hybridfree/eevblog-posts huggingface dataset:
AX-1 mission. Privatized corporations into space.. - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: April 27, 2022, 10:56:25 pm
content: Its hard for me to talk about Falcon and not make jokes, I'm sorry.They are not the first contractors in space.. There have been many previous ones.I really hope they stay safe and ** dont deorbit ISS.**

author: uer166
author_rank: Super Contributor
timestamp: April 27, 2022, 11:03:48 pm
content: Quote from: cdev on April 27, 2022, 10:56:25 pmI'm not sure you can do worse than Nauka did.. Falcon is a modern day miracle, no matter what your political opinions are.
axial capacitor support structure? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: November 18, 2023, 06:40:25 am
content: Is there a generic round part support structure for axial components that is a partial circle as hardware you can buy?and does anyone know maybe a parametric program for 3d printer prints? I want to center the axial caps in my project box. The 30uF one is heavy, and the 220nF one has tiny leads !This was supposed to be a 1 minute project and its alreadyI guess its kind of like a zip tie holder. Maybe a double zip tie holder that is good enough can be found.If anyone knows a good zip tie clamp that would work, or a series of them....

author: moffy
author_rank: Super Contributor
timestamp: November 18, 2023, 07:43:09 am
content: As I mentioned in your other post about Teflon caps, at Ferranti we used large axial capacitors that were cable tied to a double thickness pcb and wedges were epoxied either side of the capacitor. It was reliable enough for fighter aircraft.

author: coppercone2
author_rank: Super Contributor
timestamp: November 18, 2023, 08:02:36 am
content: The best I found is thishttps://www.digikey.com/en/products/detail/panduit-corp/ABMT-A-Q/810899There may be a better size, I don't have the patience to go through them right now. But if you put a bit of silicone rubber under the cap, it should sit nicely.

author: Vovk_Z
author_rank: Super Contributor
timestamp: November 18, 2023, 10:55:16 am
content: Quote from: coppercone2 on November 18, 2023, 06:40:25 amIf you don't believe in one zip tie you may use two zip ties. Just drill holes for them. Otherwise you have to tell us more about conditions.

author: coppercone2
author_rank: Super Contributor
timestamp: November 18, 2023, 10:57:02 am
content: the thing i found is pretty close but its not dedicated for components, two separate holes for each zip tie would be nice. if there was a series for different part diameters it would be sicki usually hope people enthusiastic about the topic will add extra information not hyper specific answers
Axial Moulded Carbon Resistors? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 09, 2019, 09:44:03 am
content: Hi!Just for completeness of component-lists, can anyone identify who made these little square or rectangular moulded carbon composition resistors with radial-leads, colour-coded with fine horizontal stripes on top please?I've a vague idea they might have been Philips!A lot of the old industrial boards I come across in the course of my employment use them, but I've never seen any new ones!Chris Williams

author: electrode
author_rank: Regular Contributor
timestamp: August 09, 2019, 09:58:28 am
content: Wow, that's a bit different! I know Vishay make radial resistors in similar packages, but they seem to be numerically valued, rather than with colour bands.

author: bd139
author_rank: Super Contributor
timestamp: August 09, 2019, 10:44:10 am
content: Think they were a late 60s / early 70s product. Definitely European as I saw them in some old audio kit from then. I can't find them in my Philips / Mullard data books from around then. May be another manufacturer.

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 09, 2019, 12:49:35 pm
content: Hi!The example shown is colour–coded as 100kΩ ±5% top–to–bottom, and I've seen them in imported 1960s/1970s gear myself, but I've never seen a Service Manual yet that identifies the series!Chris Williams

author: markce
author_rank: Regular Contributor
timestamp: August 11, 2019, 09:01:11 pm
content: Looks a lot like these:https://www.ebay.co.uk/itm/RESISTOR-METAL-GLAZE-THICK-FILM-0-5W-2-100ppm-15000-ohm-15k-ohms-RADIAL-x10pcs-/303024117752Vitrohm RGU?
Axis 2100 network camera with messed up picture - Page 1
Forum section: electronics / projects

author: Shirakaba
author_rank: Contributor
timestamp: May 13, 2014, 08:45:43 am
content: I got my hands on an untested Axis 2100 Network Camera. The embedded webserver seems to work just fine, but there is something wrong with the picture output. Are there any obvious reasons why the picture looks like it does?For reference, a list of most ICs on the board:Sony D1267AN CCD Vertical Clock DriverLCX04 Hex InverterAM29LV160DT-120EC 16 Megabit flash memoryAxis ETRAX 100LX System-on-chipAxis ARTPEC-1 Jpeg compression chip431AC Voltage referenceMT4LC4M16R6-5 64 Meg EDO RAMExar D98L55AIV CCD Image DigitizerAlliance AS4LC1M16E5 16 Meg EDO DRAMDS14C335 RS-232 interfaceBroadcom BCM5201 Ethernet controller

author: amyk
author_rank: Super Contributor
timestamp: May 13, 2014, 01:22:56 pm
content: If you have a scope you can check the output signal of the CCD, but anything beyond that and you're probably going to need to do some pretty hard reverse-engineering to figure out.

author: Shirakaba
author_rank: Contributor
timestamp: May 13, 2014, 01:44:52 pm
content: I was poking around with my oscilloscope, and I could see that there was raw data coming out of the CCD, passing through some ICs and entering the big asic. The asic appears to produce valid jpeg output, so it is probably something going on earlier in the signal chain.

author: mariush
author_rank: Super Contributor
timestamp: May 13, 2014, 01:59:33 pm
content: Could be that you have a bad EDO ram chip...

author: Shirakaba
author_rank: Contributor
timestamp: August 25, 2014, 06:56:53 pm
content: I have tried replacing almost every chip that I could find replacements for, and when I changed the Exar D98L55AIV CCD Image Digitizer, I finally got a picture. Either the chip was bad or I solved it by heating in that corner of the board. The picture is not the best in the world, but I guess this is as good as it gets. Thank you all for your input.

author: marshallh
author_rank: Unknown
timestamp: August 26, 2014, 02:06:47 am
content: I had a Canon camcorder that exhibited symptoms like that. The cause according to the recall was thermal cycling causing CCD bond wires to pop off.
Axoloti: DIY digital synthesizer - Page 1
Forum section: electronics / projects

author: Johannes Taelman
author_rank: Newbie
timestamp: December 17, 2015, 01:38:09 am
content: Hello!I wanted to tell you about my DIY synthesizer project "Axoloti".It's a circuit board with an STM32F427 microcontroller, stereo audio in and output, usb device and host port, micro sdcard slot, 8MB sdram.A visual patch editor, that is actually a c++ code generator, it saves you from doing the hard parts like toolchain setup, RTOS, board support, usb-midi device, usb-midi host etc, and programming a library of audio functions. A single click compiles, uploads and runs your patch, takes only a few seconds, and while running you can adjust parameters and monitor values in real time!Oh and it is open source!Axoloti started public life as a crowdfunding project January 2015, delivery started in August 2015, well received by the community, and now a 2nd batch is available.http://www.axoloti.com

author: diyaudio
author_rank: Frequent Contributor
timestamp: December 17, 2015, 11:05:41 am
content: Quote from: Johannes Taelman on December 17, 2015, 01:38:09 amReally cool, the patch panel looks like the first Reason known as Project Snowman.
AXP288 without battery - Page 1
Forum section: electronics / projects

author: flix
author_rank: Newbie
timestamp: March 12, 2022, 08:43:58 pm
content: Hi guysI want to repurpose the mainboard of an old Tablet and power it without the battery.The problem is that the Mainboard doesn't power on without a Battery, even when a charger is plugged in.Can I just apply 5v to the Battery pins or will it fry the PMIC?PMIC: AXP288Datasheet:http://download.icxbk.com/201707/cfe88ee7ef01eed7a4586ce340165da0.pdf

author: anda3243
author_rank: Contributor
timestamp: April 15, 2022, 12:17:42 pm
content: I would not apply more than maybe 4.2 V. That is what usually a single cell lithium battery is charged to. Can you measure what voltage is applied to the battery during charging?That power management chip might be more complex than the MCU I am working with.Maybe you can leave the battery inside and supply 5V trough the USB port? Or switch to a smaller battery with the same voltage?

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 15, 2022, 01:49:32 pm
content: Common Perk mining trick was to replace the battery with a 1N400x diode from the USB input to battery positive. Prior to the implementation of IP limits, some had a few dozen cheap smartphones running from a few ATX PSUs salvaged from old PCs.

author: viperidae
author_rank: Frequent Contributor
timestamp: April 17, 2022, 07:12:21 am
content: I would leave the battery in. You might find it isn't completely stable under load without the battery, as it can supply better peak current compared to an external supply with long power leads

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 17, 2022, 02:14:14 pm
content: Quote from: viperidae on April 17, 2022, 07:12:21 amAdd a capacitor. That said, none of the Perk mining setups I have seen needed any extra capacitors, and that's with up to about 3-5 feet of wire from the ATX supply.
AZ1084CD-ADJTRG1 voltage regulator - output voltage voltage is wrong, but why? - Page 1
Forum section: electronics / projects

author: pickleit
author_rank: Contributor
timestamp: May 29, 2022, 02:57:28 pm
content: Hi folks,I am using a AZ1084CD-ADJTRG1 voltage regulator to convert 12V DC (coming from a DC jack) to 5V. The VOUT from the regulator goes to the VIN of a 3.3V fixed output voltage regulator. Also it becomes the 5V rail for the board.The voltage divider formula for the AZ1084CD-ADJTRG1 is: VOUT =VREF * (1+R2 /R1) + I ADJ * R2I have tried the following values for R1 and R2 (as per the datasheet):1) 270 ohm (for both).2) R1 = 220 ohm and R2 = 680 ohm.3) R1 = 680 ohm and R2 = 220 ohm.The datasheet states:vref = 1.25I ADJ = 0.01I am issues with VOUT voltage. It should be 5.2V, but that's not what I am measuring.FYI: VIN is: 12.2 Vobservations:1) When R1 and R2 are both 270 ohms, VOUT is measured as ~2.54 V to 3.x V.2) When R1 is 220 ohm and and R2 is 680 ohm, VOUT is measured as 2.54 V.3) When R1 is 680 ohm and and R2 is 220 ohm, VOUT is measured as 1.29 V.The voltage measurements are from memory and so might not be bang on correct.VOUT was measured at VIN for the 3.3V fixed output voltage regulator.The question is:Why is the VOUT voltage not as expected?I have attached the schematics of the design this voltage regulator is being used in, and the datasheet for it too.

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2022, 03:25:27 pm
content: Did you measure the current? Does it get hot? It's possible there's a fault elsewhere, which is pulling the voltage down.The first thing you should do is, disconnect the voltage regulator from the rest of the circuit, then measure the voltage again.

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 31, 2022, 11:17:24 pm
content: Don't you forget about bypass caps at input and output?680R/220R is ok for 5.1 VDC (+/- 0.1V).

author: Colt45
author_rank: Contributor
timestamp: June 01, 2022, 12:23:34 am
content: Is Vin decently regulated? Vin max is only 13.5V, if it's a linear wallwart its probably 15V unloaded.LDOs are kind of picky about output capacitance. Do you have a picture of the circuit as built
B32671L, B32672L: Dissipation factor tan δ "(in 10-3)" - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: October 01, 2025, 09:02:48 pm
content: What do I do with the last bit of info, "(in 10-3)"?If the table states 2.0, is that 2.0 * 10^-3 or what?In particular, I'm after the ESR of 15nF at 100kHz. Just using 2.0 (from the column "<=27nF") gives over 200 Ohms. As in:ESR = tan Delta * Xc, where Xc is reactance of the capacitor at 1E5 Hz.https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.tdk-electronics.tdk.com/inf/20/20/db/fc_2009/MKP_B32671L_672L.pdf
B3603 Triple Output Power Supply Project - Page 1
Forum section: electronics / projects

author: nbritton
author_rank: Frequent Contributor
timestamp: November 25, 2015, 09:40:45 am
content: Any thoughts on converting threeB3603orB3008modules into a triple output power supply? My thinking is that you could adapt an Arduino nano, a display, some rotary encoders, and buttons to make a unified controller to control multiple modules. I was going to power them using a 19 volt laptop ac adaptor.

author: gtroc71
author_rank: Newbie
timestamp: November 25, 2015, 10:19:32 am
content: Check out this thread if you haven't seen ithttps://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/Am sure that with the reverse engineering and research they have done they would be the best to askBest of luckps. I love those little modules
Baby's first offline SMPS - Page 1
Forum section: electronics / projects

author: jmw
author_rank: Frequent Contributor
timestamp: February 25, 2020, 08:28:06 pm
content: Having now a little bit of experience building working DC-DC converters, I'd also like to learn about offline topologies that can work with mains power. What are people's favorite application notes and practical design resources? My main reference on power electronics has been Erickson'sFundamentals of Power Electronics, 2nd ed. It has chapters on modern rectifiers and resonant converters that I'm working through. The textbook is theory focused and doesn't have as much to say about rectifier and converter circuit design (and other important topics like safety and component selection), so I'm looking for something that can get me to a useful starting point for a small design project.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 26, 2020, 08:03:29 am
content: Probably good idea to start with the simple offline regulators: TOPSwitch and the like. Pair with an off-the-shelf transformer, read up on insulation, clearance and creepage, review it here if applicable, test it yourself for performance, range, EMC if possible, etc.The scope of your design work will be component selection, especially the transformer (inductance, saturation, ratio) to the regulator and application, and ensuring the layout is adequate for safety and EMC purposes.Then move on to less pre-baked designs: specifying transformer windups (wind them yourself, probably), relating that to EMC response, choosing topology, designing the switch, choosing or designing the controller, etc.Tim
Back-EMF risk to electronics? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: September 13, 2017, 02:32:49 pm
content: A 3-pole power switch on equipment connects 3-phase power to 2 loads: a 5 HP motor and the electronics cage (many PCBs that run the equipment, consisting of 1980's discrete solid-state). The switch has 3 sets of terminals: power input, motor, electronics. The switch has failed. When replacing switch with a non-original one, the market consists of common switches with only 2 sets of terminals: power and load.Is there risk of damage to electronics if both loads share a single set of terminals on such a simple on-off switch? The motor would be connected to the electronics while the motor spins down (approx 1700 rpm for 30 sec.).Thanks for your help.

author: capt bullshot
author_rank: Super Contributor
timestamp: September 13, 2017, 03:00:30 pm
content: As the original switch was done that way, there's a chance that is was done that way for a reason (including the mentioned back EMF issue). Anything else would be wild guessing.Is the motor an ordinary induction motor? If so, the voltage decay depends on what stays connected to the terminals when switched off. Especially capacitors might cause slow decay or even overvoltage while the motor is spinning down.Have you searched for switches with 2 sets of 3 contacts (6 NO contacts in total), so you can use one set for the motor and the other one for the electronics. You'd have then two power inputs to be wired in parallel and two outputs as your old switch has.Has the failed switch some kind of sequence (motor on first, then electronics or vice versa), or three steps (off, motor on, motor and electronics on)?

author: iXod
author_rank: Frequent Contributor
timestamp: September 13, 2017, 03:51:34 pm
content: Thanks very much for your reply.OE switch is just ON-OFF, 2 position. No caps on the motor, standard 3-phase induction, 240v, 5hp.Multi-terminal (separate loads) power switches non-existent, that I've seen. Maybe OE for specific applications, but not listed generic ones.TY.Edit: this for a German Polar guillotine paper cutter. (c:

author: 4CX35000
author_rank: Regular Contributor
timestamp: September 13, 2017, 03:52:40 pm
content: Might be worth checking the motor power factor capacitor is working as expected. A multimeter can do this. The value is normally written on the side of the cap.Often the sparking on the switch contacts / contactor contacts can be reduced by changing the capacitor for a new type which is normally supplied for the manufacturer of the motor or some other electrical supplier.On start up a motor can consume several orders more current than when fully running. For example, a motor may normal running current might be 2 amp, but 8 amp on start up as the motor is building up speed and also driving the load.Poor PF capacitor means your paying more on your power bill than you should to run the motor.
Back grinding WLCSP - Page 1
Forum section: electronics / projects

author: blueskull
author_rank: Unknown
timestamp: January 30, 2018, 05:15:48 am
content: I've been working on an extra low profile design that has very strict height restriction.The main chip will be used is an FPGA, iCE40LP1K, in ucBGA36 package.Despite being a 2.5mm*2.5mm tiny package with 0.4mm pitch, the chip is very thick, with up to 1mm thickness.So the question is, can I grind the chip down to 0.5mm? It is a flip chip wafer level CSP, so there's no bonding wires to screw up with.Also, generally speaking, active region of semiconductors is <0.1mm, so I don't think the grinding saw can make its way to active region.Passivation degradation is also not an issue as the finished module will be encapsulated with epoxy.Anyone have any experience on this? Can this be done?Never mind. I had a brain fart. Those chips are wire bonded with interposer. I need to find a true WLCSP chip.

author: ruffy91
author_rank: Regular Contributor
timestamp: January 30, 2018, 07:14:32 am
content: You could embed it upside down to a pouch milled in the PCB and then wire bond it to the PCB and encapsulate it in epoxy.Edit: Lattice also sells bare die, you can do the same directly with the die.
Back-matching a pulse generator - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: March 22, 2022, 07:54:23 pm
content: I'm interested in generating variable voltage pulses into 50 ohms, and I want the circuit to be back-matched. For this I'm thinking of using a half-bridge. I'm particularly concerned about edge timing... I really need as fast as an edge as I can get, and for that the switching edges of the FETs will overlap and briefly shoot through. I was thinking of killing two birds with one stone and using the same resistors for back-matching as shoot-through current limiting. Will the attached circuit look matched? Assuming the shoot through period constitutes an acceptable instantaneous power for the resistors and the duty cycle for the shoot through period times the instantaneous power is within the specs of the resistor -- will this provide a matched source? I expect this should deliver a pulse of voltage +V/2 into a 50 ohm load.
Back-powering via GPIO pin - Page 1
Forum section: electronics / projects

author: Compo
author_rank: Newbie
timestamp: June 21, 2019, 07:40:53 pm
content: I have a plug-in module for my 2.4ghz quadcopter controller that I have hard-wired. The controller outputs PPM data and the module (atmega and nrf24l01) takes these and transmits.At the moment I switch on the controller then the module (it takes 5v from the controller batteries). My understanding is that the PPM output from the controller is backpowering the module chip whenever I have the controller powered but not the module?I think the solution is to use a MOSFET with the gate connected to the module switch?Can someone confirm thats right and maybe give some help on how to wire it up?Thanks

author: viperidae
author_rank: Frequent Contributor
timestamp: June 22, 2019, 07:06:16 am
content: Can you set the gpio to open collector?Then you won't need an extra MOSFET, just a pull up resistor.

author: Compo
author_rank: Newbie
timestamp: June 23, 2019, 05:01:27 pm
content: Would I have to do that in code? I dont have access to the source.I have some si2302 n-channel mosfets.I though maybe I could use one of those on-on-on switches so the power connects then the ppm connects.

author: langwadt
author_rank: Super Contributor
timestamp: June 23, 2019, 05:12:01 pm
content: could get the equivalent of open collector with a diode and pull up resistor

author: Compo
author_rank: Newbie
timestamp: June 24, 2019, 10:47:55 pm
content: Is an open collector is for the output of a chip? Sorry but I'm not that experienced, I dont really follow

author: DaJMasta
author_rank: Super Contributor
timestamp: June 25, 2019, 12:19:33 am
content: Quote from: Compo on June 24, 2019, 10:47:55 pmUsually called Open Drain and would be available as an I/O pin configuration setting.Honestly, though, I don't think you're powering your whole main module through a GPIO pin. A bit can go through it, sure, but depending on your main module, that could easily be tens or a hundred mA continuous, which I don't think your GPIOs are going to supply readily. I'd check your other connections and verify that there isn't some extra power connection going through your wiring, and if not that, make sure there isn't anything in the bus protocol connecting the module with your powered one that would force the main module to wake up when talked to.Very difficult to say without schematics/pinouts of what's being used, I just have my doubts that a substantial amount of current is powering your main module through the GPIO without damaging something on the sending or the receiving end.

author: Compo
author_rank: Newbie
timestamp: June 25, 2019, 07:03:32 pm
content: Heres the schematic and photo:I take PPM-out and ground from the trainer port. Ever since I put this module in, my trainer cable to my PC stopped working (it has 2 wires, PPM and ground). When using the cable I have controller on and the module off. If I switch on the atmega + nrf module, the trainer cable starts working instantly, thats when I looked up this backpower problem.
Back to back mosfet questions and SMPS problem - Page 1
Forum section: electronics / projects

author: Sniper1
author_rank: Regular Contributor
timestamp: October 29, 2022, 07:58:09 am
content: So basically for mosfets should i use common drain or source? ( same question for NMOS). As of now i used a common drain PMOS config and i was wandering if i am doing it wrong or rather is there any benefit for doing it another way?Also on one of my boards i have an LDO and a buck and i can chose witch one to use with a 2 pole switch the odd thing is that when not under load both work fine but under load they go to 0V, any idea why this is happening? (PS i have the same circuit on another board and it works perfectly)

author: artis
author_rank: Newbie
timestamp: October 29, 2022, 08:39:04 am
content: Mosfets as far as I know are bidirectional devices so current can flow both ways , back to back mosfets you can wire them both drains together as well as sources, the thing that will change is how to drive the gates, because for N mosfets for example, the gate has to be above source in order to turn ON, while for P the opposite, see mosfets relays aka solid state relays, there these configurations are used and discussed

author: Sniper1
author_rank: Regular Contributor
timestamp: October 29, 2022, 01:20:42 pm
content: Quote from: artis on October 29, 2022, 08:39:04 ami know so in both cases a source is floating (or rather i am not sure it is referenced well ) would it be advised to use bery large pull ups/downs ? like 1M+

author: Peabody
author_rank: Super Contributor
timestamp: October 29, 2022, 03:06:33 pm
content: It seems to me that since it is the voltage on the gate with respect to the source that determines whether the mosfet is on or off, you wouldn't want the source to be in some possibly undefined state between the mosfets. In the datasheet for the DW01 LIPO protection circuit, it shows the N-channel mosfets with common drains. I always assumed they did that for a reason, but don't know for sure. Maybe it's just to get the body diodes in the right orientation. Of course in that circuit current will flow in either direction depending on whether the battery is charging or discharging.

author: Sniper1
author_rank: Regular Contributor
timestamp: October 29, 2022, 06:40:09 pm
content: Quote from: Peabody on October 29, 2022, 03:06:33 pmregarding the diodes it will be ok in both cases but then u may have the mod section in a odd state.I used a IC with 2 PMOS and it had all drains on 1 side so i went with that and it works, i made this question post since maybe i was supposed to do it another way i can totally see how i could route under ( + it also has some odd behavior when i used a lab power source instead of a battery )PS how do i make it so i dont end up on the main thread and stay in my post thread ?
Backfeeding MCU gate output bad? - Page 1
Forum section: electronics / projects

author: duraluminium
author_rank: Newbie
timestamp: April 16, 2021, 07:21:36 pm
content: I am trying to modify a work light (1S3P 18650 3,6V) that is controlled by an 8 pin PADUK type micro.An output from the micro goes through a 100 Ohm resistor straight to the MOSFET gate.It has the usual 100%, 50%, SOS modes. One drawback is that at the 100% setting, after 2 min, it throttles down to 16% PWM, in order to meet the battery life claim on the box. LED heatsinking is to a massive block of aluminum and not a problem.As in the picture, I would like to add a switch so I can feed the gate directly with battery voltage so I can get a mode with 100% light with no throttling.In the setup I propose, will there be a problem with me backfeeding the micro output with battery voltage, while it is either off/0V or doing a 16% PWM duty cycle at 3,6V?I thought that such outputs are protected by a diode/FET so that this wouldn't be a problem, am I correct?(I connected the circuit as in the picture for a few seconds and no magic smoke. Also I measure no big voltage drop BAT+ to MCU gate, certainly not a 0.6V/0.3V (Shottky) diode drop, so if there were protection it would be a low Rdson FET not a diode.)Is my solution reliable in the long term?I considered putting in an SPDT switch so I could choose what 'source' powers the gate and could avoid any backfeed (gate connection on COM, either MCU pin or battery on the other two switch contacts) but due to size constraints of a smaller switch (only available as a SPST) I'd prefer to use the 'backfed' option if it is safe to use.

author: Ian.M
author_rank: Super Contributor
timestamp: April 16, 2021, 07:42:10 pm
content: Not safe - the MCU will 'see' a 100R load resistor and when low the current is likely t oexceed its abs. max. Iol rating and the resulting gate voltage may well put the MOSFET in its linear region for an extended period and burn it out. However if you replace the existing resistor with one in the 220R - 330R range (depending on the supply voltage and the MCU's max. Iol specification), and make the switch pull the gate high directly via a resistor of an order of magnitude smaller than the series one from the MCU, it will work at te expense of lowering the efficiency. If ypu want to fix that as well you'd need to add a Tinylogic or similar single gate OR gate between the MCU and the existing gate resistor, with its other input controlled by the switch and a high value pull-down resistor.At that point, its probably easier to simply patch in a new MCU, dead-bugging it if you cant get a matching pinout , and write new firmware for it to disable or reduce the throttle-back.Also note that the throttle-back at two minutes may be for thermal reasons, because they've cheaped out on the heatsinking - if you run it at 100% continuously it may overheat and destry the LEDs.
Backlight for HP 34 - Page 1
Forum section: electronics / projects

author: krondor
author_rank: Newbie
timestamp: January 15, 2021, 04:57:23 pm
content: A while ago I bought a used bench meter HP 3478A which has a LC display.Unfortunately the display isn't backlit.Does anyone know if there'd be a possibility to equip a backlight on that display?Hoping for suggestions.Peter

author: bd139
author_rank: Super Contributor
timestamp: January 15, 2021, 05:06:09 pm
content: Thread here:https://www.eevblog.com/forum/projects/hp-3457a-lcd-backlight-mod-(also-for-3478a)/

author: krondor
author_rank: Newbie
timestamp: January 21, 2021, 12:37:06 am
content: Thanks a lot! I had searched but not found this thread.

author: Miti
author_rank: Super Contributor
timestamp: January 21, 2021, 11:16:43 am
content: One more linkhttps://www.eevblog.com/forum/testgear/hp3478a-backlight-my-version/msg3254516/#msg3254516
Backplane FC Fiber - SATA Converter 4Gbps - Page 1
Forum section: electronics / projects

author: max-bit
author_rank: Frequent Contributor
timestamp: November 01, 2015, 09:54:47 am
content: Over a year ago I made a projectAnd it is a 4Gbps Fibre Channel backplane (downward compatible, ie 1 and 2 Gbps) (optical) for SATA, and it's all on 3 discs.Such a project, I had the box HDD on 3 discs (originally was to FireWire) and I wanted to change.Why FC?Firstly, a large range ..... even and 200m (550m / 2000m) depending on the used converters.So the computer can be here .. and drives such as in a pretty remote location.Secondly, if it works4Gbps is already quite a challenge on the laminate FR-4 and is 2 layers.Of course we had worked for exotic connector FC ....What was needed, well, first of all PCBs (diagram)PCBOf course we had to use an adapter converter CF to SATA something to buy on ebay (a few dollars). converter based on the chip Emulex.Here's how the converter looks ....:Photos real soon ...
Backplanes, the good, the bad and the ugly? or, when to not use a backplane? - Page 1
Forum section: electronics / projects

author: magnus0re
author_rank: Contributor
timestamp: May 07, 2021, 11:49:41 am
content: Hi.I was looking at the design of some boards (they are already shipped). Produced in 100s, some expensive FPGA on them, made to be mounted in racks. 6U in height. All in the same installation.The boards are not using a backplane.Instead of using a backplane, there are separate power connections, I2C connections and CAN connections,all on the front.All that really needs to be on the front is the main I/O, basically some fast serial links, and a jtag.And I was thinking, why is it that nobody thought to use a backplane? It would make setting up the system simpler, take less time, reduce the BOM of the boards and require less cables.It could also potentially reduce the board area required, which would make the large boards cheaper. All good things, as far as I'm thinking.Or have I stumbled upon something? Is there a case to be made for not using a backplane? Have there been cases when using a backplane was a definite disadvantage?For this I turn to your collective wisdom.

author: wizard69
author_rank: Super Contributor
timestamp: May 08, 2021, 01:15:45 am
content: I have not idea what the original designers where thinking but the number one issue is that once you design a backplane interface you are stuck with it. These can get old real quick. Contrast this with using a CAN bus which has a set of standards to build to. Even if the CAN bus is on a non standard connector the signals will not change over time.Also there are other design issues. Can you use the same connector for all of your power requirements and signal requirements. If not you have to use multiple connectors and get all of your mechanicals right. By the way good backplane connectors are not cheap and in the case you have noted it isn't even clear that you need a lot of pins to connect the boards. In the end the team might have just thought that a backplane was a waste of time especially consider yet another board to design and validate.There are literally hundreds of dead backplane designs out there. If the designer could map his requirements onto an old backplane standard there might be some good in that case. In this case resuse hardware for a defunct or hardly used backplane, to build a custom installation on. But then you get into expenses again and likely many unused I/O lines. For example use an old VME backplane for your voltage sources and I/O lines.Quote from: magnus0re on May 07, 2021, 11:49:41 am

author: magnus0re
author_rank: Contributor
timestamp: May 09, 2021, 07:41:34 pm
content: Exactly the kind of answer I was looking for! Thank you very much.

author: bson
author_rank: Unknown
timestamp: May 09, 2021, 07:46:36 pm
content: Another option is a bus ribbon cable and board fingers.
Bad block markers in NAND flash - Page 1
Forum section: electronics / projects

author: niino
author_rank: Contributor
timestamp: March 20, 2020, 01:09:48 pm
content: I was wondering if the bad block markers of NAND flash can be changed (i.e. removed or added). That means: if I do a byte by byte transfer from NAND flash 1 to NAND flash 2 (assuming both are identical chips, and using flashing hardware that is not aware of bad block markers), will NAND flash 2 have the bad block markers of NAND flash 1 and lose it's own factory bad block markers? Or are they protected in some way?

author: abyrvalg
author_rank: Frequent Contributor
timestamp: March 21, 2020, 11:17:42 am
content: Bad block markers are software-level concept. Hardware has no knowledge about them at all. So they can be read/written/erased the same way as any other data.

author: amyk
author_rank: Super Contributor
timestamp: March 21, 2020, 08:50:44 pm
content: From a random Samsung flash datasheet...Quote
BAD CAPACITORS--I am lost - Page 1
Forum section: electronics / projects

author: Wimberleytech
author_rank: Super Contributor
timestamp: December 18, 2018, 03:51:46 pm
content: Today Lockheed will launch a new more accurate GPS satellite. That is the good news.The bad news is that (reading between the lines) all of the onboard buck converters may be plagued with crappy capacitors!This is sad, but kinda makes me laugh. I have repaired my TV and several monitors when caps went bad...easy enough on earth...but...So you are backpacking Denali and you look at your GPS...bad caps...now you are lost.https://www.bloombergquint.com/politics/historic-space-launch-day-includes-troubled-lockheed-satellite?fbclid=IwAR0OH8qF-D7--PZtlpcNGC9w9rAWjqCvEelrz42Du6SnBKEo1jNN6DwGrYg

author: wraper
author_rank: Unknown
timestamp: December 18, 2018, 04:06:04 pm
content: Quote from: Wimberleytech on December 18, 2018, 03:51:46 pmMost likely they are not even electrolytic and better quality than good capacitors which go into consumer equipment.EDIT: they are MLCC. And it's not like they are bad. They just were not tested to the required standart.

author: Wimberleytech
author_rank: Super Contributor
timestamp: December 18, 2018, 04:18:45 pm
content: Most likely they are not even electrolytic and better quality than good capacitors which go into consumer equipment.EDIT: they are MLCC. And it's not like they are bad. They just were not tested to the required standart.To be clear, I was not implying that they were "consumer" electrolytics.Moreover, the article indicates that there was some technical disagreement about whether the caps would really be a problem...so they will launch.

author: wraper
author_rank: Unknown
timestamp: December 18, 2018, 05:03:59 pm
content: Quote from: Wimberleytech on December 18, 2018, 04:18:45 pmYou were implying electrolytics though.

author: wraper
author_rank: Unknown
timestamp: December 18, 2018, 05:07:02 pm
content: https://www.investors.com/news/questions-raised-over-testing-on-lockheed-gps-satellite/QuoteQuote

author: David Hess
author_rank: Super Contributor
timestamp: December 18, 2018, 06:45:08 pm
content: MLCCs and especially large ones have their own problems. They are prone to cracking under mechanical stress which is a common problem when wide operating temperature extremes are present. The large ones use some type of strain relief.
bad idea? - Page 1
Forum section: electronics / projects

author: greenail
author_rank: Newbie
timestamp: September 28, 2018, 01:08:44 am
content: wondering if this a bad idea? It is a DPH5005.I'm planning on doing a big grid of 1mm holes spaced 2mm all over the bottom. Wondering how much of a fire issue this may be?

author: greenail
author_rank: Newbie
timestamp: September 28, 2018, 04:36:06 am
content: ok so I went ahead and did it. You can see the grid of holes 16x16 2mm holes for air. I may do some more in the side if I hear the fan kick on.i read wood is ok for electrical boxes.

author: tooki
author_rank: Super Contributor
timestamp: September 28, 2018, 05:05:34 pm
content: I don’t think it’s a fire risk, in that any components that overheat will probably fail below the temperature where wood catches fire.That said, check how hot this thing gets under load. Wood is a good thermal insulator, and those pinholes may not provide enough cooling.

author: gbaddeley
author_rank: Regular Contributor
timestamp: September 29, 2018, 10:48:03 am
content: What do you think the air flow will be when the fan kicks in? Will it just stir up the air in the box, or is there a path for warm air to flow out and disperse, and cooler air to flow in?

author: Ian.M
author_rank: Super Contributor
timestamp: September 29, 2018, 11:24:51 am
content: It will do sweet FA for cooling - all the holes are in the bottom, their length is high compared to their diameter and hot air rises so there will be virtually no air exchange between the box interior and exterior.

author: greenail
author_rank: Newbie
timestamp: September 29, 2018, 02:24:17 pm
content: any idea how hot these get? I have yet to hear the fan kick on but i'm typically only doing low voltage low amp stuff.I can put some more holes in the side and mount the fan against the holes.
Bad opamp circuits? - Page 1
Forum section: electronics / projects

author: orin
author_rank: Frequent Contributor
timestamp: November 25, 2013, 05:44:59 am
content: Take a look at the following:http://www.frenning.dk/OZ1PIF_HOMEPAGE/images/Tigertronics%20Signalink%20USB%20Schematic%20v1p2.pdfI have one of these devices and it oscillates at about 3.8MHz with the bottom left pot on the second page between 9 and 3 o'clock. Though this schematic may not be correct, if it is, I can't say I'm surprised. Fortunately(?) I could simply avoid those settings. I've heard a report of another unit that is oscillating in the same range.The TS462 datasheet does not claim it's unity gain stable (nor does it claim it's unstable, but other ST opamps do claim unity gain stability, so I'd assume the omission means it isn't) and that strange configuration results in gain less than or equal to 1.This is just one of the potential problems I see. The design is terrible IMO with respect to noise on the USB 5V - the two 1k resistors/33uF merely low-pass filter the noise on the USB 5V when producing VBIAS. I replaced the voltage divider with a 3V regulator followed by a divider with adjusted ratio and got a 30dB (!) improvement in noise below 100Hz.Comments?No, I can't realistically make changes to the design and test the effects - it's all surface mount.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: November 25, 2013, 06:37:54 am
content: I know you can't make changes to the design, but there's no bypass cap on U1. All those guys should have a .1uf cap on all the supply pins. As for the USB 5V line...it probably would have been better to use a ferrite bead at the input or at least a better LPF.And what a horrible datasheet for the TS462. They sure don't give you much, do they? I just noticed, are you actually talking about U2? I don't know man. You said you got the noise down below 100Hz. Are you know just seeing line noise?

author: orin
author_rank: Frequent Contributor
timestamp: November 25, 2013, 06:09:08 pm
content: Quote from: Cigarsnob on November 25, 2013, 06:37:54 amThe noise was broadband - see attached pictures which shows the spectrum with no input. It shows the low-pass nature of the filtering. Spectrum.jpg before my modification and spectrum_after.jpg after my modification.Yes, the TS462 datasheet is awful.U2B appears to be the problem with oscillation, but I've not yet fished around with the SA and detector loop.The use of U1A is also questionable with a gain of -0.1.And I've not yet got to the seemingly unnecessary AC coupling from the transformer to T1 - just return the transformer (secondary in this case) to VBIAS and DC couple it. That way, noise on VBIAS doesn't get added to the signal at this point. As it stands, noise on VBIAS at the + input of U2B is added to the signal at the - input.
Bad step response - Page 1
Forum section: electronics / projects

author: xzswq21
author_rank: Frequent Contributor
timestamp: November 03, 2017, 08:21:00 pm
content: HelloI have a deferential 50R source. the source is noisy and I should put a in-line LPF between the source and the FDA.But there is an odd problem.when I don't put any LPF between the sorce and the FDA the step response is very good :But when I put a LPF with fc=15MHz between the Source and the FDA, the step response is not good. I couldn't overcome on this issue.even in a simple circuit like below:(50R source)------>Cable------> (15MHz 50R in-Line filter)----> (50R terminated)if we want to check the step response the problem appears again!what should I do?can I use a Digital FIR filter instead of an high order LPF filter at the input of the FDA? (I want to improve the SNR and THD to have a better ENOB parameter.)if I use such method there is no stability issues in the Analog circuit.I have attached the circuit file.Regards

author: Kleinstein
author_rank: Super Contributor
timestamp: November 03, 2017, 08:29:26 pm
content: To get a good step response one wants a filter with lower Q and a lot linear phase response. So more like a Bessel type filter. However this will mean a less sharp drop in response to higher frequencies. So one might need to go down in frequency or use a higher sampling rate to avoid aliasing.

author: xzswq21
author_rank: Frequent Contributor
timestamp: November 03, 2017, 09:18:25 pm
content: Quote from: Kleinstein on November 03, 2017, 08:29:26 pmDearyou are rightthere is a simple RC low pass filter after the FDA. it's actually an AAF or RFI filter as an Anti-aliasing filter or to get rid of some noise and distortion.as you mentioned I should use a linear phase filter at the input the FDA but for my application it does not reduce the noise effectively.so I think I should filter the output digitally. bcoz in this situation there is no stability issues in my Analog circuit and I could reduce the noise.after the FDA is actually an high speed ADC.does this method improve the SNR and THD to have a better ENOB?Thanks
Bad USB cables or jacks? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: July 17, 2017, 04:34:41 pm
content: I seem to be having a recurring issue. As mentioned in a few threads in the past regarding USB shield grounding, in the setups I'm using I have the shield of the USB cable shorted to ground, with the electronics shorted to chassis ground through mounting holes and an EMI gasket to minimize the amount of material between the chassis around the USB connector and the shield ground.The issue that I'm having is that the device would routinely come up as "malfunctioning" with select USB cables from inventory. Meaning same cable design, same supplier, but some of the batch do not seem to work. Switching to another cable tends to fix it but that original cable may work for other devices.Could this be indicative of an odd ground looping issue? or perhaps an issue with the USB-B socket? Maybe on some boards the prongs on the socket just aren't protruding far enough to make a solid connection to the cable. This could mean that on other devices those prongs could extend far enough for a solid connection.Since these USB sockets are through-hole, could it be an assembly issue where they used too high of a heat on the pins causing some of the plastic in the connector to melt that would cause the prongs to 'relax' slightly and not make sufficient contact with the cable?Lots of thoughts here, but was wondering if someone may have run across a similar problem and found a solution that may be applicable.
Baidu download help: ADS1256 AD module files - Page 1
Forum section: electronics / projects

author: Nominal Animal
author_rank: Super Contributor
timestamp: January 21, 2020, 01:08:10 am
content: Shenzhen LC Technology Co., Ltd. makes anADS1256 AD module, based on theTexas Instruments ADS1256IDB24-bit 30kSPS 8-channel (4 differential) delta-sigma ADC chip:Similar boards are available on fleabay, banggood, aliexpress and so on. It is a somewhat simplified version of the TI ADS1256 evaluation module, but seems to follow the application recommendations in the TI datasheet.It turns out that company has a ZIP file, LC-ADC-1256.zip, that should be somehow downloadable athttps://pan.baidu.com/s/1dwVWa24B2nFKWDXbcXw9Qw, but I can't get it. Could someone speaking Chinese help me download that? Or send me the file in email? (My address isshown on my home page.)I don't expect that file to reveal anything particularly new, but it might contain something that is not immediately obvious looking at the board (or the ADS1256 datasheet).

author: thm_w
author_rank: Super Contributor
timestamp: January 21, 2020, 01:29:54 am
content: It looks like a similar file is here, but still have to register:http://www.51hei.com/bbs/dpj-139448-1.html

author: ebclr
author_rank: Super Contributor
timestamp: January 21, 2020, 12:01:45 pm
content: Here it's

author: ebclr
author_rank: Super Contributor
timestamp: January 21, 2020, 12:07:52 pm
content: RENAME *.DOC TO *.RAR AND DECOMPRESS

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 14, 2021, 04:50:17 pm
content: For others searching for data...A direct search on github gives you some 60+ projects.https://github.com/search?q=ads1256

author: sorin
author_rank: Frequent Contributor
timestamp: March 31, 2022, 11:16:36 pm
content: A little bit late, but here they are: