hybridfree/eevblog-posts huggingface dataset:
Infrared emitter and detector component - Page 1
Forum section: electronics / projects

author: rcourtney
author_rank: Contributor
timestamp: August 20, 2018, 03:09:43 pm
content: Trying to locate a source for infrared emitter/detector functions both in same device. Ideal device could have the detector in the center of emitters (6 perhaps)?May try SMD detector in center of 6 SMD LEDs.Possible detector: AMS.com TSL25721 using channel 1

author: floobydust
author_rank: Super Contributor
timestamp: August 20, 2018, 08:48:20 pm
content: Are you sensing position or distance?There are IR linear distance sensors, and slotted/reflective optical sensors which have both emitter and detector in one package. Usually an LED and phototransistor.Making one is not fun, a lot of work. Ambient light as DC from the sun, AC from incandescent lamps and HF AC from CCFL/LED lights is always present.Sharp distance sensors

author: rcourtney
author_rank: Contributor
timestamp: August 23, 2018, 06:18:00 pm
content: Are you sensing position or distance?Amplitude of reflected IR light from image through controlled optics.
Ingenico iSC350 Teardown and Analysis - Page 1
Forum section: electronics / projects

author: cakekelly
author_rank: Newbie
timestamp: May 16, 2017, 05:08:41 pm
content: I have pictures of my teardown here:http://imgur.com/a/zx8Ih. I bought a few of these with plans to gut them, using the enclosures for film cameras. However, I've gained interest in at least getting the display on, or turning on a few illuminated LED keys on the device. I have the DC power wire, RS232 to the machine, which also has a DC coaxial power connector on it, like this:https://www.crystalfontz.com/phpthumb/phpThumb.php?src=/images/products/WR232Y18/WR-232-Y18_Detail.jpg. Does anyone have any tips on powering this machine, or at least the lights, should I try and power the LED on the keyboard directly or should I try and get to the boot screen?
Ingress-protected rotary encoders for user input? - Page 1
Forum section: electronics / projects

author: rf-fil
author_rank: Regular Contributor
timestamp: August 05, 2025, 05:00:32 am
content: I can't seem to find any encoders that meet my needs: at least 20 detents, push-switch, panel mounted, at least IP54. There do seem to be IP67 products out there with such encoder inputs. I would think that adding ingress protection externally to the encoder will require a seal around the shaft. Which would add unwanted friction. How would I seal it and still allow for the length-wise movement for the push-switch input. I must be missing something. Thoughts / tips?

author: Terry Bites
author_rank: Super Contributor
timestamp: August 05, 2025, 05:43:24 pm
content: https://www.directindustry.com/industrial-manufacturer/ip66-rotary-encoder-156394.htmlThey aint cheap!

author: bsdphk
author_rank: Regular Contributor
timestamp: August 06, 2025, 09:08:45 pm
content: One piece of kit I've seen, designed for way beyond the IP scale, had a hall sensor on the inside of the seal and a shaft with a small magnet in the outside environment and no pentration. Pushing the button was sensed by the field-strength.
Initialization and reconfiguration of Skyworks Si5332 - Page 1
Forum section: electronics / projects

author: troiden
author_rank: Newbie
timestamp: January 22, 2024, 01:28:38 pm
content: In our new board we faced an issue with Si5332. It is main clock generator in our system and we planed to configure it via I2C interface by MC, but we can't do anything. Every time we transfer generator from READY to ACTIVE mode - all setting are dropped to their default values.It looks like part had been already preconfigured with something, we can read back DESIGN_ID value "IX_BL".Maybe someone faced similar problems and can push us in right direction? Or we are stuck with unusable board?
inject/eject handle to the module in back planes - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: September 05, 2024, 08:58:01 pm
content: What is the original name of the thing I call the inject/eject handle or latch module in the back planes? Can I find it on digikey?

author: Someone
author_rank: Super Contributor
timestamp: September 05, 2024, 09:41:05 pm
content: eurocard ejector
Inline AVC on XLR - Page 1
Forum section: electronics / projects

author: shaddow
author_rank: Newbie
timestamp: September 04, 2018, 06:17:54 am
content: I have a question someone might have a answer too.I am looking for a inline AVC via XLR Mic setup (old type 3 pin XLR)What the problem is;One of the clubs I am with has a PA system and uses wired mic'sThe problem is when members use the mic 98% don't use it right and so sometimes there hard to hear or they yell down the mic, there is also people that like to move the mic while they are talking.The hard part is keeping the volume at a level that everyone is happy (Yes thats almost imposable).The club wants to use what they have and so its my job to make fix there problems with it.I am looking for a AVC Automatic Volume Control that can run in line and it would be great if it can be phantom powered too, I don't mind a kit make or off the shelf (Price dependent)The PA is a “TOA A-512A” and the mic's use the XLR connection that is 200ohm 0.3mv Balanced that can also have +15vdc Phantom power feed to the mic's.The PA isn't connected to mains power most of the time, it runs via the 24vdc feed in that is fed from a 12v battery via a step up trans.The speakers are all 100v, but we are also looking at other outputs for wireless speaker stands thats why I need it on the inputs and not outputs.Can any one help or know of a product or wiring datagram that might do the job.

author: stevelup
author_rank: Regular Contributor
timestamp: September 04, 2018, 07:39:13 am
content: You can fix this only with education, not technology.

author: xani
author_rank: Frequent Contributor
timestamp: September 04, 2018, 03:22:41 pm
content: Make them a VU meter thingy but with three huge lights "OKAY", "SPEAK LOUDER", "STOP YELLING".Then put a compressor with limiter behind it and tweak knobs until it gets better. Limiter should make yellers at least bearable, compressor will make whisperers a bit better

author: LapTop006
author_rank: Unknown
timestamp: September 05, 2018, 02:39:15 am
content: You might be able to hack an existing audio compressor that can take a mic input such as theBehringer FBQ 100to take what power you do have.That should reduce the issue.

author: shaddow
author_rank: Newbie
timestamp: October 02, 2018, 03:56:58 am
content: Sorry everyone, for some reason I am not getting replies emailed so I have to log in to see what was posted.Stevelup.Educating them is about 0%They even have trouble turning the mic on and worse OFF then complain when people hear them talking.I just hate having to sit in front of the Amp adjusting for the sods, but then auctioneers are the worse as all they can do is yell down a mic.XaniThey wont read and worse they still think they are right and it should just work.

author: Bassman59
author_rank: Super Contributor
timestamp: October 02, 2018, 06:00:52 pm
content: Quote from: shaddow on October 02, 2018, 03:56:58 amJust walk away from this clusterfuck.Actually, no, don't walk. Run.
Inline JSX connectors/couplers? - Page 1
Forum section: electronics / projects

author: reflowman
author_rank: Contributor
timestamp: May 08, 2018, 12:18:40 pm
content: I have a load of enclosures with hard wired sensors sprouting out of them.They are a PITA to modify as the sensors have to be moved along with the electronics.I want to chop the sensor leads and insert some couplers. (3V3, 1mA max, 3-5 way, polarised, indoor use. Think small lipo connectors, JSX, ...).I foolishly thought it wouldn't be a problem but I can't find any cheapo preassembled/crimped leads in flying plug and matching flying socket.(I bodged a coupler from 0.1" header, socket, hot snot and heat shrink but it took ages and I'm not proud of it.)I guess I could chop some JST type extension leads in two but they're a bit chunky for signal wire.Any "cost effective" ideas please? DIN plugs need not apply!

author: sokoloff
author_rank: Super Contributor
timestamp: May 08, 2018, 01:45:45 pm
content: I've made tiny circuit boards with board-to-wire sockets on them for situations like this.It first feels like a "waste", but works really well and as long as you can afford a 2 week lead time, is dirt cheap.I'd love to know of a pure wire-to-wire solution, but for some connector types, those seem to made of unobtanium.

author: reflowman
author_rank: Contributor
timestamp: May 08, 2018, 04:10:56 pm
content: Quote from: sokoloff on May 08, 2018, 01:45:45 pmWell there's a thought - thank you! A socket on a hacked up piece of prototype board potted in a lump of Sugru self-set rubber. I like it.

author: sokoloff
author_rank: Super Contributor
timestamp: May 08, 2018, 04:46:47 pm
content: Quote from: reflowman on May 08, 2018, 04:10:56 pmHah. Now you gave me the idea to make some of those out of Veroboard that I have rather than always waiting for boards to come in.Last weekend, I soldered two board-to-board connectors together [which was a bear] because I couldn't wait for boards to come in. I'll bet that I had a stack of protoboards within 18" of where I was working and it never occurred to me to use those instead of trying to flux the crap out of connectors and solder them to each other... So thanks right back!
Inline resistor IC - Page 1
Forum section: electronics / projects

author: Sangharsh Sharma
author_rank: Contributor
timestamp: May 11, 2019, 09:26:51 am
content: I am using seven segment displays for a project I'm involved in. I have to connect resistors to each pins of the IC and my circuit is already is very complex. So, this complicates things even more. I once saw in internet somewhere, a inline resistor IC , that has resistor connected inline inside t. So, basically it can be used as a substitute. I can't find the IC anywhere. What's the name of that IC? Could anyone help me?

author: sleemanj
author_rank: Super Contributor
timestamp: May 11, 2019, 09:40:47 am
content: You are looking for a resistor array, aka resistor network, they come in various packages, some look like ICs, some look like sideways smd resistors, some look like sil packages...https://www.google.com/search?q=resistor+array&safe=off&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj_ubCxl5PiAhXEPo8KHcFDBFEQ_AUIDigB&biw=1680&bih=959

author: Kalvin
author_rank: Super Contributor
timestamp: May 11, 2019, 10:14:18 am
content: Have you considered using SMD resistors, like 0805-size or 0603-size. They are cheap, easy to obtain, small yet quite easily solderable by hand, and they do not require drilling for the wires.
Inline USB 2.0 switch for test automation – how to simulate clean disconnect/rec - Page 1
Forum section: electronics / projects

author: mastupristi
author_rank: Newbie
timestamp: April 22, 2025, 03:56:01 pm
content: Hi all,I'm working on a small USB-controlled inline device that sits between a USB host (typically a PC with a USB-A or USB-C port) and a USB device (either USB Micro-B or USB-C).The goal is to simulate aUSB cable disconnect/reconnectunder software control — to trigger device re-enumeration, activate bootloaders, or perform power-cycle testing as part of automated QA.The USB link is always USB 2.0, and devices may be either Full Speed or High Speed.Use caseI work with different classes of devices:A USB 2.0 device with a Micro-B connector, drawing minimal current, no negotiation involvedA USB 2.0 device with a USB-C connector thatrelies on current negotiation, e.g. it negotiate to draw 1.5 Aetc...I would like to be able to disconnect/reconnect the device to the host in a controlled way. Just like a switch that behaveexactly like a passive cableduring normal operation, but simulate a physical detach/reattach event when controlled by a microcontroller (e.g., via GPIO).In this scenario, the system should remain as transparent as possible and not interfere with expected power negotiation behavior, especially for USB-C devices.“Active” components, such as hubs, could be used instead, but always with the ability to disconnect ports via softwareConstraintsUSB 2.0 only (no USB 3.x or USB PD involved)Host is USB-A or USB-CDevice side may be USB-C or Micro-BSome USB-C devices expect 1.5 A capability (maybe more in the future)Devices may run at High Speed (480 Mbps), so any switching must be signal-integrity friendlySimple, robust implementation preferred (ideally without requiring USB drivers or protocol stacks)Conceptual block diagramHere's the high-level idea:The "switch block" might control VBUS, CC (for USB-C), and possibly D+/D− if needed.Open questionsI'm evaluating a few possible approaches, and I’d love to hear feedback from others who’ve worked on similar USB tools:What USB lines need to be switched to properly simulate aclean detachfrom the device’s perspective?Is switching only VBUS enough?Do I need to disconnect CC (for USB-C)?Should D+/D− be switched as well for High Speed?Is there a better approach using USB redrivers with enable/disable control?Would a USB 2.0 hub IC (e.g. USB2412) with per-port power control be a better, more spec-compliant choice?What kind of switches (analog/SPDT/SPST) are usable for CC or D+/D− in USB 2.0 High Speed?Any other chip suggestions or reference designs?I'm not looking for one specific solution — I'm open to advice on architecture, part selection, and general experience.Has anyone here built something similar? Any thoughts are welcome.Thanks in advance!
INMP441 mems microphone module footprint? - Page 1
Forum section: electronics / projects

author: that_guy
author_rank: Contributor
timestamp: January 02, 2021, 11:34:47 am
content: Can someone who's got this INMP441 module please tell me the distance between the two rows of 100mil pin headers?I've ordered a couple that are on the way on the slow boat from China and have eyeballed that distance at 300mil but am not confident enough to submit my design for a carrier board to JLPCB based on my guess.

author: somuchtyler
author_rank: Contributor
timestamp: January 03, 2021, 07:26:33 am
content: It is 300mil since the spacing is designed to fit the middle of a breadboardhttps://youtu.be/m8LwPNXqK9o?t=73

author: that_guy
author_rank: Contributor
timestamp: January 03, 2021, 11:20:03 am
content: Thanks very much for spotting that. YouTube was the one place I didn't search!
Input and output impedance of a push pull amplifier using MRF300AN, MRF300BN - Page 1
Forum section: electronics / projects

author: kopcicle
author_rank: Newbie
timestamp: March 23, 2020, 06:09:33 pm
content: So I woke up one day to the the NXP MRF300 and started pushing pixels...

author: kopcicle
author_rank: Newbie
timestamp: March 23, 2020, 08:11:45 pm
content: [ Specified attachment is not available ]

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2020, 10:03:25 pm
content: Hmm, no ground support in the middle? I guess there's going to be another layer under that.Tim

author: profdc9
author_rank: Frequent Contributor
timestamp: March 23, 2020, 11:03:21 pm
content: RF MOSFETs usually have the case as the source rather than the drain, and so the transistors can be connected directly to a heatsink below and the heatsink can be grounded. Of course, any anodizing has to be removed from the heatsink to make contact.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 24, 2020, 02:23:58 am
content: Yeah, that's the case here. I'm thinking the source pin may end up soldered to bottom side copper somehow (e.g. loose copper foil?). Bottom side copper being clamped (preferably with help of EMI gasket) to the heatsink (non anodized, as mentioned!) would be okay as well.Tim

author: kopcicle
author_rank: Newbie
timestamp: March 24, 2020, 05:27:58 pm
content: TimMore or less nearly correct. The MRF300 AN has a companion part with the gate and drain pins swapped. The source is the center pin as well as the tab.This makes for easy mounting as well as layout.
Input and output impedance standards for video signals? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: October 08, 2022, 11:27:22 pm
content: Is the input impedance the standard for all analog and digital signals, 75 ohms?what about the output impedance, is there a standard output impedance for video?

author: boB
author_rank: Frequent Contributor
timestamp: October 08, 2022, 11:30:40 pm
content: AFAIK, yes. 75 Ohms for input and output on video.

author: Benta
author_rank: Super Contributor
timestamp: October 08, 2022, 11:37:49 pm
content: Yep, 75 ohms for output, input and cable. Professional video uses 75-ohm BNC connectors for RGB/Sync. Dunno what you mean by digital video in this context?

author: Terry Bites
author_rank: Super Contributor
timestamp: October 09, 2022, 11:14:02 am
content: A standard is a standard . 75R is used to get greater bandwith that a 50R will give. A 75R cable is lossier but has lower group delay. 50R is narrow band. An FM radio broadcast may have a bandwith of 200kHz. SD video will need 4.35MHzDigital video uses 110R, often sent over 75R using a matching transformer. It's worth learning how to tell a 50R BNC from a 75R BNC, a subtle difference.Pro analog audio uses 600R as do copper telephone lines.You dont need an emitter resistor to gnd if you DC couple. Send a current not a voltage. Just drive the line from the emitter via a 75R. .Avoid caps if you can. Sag and such. Video line drivers are very low cost items, they abound in consumer video kit. EG THS7316DRG4

author: Benta
author_rank: Super Contributor
timestamp: October 09, 2022, 06:37:41 pm
content: Quote from: ELS122 on October 09, 2022, 12:49:33 amSo why do you ask about analog video? Wasting our time for fun?

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 10, 2022, 01:59:46 am
content: Almost every digital video standard uses differential pairs with about 100 ohms impedance, the biggest exception being SDI which was meant to run digital video over existing analog video cables.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 11, 2022, 06:43:54 pm
content: www.maximintegrated.com/jp/design/technical-documents/tutorials/1/1184.htmlThere is always the ITU, founded by Napoleon III.www.itu.intStill owned an operated by petty dictators I imagine. Actually they're decrepit bond villains but I'm splitting hairs.ISO/IEC JTC 1/SC 29You used to have have to include a picture of a young woman looking back over her shoulder to demonstate video standards.Standards have improved and thankfully this is no longer a requirement.

author: Datman
author_rank: Regular Contributor
timestamp: October 13, 2022, 02:21:34 pm
content: With 39 or 180 ohms to gnd, output impedance will surely be lower than 39+39 or 180+68 ohms!
Input bias current correction on switchable non inv opamp - Page 1
Forum section: electronics / projects

author: Kevin.D
author_rank: Frequent Contributor
timestamp: January 27, 2013, 01:55:24 pm
content: Hi guys can some pro help a hobbyist please.I have a non Inv op amp with switchable gains in my design.Lets say I just switch the value of the ground resistor in the feedback to change gain from 10 to 100 X .Now the problem is in how to compensate for the input bias current of the op amp ,normally your supposed to put one resistor in the + input equal to the parallel combination of the two feedback resistors .But if you changing those values when your switching gain , then how can you calculate it . ?I know someone going to suggest to switch to a op amp with Fet inputs and lower bias current's but I would like to use the amp I already got if at all possible .

author: Tube_Dude
author_rank: Regular Contributor
timestamp: January 28, 2013, 01:39:44 pm
content: If you just need to amplify AC signals, use a electrolytic capacitor in series with the lower arm feedback resistor ( FB resistor to ground)...

author: Kevin.D
author_rank: Frequent Contributor
timestamp: January 28, 2013, 03:13:31 pm
content: Sorry what's that got to do with my question ? ( BTW it's only a dc amp I am switching anyway) .l am using this technique to make a "pga" and switch gainslike this page shows you here and switching with mosfets .http://www.ecircuitcenter.com/Circuits/op_PGA/op_pga.htmBut they don't mention here or any other web page that shows you techniqueanything about input bias correction resistor values when your doing this .If your using bipolar input amp with large input bias currentsthen you need a resistor in the non inv terminal to compensate for the error ,yes.?It's value supposed to be equal to the parallel value of the two feedback resistors .But if your switching them like you are here then your changing the value of the feedback resistors so that one will need to change to yes .?since nobody answered I will take that as a " there is no solution to this except to use Fet input op amps". ?

author: CarlG
author_rank: Regular Contributor
timestamp: January 29, 2013, 06:39:25 am
content: Have you considered switching in another compensating resistor at the non-inverting input as well, to match the inverting input resistance?Otherwise, I happened to see the attached app note of (unipolar) IBreduction [from LM324 datasheet]. If IBis bipolar it gets a bit more complicated.
Input Circuit from 12V to 3.3V Logic High Low - Page 1
Forum section: electronics / projects

author: OneGeekGuy
author_rank: Regular Contributor
timestamp: May 10, 2025, 06:05:26 am
content: Hi everyone,I am working on a design in which I need/would like to have a wired switch connected between 1m and 2m away from an MCU. I was thinking about simple solution but reliable at the same time, and probably over thinking about it.The idea is that the Switch will be normally close and using NMOS-PMOS input stage in a way, I have on the NMOS the 12V, and on the PMOS the 3.3V. Also considering NMOS would be pulled up, when the switch normally closed is connected I can somehow detect on the MCU startup that the switch is connected. Well, and in normal conditions as well.I would use as said a simple NMOS PMOS configuration, and do not worry more about it, protect the NMOS gate with a TVS/Capacitor (High speed switching is not required), and that is all. But I was thinking if it would make sense to go to another topology, using a buffer driving a mosfet gate, or something similar and wanted to hear suggestions, opinions and experiences.In this case optocoupler is not an option because the grounds from 12V and 3.3V which come from the same device are tied together there is no isolation.I could also use the 3.3V instead of the 12V for the switch action, but I did not want to route the 3.3V on a 2m cable outside.The application is generic, I do not need to run any kind of testing on it (regarding transients, ESD.....) but just want to make things properly.Thanks!

author: eleguy
author_rank: Regular Contributor
timestamp: May 10, 2025, 06:21:42 am
content: Gate resistor, well selected bidirectional TVS and some care for potential back EMF should do the trick. Protect both ends of the cable and MCU is safe as well.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: May 10, 2025, 07:22:50 am
content: Quote from: OneGeekGuy on May 10, 2025, 06:05:26 amThis can be as simple as 2 or 3 resistors, you do nothaveto use any active parts.Simplest is 2 high value resistors that divide the 12V down to 3.3V, and gives a switching threshold proportional to the MCU threshold (CMOS typical of 50% would give 6V)The high values use the ESD protection in the MCU pins.You may choose to add a 3rd wetting current resistor, that gives a few mA through the switch for more reliable long term operation.
Input current limited buck converter - Page 1
Forum section: electronics / projects

author: daywalkerdha
author_rank: Contributor
timestamp: November 02, 2017, 09:06:58 am
content: For a project, i am looking for a buck converter that i can use in a kind of constant-current/constant-voltage mode. I need a 15V supply that limits the output voltage so that it never draws more than 1A from it's power source. It will be used for a heater that only wants more than 1A while heating up. Once it has achieved it's target temperature, the steady state current will be lower than 1A. I want to use the input-current limited buck converter to be able to use a smaller power supply(trading for heatup time). Can anybody recommend a chip? Integrated switch would be preferred. But it should be a switching regulator, not just a LT3080 or similar in constant current mode.

author: Zero999
author_rank: Super Contributor
timestamp: November 02, 2017, 11:51:23 am
content: Don't double post!https://www.eevblog.com/forum/projects/input-current-limited-buck-converter/

author: ogden
author_rank: Super Contributor
timestamp: November 02, 2017, 12:23:50 pm
content: Consider MC34063A/KA34063A. It's oldskool, <100KHz, but does what you want.http://www.onsemi.com/PowerSolutions/product.do?id=MC34063A

author: Simon
author_rank: Unknown
timestamp: November 02, 2017, 12:40:26 pm
content: Please do not double post.
Input Filter In-Rush Current Limit Design - Page 1
Forum section: electronics / projects

author: rbola35618
author_rank: Frequent Contributor
timestamp: May 31, 2022, 04:23:58 pm
content: In this video, I show a design procedure in how to design an In-Rush Current limit circuit (also known as a slow start circuit). In an input filter, we usually add capacitors to the input filter to attenuate the SMPS current from corrupting the input bus or input voltage. However, adding more capacitors to the input filter will increase the in-rush current spike. To lower the in-rush current, you need to add a slow start circuit, or an in-rush current limit. Questions, request for TopSPICE files, and comments can be sent to rbola35618@aol.com. I hope you find this video useful.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: May 31, 2022, 05:06:42 pm
content: Thank You, Robert!
Input overvoltage protection - Page 1
Forum section: electronics / projects

author: rakeshm55
author_rank: Regular Contributor
timestamp: April 27, 2012, 06:06:40 pm
content: HiIn one of my projects the input power source is a regulated 5V wall wart supply. I wanted to provide an input protection for over volt condition, For this I have put in place a Tanzorb 5V and PTC. Now breakdown voltage for tanzorb is about 6.4 to 7.25V approx.The input protection is followed by a boost regulator for 5.2V. Please refer to the attachment. when I apply voltages a near 6.5V to 8V the PTC is not tripped though Tranzorb heats up (200mA current flow i could measure). The o/p voltage of boost regulator at this high voltages are same as i/p 6.5 to 8V .i have ckts at the o/p of boost which gets damaged if stressed above 5.5VHow to provide a proper input protection???Can I shut down the regulator??Please help

author: bilko
author_rank: Frequent Contributor
timestamp: April 27, 2012, 06:22:29 pm
content: At this low voltage level classic designs use a crowbar protection circuit consisting of basically a zener diode and thyristor. When input goes over voltage the zener triggers the thyristor blowing a fuse disconnecting the supply

author: rakeshm55
author_rank: Regular Contributor
timestamp: April 28, 2012, 04:02:14 am
content: Sorry that I forgot to mentionThe input regulated 5V powers up a boot regulator and a Li ion battery charger. Charger Max input voltage is 6.0V So protection needs to be at the i/p stage.Quote from: yachtronics on April 27, 2012, 06:22:29 pmwhat is crowbar protection circuit used with a current draw more than 1A. My PTC av current is 500mA.Quote from: AcHmed99 on April 27, 2012, 07:18:08 pmWont this ensure a reliable protection down . Please advice.

author: jahonen
author_rank: Super Contributor
timestamp: April 28, 2012, 11:00:49 am
content: Why not just use a P-channel FET which simply disconnects the power to the device when input voltage exceeds some pre-defined limit? Then put a TVS which protects the FET.Regards,Janne
Input pot for LM386 audio amplifier. - Page 1
Forum section: electronics / projects

author: shteii01
author_rank: Frequent Contributor
timestamp: June 22, 2017, 12:31:06 am
content: I am looking at the reference schematics in the lm386 datasheet. They show 10k pot at the input. But they don't say what kind of pot it is. Is it linear or logarithmic?datasheet:www.ti.com/lit/ds/symlink/lm386.pdf

author: debininja
author_rank: Contributor
timestamp: June 22, 2017, 12:39:09 am
content: You can use either, but usually, audio amps use log pots for varying the loudness.The sense of hearing is logarithmic. The speaker must output 10x more power for our ears to notice it to be twice as loud.

author: Audioguru
author_rank: Super Contributor
timestamp: June 22, 2017, 12:40:05 am
content: Our hearing's sensitivity to loudness is logarithmic so a volume control should also be logarithmic.
Input Power Peak Requirement - Page 1
Forum section: electronics / projects

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: July 24, 2019, 07:51:13 pm
content: I have a design project I am working on and I am having a bit of confusion with a specification. The specification is:The input power peaks shall meet the following requirements:Current time product <= 10 A.sPeak time <= 0.5 sI am not quite sure how to interpret the requirement. It is just confusing me. Say the input voltage is 12V. 12 V * 10 A.s = 120 J, 120 J / 0.5s = 240W.To me it seems like the peak time could be tiny and you could have a huge current briefly and the requirement would be satisfied. I guess what I am trying to get help with is the intent of a specification like this.

author: bob91343
author_rank: Super Contributor
timestamp: July 24, 2019, 07:53:36 pm
content: Yes the input isn't completely specified and does allow for large currents of short duration.Your computation of 240 W is only the peak power.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 24, 2019, 08:23:55 pm
content: A.s == C (coulombs). It's a charge figure.They shouldn't call it a power figure, since it has nothing to do with power, in and of itself. Can you ask the customer to clarify/correct, or is this something you have little recourse about?If the supply voltage is 12V, you can use a maximum of Q/V = C (that's capacitance) or (10 A.s) / (12V) = 0.83 F (farad).Seems like quite a lot, and even a modest motor would have trouble drawing quite that much inrush I think?The time frame needs a definition (peak above what threshold?) but it further implies that the input current should be limited to, roughly, something around 20A. Depending on how that is defined (instantaneous, average over the duration, etc.?), it may be less stringent than that.The energy associated with this charge, is also unclear; but if it is a linear capacitance being charged, then the energy is not the product again, but half. Consider E = 0.5 C V^2, then sub in C = Q/V. Mechanically speaking, it's the same relationship between momentum (kg.m/s) and energy (kg.m/s^2).Tim

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: July 25, 2019, 02:31:11 pm
content: Thanks Tim. Yeah I sent an email yesterday asking them to clarify the requirement, and its intent. I will let everyone know what exactly that is.

author: bigamps
author_rank: Newbie
timestamp: July 25, 2019, 03:53:14 pm
content: I guess I'd interpret it as 20A would be OK for 0,5s, but 40A would also be OK as long as they don't stay for more than 0,25s, or even 50A for 0,2s, and so ok for even shorter times. That is, the current * time product must be <=10As. Like somebody said it is like limiting the input capacitance.Enviado desde mi Aquaris X5 mediante Tapatalk

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: August 05, 2019, 06:28:11 pm
content: The requirement was changed to:"The input circuit must be able to withstand its own maximum inrush current."Much less confusing but still pretty vague.
Input protection for a buck boost converter (2.5-12V) - Page 1
Forum section: electronics / projects

author: neoraptor
author_rank: Newbie
timestamp: March 22, 2023, 03:11:59 pm
content: Hello,I have a project for RC planes where I want to connect either a 1S or 2S LiPo (2.5V-8.4V) to an ESP32 and a few components (ca 500mA load).I will have frequent battery swap.I would like to use the TPS63060 (buck boost controller) in order to cover a wide range of voltage (2.5-12V).However, I have an issue where the TPS and/or the ESP sometime die at startup, probably due to the inrush current.Adding a bigger capacitor (47uF) at the input helps, but it doesn't completely solves the issue.The current implementation is attached bellow.I tried to delay by a few ms the Enable ping from the TPS63060 with an RC filter but it didn't help.How is it possible to harden this circuit?I thought about a few things, but would like to hear some good/better practice:* Using the Power good signal to commute the load?* Use a MOSFET at the input to have a clear switch ?* I saw the LTC4365 but it may be overkill ?Thanks in advance.

author: Kim Christensen
author_rank: Super Contributor
timestamp: March 22, 2023, 03:53:15 pm
content: Quote from: neoraptor on March 22, 2023, 03:11:59 pmHave you tried a lowpass LC filter on the input?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 22, 2023, 04:13:17 pm
content: Use an electrolytic, a bigger capacitor with some ESR added (that's what the electrolytic is doing), or add a TVS.Quote from: Kim Christensen on March 22, 2023, 03:53:15 pmYes: the inductance is the cable between battery and converter. The problem is most likely the lack of termination resistance around the filter.Tim

author: neoraptor
author_rank: Newbie
timestamp: March 22, 2023, 05:59:42 pm
content: Thank you both for your answers.Are electrolytic capacitor also availble in SMD format? Which size are usually used for this kind of application ?My board is quite small and I would like to keep it as compact as possible.Adding a TVS would prevent the overvoltage but will it also help prevent the initial inrush current?Thank you

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 22, 2023, 06:20:18 pm
content: Yes. 100uF 10V would be what, a 7x7mm chip?Inrush current is another matter. Is that causing stress on something else? Contact wear? If the only effect is overshoot on hot-plugging, I wouldn't worry about it. (To be clear, shunt methods (ESR cap or TVS) increase the peak current or duration.)If you must, a series limiter will be necessary, such as an electric fuse, or a precharge circuit, etc.Tim
Input protection for outdoor battery operated device - Page 1
Forum section: electronics / projects

author: miceuz
author_rank: Frequent Contributor
timestamp: February 19, 2017, 10:23:10 am
content: I have a project where battery powered electronics will be housed in plastic enclosure. Some digital IO will be connected to switches and active sensors outside of the box. The system will be installed either on the field in the grass (outdoor environment) or in old house with no electrical installation and earthing (think 19th century homestead museum).How do I go about protecting the digital inputs from ESD? Which level ESD should I target to (say, dry environment in wooden house)? I have read the recent threads on the forum -- all of them give a lot of good insights, but mostly they talk about diverting the dangerous currents into earth and burning them in protection devices. How do I do this in floating battery powered application? Should I have a "protection ground" connected to the system ground via ferrite beads? Should I add earthing by hammering a rod to the ground? Batteries will be removed and replaced - how do I protect battery input?

author: Zero999
author_rank: Super Contributor
timestamp: February 19, 2017, 10:30:58 am
content: Treat both supply rails as earth/ground. Use diodes to divert ESD into the supply rails. If the supply rails are properly decoupled, then the tiny static charge will only change the supply voltage by a few mV, by charging/discharging the decoupling capacitors slightly.
Input voltage for Grove Barometer (BMP280) Sensor module - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: December 23, 2022, 12:22:59 am
content: Hi all,I was looking the Barometer (BMP280) Sensor module from Seeed and they claim that it operates in 3V3 and 5V.https://wiki.seeedstudio.com/Grove-Barometer_Sensor-BMP280/However, I do not understand how it operates in 3V3. Looking at the available schematic, the Vcc feeds the LDO's input and the high side of the voltage translator. The LDO requires a min. input voltage of Vin=Vcc + dropout voltage (that is 250mV) = 3.3 + 0.25 =3.55V. How will it work in 3.3V?LDO XC6206P332MR-G specs:https://eu.mouser.com/datasheet/2/760/TOSL_S_A0007229533_1-2575067.pdfAm I missing something?

author: Andy Watson
author_rank: Super Contributor
timestamp: December 23, 2022, 01:02:19 am
content: The "device" in question, the BMP280, claims to operate between 1.71V and 3.6V. The regulator appears to be limiting the maximum supply voltage to 3.3V Provided the BMP280 has enough voltage to trip the logic levels of the voltage translator, everybody will be happy

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 23, 2022, 01:47:14 am
content: Look at the "Output Voltage vs. Input Voltage" graphs to get a hint.As you probably guessed, for an input below the rated regulated voltage+dropout, the output will not be regulated, but it will follow input with a small dropout, and you'll still have a small wasted current into the LDO. You can always remove and bypass the regulator if you don't want that, but for all practical purposes it shouldn't make much of a difference.

author: Nikos A.
author_rank: Regular Contributor
timestamp: December 23, 2022, 01:59:49 am
content: Thank you guys!! It is clear now
Input voltage limits. - Page 1
Forum section: electronics / projects

author: kvresto
author_rank: Regular Contributor
timestamp: October 31, 2014, 12:35:47 am
content: Hi All.I’ve been playing with op configurations, and there is one thing I can’t test on my bench at the moment because I don’t have a dual rail adjustable power supply, The best I can manage is a fixed +-5V.On the simulator these two op amp configuration work fine. I’m attenuating a 15Vpp signal and getting 3.75Vpp output. All good but if I build this cct, I want to power the op amps from +-5V. Will my op amps work, or does my supply need to match the highest input voltage?The data sheets give [ Input Voltage = (V–) –0.7V to (V+) +0.7V ], but will the attenuation do its job for each of these two configurations?.CheersKv

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 31, 2014, 01:51:48 am
content: The circuit will work for most any input voltage, you'll simply see clipping when an input or output pin goes beyond its useful range.Tim

author: kvresto
author_rank: Regular Contributor
timestamp: October 31, 2014, 02:46:36 am
content: Thanks T3sl4co1l, actually I need to make a correction, VIN = 30Vpp.cheers
INR18650-25RM Battery Protection Circuit (High Discharge) - Page 1
Forum section: electronics / projects

author: Leo86
author_rank: Contributor
timestamp: December 02, 2019, 01:06:55 pm
content: Hi,I am doing a project that uses the INR18650-25RM high discharge battery and the circuit I used in my prototype didn't work because I extracted a 9A (continuous) current from the battery.The circuit I was using to protect the battery was this:https://www.eevblog.com/forum/projects/pain-and-suffering-getting-the-dw01-and-8205a-protection-circuit-work-right/But as I said, this circuit can not stand when it pulls too much current from the battery.To solve this problem I am considering replacing the circuit with the MOSFET FS8205 with two DMT2004UFV-7 which has a higher current.Does anyone have any suggestions?

author: jbb
author_rank: Super Contributor
timestamp: December 02, 2019, 05:33:50 pm
content: The standard protector chips protect on voltage and current. Voltage is sensed directly, and current is sensed by the voltage drop across the protection MOSFETs. So you don't actually care about the MOSFET 'current' rating (which is generally not very useful anyway), but instead the MOSFET on resistance at theavailable gate drive voltage(i.e. cell voltage). This could be as low as 2.5V, so check your MOSFETs carefully, and be prepared for quite big tolerances when the temperature changes.Paralleling MOSFETs will reduce the on resistance and thus get a higher trip current.The protector chips come in a variety of configurations, with different voltage and 'current' (i.e. voltage drop across the MOSFETs) settings.One interesting wrinkle: the discharge current is passing through 2 MOSFETs in series, which doubles the resistance. You might be able to find (and source, don't forget sorting) a protector chip which lets you haveseparatedischarge and charge connections, with the discharge current only passing through a single MOSFET. This instantly halves the resistance. The charge input might only need a 3A rating, which makes MOSFET selection much easier.
Inrush current limiting  - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: January 11, 2024, 10:51:14 am
content: I have a 600VA transformer connected as an auto transformer to reduce 240V mains to 220V , (15A breaker). I have not measured inrush current but it's a decent enough kick to cause a momentary dimming of the lights on power-up.Prefer to not have to go to the trouble of adding a relay or triac type inrush limiter if I can get away with a simple permanently connected ICL, perhaps something like this:https://www.digikey.ca/en/products/detail/ametherm/SL32-10015/749898No load primary current is only 100ma, and the 220V load is intermittent in nature ranging from 1-10A with some very short duration 100ms peaks up to 15-20AI would mount the ICL on a pair of spare terminal blocks in free air.Do you think this will be adequate?[ Specified attachment is not available ]

author: Andy Chee
author_rank: Super Contributor
timestamp: January 11, 2024, 11:05:34 am
content: If you use NTC thermistors without a bypass relay, use a couple thermistors (or three!) in series in order to reduce heat dissipation.https://sound-au.com/project39.htm

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 11, 2024, 12:02:56 pm
content: Can't see the picture:Do people resize images anymore?

author: Jester
author_rank: Frequent Contributor
timestamp: January 11, 2024, 02:07:39 pm
content: Quote from: T3sl4co1l on January 11, 2024, 12:02:56 pmThe image looked okay on my PC, regardless I cropped the original image, can you see it now?

author: Vovk_Z
author_rank: Super Contributor
timestamp: January 11, 2024, 05:24:12 pm
content: I don't know a lot about ICL but NTC resistors work fine for this.
Inrush current limiting circuit - Page 1
Forum section: electronics / projects

author: ploutone
author_rank: Newbie
timestamp: June 12, 2017, 11:04:39 pm
content: HelloFor my boost PFC design that I am currentely working on, I need a current limiting circuit for the capacitor inrush current in start up, the widely used circuit in this type of applications cases is shown in this figureThe relay is turned on after some miliseconds when the capacitor is fully charged and the diode is reversed baisedMy question: how can I determine the amount of current drown by the capacitor and more importantly, on what criteria will I choose the diode and the NTC resistor on and based on what?Thank you very much.
Inrush into offline flyback via 10R, 1W resistor - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: July 29, 2018, 09:29:34 am
content: Hello,We are doing a 30W PFC’d Flyback SMPS with an input stage as in the attached. We have a 10R inrush resistor which is ROX1S (datasheet below).Just to see what would happen, I changed the X2 capacitor, C1 from 220nF to 2u2.The 10R inrush resistor was damaged the next time I switched the power supply on, obviously due to inrush into the 2u2. (there was also a 1A fuse [not shown in schem] which did not blow). The resistor did not appear physically damaged, but was open circuit when checked.I would not expect a surge rated 1W resistor to blow under these circumstances.Nothing in the datasheet says it would blow up due to such a short term power spike…..i mean, as you can see in the LTspice simulation, the power peak is 10kW and the waveform shape is like a 1.5us/25us ‘spike’.I mean, surely this is far too short a time to heat up such a resistor to the point of damage?(the power supply worked fine when I replaced the 10R and changed back to a 220n X2 capacitor)When the 220n X2 capacitor is fitted for C1, then the power peak is 8kW and the spike is of a 500ns/2.5us shape. How would we know that this wouldn’t cause wear out over time and blow up?[we are now trying to come away from NTC’s for inrush limitation as they don’t work well when hot, and also, inrush relays etc are too expensive for us…as such, we now want to have an inrush resistor, sized to dissipate no more than 400mW for the sake of efficiency…after this , I confess I will probably put an NTC in aswell].The resistor cannot have heated up much at all in the 26.5us of the power surge……so this actually makes me wonder, what is the long term effect of inrush into the X2 capacitors is? …..what is the time wear out process for them, years, decades?ROX1S resistor datasheet:http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7F1773271%7FE%7Fpdf%7FEnglish%7FENG_DS_1773271_E.pdf%7F3-1625892-1
Inside China's Accelerating Bid for Chip Supremacy - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 05, 2021, 02:36:17 pm
content: if chip is supreme but the documentation is shit, it is still shit.

author: fcb
author_rank: Super Contributor
timestamp: June 05, 2021, 04:24:33 pm
content: Pretty sure that toaster oven in the first 15 seconds doesn't have a silicon chip in it.

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: June 05, 2021, 10:47:07 pm
content: I miss Treez.

author: jonroger
author_rank: Regular Contributor
timestamp: June 05, 2021, 11:38:16 pm
content: It is a concern when the lowest cost chips aren't readily available outside of China and are documented only in Mandarin.

author: xani
author_rank: Frequent Contributor
timestamp: June 06, 2021, 09:19:04 pm
content: Quote from: fcb on June 05, 2021, 04:24:33 pmThere are chips dedicated for toasters.Here is one with bagel pinhttps://www.diodes.com/assets/Datasheets/PT8A2514A.pdf

author: Bud
author_rank: Super Contributor
timestamp: June 07, 2021, 04:45:04 am
content: What is the deal with them measuring the CPU socket, seems a picture for "Stock image fails" tread

author: fcb
author_rank: Super Contributor
timestamp: June 07, 2021, 11:23:10 am
content: Quote from: xani on June 06, 2021, 09:19:04 pmIndeed - pretty sure that's been chip-of-the-week on The Amp Hour at least twice. However that toaster oven doesn't contain semiconductors.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 07, 2021, 03:28:43 pm
content: It depends on the chip.For new technologies its a stich up and ASML have a monopoly on 2nm and 5nm FAB achines.(ASML by the way has a vastly over rated share price.)There are plans afoot to make sure china cant get these latest EUV FAB machines.Its unlikely that such machines could ever be reverse engineered. You just cant get the parts!Currently ASML, Intel, Samsung and TSMC are operating a cartel in new chip technologies. Allegedy...Its hard to see how China will get a foot in the door.

author: Marco
author_rank: Super Contributor
timestamp: June 07, 2021, 08:28:02 pm
content: Quote from: Terry Bites on June 07, 2021, 03:28:43 pmTSMC and ASML that is.TSMC clearly has some secret sauce to make their machines work far better for them ... all the ASML employees always pretend there is no way some lowly customer is allowed to change anything inside the machine, but when one customer buys nearly all your machines they can get stuff done without 99% of lowly ASML employees being in the loop.TSMC have hinted at having some kind of virtual pellicle ... maybe they charge the debris with a wide electron beam so it can be more efficiently electrostatically repulsed or something.