hybridfree/eevblog-posts huggingface dataset:
Lipo battery in series? - Page 1
Forum section: electronics / beginners

author: Dave Wave
author_rank: Contributor
timestamp: August 03, 2016, 11:31:07 pm
content: So I am building a solar powered weather station.Power is limited and cold weather performance is important.I have several sensors that require 12v, but the cpu runs off 3.3v. My plan was to use 3 lipo batteries in series to net about 12v. That could power my sensors directly, then use a step down for the cpu.The problem is charging the battery.The cells have a battery protection IC built in. Will this even work wired in series? Are there going to be issues with balance? Both the charge and discharge rate is going to be slow. Over a 10 hours for a full charge, over a week to discharge.The other option is both a step up and step down from single cell lipo, but I am going to loose some efficiency on the step up side.Thoughts?Thanks,Dave

author: Signal32
author_rank: Frequent Contributor
timestamp: August 03, 2016, 11:38:01 pm
content: Quote from: Dave Wave on August 03, 2016, 11:31:07 pmYes, it will work.Quote from: Dave Wave on August 03, 2016, 11:31:07 pmNo major issues that you should concern yourself with unless one of the cells is damaged.Depending on the charge voltage you probably are going to have to step up the voltage anyways if you're using 3 cells.To give a good answer we would need to know what voltage / amps your solar cell is providing and how much current your sensors and micro are using.

author: Ian.M
author_rank: Super Contributor
timestamp: August 03, 2016, 11:52:15 pm
content: Quote from: Dave Wave on August 03, 2016, 11:31:07 pmSeehttp://batteryuniversity.com/learn/article/charging_at_high_and_low_temperaturesConsumer LiPO cells cannot safely be charged below 0 deg C. Consider a 12V Lead Acid battery!Make sure you have enough panel area for charging during your location's worst month for insolation and enough battery capacity to ride out the month if its worse than average.

author: Dave Wave
author_rank: Contributor
timestamp: August 04, 2016, 01:10:49 pm
content: Crap...I never thought about charge under cold temperatures....I am going to SLA.Thanks for the help.Makes one wonder about the viability of electric cars in cold climates. Not every person has a heated garage to charge the car in.-Dave
Lipo battery pinout  - Page 1
Forum section: electronics / beginners

author: lartsu
author_rank: Contributor
timestamp: January 01, 2018, 03:41:31 pm
content: Can you say what are two pins in the middle of the "original" battery (for Sierra aircard 762s).I have tried to connect the two wires 3.7 Lipo battery the modem but it’s not starting to load battery. Is the remaining pins for lipo battery protection? Are there any solutions to bypass this?All advises are welcome!

author: janoc
author_rank: Super Contributor
timestamp: January 01, 2018, 04:25:18 pm
content: The two extra pins are likely for a thermistor for sensing temperature of the battery. If the device doesn't see them connected (resp. the resistance between them is not some reasonable value), it will evaluate it as a battery fault and refuse charging for safety reasons (overheated LiPo = kaboom).

author: lartsu
author_rank: Contributor
timestamp: January 01, 2018, 06:03:09 pm
content: What is the best guess about resistance size?

author: kjr18
author_rank: Regular Contributor
timestamp: January 02, 2018, 08:01:45 pm
content: These are very common things in mobile phone batteries. You can call it BSI: Battery Size Indicator. In this case it might be a resistor to ground on one of these pins and other might be a temperature sensor (a simple thermistor), no idea which is which.

author: Nusa
author_rank: Super Contributor
timestamp: January 02, 2018, 09:27:13 pm
content: That "original" battery is clearly not the actual original, but it is a correct choice for that device. You should be able to just put it in and have it work, with all four pins connected. Assuming there is nothing else wrong with the device.

author: lartsu
author_rank: Contributor
timestamp: January 03, 2018, 09:09:39 am
content: I don't have ~original batteries for this device (just a picture from net) . I have only 3.7 lipo battery which doesn't have protection circuit with NTC. I would like to to bypass this feature.

author: janoc
author_rank: Super Contributor
timestamp: January 03, 2018, 12:13:01 pm
content: Quote from: lartsu on January 03, 2018, 09:09:39 amThat's a bad idea - if the device has a fast charger, it may be relying on that thermistor to limit the charging current into the battery in order to minimize the charging time while still keeping things (battery temperature) safe. If you bypass this, it may literally blow up in your hands if you are unlucky. Equipment manufacturers rarely put extra components somewhere where they aren't really needed because it costs money.Without knowing how the built-in charging circuit works this is quite a dangerous thing to attempt.

author: paulca
author_rank: Super Contributor
timestamp: January 03, 2018, 12:14:07 pm
content: This might help.https://sayyedhamid.blogspot.co.uk/2011/05/all-about-battery-connector-pinout-of.htmlHowever the pin outs are not standard. So without a sample battery to probe you are going to be a bit stuffed working out how to fake what is most likely the BSI and BTemp
LiPo charger and power path switcher module similar to TI's BQ246XX series - Page 1
Forum section: electronics / beginners

author: ealex
author_rank: Frequent Contributor
timestamp: October 17, 2017, 10:32:57 am
content: HelloFor some projects i need a module / board that will be able to :- charge a LiPo pack from an external power pack- switch the output from the external power pack to the LiPo pack when the external power pack voltage is out of rangeThe LiPo pack will have it's own protection and balancer, so that's not needed.I've looked at available IC's and the BQ246XX series from TI does everything I need:http://www.ti.com/lit/ds/symlink/bq24618.pdfAfter looking over the datasheet i don't think i'm able to make and properly test a board of that complexity.Do you know of any available modules that have the two functions ?I've looked over ebay but the keywords i used did not provide anything useful.( example application: portable pack for a TS100 soldering iron or a portable PSU using one of the modules shown by Dave / Shahriar )

author: sdouble
author_rank: Frequent Contributor
timestamp: October 17, 2017, 01:43:12 pm
content: I'm working on a similar project, using the very same part.should not be too complicated. the datasheet is well documented.

author: RoadRunner
author_rank: Frequent Contributor
timestamp: October 18, 2017, 09:38:00 am
content: there are many modules available for BQ24650 off ebay for about 15 USDthey are really simple , trust me on this.i have designed my own module based on BQ24650 for solar charger, i have been rigorously using this more than one year, it seems to be really robust solutionhttp://www.circuitvalley.com/2016/09/mppt-solar-liion-li-ion-charger-battery-TI-BQ24650-micro-controlled-mppt-algorithm-led-driver.htmlthis was part of this projecthttp://www.circuitvalley.com/2016/10/solar-led-light-li-ion-mppt-battery-status-msp430.html

author: ealex
author_rank: Frequent Contributor
timestamp: October 18, 2017, 11:58:27 am
content: niceas you say, the datasheet is quite clear and has a full example.i'll try making my own boards and maybe put some for sale if there is interest in itthanks
LiPo charger MCP73831 - Implementing Tri-state logic LED - Page 1
Forum section: electronics / beginners

author: made2hack
author_rank: Frequent Contributor
timestamp: June 21, 2016, 06:50:08 pm
content: Hello all,Here's the circuit I'm using with anMCP73831to charge a single 18650 LiPo cell. I have the /1 at the end and the STAT pin is a Tri-State logic output.Can I use this to drive a common Cathode Red/Green LED? How would this work? I want say red when it's charging and green when it stopped?Right now the led just stays on when it is charging as above and lightly flickers when the battery is disconnected.Thanks

author: Signal32
author_rank: Frequent Contributor
timestamp: June 21, 2016, 08:31:08 pm
content: You can't drive a common cathode LED without additional components. (additional components = anything other than current limiting resistors).You can drive two separate LEDs without additional components, though inefficiently.For common cathode LED's you would need 2 transistors, a NPN and PNP.http://www.electronicshub.org/wp-content/uploads/2015/01/7.-Transistors-Driving-LEDs.jpgLike above, only for the NPN, put the load on the emitter. You might also need to put the current limiting resistor up on top of the collector, for both cases.

author: Buriedcode
author_rank: Super Contributor
timestamp: June 21, 2016, 10:16:34 pm
content: I have used these before and for one product, I simply used a common anode tricolour LED (that is, two LED's with their anodes commoned, not bicolour). Anode was connected to the input power supply, the green cathode was permenantly grounded via suitable resistor. The red cathode was on the STAT pin. So with no power supply, LED off. Charging - yellow, done - Green. But it was also green when no battery was present.You would implement a 'red - charging, green - done' with same LED, but with an extra NPN transistor on the green cathode. So when the STAT is low, transistor is off, but pulls the red cathode low. When STAT is high, transistor on, green LED on, red off.There's many ways to do this with relatively simple components just depends on what kind of indication you need.Another option would be a bicolour LED, with one side connected to STAT and the other the centre of a voltage divider between charger input and ground. The resistors would permanently draw current (say ~500 ohms, total 1k, across 5V = 5mA) but would mean the LED would be one colour when STAT is high, another when low, and 'off' for high-Z. For projects where I have used this I replaced the voltage divider with a ~2kHz CMOS schmitt trigger oscillator. Has the same effect but reduces quiescent current consumption - handy if you're driving lots of these LED's.
Lipo driven 5v out/1amp++ power supply, possible? - Page 1
Forum section: electronics / beginners

author: eevfan007
author_rank: Contributor
timestamp: April 29, 2014, 09:59:50 pm
content: Hi!I'm trying to power a gnublin SOC (http://en.gnublin.org/index.php/GNUBLIN-DIP) from a lipo battery. I used a booster chip (NCP1402SN50T1G/ 200mA current max) to boost the lipo's 3.x to 5v.I then used the 5V for the USB connector (not in the picture on their website, just soldered on afterwards), and stepped the 5v down again to a regulated 3.3 for the main SoC.The gnublin boots fine, and can be in operation for a long enough time. But I want to use this to charge an iphone connected to the USB.It seems to be a current issue, because it just can't supply enough current through the usb connector from the booster IC to actually start the charging. If I add a secondary source of current, i all works fine. The gnublin boots, the usb works fine and it will charge an iphone quite fast.So the question is;Is it possible to create a power supply that uses lipo batteries, steps it up to 5v and is able to deliver 1+++ amps ++ of current?I have founds some booster ICs that go up to 800mA, but they are in a really hard to solder package. Anyone know of a solder friendly 1amp ++ booster IC?Any advice is greatly appreciated.

author: eevfan007
author_rank: Contributor
timestamp: April 29, 2014, 10:20:08 pm
content: Update: Found this on digikey, would that be able to step up a lipo 3.X to 5V and deliver 1amp+ of current ? Looks like it....?http://www.digikey.com/product-detail/en/TPS61032PWP/296-27007-5-ND/1672132

author: kaindub
author_rank: Regular Contributor
timestamp: May 01, 2014, 01:25:54 am
content: It's the iPhoneAll Apple devices have logic built in to them that works as followsFirstly, they assume that they are plugged into a standard USB port capable of only supplying 500mA. Ther device then sets the charge rate at 'low' and whilst charging is actually happening, your device does not indicate that. Trust me it is charging as long as there is 5V at the USB port. It will take some 10 hours to fi=ully chargeIf you plug your Apple device into a special Apple charger then the device knows this and will charge at about 2A. How does it know its plugged into a special Apple charger? Apple places a voltage on the D= and the D- terminal of the USB port (of the charger). The connected device senses these voltages and then decides what charging current it can use, knowing that there is 2 A available.A quick Google will tell you the voltages to set on the pins. the voltages are just set bu some resistors between 5V and 0VRobert
LiPo limiter. Pls review. - Page 1
Forum section: electronics / beginners

author: liviu.gelea
author_rank: Contributor
timestamp: March 24, 2023, 11:44:10 pm
content: Hello. I want to create a current limiting circuit that protects a 3S LiPo battery when charging a super-capacitor bank (used for my kweld)This is what I've come up with so far. Please note a fuse is also planned in case something fails, but I didn't include it in the schematic.Circuit simulation linkAre there any gotchas I might have missed?These are the components I'm working with:I know that radiator is a poor fit. I think with proper cooling I might get mySUP90P06to pass quite a few amps but I'm not sure my calculations are correct.For example, if I attempt to pass 10A through it, assuming the load is a dead-short, the P-fet will need to dissipate the full 140W. Will a radiator that handles under 0.5K/W get me there? the package thermal resistance is 0.6K/W In this case the Rgs should be around 1.4 Ohm but I'm worried Rgs varies significantly with temperature and I can't really figure out if I'm missing something.I really don't see how this FET can handle the rated 90A continuous with so much internal thermal resistance.Perhaps at smaller voltages?Thanks in advance.PS, I might be a bit optimistic with my 10A target. I might use more FETS in parallel to get there. In fact the battery itself should be able to handle hundreds of amps. I would have aimed quite a bit higher i I found it remotely possible with what I have at hand.

author: liviu.gelea
author_rank: Contributor
timestamp: March 25, 2023, 12:17:59 am
content: I have a 100 w, 1 ohm resistor. Am I over complicating this?

author: Manul
author_rank: Super Contributor
timestamp: March 25, 2023, 01:13:47 pm
content: It could be a better idea to use a switching converter for that (constant current). More complicated, but much more efficient. You need to weight different ideas.

author: liviu.gelea
author_rank: Contributor
timestamp: March 25, 2023, 04:40:59 pm
content: That wouldake sense for me since I'm already working on a constant power buck converter. Might add constant current capability and curent limiting capability and use that project for this purpose. I'll see what I can get done. Thanks
lipo loadsharing circuit fit my needs / scourcing issues - Page 1
Forum section: electronics / beginners

author: simondid
author_rank: Contributor
timestamp: June 21, 2016, 06:12:05 pm
content: Heyso i’m traying to find a lipo charing / loadsharing circuit that fit’s my needsMy circuit is going to draw around 300-400ma at peak normal / low power mode witch it is going to be for most off the time. Shut end op around 10-50ma.I’m aming to have around 3-6 18650 lipo batteryhttp://www.ebay.com/itm/201468564314in parallel and a setup converter to supply the 5v needI found this adafruit bordhttps://www.adafruit.com/products/2465witch seems to fit my needs but I’m having trouble scouring it in my country… plus the price is kind of high.So I’m looking for a new circuit bord that fit the same needs I blog post describing a load sharing circuithttp://blog.zakkemble.co.uk/a-lithium-battery-charger-with-load-sharing/but as I’m lacking acces to pcb and wut like the bord to be as small as possibleany suggestions where I can find a circuit that fit this needs? Preferably premad so I only need to connect my battery and circuitExtra questionthe adafruit charger is rated at 1000c is this much ore to little for the battery mentioned above ?

author: Audioguru
author_rank: Super Contributor
timestamp: June 21, 2016, 11:40:48 pm
content: Lithium batteries that are Chinese, no-name-brand, high capacity and are sold on ebay are frequently fakes.

author: Signal32
author_rank: Frequent Contributor
timestamp: June 22, 2016, 12:28:26 am
content: Currently the highest capacity 18650 battery is 3400mAh, perhaps 3600mAh, and they are ofcourse very expensive. The ones you linked to are most certainly fake and probably have <1000mAh worth of capacity. Extract the cells from a laptop battery for good price/quality."the adafruit charger is rated at 1000c"I think the model number is 1000c, it is rated for 1000mAh. Anyway the only thing that will happen is the battery will take more time to charge, it's not that it will not work.Perhaps this might work for you:http://www.ebay.com/itm/0-5A-Single-cell-Li-ion-Battery-Protection-Board-Mobile-Charging-Boost-Board-/231319638186?hash=item35dbb990aa:g:pD0AAOSwPe1UAHwY

author: simondid
author_rank: Contributor
timestamp: June 22, 2016, 02:24:09 pm
content: thanks for the ebay linkso a few questions the module has 0.5a charring lets say i'm using 6 batteries in parallel will make it a bad for charring (like damage and stuff) ore just a super slow charge?

author: Signal32
author_rank: Frequent Contributor
timestamp: June 22, 2016, 06:06:00 pm
content: Yes, only issue would be charging would be slow. 6 2500mah Batteries in parallel would be charged (from complete discharge) in aprox 30 hours.
Lipo powered Lipo warmer? - Page 1
Forum section: electronics / beginners

author: Zeecue
author_rank: Contributor
timestamp: November 29, 2018, 09:53:53 pm
content: HiAs I have quite a few powertool batteries that don't like to be cold and perform at the same time I was thinking about making a warmer/heater for them.The batteries I'll use for the "supply" is Makita 18V 4-9AH batteries.I was thinking about using a PTC heater, most I can find is 12V or 24V with a set temperatue at 60-120 degrees C, but how will they perform on a 18V supply?A temperature at around 20 degrees Celsius would be my target temperature.Any inputs will be appreciated.And thanks to the nice people on the Eevblog IRC channel for helping me so far.Sent from my MI 8 Explorer Edition using Tapatalk

author: spec
author_rank: Frequent Contributor
timestamp: November 30, 2018, 10:31:06 am
content: Hi Zeecue,Presumably you don't like using LiPo batteries at a low temperatures because you are concerned about stressing, or even damaging them. If that is the case, don't worry.So long as the batteries are above a critical temperature, which IIRC is around 0 degC (TBC), they will be fine.A lower temperature does mean that the battery will have less capacity, its terminal voltage will be lower, and its internal resistance will increase, but not enough to cause a problem in most applications.But the ironic thing is that batteries self-heat anyway when they are sourcing current, especially in power tools, so effectively there is a heater already built in. It's the battery core temperature that counts, not the case temperature, although the two are related.In general, with most components, the biggest negative impact on reliability is temperature.If you would like further information on batteries, including LiPo, just Google, Battery University for a well-written guide.PS: In certain products like, mobile phones, e-cigarettes, laptops, and power tools, the batteries have a hard time. The charging and discharging regime is designed to give maximum capacity, rather than good battery life, so in these applications battery life is quite limited anyway.

author: beanflying
author_rank: Super Contributor
timestamp: November 30, 2018, 10:46:02 am
content: Quote from: Zeecue on November 29, 2018, 09:53:53 pmMove to a better climateI wouldn't worry about them when in use unless that use will be light and sporadic as mentioned in the last post they will self heat internally in reasonable use. You want to keep them stored prior to use as you suggest circa 20C would be a good place to start. Grab one of these and run it off a car or plugpack and not waste your power tool batterieshttps://www.ebay.com.au/itm/12v-Portable-Car-Fridge-Cooler-Warmer-Thermoelectric-Camping-Caravan-7-Liter/253999514149?hash=item3b238d0225:g:6wcAAOSw~bhb-7se:rk:9:pf:0
LiPo short circuit protection and charging   - Page 1
Forum section: electronics / beginners

author: gus789
author_rank: Contributor
timestamp: June 14, 2018, 09:20:54 pm
content: Hi Folks,I am working on a design that runs on a LiPo battery. Due to space restrictions, the charging circuit (based on the MCP73831 @ 4.2V) is located on a separate board that connects to the target for charging. The battery is charged through a pin header on the device that provides direct access to VBAT and GND. I am concerned that having VBAT exposed on the header may present a small but non-negligible chance that the VBAT and GND header pins may come into contact during use, and would like to add some short circuit protection.My question is what is the best way to accomplish this? I am thinking that upgrading the MCP73831 to the 4.5V version and then adding a Schottky diode on VBAT on the target side could be an option. Is there a better way to accomplish this? Thanks!
LiPo to 10-12V boost with low-noise and very low-load output - Page 1
Forum section: electronics / beginners

author: jram112
author_rank: Contributor
timestamp: January 20, 2014, 06:40:15 am
content: I'm trying to boost a single cell lipo (3-4.2V) up to 10-12V. I need a low-noise boost converter for a low-current load application (<0.5 mA). I've tried a switching boost converter using a TI LM2704, but the output is quite noisy. The load is so low that it's like i'm using an unloaded power supply. All of the switch mode regulators I looked at don't even characterize the device at the really low currents that I'm using or even say there is a minimum current which is far above my load current.I'm considering using two cascaded charge pump IC's (~4x boost) in hopes for a lower noise output, but I have no experience with charge pumps.1. Do charge pumps typically have lower noise output? Some of my readings suggest that they do.2. Will using switch mode boost converters have higher noise with really low load current?3. Is there an alternative for boosting the voltage for a 0.5 mA application with a small pcb footprint?

author: mariush
author_rank: Super Contributor
timestamp: January 20, 2014, 07:06:01 am
content: I recently did a project using LT1307:http://www.linear.com/product/LT1307( 600kHz, 1-5v in, 100mA max)Now I didn't test the ripple voltage particularly but with a good pi filter on the output there should be very small ripple.Datasheet:http://cds.linear.com/docs/en/datasheet/1307fa.pdfThe LT1307 is also available in DIP package and with a bit of attention you can test it on a prototyping board.If you read the datasheet, there's a LT1307B version which is designed to have much lower ripple at small currents, and there's also some suggestions that let's you lower the ripple even more.page 9 :Quote

author: Psi
author_rank: Super Contributor
timestamp: January 20, 2014, 09:27:15 am
content: Have you considered boosting up to say 14V and then putting a linear LDO reg on that to get a nice clean +12V ?

author: digsys
author_rank: Unknown
timestamp: January 20, 2014, 09:56:03 am
content: Quote from: jram112I've used the MAX1044 on many occasions, and for the current you require, it's very little ripple. Have at least 1x 0.1uF, 1x 0.01uF andapp 4u7F low ESR caps close to the charge pump. You don't need 2 ICs, you can voltage double them.
Lipo/li-ion chargers and output capacitance - Page 1
Forum section: electronics / beginners

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: December 08, 2022, 04:46:08 pm
content: I found a schematic for a popular cheap purpose-made lithium polymer battery charger, the IMAX B6. The schematic is a bit complex for me but I believe the battery immediately follows the 820 uF output capacitor (see the green box immediately above the bottom rightmost green box.)Connecting a battery to the output would then result in a large and uncontrollable current into the battery due to the output capacitance. Isn't this detrimental to the life of the battery (and charging safety)? In practice, is this typical of all lithium polymer/lithium ion chargers? Or is there some sort of feedback loop implemented to slow this current dump -- and if so, what does this feedback typically look like?

author: wasedadoc
author_rank: Super Contributor
timestamp: December 08, 2022, 04:56:22 pm
content: An 820uF capacitor can only provide a large current for a very short time. Also the negative end of the capacitor is not connected directly to the battery negative. There is a MOSFET and a 0.03 Ohm resistor which will limit the current somewhat. Furthermore the capacitor is discharging into a load which has its own emf. It is only the difference between the capacitor voltage and the (non-zero) battery voltage which drives the current flow.

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: December 08, 2022, 05:12:57 pm
content: Quote from: wasedadoc on December 08, 2022, 04:56:22 pmLet's say a single cell 2 AH battery at 3.2 V is connected to the output which sits at 4.2V. Then we have 1V difference / 0.03 ohm = 33 A peak? I imagine it's a bit less in real life, but this is likely far above the recommended charge rate 1 C = 2 A? Or does it not matter (and no feedback loop is built to control it) because this current lasts for a comparatively short amount of time?

author: mikerj
author_rank: Super Contributor
timestamp: December 08, 2022, 06:03:40 pm
content: Quote from: ifonlyeverything on December 08, 2022, 04:46:08 pmThe IMAX B6 chargers output cannot be enabled until it sees that a battery is connected and the voltage falls in the correct range for the battery type and number of cells configured in the menu system. This means there will be a brief inrush of currentfromthe battery into the capacitor when the battery is connected, but not the other way around.
Liquid EC meter amplifier. Need help understanding schematic. - Page 1
Forum section: electronics / beginners

author: anthonyone
author_rank: Newbie
timestamp: June 23, 2020, 08:42:07 pm
content: Hi guys,im trying to understand the amplifier configuration circled in red. I was probing around an off the shelf EC meter for arduino since it died due to short in the caps. I tried making a schematic by probing the pcb and i couldn't understand the amplifier config circled in red.Any help is appreciated.Thanks.

author: TimFox
author_rank: Super Contributor
timestamp: June 23, 2020, 08:53:27 pm
content: I didn't analyze the circuit carefully, but it looks like a precision rectifier or absolute value analog computation circuit, where the diodes only switch current and their voltage drop does not contribute an error.Books on op amp applications usually discuss these circuits.

author: eblc1388
author_rank: Frequent Contributor
timestamp: June 24, 2020, 01:10:21 am
content: As TimFox has mentioned, the circuit is a form of precision rectifier circuits using 5 resistor of equal value. It is the same topology(albeit reversed output polarity because of the diodes) as the blue square marked circuit shown below.For its complete theory of operation, you can take a look at the following link:https://www.electronics-tutorial.net/analog-integrated-circuits/precision-rectifier/modified-precision-full-wave-rectifier/Please also take note of possible mistakes in the schematic:1. the part number of another IC. The IC should be CD4060BM instead.2. the EC_OUT polarity is negative w.r.t. circuit GND. This is in conflict with output diode D6 unless output level never exceed -0.6V. Please confirm polarity of diodes D8 & D9

author: anthonyone
author_rank: Newbie
timestamp: June 24, 2020, 08:29:57 am
content: Quote from: eblc1388 on June 24, 2020, 01:10:21 ameblc1388 thanks a ton the polarity of the diodes D8 and D9 was the issue. I built the entire circuit on a breadboard and it works!!!Quote from: TimFox on June 23, 2020, 08:53:27 pmThanks TimFox i started learning about full wave precision rectifiers. Is there any book in particular which is noob friendly?

author: TimFox
author_rank: Super Contributor
timestamp: June 24, 2020, 01:28:13 pm
content: A classic is Jung's "IC Op-amp Cookbook", which has gone through several conditions.https://www.abebooks.com/IC-op-amp-cookbook-Jung-Walter-G/30081731328/bd?cm_mmc=ggl-_-US_Shopp_Trade-_-used-_-naa&gclid=EAIaIQobChMI046D68aa6gIVC77ACh3vzAtdEAYYAiABEgJH7fD_BwE
LIS3DH accelerometer won't work as it should - Page 1
Forum section: electronics / beginners

author: Kemme
author_rank: Contributor
timestamp: September 02, 2017, 10:27:25 pm
content: HelloI have a problem with setting LIS3DH and it literally starts to drive me crazy.What I want it to achieve is to configure it to set pin INT1 down when the device experiences an acceleration change of 32mg lasting for 0.5s.Basically I want it to detect movement.Here are my settings:CTRL_REG1 = 0x20 //10Hz, normal power mode, ZXY enableCTRL_REG2 = 0x00 //no HP filtersCTRL_REG3 = 0x40 //IA1 enableCTRL_REG4 = 0x10 //scale 4gCTRL_REG5 = 0x08 //interrupt 1 pin latchedINT1_THS = 0x01 //32mg thresholdINT1_DURATION = 0x05 // 0.5s to activate interruptINT1_CFG = 0x7F //6D direction mode enabled, all directions enabledThen I read INT1_SRC register every second and probe the INT1 pin with the scope. The result is that INT1_SRC is always 0 and INT1 never goes down.Funny thing is that when I change the threshold from INT1_THS = 0x01 to at least INT1_THS = 0x0A everything seems to work OK.What am I doing wrong? Why isn't it working with lower thresholds?Thanks in advance.
LIS3MDL pololu, bad readings via SPI. - Page 1
Forum section: electronics / beginners

author: eejam
author_rank: Newbie
timestamp: August 27, 2016, 12:34:46 am
content: Hi, is there any one with experience with the LIS3MDL sensor, and SPI !?I've implemented, some code to read from the LIS3MDL via SPI, and it works, except that values are always noisy and extremely high.I know that, because, reading from the same device via I2C, gives-me stable (low noise) values, with accurate behavior. E.g. if I bring a magnet near the sensor, the sensor modulus of the magnetic vector, behaves accordingly to the distance of the magnet, as for in SPI it doesn't ...I've checked, the SPI clock mode, and from the data sheet (http://www.st.com/content/ccc/resource/technical/document/datasheet/54/2a/85/76/e3/97/42/18/DM00075867.pdf/files/DM00075867.pdf/jcr:content/translations/en.DM00075867.pdf) seems to be MODE3. I'm using a low clock speed (100kHz), and tried other combinations with same result.Somehow it seems I have a misbehavior in the sensor via SPI ...Any one with experience in this sensor, and SPI to give-me some hint?Thanks,BR,mc
LISN doubt - Page 1
Forum section: electronics / beginners

author: bonzer
author_rank: Regular Contributor
timestamp: March 05, 2020, 11:53:56 pm
content: Hello everyone! Please help me to understand the structure of a Line Impedance Stabilization Network. I don't know if it's all the same around the world but I'm from Italy and so we have here Live, Neutral and Protection Earth for power lines. What I know is that my power connection to the LISN should be filtered from incoming disturbances because I want only my EUT's conductive disturbances to be measured. I don't know if that may be useful to know but usually before power connection to LISN we have also a transformer used to prevent the activation of the differential interrupter because it could react as we have from live a current going to PE resulting in a difference from coming back current through neutral. Anyway my question is: this type of filter as showed in the schematic will for sure filter my CM disturbance coming from power. Would it also work for DM? I'm not sure about that.--modified--Just want to add that in the scheme by SA I mean Spectrum Analyzer, or it can be an ASA-Automatic Spectrum Analyzer. Capacitors are used to give low impedance in high frequency while the two inductors I suppose have no common core or negligible mutual inductance so they can give high impedance in high frequency.

author: bjbb
author_rank: Contributor
timestamp: March 06, 2020, 04:03:14 pm
content: ISNs are described and/or specified per the EMC standard scoped for the end-use equipment. CISPR16-1-2 and ANSI C63.4 are common references. If you deviate from the suggested connections, your test data, at worst, may have no meaning; and at best, maybe valid only for comparison for your local stuff.Test labs/notified bodies typically disallow the common 'safety' disconnect devices and employ large filter banks to supply their ISNs.
LISN schematic understanding - Page 1
Forum section: electronics / beginners

author: MarcoDeMatteo1979
author_rank: Newbie
timestamp: February 02, 2017, 01:56:36 pm
content: Hallo, everyone.For the schematic of the LISN in attachment, could anyone explain why the Inductance and the resistance are in series and both in parallel with the 50 Ohm Resistor?Wouldn't it be the same to leave the 50 Ohm resistor, if the objective is to have a constant impedance at high frequencies?Thanks!FAP.S. : Not an electric expert, so hope you would excuse me if the question is silly

author: hfleming
author_rank: Regular Contributor
timestamp: February 03, 2017, 12:35:01 am
content: Are you sure the 50R resistors are real, and not just the representation of the input impedance of the analyzer that you use to monitor the noise from the EUT?
Lisocl2 Battery EOL Monitor review - Page 1
Forum section: electronics / beginners

author: Sultanpepper123
author_rank: Regular Contributor
timestamp: January 12, 2022, 06:17:25 pm
content: Hello everyone,I'm working with a device which will use Lithium thionyl chloride (non-rechargeable) batteries as a backup source ; their discharge curve is quite flat and AFAIK you cant tell how is the battery in terms of whether it's good or about to die(EOL) unless you apply a dummy load, there are other more complex methods but my application requires me to save every penny and the client just wants to know if the battery is good or dead. Now the circuit is working but I would like to make sure If im actually doing it correct or outright far from the right path.My concerns :1. If this method of applying a dummy resistor when needed and measuring from the ADC at that time is a legit method2. If I should be concerned that the Voltage divider and the ADC might eventually drain the battery , I added a Mosfet to cut off or connect the path between the Battery and the voltage divider and ADC.Thanks in advanceSP
list of gopro models specs wanted  - Page 1
Forum section: electronics / beginners

author: sony mavica
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:14:15 am
content: ive looked on google but i only find specs for the newer modelsdoes anybody know where i can find a list of specs for the first gopro to the newest one thanks

author: jackbrouno
author_rank: Newbie
timestamp: August 13, 2014, 11:35:56 am
content: It should be easy to google it

author: dhlavaty
author_rank: Newbie
timestamp: August 13, 2014, 01:04:09 pm
content: Start here:http://en.wikipedia.org/wiki/GoPro

author: sony mavica
author_rank: Frequent Contributor
timestamp: August 13, 2014, 10:19:55 pm
content: Quote from: dhlavaty on August 13, 2014, 01:04:09 pmthanks but it does not show all the specs but as you say its a start

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 13, 2014, 10:30:24 pm
content: It is not clear what benefit you perceive from concealing WHAT particular specs you are seeking?

author: Smokey
author_rank: Super Contributor
timestamp: August 14, 2014, 01:54:02 am
content: I was actually looking for exactly the same data a while back when I was thinking I could score an older model gopro on ebay, but I realized I had no idea how many different models there have been or what their specs are.http://www.goprobuyersguide.com/The different model summary is at the bottom 1/4 of the page.

author: sony mavica
author_rank: Frequent Contributor
timestamp: August 14, 2014, 08:33:43 am
content: Quote from: Smokey on August 14, 2014, 01:54:02 amthank you so much
List of Usenet newsgroups which might be helpful - Page 1
Forum section: electronics / beginners

author: kshitij
author_rank: Newbie
timestamp: January 27, 2016, 02:20:02 pm
content: While these forums are an incredible resource, here are some old school newsgroups where you may still find helpful folks who learnt stuff without Google or Wikipedia to help them.These newsgroups are spam-free (and active for a little over 15-20 yrs) , for the most part. An easy way to wade through the ad bots is to check for threads with only one post. More often than not, it's an advertisement.The links are formatted like:https://groups.google.com/forum/#!forum/<group name>for e.g.,https://groups.google.com/forum/#!forum/alt.comp.lang.learn.c-c++Mods should feel free to merge this thread with the sticky on books and primers if they wish.1)alt.comp.lang.learn.c-c++:Beginner's C and C++ questions go here2)comp.lang.c:Questions related to generic (os-agnostic) C preferred. Slight overlap with the learn group.3)comp.lang.c++4)comp.dsp:Thesignal processing group5)sci.electronics.basics: for fundamentals6)sci.electronics.cad: pcb design et al.7)sci.electronics.components: Good for those rare part datasheets. People sometimes post their own chipset test data.8)sci.electronics.design: Occasional overlap with the CAD group, and, oddly, some physics questions.9)sci.electronics.equipment10)sci.electronics.repair11)comp.arch.embedded: Useful enough for AVR32 and MSP hobby questions. Some responses for ARM.12)comp.realtime: Some experienced (read elderly) gentlemen do post some amazing tips occasionally13)alt.lang.asm: Assembly fanatics (MASM, FASM etc.). Use the embedded, microcontroller or fpga newsgroups if you want to discuss specific hardware14)alt.microcontrollers.8bit: Just an FYI, that, you are likely to get more helpful results about 8 bit AVR's from avrfreaks forums.15)comp.soft-sys.matlab: Surprisingly better caliber of questions than the matlabcentral forums.16)comp.arch.fpgaAs a norm, try to search for whatever you are looking for before posting.Also, this is a little off topic, but all these newgroups used to have an FAQ , sort of like a sticky post (loooong time ago, before Google, when Yahoo and Netscape Navigator ruled). If I find some of those still available, I might link them here.I did find the C FAQ for thecomp.lang.cnewsgroup. It's athttp://c-faq.com/index.htmlStill very helpful if you are into embedded C.PS: I'm not old.
Lithium 1.5v AA battery shwoing 1.7V? - Page 1
Forum section: electronics / beginners

author: DW1961
author_rank: Frequent Contributor
timestamp: October 13, 2020, 05:39:16 pm
content: I have a carbon monoxide alarm in my house and it's giving me the beep beep alert. I checked the batteries with a MM on the 1.5V setting, and they all show 1.7V.1.7V seems really high, and if they are 1.7V then they aren't worn out. So I'm wondering why I'm getting that low battery alert?

author: Peabody
author_rank: Super Contributor
timestamp: October 13, 2020, 09:23:53 pm
content: 1.7V is normal for that battery under no load or very low load. You may be getting a battery warning, but not necessarily a low battery warning. The detector may not be designed to handle the high voltage.

author: tooki
author_rank: Super Contributor
timestamp: October 14, 2020, 12:29:04 am
content: Wikipedia saysQuoteSounds like the batteries are actually empty. Test them under load, chances are the voltage is collapsing.

author: DW1961
author_rank: Frequent Contributor
timestamp: October 14, 2020, 12:58:06 am
content: Guys, I did test them under load using the MM battery test function, which I thought puts it under a load (not a full load of course).I tried alkaline AA batteries--same thing.These batteries have been in that unit for about a year with no problems. The unit was manufactured in 2011, so it may have been giving me an end of life alarm. From what I've just read, the intended working life of a carbon monoxide alarm is 5-7 years."End of Life Warning – Seven years after initial power up, a Kidde CO alarm will begin chirping every 30 seconds. The chirp will not stop until the unit is powered off." That's what it is doing.Even though it says 2001 on it, it may not have been powered on until 2013. I just bought a replacement--same brand same model and should just slide back on teh wall plate.Is there anything I can tear apart and salvage from it, like a PCB, etc--hehehe.
Lithium battery charger - Page 1
Forum section: electronics / beginners

author: zerorisers
author_rank: Regular Contributor
timestamp: December 16, 2014, 04:58:21 pm
content: I hear all these things about balancing circuts when people talk aboit charging lithium batteries. I have been slowly making a high capacity lithium batyery pack to plug into my phone. All batteries are in parralell along with the current phone battery. Sometimes the battery shows as the normal but is able to use power from the battery pack and other times it shows a question mark and showsit is an unknown battery still pulling power. Why is this? Thank you, and I appolagize for poor formatting I am on my phone.

author: cpt.charlie
author_rank: Contributor
timestamp: December 16, 2014, 11:07:04 pm
content: Maybe the battery charge monitoring circuit is unable to work with "high" capacity batteries and thus unable to determine the remaining charge.

author: sleemanj
author_rank: Super Contributor
timestamp: December 16, 2014, 11:20:16 pm
content: Check the basics, is the cable plugged in properly, check the resistance of the cable, are you noticing it gives the "?" when using a specific cable, and not with another cable.The problem you describe sounds symptomatic of your "high capacity" battery not presenting the appropriate configuration data or data-pin setup to the device to indicate that it is capable of supplying more than the 500mA standard for USB and so your phone is falling back to 500mA only.

author: zerorisers
author_rank: Regular Contributor
timestamp: March 05, 2015, 02:15:44 pm
content: Sorry about my inactivity, i took apart the old batter and the actual lithium cell was replaced with a higher capacity battery, after a while i believe i killed the charging circuit on the phone itself as when it is plugged in I don't even get the light saying it is plugged in. So the pins are all the same. I have used the same charger for a long time, even still use it with my new phone.
Lithium Battery Chargin Ebay Board Mod ?? - Page 1
Forum section: electronics / beginners

author: locoo
author_rank: Contributor
timestamp: September 03, 2016, 11:58:38 am
content: HiI dont know if it is possible or cost effective , correct me if not.I have an old Cordless drill NIMH 14.4 v and want to replace the battery with liion.But i would like to make my on BMS .Was thinking buyingeBay auction: #http://www.ebay.com/itm/10PCS-5V-Micro-USB-1A-18650-Lithium-Battery-Charging-Board-Charger-Module-/201414932553?hash=item2ee543f849:g:oEEAAOSwrklVO5q7But it has Max 2A Fet for overdiscarge protection and i need more my Liion can give out 15A burst .So what i want is to pull out the existing mosfet and replace it with a big TO220 some .I dont , i cant see will that work or what new fet to pick out , will the small DW01 be capable to run a big mosfet.

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2016, 12:52:44 am
content: A 4S pack might be a bit too much voltage (16.8V fully charged) but 3S is probably not enough (12.6V fully charged). If the motor and control circuitry isn't designed for the extra voltage they could be damaged.Also your cells are probably not sufficient if their burst current rating is only 15A. You should use low capacity high current cells, something like these (30Acontinuousdischarge):http://lygte-info.dk/review/batteries2012/Keeppower%20IMR18650%201600mAh%20(Black)%202014%20UK.html

author: locoo
author_rank: Contributor
timestamp: September 04, 2016, 09:51:43 am
content: But but 14.4v is a nominal voltage 14.4v÷1.2v =12 cellsFull12cells×1.45v = 17.4v1.45 v is cca fully charged Nimh cellSo 17.4v is almost prefect 4sThe cells I will use arehttps://batterybro.com/products/samsung-15q-inr1865015q-1500mah-18aAnd 15A burst I said is what I think the drill will pull Maaax probably much less.But my question was not obout the cells but can convert this cheap bms from eBay to run more than 2 amps ading an external Fet.Thanks
Lithium Battery Chassis/Housing composition? - Page 1
Forum section: electronics / beginners

author: THATguy
author_rank: Regular Contributor
timestamp: February 10, 2017, 09:25:04 pm
content: The metal housing of a Lithium battery is made of steel.What kind of steel is it?Doesn't appear to be corrodable, stainless, nickel coated, carbon steel?I imagine that pure iron would be risky as it oxidises on the outside and could also try to steal the Oxygen from the Lithium oxide if they were close on the inside.I want to have a go at making an experimental battery housing, and would rather not make something explosive.Also want to experiment with Sodium battery housing, if anyone knows of a suitable housing that wouldn't react?

author: james_s
author_rank: Super Contributor
timestamp: February 10, 2017, 09:27:21 pm
content: I thought it was nickel, at least nickel plated. I've never looked into the matter but I spot weld nickel strips to the cells when I make battery packs.
Lithium Battery Monitor - Page 1
Forum section: electronics / beginners

author: metRo_
author_rank: Regular Contributor
timestamp: October 03, 2014, 10:53:41 pm
content: Hi allAs we know if a Lithium battery runs low it will be damaged so I'm looking for somekind of monitor that I can use that break the power from the circuit if the Lipo run low voltage. I looked on ebay but everything I found are chargers :sDo you know anything that can I use on my circuit? It consist on a Lipo battery and some leds, I just don't want the battery to go below 3.6V.

author: VK5RC
author_rank: Unknown
timestamp: October 04, 2014, 12:19:58 am
content: I can't find the exact circuit easily but silicon chip magazine in the last 12 months had a low voltage cut off circuit, it had very low drain current, regards Rob

author: TriodeTiger
author_rank: Regular Contributor
timestamp: October 04, 2014, 12:37:12 am
content: Isn't this the prime use for a voltage reference? i.e. the TL431:http://www.digikey.ca/product-detail/en/TL431CZ/1026-TL431CZ-CHP/2521470You can set it to anything you want between a bit above 2V and up to around 30V.

author: goingjag
author_rank: Contributor
timestamp: October 04, 2014, 02:07:21 am
content: I thought Lithium's kept their voltage high right up until they are almost dead, with their amperage dropping off?It may be a function of electronics in my Ryobi Lion battery packs, but they work great until they have no juice left, then nothing, unlike my ni-cads which start loosing their punch as the get used up.The Lion's always recharge fine, and there is no warning with them to not drain all the way down, but then maybe they already incorporate the electronics you are looking to create for your project.

author: VK5RC
author_rank: Unknown
timestamp: October 04, 2014, 04:22:38 am
content: Here is the articlehttp://www.siliconchip.com.au/Issue/2013/September/LifeSaver+For+Lithium+%2526+SLA+BatteriesIt uses a zener diode reference, the tl431 only uses down to a few mA so it may be better.I think good LiPo tools cut off battery before they discharge too much.I recall also seeing an ad for a LiPo controlling chip, which I recall also controlled charging as well as cut off voltage.

author: metRo_
author_rank: Regular Contributor
timestamp: October 04, 2014, 02:30:39 pm
content: thank you allReading thishttps://www.eevblog.com/forum/projects/lipo-protection-charging-module/I found that there is lipo batteries with built in protection. How do I know if per example ithttp://www.clickplus.pt/p2346has builtin protection or not?BTW I found on ebay the protection circuit:http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=Protection+Circuit+Module&_sop=15