hybridfree/eevblog-posts huggingface dataset:
INA293 shunt amplifier response delay/confusion - Page 1
Forum section: electronics / projects

author: uer166
author_rank: Super Contributor
timestamp: July 29, 2021, 12:28:29 am
content: I have a boost converter with a 5mOhm shunt amplified by a INA293B2 amp. The first single pulse tests went good regarding power stage but I see a5us10us delay from when the current starts ramp, to the INA293 very quickly ramping up to the correct voltage. So far I've checked:Input offset: 80uV worst case, which cannot explain such a large delay/offset. In my trace the output corrects itself at ~0.25V out, which would correspond to 0.25/50=5mV offset??Settling time: doesn't apply since this is a nice linear ramp from 0, but still it's ~1us, not 10Power rail is perfectly flat during the pulse at the ampI had the same problem with the internal STM32F3 opamps, surely thought this amp would fix and actually track current like I require. What did I miss?

author: StillTrying
author_rank: Super Contributor
timestamp: July 29, 2021, 01:41:32 am
content: It does look like an op amp coming out of saturation to me. Is this something to do with it, page 15 on the data sheet."The linear range of the output stage is limited to how close the output voltage can approach ground underzero-input conditions. The zero current output voltage of the INA293 is very small, with a maximum of GND + 20mV. Make sure to apply a differential input voltage of (20 mV / Gain) or greater to keep the INA293 output in thelinear region of operation."I don't know the solution if it is.

author: uer166
author_rank: Super Contributor
timestamp: July 29, 2021, 01:51:15 am
content: Ah, I think this is related to the issue, which is vaguely similar to the output linear operation but it's to do with the input:"8.2.2.1 Overload Recovery With Negative VSENSEThe INA293-Q1 is a unidirectional current sense amplifier that is meant to operate with a positive differentialinput voltage (VSENSE). If negative VSENSE is applied, the device is placed in an overload condition and requirestime to recover once VSENSE returns positive. The required overload recovery time increases with more negativeVSENSE."Really wish TI gave actual numbers here.I think any input voltage of 0V + Vos (the 80uV or so) can be considered negative, depending on that opamp's input offset. I've biased the +ve input to 180 uV and now the issue is gone. I think in next rev I'll bias it to the 20mV/gain to be 100% sure, this will require extra series resistors between shunt and INA inputs..

author: StillTrying
author_rank: Super Contributor
timestamp: July 29, 2021, 02:13:34 am
content: It's amazing how hard you have to study a data sheet, all the while thinking 'what if'.
Ina3221 workings - Page 1
Forum section: electronics / projects

author: Klompenzijncool
author_rank: Newbie
timestamp: July 07, 2020, 09:41:40 am
content: Hello,I hope someone can help me because I’m starting to pull my hair out.I’m was trying to learn something about the I2C protocol. I had an INA3221 at hand so I started reading and writing stuff to the registers. Al great, learned a lot, except:How on earth do I convert the register values to an actual reading. The hex reading it gave me in register 02 is 13 48. My voltage reads 4.9v. I’ve checked the datasheet (didin’t help me), checked the Arduino library (didn’t understand that) and checked the Internet. There I learned that I had to multiply that value with the value of the LSB. So 1348 * 8mV. That doesn’t make 4.9v. Also tried 4mV. Didn’t work either.Is there anybody that can explain to me what I have to do?Thanks in advance,Michel

author: Zarhi
author_rank: Contributor
timestamp: July 07, 2020, 10:21:31 am
content: Hex 1348 is 4937 decimal.

author: Klompenzijncool
author_rank: Newbie
timestamp: July 07, 2020, 06:27:04 pm
content: Yessss,Thanks Zarhi. Seems like I was thinking way to hard.
INA826 (instr. amp) - can I use mosfet to switch different gain resistors? - Page 1
Forum section: electronics / projects

author: dusan
author_rank: Regular Contributor
timestamp: June 11, 2024, 01:36:33 pm
content: I have INA826 and I'm trying to measure current from 1uA to 100mA using 1R shunt and I want to switch between 2 ranges (100x Rg=470, 1000x Rg=47). Can I use mosfet across that 470R gain resistor and when I want to "remove" it I simply sort it with mosfet?The image is from datasheethttps://www.ti.com/lit/ds/symlink/ina826.pdfexample and shows 3.5mOhm I'll use 1ohm shunt, I don't have actual schematic yet.2 Gain resistors and 470R shortable by mosfet:Code:|47R|-------drain470R|--------source|

author: Zero999
author_rank: Super Contributor
timestamp: June 11, 2024, 05:38:12 pm
content: It's generally a bad idea, because the MOSFET needs to be biased on which requires the gate voltage to be taken above the source. An analogue switch would avoid this, but it will have a much higher on resistance. A reed relay would be better.Why not use a programmable gain amplifier?

author: harerod
author_rank: Frequent Contributor
timestamp: June 11, 2024, 06:39:32 pm
content: This can be done. However, you need to know a bit about the internals of your INA to get the bias of the MOSFET right:https://www.eevblog.com/forum/projects/ad627-rg-connection/msg5221824/#msg5221824ADI support was a bit slow to understand and react to my request. I only got an answer after I had built the prototype. Works like a charm, btw.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 12, 2024, 12:18:40 am
content: As an alternative, you can also use mulltiple shunt resistors either in series or parallel, and then switch some of those with MOSfets. Even SOT-23 Fets can switch multiple amps these days and can have a low Rds-on.But whatever method you choose, you will have to deal with this resistance of the FET itself (which is both temperature and voltage dependent) and with current leakage.
INA826 Output Voltage Issue – Completely Off - Page 1
Forum section: electronics / projects

author: Fab64
author_rank: Newbie
timestamp: April 12, 2025, 02:15:44 pm
content: I need to measure a small current in the range of 1 µA to 10 µA, so I chose the circuit inFig 1and began by simulating it.The output offset voltage is estimated using the circuit inFig. 2.Using the formulas:VD = (Vout − Voffset) / GIR1 = VD / 100The simulation yields a current of approximately 1.03 µA, which is quite close to the expected value.I built the circuit from Fig. 1, measured the offset voltage as per Fig. 2, and found an offset of approximately 5 mV.The measurements seem to be in line with the expected values:VD = 0.094 mVExpected Vout = (0.094m * 227.9 + 5m) = 26.423 mVMeasured Vout = 26.2 mVEstimated VD was 93.025 mV, which pretty close to the measured voltage.Since the common-mode voltage in my actual circuit can exceed the supply voltage of the INA826, I simulated the circuit shown inFig. 3,, which provides isolation from the DUT.R6 and R7 are included according to the guidelines in Section 8.3.6 (Input Bias Current Return Path) of the datasheet.The simulation yields a current of approximately 0.999 µA, which is even closer to the expected value.Unfortunately, the actual circuit gives a Vout which is completely incorrect:VD = 0.113 mVExpected Vout = 30.752 mVMeasured Vout = 3.5 mVAs far as I can tell, based on a measured VCM of approximately 474 µV and using the TI-provided tool (seeFig. 4), the amplifier appears to be operating within its linear region.Could you help me understand what might be going wrong?
INAMP CMRR - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: November 13, 2013, 09:28:34 am
content: I was making a high side current measurement circuit using a INA126PA INAMP, as that's what I had on hand.Anyway, I'm scratching my head over the CMRR, so please tell me what I've got wrong here.- Power rails to the INAMP are +/- 15V.- The output ref pin is at the center of the +/- 15V rails.- Gain is set to 100x with an external resistor.- With both inputs shorted to the ref pin (i.e. zero CM voltage), the output is about 3mV, which will be the input offset voltage x100.- With the inputs shorted together, and raised 5V above ref, the output is 310mV.- With the inputs taken to -5V from the ref pin, the output is -300mV.- Other than the surprisingly high CM output, the circuit works as expected (i.e. the correct gain of 100x is seen on a differential input voltage with all tested CM voltages.)So according to my calcs, this doesn't add up. Minimum CMR from the datasheet is 74db.10^(74/20) = 5012 = diff gain / cm gaintherefore, CMgain = 100/5012 ~= 0.02So the output should be < 0.02 * 5 = 100mV

author: tszaboo
author_rank: Super Contributor
timestamp: November 13, 2013, 04:27:38 pm
content: Series resistance on the REF pin can degrade the CMRR by magnitudes. Are zou driving it with a low impedance source?

author: Harvs
author_rank: Super Contributor
timestamp: November 13, 2013, 10:45:58 pm
content: moment...Yes that's pretty much it. I've got an offset trim circuit feeding the ref pin similar to the one described in the datasheet. But instead of hooking the ref pin to the output of the buffer, I stupidly hooked it to the wiper of the 10k pot. Problem solved, output due to CM is now in the 1 or 2 mV.

author: tszaboo
author_rank: Super Contributor
timestamp: November 13, 2013, 11:58:02 pm
content: That is all right... I've seen it in production
iNAND dumper - PCB Advice - Page 1
Forum section: electronics / projects

author: desowin
author_rank: Contributor
timestamp: April 10, 2011, 03:13:53 pm
content: This circuit is supposed to dump contents ofSDINB1-4096flash chip. It's going to be used once (1 read, and 1 write operation). I don't really care about speed - whole day for dump/write is acceptable.Most of the parts used are in my drawer.It would be appreciated if someone would point me out the obvious mistakes in this design. I plan to order the PCB from ITeadStudios (hence the board is 50x50mm).Also, any comments regarding the footprint I did for this iNAND chip would be nice - I have no prior experience with BGA chips at all.Proejct files (eagle) are available here:http://dl.dropbox.com/u/22631182/sansa.zip(Updated - fixed the airwire, moved the cap to not be so close to the edge):http://dl.dropbox.com/u/22631182/sansa2.zip

author: Unknown
author_rank: Unknown
timestamp: April 10, 2011, 04:37:42 pm
content: You have an airwire on the PCB?C2 is very close to the edge of the PCB. There is plenty of room for improvement of the PCB layout, but it is not critical. Make sure your design rules are set for itead and dont push your luck by using the lower end of their specififcations if you can.Regarding schematic and component values, if you have read and followed the datasheets of both parts you will be fine.About the BGA footprint, you can mirror the top layer and print it on an acetate transparency. Then flip the memory chip over and overlay the acetate print to check your footprint. Of course you can rely on the datasheet package dimensions if you are confident.Happy hacking.

author: desowin
author_rank: Contributor
timestamp: April 10, 2011, 05:03:33 pm
content: Oh my, I didn't directly connect the GND to the LDO (hence the airwire can be seen)Do you mean C4 (which is 2.2uF) instead of C2?

author: Unknown
author_rank: Unknown
timestamp: April 10, 2011, 06:43:47 pm
content: Sorry, yes C4.

author: somsof62
author_rank: Newbie
timestamp: December 29, 2013, 09:16:53 pm
content: Hey,I came across your PCB and I would really like to know if your attemp to dump the iNAND was successful?Best greetings,somsof62
InAs infra red detectors - Any insights on how to interface to them? - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: August 29, 2020, 07:21:02 pm
content: I wish to learn how to interface to InAs infra red detectors.Are they similar in functionality and performance to PbS devices?Does anyone have experience and wish to share?

author: graybeard
author_rank: Frequent Contributor
timestamp: August 30, 2020, 04:48:51 pm
content: If it is a PN junction you can reverse bias it and treat it like a PiN detector into a trans impedance amp or as a photocell into a voltage amplifier. The manufacturer should have a data sheet.Because of the small band gap leakage currents will be high. Instruments I have used that employ them use liquid nitrogen cooling to reduce thermal noise and leakage.

author: AndersJ
author_rank: Frequent Contributor
timestamp: September 01, 2020, 05:13:38 pm
content: Thanks graybeard for helping me understand InAS devices.Your response triggers new questions.PbS sensor sensitivity and dark resistance vary significantly with temperature.Do InAs devices exhibit the same temperature dependance?When reverse biased,will the DC output level vary with temperature,similar to PbS devices with a load resistor to a bias voltage?Is InAs sensitivity similar to PbS sensitivity,i.e. do InAs devices require about the same amplifier gain as a PbS device?Are InAs devices always based on semiconductor junctions (therefore plarized)or can they also be resistive (non polarized)?

author: AndersJ
author_rank: Frequent Contributor
timestamp: September 09, 2020, 06:16:49 am
content: Bumping this thread, hoping for someone to jump in.

author: photin
author_rank: Newbie
timestamp: July 13, 2025, 10:41:43 am
content: InAs detectors are Photovoltaic diodes, in comparison to PbS/PbSe are photoresistors.InAs detectors works from DC, and unbiased (no polarisation needed). Unbiased they do not have 1/f noise.PbS/PbSe have strong 1/f noise, and works best ~kHz range, strong fluctuations vs temperature, require usually TEC thermoelectric coolers to stabilize them.PbS/PbSe detectors spectral sensitivity shift toward longer wavelengths with cooling, whereas InAs detectors opposite = the responsivity move toward shorter wavelengths.InAs are more stable and faster (MHz ranges no problem).InAs detectors require transimpedance amplifiers (TIA). Please have a look on those two literature, to get familiar with the TIA interface topic:1. Graeme, old but very detailed and insightfullhttps://archive.org/details/photodiodeamplif0000grae2. Mark Johnson, wonderful book samplehttps://www.accessengineeringlibrary.com/binary/mheaeworks/eb32e99b7167b496/eb0f822b9e164aa332b7fa43b5e4860a1f7865b294d510a43131e93dc69cfd46/book-summary.pdfRare study of InAs vs PbS detectors:https://www.researchgate.net/publication/279231629_InAs_Photodiodes_for_343_Radiation_ThermometryKK
Inconsistencies in EM Theory the Kelvin Polarization Force Density Contradiction - Page 1
Forum section: electronics / projects

author: Z_Losonc
author_rank: Newbie
timestamp: November 11, 2018, 07:07:36 pm
content: This is not electronics in its strict sense, but electrostatics, which being part of electrical engineering, might be of interest to some of the forum members. I am posting it here because there are many electrical engineers with masters degree here who can easily refresh their knowledge of electrostatics and offer valuable input about the subject presented in the paper.All experts are invited to find any grave error in the calculations of the below paper that would explain and fix the presented contradictions. (But please, point out the exact error, and also show the correct way of calculation). No satisfactory explanation for this paradox has been found since 2003 when it was first published (at least I am not aware of any). Alternatively if anyone reads and understands the calculations, and can't not find any grave error in them, then it would be greatly appreciated, if you would post that you haven't found any error. This would help as much as finding an error. Here is the paper:Inconsistencies in EM Theory - the Kelvin Polarization Force Density ContradictionAbstract:Calculations of resultant electrostatic force on a charged spherical or cylindrical capacitor with two sectors of different dielectrics, based on the classical formulas of electrostatic pressure, Kelvin polarization force density, and Maxwell stress tensor predict a reactionless force that violates Newton’s 3rd law. Measurements didn’t confirm the existence of such a reactionless thrust, thus there is an apparent inconsistency in the classical EM theory that leads to wrong results.for printing there is a high resolution (300DPI) version (10MB) at:http://vixra.org/pdf/1810.0468v2.pdfIf you want a low resolution smaller file version, you can download this:http://gsjournal.net/Science-Journals/Research%20Papers-Mechanics%20/%20Electrodynamics/Download/7520It is sufficient to read only the first 22 pages, the rest (Appendix) is only the description of the used measurement equipment.Zoltan Losonc
Altium error not making sense... "Same net having multiple names"... - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: January 05, 2025, 06:08:56 pm
content: Hi,I have a hierarchical design with 6 channels as shown in the attached screenshot. Some nets like the RS485 are all joined together across all channels. Some nets like the HNDSHK_B are all independent (i.e. not connected across channels).For some reason I get hundreds of errors for several nets like the uC_IO_HNDSHK_B. This is an example:Nets Element: uC_IO_HNDSHK_B1 has multiple names (Net Label uC_IO_HNDSHK_B1, Net Label uC_IO_HNDSHK_B1, Net Label uC_IO_HNDSHK_B1 (Inferred), Net Label uC_IO_HNDSHK_B_EDGE1, Net Label uC_IO_HNDSHK_B_EDGE1)For example, looking at net uC_IO_HNDSHK_B it looks like it generates uC_IO_HNDSHK_B1 and uC_IO_HNDSHK_B_EDGE1. Where "EDGE" is the repeated sheet name.Any idea why am I getting that error?Does anybody have any suggestions?Thank you!

author: Niklas
author_rank: Frequent Contributor
timestamp: January 05, 2025, 10:07:11 pm
content: This is common to get when repeating a schematic block. There is one TOP_LEVEL_NAME outside of the block, that is linked to a net named TOP_LEVEL_NAME_CHANNEL# inside the repeated blocks.The fixPlace a No ERC (Place>Directive>Generic No ERC) on error nets outside of the repeated block.Double click on the ERC to change the settings from the default All violations, instead select something more useful. There is an option to suppress the issue with multiple names in the bottom section.Pictures and more info here:https://www.altium.com/documentation/altium-designer/design-validation#controlling-the-printing-of-no-erc-directives

author: Benta
author_rank: Super Contributor
timestamp: January 05, 2025, 10:30:52 pm
content: Better post in the Altium forum, I think.
Increase Voltage to 14.4V HP DPS-750RB-A HSTNS-PD18 - Page 1
Forum section: electronics / projects

author: flywire
author_rank: Contributor
timestamp: December 11, 2023, 08:49:53 pm
content: Inspired byhttps://www.eevblog.com/forum/projects/hp-hstns-pd30-voltage-modI'm looking for the mod to increase the voltage to 14.4V for the HP DPS-750RB-A HSTNS-PD18 :

author: flywire
author_rank: Contributor
timestamp: December 11, 2023, 09:26:21 pm
content: This topic is a duplicate of the unansweredhttps://www.eevblog.com/forum/repair/hstns-pd18-(aka-delta-750)-ovp-hack/

author: coromonadalix
author_rank: Super Contributor
timestamp: December 12, 2023, 03:48:31 pm
content: and why create another thread ??

author: Vovk_Z
author_rank: Super Contributor
timestamp: December 13, 2023, 11:31:54 am
content: That is PC (server) power supply. This means it has voltage monitors which monitor output voltages if they are in +-10% window. So, to move output voltage out of the normal working ATX range you have to mess with it's voltage monitors.

author: pienari
author_rank: Regular Contributor
timestamp: December 13, 2023, 06:14:59 pm
content: Im still trying to find ovp solution for HP PL28.Ovp kick in 13.6v
Increased current problem. - Page 1
Forum section: electronics / projects

author: stefan_trekkie
author_rank: Contributor
timestamp: December 27, 2019, 11:13:07 am
content: Hello. I have a design issue with finished project. I have to drive 4 separate coils at 60 to about 300 Hz and have been told that the current must be 1A each and i have done it with 4 PNP BJTs "КТ818Г" (Russian made ~ 10 amps, TO-220 package) FOr 1 amp i had them naked but not they tell me that has been mistake and the current must be 4 amps and it is not working in the moment. Have to increase it .. That is ok but i don't have space for radiators inside the tiny box ... Should i go for some high power mosfets and again - naked ? (expensive stuff) This device will work more then 90 min at time.

author: StillTrying
author_rank: Super Contributor
timestamp: December 27, 2019, 12:45:34 pm
content: "but i don't have space for radiators inside the tiny box"If the box is metal could you use the box itself as the radiator,probablyneeding the TO-220's tabs to be isolated from the box....Which probably still won't be enough heatsinking.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 27, 2019, 05:44:21 pm
content: It depends on the control signal that goes to the base. If the voltage level is right, it may work with P channel mosfets. One may need a logic level type and a relatively low voltage one to get a R_on that is low enough.

author: stefan_trekkie
author_rank: Contributor
timestamp: December 27, 2019, 06:42:09 pm
content: I was scrolling in the local electronics catalogs and found nice mosfets with high current ratings .. With 0.008 Ω D-S resistance.. with 4 amps .. That is below 0.2W .. 2€ per piece .. I was with wrong impression that will be at least 10€ peaceQuoteIt is analog 12 volt with op amps and driver transistor (it was necessary for the power BJTs) .. Not a problem at all i will change it.QuoteNope, a plastic .. I had somewhere in the parts a nice npn's for the TV vertical deflection with isolated collector

author: StillTrying
author_rank: Super Contributor
timestamp: December 28, 2019, 01:02:51 pm
content: "I have to drive 4 separate coils at 60 to about 300 Hz and have been told that the current must be 1A each and i have done it with 4 PNP BJTs "КТ818Г".... It is analog 12 volt with op amps and driver transistor (it was necessary for the power BJTs)"I can't tell whether the coils are driven with square waves or sine waves, which makes quite a difference to the dissipation in the drivers.

author: stefan_trekkie
author_rank: Contributor
timestamp: December 28, 2019, 08:42:41 pm
content: Square waves on motorcycle fuel injectors. My friend is running experiments on that stuff.. It is ready and running

author: daqq
author_rank: Super Contributor
timestamp: December 28, 2019, 09:09:37 pm
content: You can get really cool MOSFETs these days for peanuts. Depending on how you are driving your transistors now, you may or may not need a rework of the driver. MOSFETs are awesome, provided they are used properly

author: langwadt
author_rank: Super Contributor
timestamp: December 28, 2019, 11:28:43 pm
content: schematic?
increased engine speed at the lowest cost - Page 1
Forum section: electronics / projects

author: Gerelectronic
author_rank: Contributor
timestamp: November 01, 2020, 08:53:23 pm
content: Hello!I'm new. I really need a help.i want to increase speed of an engine at the lowest cost possible.The circuit is attached.Thank you.

author: bob91343
author_rank: Super Contributor
timestamp: November 01, 2020, 08:57:22 pm
content: Not enough information.

author: Gerelectronic
author_rank: Contributor
timestamp: November 01, 2020, 09:34:46 pm
content: sorry if I didn't make myself clear. in practice I would like the motor to run at the maximum speed that the circuit is able to offer. I would therefore like to modify the circuit to ensure that the maximum possible voltage reaches the motor. I would like to modify the circuit as little as possible, in order to obtain a very low modification cost. Thanks again.

author: pwlps
author_rank: Frequent Contributor
timestamp: November 01, 2020, 10:06:40 pm
content: The only limiting factor I see is the VCEsat of Q2, somewhere between 0.3 and 1V depending on the current.This is if the PWM duty cycle can go up to 100%. If it can't get rid of the circuit and connect the motor to Vcc : definitely the lowest cost

author: Doctorandus_P
author_rank: Super Contributor
timestamp: November 02, 2020, 02:24:56 am
content: For maximum motor speed, just add a wire between the emitter and collector of Q2.

author: Gerelectronic
author_rank: Contributor
timestamp: November 02, 2020, 09:34:45 am
content: the speed of the motor, however, must depend on the signal coming from dac 0830. I would like to be able to optimize the quality of the signal coming from the dac, in order to get the maximum amount of information possible to the motor which leads to greater speed.the signal c (red) is the one that reaches the engine, but it should be better, unfortunately the engine gets less signal than it should.for more information see the attachment.Sorry again.Thank you so much.

author: pwlps
author_rank: Frequent Contributor
timestamp: November 02, 2020, 12:49:55 pm
content: Quote from: Gerelectronic on November 02, 2020, 09:34:45 amThe motor gets the maximum voltage when Q1 is on, therefore U2 output high (although I find it strange that there is no resistor between the U2 output and the base of Q1, it just uses the short current of the LM356 ?) and U4 output low.If the yellow trace corresponds to U4 output then it is strange, I would expect it to be a square signal.Looks like it is more a software problem.At any rate if you program the ADC to output a continuous low then the motor will get the maximum power.If you want the motor voltage transitions to look cleaner you can try putting a big decoupling capacitor (like C3 but at least 10uF) between the emitter of Q2 and the ground.
Increasing accuracy in oscilloscope amplitude measurements - Page 1
Forum section: electronics / projects

author: martinv
author_rank: Contributor
timestamp: May 03, 2013, 01:10:33 am
content: Is it ok to 'clip' a waveform to get more amplitude resolution when making a voltage measurement on a digital oscilloscope? It appears to be no problem, but I was wondering if the clipping or off scale portion can cause any unwanted skew to the measurement.Example: The following 2 waveforms areexactlythe 'same' waveform. The 2nd is just zoomed in in the amplitude scale. I am trying to accurately measure the time at exactly 400mV. Note in the first waveform zoom level didn't allow the cursor to be placed at exactly 400mV.

author: MrsR
author_rank: Regular Contributor
timestamp: May 03, 2013, 02:29:37 am
content: Just using the 10 to 1 screen zoom will not make any difference as you have already triggered on the wave form, you have captured the data and now you are just changing the magnification of the screen not the data.What you haven't shown is from where in the wave form are you starting to measure the time.Your screen shot doesn't have a complete wave form to measure time, unless you are measuring time from zero volts to 400 mV.Rachael

author: martinv
author_rank: Contributor
timestamp: May 03, 2013, 05:38:04 am
content: Quote from: MrsR on May 03, 2013, 02:29:37 amI probably should not have used the word "exactly". I DID retrigger the waveform on the 2nd screenshot and just meant it is the repeating waveform so each example is the 'same'. The time axis is the same in both plots. The start time in both captures is on the first division which is the falling edge of the waveform, which is mostly hidden under the white cursor 'A'.I guess the simple question is: Can a part of a waveform off scale on the vertical axis skew the voltage measurement on the display. Can it overload the A/D...?

author: jmole
author_rank: Regular Contributor
timestamp: May 03, 2013, 06:43:17 am
content: Quote from: martinv on May 03, 2013, 05:38:04 amA/D inputs are always going to be clamped to some voltage that won't damage them in a good scope. It's the recovery characteristics of the clamping circuitry that can degrade the performance.
Increasing current capacity with XL6009 modules - Page 1
Forum section: electronics / projects

author: abhishekkumar1902
author_rank: Regular Contributor
timestamp: August 10, 2019, 04:52:31 am
content: Hi, I am new to electronics. In one of an application, I want to boost 5v to 10v with a load current of around 1.8 amps, in which case the input current will be more than 4amps which is heating the XL6009 chip like anything and will definitely fry it up. XL6009 is capable of handling only 3 to 4A current. Is there a way, I can hook up these XL6009 modules in parallel so that they share the current between them?i tried the following way of parallel operation but I observed that the current was still flowing more through one module and it was heating a lot while the other one was cool?
Increasing discharge current rating of LiFe battery, limited by BMS - Page 1
Forum section: electronics / projects

author: najrao
author_rank: Regular Contributor
timestamp: February 02, 2022, 03:45:20 pm
content: I have a 4S LiFePO4 20Ah battery with large prismatic cells. It has a built-in balancing BMS, which I suspect cannot take more than 15 or 18A. The two usual mosfets are AO D448, specced at 5mO×2, and no heatsink.An extra high current lead is fitted directly to the battery negative, which can be used for higher discharge current, but bypasses the BMS.I propose to use this, but fit an external sub-milliohm mosfet as a switch. This mosfet would be turned on by the BMS's output negative terminal itself, so the BMS still protects against deep discharge for example. Charge current would still be limited, so no issues there for the BMS. For short-circuit protection, I am considering a 40 or 50A automotive fuse.It is inconvenient to replace the D448's on the BMS board.Any other caveats?
Increasing the voltage of a power supply - Page 1
Forum section: electronics / projects

author: ninja_zx11
author_rank: Newbie
timestamp: April 20, 2025, 07:39:46 pm
content: Hi all,I have a power supply which uses UCC28950 Phase-Shifted Full-Bridge Controller. Currently its outputting 12.27 Volts DC and I would like to bump it to 14 Volts.Could anyone please suggest me which resistor I should change to achieve 14 volts? I am attaching the pic. Thanks.

author: moffy
author_rank: Super Contributor
timestamp: April 20, 2025, 10:21:00 pm
content: I would guess decrease the value of R104 slightly, do it in small steps and test to make sure it is doing what you expect.

author: ninja_zx11
author_rank: Newbie
timestamp: April 20, 2025, 11:48:39 pm
content: Many thanks!! I will try with 2k (R104) as according to voltage divider calculation, it will give around almost same volts (2.5v)at EA- pin with 14volts output.
Incremental encoder direction signal decoding - Page 1
Forum section: electronics / projects

author: AlexResch
author_rank: Regular Contributor
timestamp: September 04, 2018, 10:06:53 pm
content: Too keep it short : what is the easiest way to get a direction signal from an incremental encoder ? I need to control the direction ( and position ) of a small stepper motor and the drive wantspulseanddirection. Pulse I can do, direction not.

author: Wimberleytech
author_rank: Super Contributor
timestamp: September 04, 2018, 11:25:21 pm
content: For a rotary encoder...

author: cncjerry
author_rank: Unknown
timestamp: September 06, 2018, 01:59:52 am
content: if you hook two steppers back to back (without power) you can turn one with the other based on the EMF generated by the one you turn. Not much torque at all but it is interesting.Look up quadrature encoding. This is how you decode encoders with a microprocessor. The two pulses are offset so that dependng on how the encoder turns, one or the other pulse will lead or lag the other and based on that, you get the direction and step.So turning one way you'll get a pulse train of ABABABAB as to which leads the other; The other way, BABABABABA. Remember, that the transition from A to B and from B to A is which leads. So you really have A, and while A, then B; The other way, B and while B, then A. I think they call it quadrature because you can have four states: not A & not b; A; B; A & B. Most microprocessor libraries have quadrature encoder libraries or code.Jerry

author: intabits
author_rank: Frequent Contributor
timestamp: September 07, 2018, 02:23:45 pm
content: Looking at some old assembler code I did for a servo controller, it's simple in software if you have a microcontroller involved.On the falling edge of one encoder channel (I used that as in interrupt), look at the other channel. If that's high, it's rotating one way, if low, it's rotating the other way...(which is what the circuit above does in hardware)

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 07, 2018, 02:38:05 pm
content: I have used the principles given here successfully in a few projects:https://tutorial.cytron.io/2012/01/17/quadrature-encoder/

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 07, 2018, 02:49:52 pm
content: If pulse for the drive would trigger high- or low going you could hook the encoder directly to it, it's not going to be simpler than that.

author: Wimberleytech
author_rank: Super Contributor
timestamp: September 07, 2018, 03:25:16 pm
content: Quote from: Wimberleytech on September 04, 2018, 11:25:21 pmIf all you want is DIR, you can eliminate the inverters since CLK is buffered internal to the 4013.
indentifying unmarked current sense transformer - Page 1
Forum section: electronics / projects

author: yanir
author_rank: Regular Contributor
timestamp: September 22, 2011, 05:38:04 pm
content: I am working on a reverse engineering project that is fairly simple, but there is one unmarked part that I want to know the specs of. It appears to be a current sense transformer. I know it carries ~12A (full load) 115VAC @ 60hz on the current side. I just don't know what the turn ratios are and what the voltage/amp spec is on the "sense" side. I've never worked with these before and had to figure out what this was in the first place. Now that I know (i'm quite please with myself for that) I still need to know the specs.One idea I had is to run an amp through it and see what the linear response is. but that won't tell me the whole story, like max current, optimal range etc.Any thoughts on this?
independant phase control of all h-bridge legs? - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: October 08, 2014, 08:44:45 am
content: So the H bridge can typically be controlled by two complimentary signals with phase adjustment (for power adjustment), such as for motors.Could any benefit be seen from using four phase adjustable clocks? So that timing could be matched to the nanosecond to account for variations in gate drive current? (or staggered, if there is a reason for it!) Like, so you can time the firing of the H-bridge legs to 1 nanosecond.Just curious, had this pop into my head.Just looking at it, I figure it does not really matter.

author: nuno
author_rank: Frequent Contributor
timestamp: October 08, 2014, 09:32:49 am
content: The h-bridge driver (that is, the one controlling directly the 4 switches) can vary widely in complexity. I can think of one (actually a half-bridge MOSFET driver) that can dynamically adjust the timing with ~4ns resolution to reduce/eliminate diode reverse recovery current, by preventing the intrinsic body diode from turning on. I think I also remember seeing some microcontroller with complementary PWM outputs with sub-nanosecond resolution adjustable dead time.

author: Phoenix
author_rank: Frequent Contributor
timestamp: October 08, 2014, 12:04:48 pm
content: Soft switching techniques depend on accurate timing of the switch transistions. Some methods use a resonance and time the switch transition to the zero crossing to achieve either zero voltage or zero current switching.I know the newer TI C2000 series MCU's have a high resolution PWM system capable of ~200ps resolution (e.g. TMS320F28069). I havn't yet decided if I need to use this in my current project (going to be switching at x00kHz), but will probably set it up in the coming weeks to test anyway. I don't think I need quite THAT resolution, but the 90MHz clock on the MCU limits the resolution to ~11ns.
Indistinct photo, please help identifying part number. - Page 1
Forum section: electronics / projects

author: TerraHertz
author_rank: Super Contributor
timestamp: July 28, 2015, 04:04:40 am
content: From a photo off the net, I'd like to identify the National Semiconductor (now a division of TI) switching regulator. See red arrow in pic.The NS symbol is clear, but the part number is indistinct.I think it is LM34?? and is probably one of the Simple Switcher series.All I know about the specs (Chinese manufactured RGB LED controller) is that the input supply is stated to be DC 5 to 24V. But this may be inaccurate.Output is probably 12V, at a few amps capacity.Package appears to be TO-263 (S) or similar. 5 leads plus tab.Online info from TI doesn't seem to have anything like a full line chart. Only pages pushing recent parts.And my paper NS databooks are all too old.Similar numbers I can find online are all the wrong package:http://www.ti.com/lit/ds/symlink/lm3489.pdfVSSOP-8http://www.ti.com/lit/ds/symlink/lm3485.pdfVSSOP-8http://www.ti.com/lit/ds/symlink/lm3475.pdfSOT-23-5http://www.ti.com/lit/ds/symlink/lm3477.pdfVSSOP-8Does anyone recognize it?

author: Guitarbro
author_rank: Newbie
timestamp: July 28, 2015, 04:19:11 am
content: lm3450 Led driver?http://www.ti.com/lit/ds/symlink/lm3450.pdf

author: TerraHertz
author_rank: Super Contributor
timestamp: July 28, 2015, 05:11:29 am
content: Quote from: Guitarbro on July 28, 2015, 04:19:11 amNo. The part I'm after is the input DC power converter for the board. It takes a DC input in the range 5 to 24V, and everything else on the PCB including processor, bluetooth link, and 4 variable LED output drivers (for 12V RGB LED strips) runs off its output. Which I assume is 12V.The unit is intended to be run from a plugpack.I want to find the datasheet to see how this power converter treats a LiPo 12V battery pack. It seems to me it will destroy the battery rapidly by discharging it way below the LiPo specs lower voltage limit. But I want to be sure.

author: Guitarbro
author_rank: Newbie
timestamp: July 28, 2015, 06:42:33 am
content: I think i figured it out. the second line is the part number, not the first. Looks to be a LM2575-5 .

author: TerraHertz
author_rank: Super Contributor
timestamp: July 28, 2015, 07:24:41 am
content: Quote from: Guitarbro on July 28, 2015, 06:42:33 amAh! Yes that would make sense. I was surprised that regulator could be supplying the current for 3 or 4 long 12V LED strips (via separately adjustable current sinks.) But if it's a 5V regulator, it's just supplying that CPU-bluetooth module at well under an amp, and the LEDs are drawing directly from the supply voltage. Which doesn't matter since the drives are current mode.Package matches:http://www.ti.com/lit/ds/symlink/lm1575.pdfThanks!
Individual cell monitoring of 2S and 5S Lipos - Page 1
Forum section: electronics / projects

author: thesassyindian
author_rank: Newbie
timestamp: October 27, 2016, 09:19:14 pm
content: Hello folks!I have a project requiring the individual cell monitoring of separate 2S and 5S Lipos centered around a 328p.I could go the obvious route of using a voltage divider with >100k resistors with 0.5%-1% tolerances and a precision AREF chip.However, I was wondering whats the best solution for this. I've seen the BQ769x0's from TI, but they do a minimum of 3 cellsAny help would be greatly appreciated!Thanks!!

author: juanfermed
author_rank: Regular Contributor
timestamp: October 30, 2016, 06:29:44 pm
content: Hi,I am not sure your question is clear.1) What is exactly what you want to monitor? Voltage, current, temperature, charge...2) What is a 328P? The atmega328P, due to "328p" and "centered" I also imagine you might refer to a 328V string of cells and the 2S and 5S are in the center of the string?... please make it clear.- Juan

author: LHelge
author_rank: Contributor
timestamp: November 01, 2016, 01:24:52 pm
content: The lowest cell could be measured by a A/D, if you are talking about an Atmega328P, which is a 5 V processor, you don't even need any level translation. The 1 or 4 cells above could be translated by a OP-amp in difference mode.

author: jt
author_rank: Regular Contributor
timestamp: November 02, 2016, 02:58:08 am
content: Take a look at the SII catalog linked below. Note that some of the components listed to support only 3s or 4s cell topologies can actually be cascaded to support larger strings - dig into the data sheets to find the relevant application noteshttp://www.sii-ic.com/en/semicon/products/power-management-ic/lithium-ion-battery-protection-ic/My disclaimer here is if you are new to hardware design, pick a battery pack with integrated cell protection. Cell protection isn't overly complicated, but the consequences can be pretty extreme if you get something wrong. You are probably aware of the Samsung issues; they aren't the only ones having problems:https://www.wired.com/2016/10/samsung-isnt-one-lithium-ion-problems-just-ask-nasa/
Individually addressable tungsten lamps? - Page 1
Forum section: electronics / projects

author: corgon
author_rank: Contributor
timestamp: February 27, 2025, 09:47:14 am
content: Why not!Just for fun, built on breakout boards. Based on the WS2811 chip and a P-MOSFETs.It can drive three tungsten lamps with PWM, three small DC motors, or, of course, three relays (on/off), with one WS chip.Does it have any practical use? Probably not, but maybe something will come up.

author: LaserSteve
author_rank: Super Contributor
timestamp: February 27, 2025, 09:51:07 pm
content: Gas Filled Tungsten Lamps are faster.😊

author: prosper
author_rank: Regular Contributor
timestamp: February 28, 2025, 03:43:14 am
content: hah! i did the same thing a while back. Made me yearn for a sot23 ws2811.There's all sorts of creative things you can do with that IC
Inductance converter - tips for best design? - Page 1
Forum section: electronics / projects

author: rvalente
author_rank: Frequent Contributor
timestamp: November 03, 2021, 12:59:59 pm
content: Hello Mates,I'm looking for tips to make this circuit as simple and reliable as possible.I need to read position sensors, which are basically variable inductors, accordingly to the indexer pin position the inductance varies from 16 mH to 48mH.This signal has to be converted to a 0-10V(or 4-20mA) so the PLC can read it.I need some diagnostics: sensor disconnected or shorted (e.g. 0 to 0.5V for disconnected and 9.5 to 10V for shorted, or something like that).I was thinking to use the classic RLC approach, a sinusoidal 1KHz over a known resistor, rectify, integrate and buffer.I'd like this to be full analog, no mess with ADCs and DACsIs there any base project I could start on? Or maybe some older RCL equipment I could check the circuit and inspire myself?Greetings, Renan

author: RoGeorge
author_rank: Super Contributor
timestamp: November 03, 2021, 06:18:59 pm
content: See if these inductance to digital converter ICs fits:https://www.ti.com/product/LDC1614,https://www.ti.com/product/LDC1051families and alike.
Inductance of distributed air gapped core - Page 1
Forum section: electronics / projects

author: Gowda1
author_rank: Contributor
timestamp: January 21, 2021, 12:13:06 pm
content: Hey,I have got two E70/33/32 core of N87 material, one with centered airgap of 8mm and another one is un-gapped core. I measured the inductance for N number of turns with centered gapped core and also I measured the inductance with 4mm airgap in the each leg (which gives effective airgap of 8mm). But I am getting different inductance value in both cases, for higher number of turns I am getting difference of 1 to 1.5uH. I am getting more inductance for distributed gapped core. I do not understand the reason behind it. I designed my own coil former(bobbin) just to give 4mm airgap in each leg and also tried putting a plastic of 4mm on each leg and measured it but the inductance is different in both the cases. I would want to go with distributed air gap because of its advantage. But I would like to know what is the reason to have different inductances in both the case. If anyone has experienced this please let me know.

author: jonpaul
author_rank: Super Contributor
timestamp: January 21, 2021, 02:53:45 pm
content: distributed gap = throughout material, like powdered iron.You get either a single center leg ground gap from mfg OR use spacers for 3 gaps, center and each leg, NOT distributed gap.So you post tilt is confusing.What is your design goal?Jon

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 21, 2021, 04:01:08 pm
content: Well, two is more distributed than one.The cross-section in the air gap is wider because flux spreads out (fringes) there; so, Ae is effectively over-counted for a given gap (effectively, under-counting the air gap). This affects linearity of setting the gap (inductance drops proportionally with gap, for small gaps, but slows down as the gap width approaches the width of the limb), but without an exact formula or curve, I'm not sure how to relate that to different distributions of gaps.On E70, the outer limbs are 11mm thick? 4mm is the same fraction of width, that 8mm is of the center limb's 22mm width. That at least should suggest they have the same fringing effect, while counting for half the amount of the center-only gap. Which suggests the inductance should be higher, because the center gap having less fringing and a shorter gap, will add less than half the reluctance of the center-only case?And which way around was your observation? 1.5uH equal-gap, 1.0uH center-only? I guess that checks out.BTW, in either case, beware of the fringing flux around the gaps, keep wire away from them if possible and use litz cable if available. The fields there are quite intense and cook wire quickly!Tim

author: Benta
author_rank: Super Contributor
timestamp: January 21, 2021, 05:59:10 pm
content: I'm having a déja vu moment here:https://www.eevblog.com/forum/beginners/air-gap-in-inductor-core/msg3358738
Induction loop receiver - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: June 05, 2019, 08:47:05 pm
content: A quick project I knocked up.Apologies for the audio - might have been overdriving the camera.The sensor is a strobe trigger transformer from Jaycar (suggested by an article in Silicon Chip - there was a kit but apparently discontinued)Inspired byhttp://www.techlib.com/electronics/induction.html&https://goughlui.com/2014/10/04/project-audio-induction-loop-receiver-part-1/

author: mikerj
author_rank: Super Contributor
timestamp: June 06, 2019, 10:44:14 am
content: Really interesting, guess hearing aid users must quickly learn to disable inductive pickup when on trains! How far away can you pick up overhead power distribution cables?

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: June 06, 2019, 01:04:14 pm
content: Pretty much everywhere you go there's hum from power lines and in the street. Would be interesting to take it outside the suburbs.I think that proper hearing aids have AGC. Also I think my unit may have slightly excessive gain.