistance (hence small time constant), but it actually lasted for about a minute. Does anyone have an explanation for this?!

author: ebclr
author_rank: Super Contributor
timestamp: August 03, 2016, 12:55:18 am
content: " LED has negligible resistance "Well , a typical led need 2.7V and 20 ma, by Ohm's Law will have a Req of 135 ohm at that voltage and tension, This is not so small as you may think. also with 4.4V and 1 Farad you are killing you Led live expectancy, because you are forcing a much higher current than specified powering with 4.4 V initialy

author: alsetalokin4017
author_rank: Super Contributor
timestamp: August 03, 2016, 03:42:59 am
content: Don't use a LED for this. The LED is a very non-linear load, its behaviour changes radically around its "forward voltage" Vfparameter. Above its rated Vfit will have seemingly low resistance. As the applied voltage drops to close to the rated Vfits effective resistance will increase, becoming very high when the applied voltage is below the Vfparameter. So it is a poor choice for determining capacitor discharge curves, as you will be seeing more of the behaviour of the LED than of the capacitor.You need to use a purely resistive and linear load, like a simple resistor. It would be an instructive exercise to use an oscilloscope to monitor the voltage on the capacitor as you "short" the cap through resistors of different values. Each resistor value will give you a different discharge voltage curve as seen on the scope. This experiment will show you graphically what is meant by the "time constant".https://en.wikipedia.org/wiki/RC_time_constant

author: Zero999
author_rank: Super Contributor
timestamp: August 03, 2016, 07:55:54 am
content: Quote from: Salmannm94 on August 03, 2016, 12:44:18 amWhat sort of 1F capacitor is it?If it's a memory back up capacitor, then this should be expected, as it will have an effective series resistance of 100R or more.

author: Salmannm94
author_rank: Newbie
timestamp: August 03, 2016, 04:44:11 pm
content: Quote from: Hero999 on August 03, 2016, 07:55:54 amI looked it up, and it's actually a double-layer memory back up capacitor. I had no idea that they can have internal resistance this high
1G74 and 2G74 different - Page 1
Forum section: electronics / beginners

author: diyinhk
author_rank: Contributor
timestamp: July 19, 2014, 08:19:16 am
content: http://www.mouser.com/ds/2/302/74LVC2G74-352817.pdfhttp://www.mouser.com/ds/2/302/74LVC1G74-350009.pdfI cannot figure out the different from the datasheet.is it the same part and the different part number is due to history reason

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 19, 2014, 08:02:55 pm
content: Idunno, but the markings are even the same...Tim

author: CarlG
author_rank: Regular Contributor
timestamp: July 19, 2014, 08:46:46 pm
content: I can't find any difference between the NXP '1G74 vs. '2G74 datasheets either, but the TI corresponding datasheets show some differencies. E g TI '1G74 is only specified at 3.3 and 5V for -40 to +125, and for some packages not recommended at all for that temp range.My guess is that NXP supplies the '1G74 as a 2nd source for TI. TI and NXP have had some sort of mutual "2nd source agreement" on std logic; however I don't now if that't the case anymore.The LVC/ALVC nomenclature is a bit confusing since some parts' '1Gxx refers to "1st generation" while other refers to "single gate" (and '2Gxx to "2nd generation" and "dual gate", respectively).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 19, 2014, 10:40:04 pm
content: I always thought it was package size or gate count, i.e., it's a single gate but in a 2G (TSSOP8 or whichever others) package. But something like a 3G14 is in the same package because it's counting gates.Not that it has to be consistent. Numbers are inconsistent all over the damn place. Look at the x86 instruction set...Tim
1Gb RJ45 pinout (with magnets) - Page 1
Forum section: electronics / beginners

author: sw_guy
author_rank: Regular Contributor
timestamp: February 08, 2024, 02:06:59 pm
content: There are a few variations of RJ45 connectors (with magnets). This is mainly about the center tap line. I am not sure how to connect P1 and P10. I can see that on some connectors P10 is connected to GND and P1 to GND thru 10nF capacitor. Does this apply to this RJ45 connector as well?Thanks in advance!

author: tszaboo
author_rank: Super Contributor
timestamp: February 08, 2024, 02:32:13 pm
content: From what I remember the different connections for Ethernet magjacks have to do with two things:1) Plastic of metal housings2) PoE is expected or notIf you want more info than you ever need about Ethernet, Würth has a book about it, "Triology of magnetics" one of the three books deep dive into it.

author: sw_guy
author_rank: Regular Contributor
timestamp: February 08, 2024, 07:06:00 pm
content: Thanks for the information. I am sure there are plenty of books, but I was hoping maybe someone knows the answer.sw guy

author: Halcyon
author_rank: Unknown
timestamp: February 09, 2024, 10:26:57 pm
content: Duplicate post.https://www.eevblog.com/forum/projects/i-dont-know-how-to-wire-rj45-connector-with-magnets/
1Hz Square Wave/Clock Generator - Page 1
Forum section: electronics / beginners

author: varunkoganti
author_rank: Contributor
timestamp: July 26, 2021, 03:14:15 am
content: Hi Everybody,The project is simple, I am trying to build a digital clock, this requires a 1Hz timing.My idea for the 1 Hz timing is to use a 32.768KHz crystal and then count the crystal using a 15-bit counter(2^15 = 32768), this would give me 1 sec.I built up the circuit (Pierce oscillator),Capacitors = 18pF.Rfeedback = 1M ohm.The inverter is a 74HC04 by TI(Texas Instruments).I tried measuring the wave form using my arduino's digital read and this is what i keep getting.I need help, is this actually correct, I do not have an oscilloscope.

author: perieanuo
author_rank: Frequent Contributor
timestamp: July 26, 2021, 06:44:40 am
content: for 1HZ someone don't need a 1GHz capable scope, almost all multimeters today have ac freq functionto answer your question, we need oscillator's schematics, maybe osc photos, interface schematics with ardu, ardu code. not easy to digg into something with no info at all

author: Zero999
author_rank: Super Contributor
timestamp: July 26, 2021, 08:41:25 am
content: The 74HC04 isn't the best IC to use for a crystal oscillator. The 74HCU04 is more suitable. The 74HC04 has buffered outputs. Each inverter really has three logic inverters connected in series. When configured in the linear region, the extra gain and phase shift can cause it to oscillate at an unpredictable high frequency.Why not use the 74HC4060? It contains an unbuffered gate and a counter, to give a range of lower frequencies, which are easier to use.There are also ICs, which are specifically designed to make a crystal oscillator such as the :74LVC1404 and 74LVC1GX04.https://www.ti.com/lit/ds/symlink/sn74lvc1404.pdfhttps://assets.nexperia.com/documents/data-sheet/74LVC1GX04.pdf

author: varunkoganti
author_rank: Contributor
timestamp: July 27, 2021, 03:04:52 am
content: So i have looked into the suggested ICs, unfortunately I couldn't find DIP version of 74lv1404 at my location, I have had a look into 74HC4060, which was available.I made up the schematics. I will order these parts and try it out as per below on a breadboard.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: July 27, 2021, 04:15:29 am
content: For the CD4060 I've used 10M for the resistor and it works.