hybridfree/eevblog-posts huggingface dataset:
OVP ICP DC to DC Buck Converter - Page 1
Forum section: electronics / beginners

author: axis937
author_rank: Newbie
timestamp: July 10, 2024, 01:44:23 pm
content: Hello everyone. I am new to electronics and just got my first Buck n Boost . To play safe for the first time, into a USB charger 12V 1.5A. On the converter screen, no matter what adjustments i do to the settings even under memory, nothing seems to change the voltage. Its like its got its mind on its own. I decided to try it with a RC car battery 7.2v 1100mah and received the same results. i have nothing plugged into the output and yet i see the Current Values.Attached are the pictures. Errors i am getting is OVP and ICP at times. I did not plug in anything on the output side.Any solutions to this?

author: thm_w
author_rank: Super Contributor
timestamp: July 10, 2024, 10:52:40 pm
content: If its reading values with nothing connected on the output its possibly damaged.Do you have a multimeter to measure voltage at the input and output? And current at the input?

author: axis937
author_rank: Newbie
timestamp: July 11, 2024, 05:02:01 am
content: Hiya, thank you for the reply. I managed to solve the OVP and ICP issue by reading up on the settings based on what is the Power Supply voltage and current that is incoming.to answer you question, multimeter shows the right incoming value and its also right on the converter LCD.On the outgoing part, there is no load connected to it. Multimeter readings shows 0V as well. BUT...on the buck converter its showing reading.This is brand new out of a box. Unfortunately i threw away the box and wont be able to return it.Any idea what could be wrong. any advice is appreciated.

author: Phil1977
author_rank: Frequent Contributor
timestamp: July 11, 2024, 05:49:05 am
content: Did you connect just the battery as a voltage source to the input and to nothing else? These units like you have one are prone to ground loops of hell (tm) if input and output circuitry are anyhow in connection.A second thing is: Also these DC/DC units are cost optimized by transferring production steps into software development. That means, the first time they are powered up, or maybe even every time they are powered up, they "re-tune" their regulation loop by the microcontroller. Current regulation seems even to be done completely by software. It could be worth a try to power cycle it a few times, connect it to another PS and slowly increase input voltage.And of course, check the PCB for bad solder joints and blown caps...
OVP without Voltage Drop ??? - Page 1
Forum section: electronics / beginners

author: IamSynthetiC
author_rank: Regular Contributor
timestamp: June 14, 2020, 06:58:22 pm
content: Greetingsi am trying to measure some voltage by directly conecting the line to a voltage divider an into an analog input of an ADC.How can i protect the ADC from overvoltage or spikes, without affecting the measurement? (or affecting it in a predictable manner)Thanks a lot.Have a good day.

author: Vovk_Z
author_rank: Super Contributor
timestamp: June 14, 2020, 07:35:13 pm
content: Some datasheets have a typical circuit how to do.It is usually good to put opamp buffer before an ADC input. And make typical protection for this opamp (it can be or not in an opamp datasheet too).Look at something like "Op amp application" books, or "The Art of Electronix" too.

author: Laszlo
author_rank: Contributor
timestamp: June 26, 2020, 04:06:41 am
content: As Vovk suggested you should use an opamp (such as an ua741) configured as a voltage follower to make sure that the output of your divider will not change once you connected it to your ADC.If you have enough margin, you could use a Zener diode to clamp the spikes down. Or you could use TVS, or a MOV at the input of your voltage divider to provide overvoltage protection.Nevertheless, without knowing the threshold of your ADC, and your input voltage, its a bit difficult to help.

author: Kleinstein
author_rank: Super Contributor
timestamp: June 26, 2020, 09:58:05 am
content: The input protection is usually working in 2 steps: clamp the voltage by something like diodes, MOV or Zener diodes and limit the input current by something like a resistor (this can already be the divider), PTC or depletion mode FETs.Which way to go depends on the impedance, voltage levels, acceptable errors and the required level of protection.With a divider at the input, the protection may actually be in 2 steps, coarse before the divider (e.g. with a MOV / sparc gap) and the final protection after the divider, using the divider for current limiting.
OVP - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: October 02, 2013, 11:44:51 pm
content: Can someone explain to me what Over Voltage Protection is suppose to do on a power supply? I thought you set the voltage, press the button, then if the voltage goes above the setting it shuts down the outputs. Can't seem to get mine to do that. The OCP works as you would expect..

author: Unknown
author_rank: Unknown
timestamp: October 02, 2013, 11:54:51 pm
content: OVP can protect against two types of faults: an absent-minded person accidentally changing controls (think turning the button on the wrong power supply while it's connected to an expensive FPGA) or a fault inside the power supply. To protect against the latter, some power supplies feature a crowbar circuit that will short the outputs if the voltage exceeds the set threshold. This can even protect against a shorted pass transistor. In other cases it's just a software limit, this only prevents wrong control settings.

author: tony3d
author_rank: Frequent Contributor
timestamp: October 03, 2013, 12:34:55 am
content: Well I can't seem to get to work with wrong control settings. So I guess it's just for internal faults. SRA Solder doesn't seem to have a clue how it works either. I tried emailing Korad, but no reply. Oh well everything else seems to work fine. Bugs me though that there is a feature that seems to do nothing.

author: Dave
author_rank: Super Contributor
timestamp: October 03, 2013, 01:16:10 am
content: Quote from: alm on October 02, 2013, 11:54:51 pmThere is always the third option: A very impolite load that causes the power supply to oscillate, so the voltage exceeds the OVP limit.

author: geraldjhg
author_rank: Regular Contributor
timestamp: October 14, 2013, 08:00:37 pm
content: shut it downnot easy to trip if done with the same power supply
Owen AG1022F Problems. Need Help - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: July 14, 2016, 04:22:12 pm
content: Hi All, Well I received my Owon AG1022F signal generator today, and think it my have an issue. I may be doing something wrong, but the Logarithmic function of the Sweep section does not appear to be working properly! When I switch from linear to log I get a DC signal. Weird! Any ideas? So far everything else seems fine. I think the unit has the most current Firmware version 6.0. Thanks.

author: tony3d
author_rank: Frequent Contributor
timestamp: July 15, 2016, 04:20:12 am
content: Ok, maybe I don't understand how the log function works. I can get a waveform by changing the time base when I switch to log, but still no sweep. Can someone explain how the log sweep function should be working?

author: tony3d
author_rank: Frequent Contributor
timestamp: July 15, 2016, 04:52:43 pm
content: Found out it is a bug in the newest firmware, and Owon will have a fix within the next two weeks.

author: svetlov
author_rank: Regular Contributor
timestamp: May 14, 2018, 10:08:13 am
content: Hello! tell me, I have such a problem-when the generator is turned on, the start screen lights up and the longer it does not go to the settings menu of its functionsthe device itself is new - before it workedon this forum there was a post with a similar problem - where the comrade replaced the operational amplifier by solving this problemdo not help to find a link to this messageThank you so much
Owon AG1012 Function Generator - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: July 02, 2016, 02:51:53 am
content: Hi all, I just ordered an Owon AG1012 Function Generator from Salaig, and I think I ordered the wrong version. I need to be able to sweep between a given frequency range. Does the non "F" version support even basic sweep functions, or will I need to send it back for the AG1012F version? Thanks.

author: MarkF
author_rank: Super Contributor
timestamp: July 02, 2016, 10:35:59 am
content: I've been looking at the 5MHz version for awhile now. But, I really don't have a need for it.From the spec page, the difference is the modulation capabilities. What it lists are: AM, FM, PM, FSK, Sweep and Burst. Which I would take that the non-F model won't do the sweep you want.

author: tony3d
author_rank: Frequent Contributor
timestamp: July 02, 2016, 12:07:55 pm
content: That's what I thought. The is to be delivered this coming Thursday, but the people at Saeileg won't be back till Wendsday due to the holiday.. All I can do is call them, and see if it's possible to have the unit delivery stopped, and sent back, then reorder.
Owon B41T+ connecting to PC? - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: August 17, 2023, 01:21:52 pm
content: This is not my primary multimeter, primary is UNI-T UT61E+. But still I'd love to connect it to PC, see what's up. I did connect it to iPhone, no problem. However with PC I'm having a problem.Dongle is none Owon, but it is bluetooth 5.0 and I can see the multimeter when scanning for bluetooth devices. But I can not connect to it. Installing software and driver does nothing.Who faced this problem? What am I doing wrong?
OWON ODP6033 - "Voltage Leak" - Page 1
Forum section: electronics / beginners

author: dupreezarmand
author_rank: Unknown
timestamp: February 25, 2021, 02:12:14 pm
content: Good day,I recently purchased an OWON ODP6033 Bench Power Supply and it is working well. I noticed the other day, while my power supply was still hooked up to my Electronic DC Load, 2.8mV to 4mV were present at the output of the power supply, with the channel output disabled.If I short out the positive and negative on the power supply then the reading on the Electronic DC Load goes to zero as expected. When I remove the fault, the capacitor (I believe) is charging again and it reaches 15mV and then starts to taper down and eventually reach the 4mV mark.I disconnected the DC Load from the power supply and measured the power supply output terminals directly, and it remains 2.8mV to 4mV.When I enable/disable a channel on the Power Supply I don't hear a relay. I can see there is a bleeder resistor, because the voltage does drop rather quick, until about 15mv.I am going to investigate this over the coming Weekend, but any ideas on what to look out for would be appreciated?Thanks.

author: sahko123
author_rank: Frequent Contributor
timestamp: February 25, 2021, 02:14:33 pm
content: it could be that the output is floating when the supply disables the output and causes the voltmeter to show a few millivolts
owon rds1021 vs owon vds1022 oscilloscope - Page 1
Forum section: electronics / beginners

author: Riaj159
author_rank: Newbie
timestamp: September 04, 2016, 05:04:56 pm
content: I have recently ordered owon vds1022 usb oscilloscope & today i have checked on amazon about " OWON RDS1021 Wave Rambler USB Pen Scope" price.The price have been reduced to 49$ !.As already ordered the " owon vds1022 " one which have cost me 73$ from ebay,now it seems that "OWON RDS1021" might be better choice for me as two channel oscilloscope is not my concern but low price & sampling rate is.Both advertised as 100msps oscilloscope & have almost similar specifications .EEVblog helped me a lot about finding teardown pic of owon vds1022 scope,now i'm interested in teardown pic of owon rds1021 and side by side comparison based on hardware.Also i have seen SainSmart VPO1025 pen scope have used the same pc software as owon's pc software.Can anybody help me about that?thanks in advance

author: Gyro
author_rank: Super Contributor
timestamp: September 04, 2016, 06:37:09 pm
content: I haven't come across the RDS1021 yet, but from what you say it is a 100Msps single channel pen scope. The VDS1022 is 100Msps on both channels at the same time. Given a price difference of only $24 I would go for the VDS1022 every time. I'm sure you would find yourself missing the extra channel very quickly, and a pen type scope is never going to be as easy to hold / attach as a proper scope probe.P.S. It looks as if SainSmart have decided to give up on honest product development and rely on piracy instead. They've already done it to JYE Tech with their little DSO138 scope kit and it now looks as if they're doing the same to Owon. It's clearly getting tougher in China if Chinese companies have started pirating other Chinese companies products rather than western ones.

author: Riaj159
author_rank: Newbie
timestamp: September 05, 2016, 12:49:55 am
content: Thanks for your reply gyro. your OWON VDS1022I Quick Teardown (versus the Hantek 6022be) topic helped me a lot about choosing my 1st oscilloscope .It was a great help for me to know about the internal construction of OWON VDS1022 with those teardown photos you had posted on eevblog , thanks again.Oops! I have totally missed the fact that AD9288 had dual individual ADC in a single chip,so individual channel can achieve 100msps. Thanks for pointing out that fact. now it feels like I choose the best “ bang for the buck ” one

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2016, 01:17:13 pm
content: Glad I could help.
Owon sds7102  and octopus  no clean result - Page 1
Forum section: electronics / beginners

author: J4e8a16n
author_rank: Regular Contributor
timestamp: August 06, 2015, 06:21:51 pm
content: Hi,I tried to use octopus with my Owon and did not get nice results.http://howtoresolved.com/tube/WWY-pakm_OM/197-simple-v-i-curve-tracer-using-an-oscilloscope-and-function-generatorCould using sine, square, or saw wave make a difference?JPD

author: unitedatoms
author_rank: Frequent Contributor
timestamp: August 06, 2015, 06:49:56 pm
content: The guy in your first video link mentions that more correct approach is to use current probe or differential probe, because V channel needs to show V only of DUT without added R*I value of current sense resistor. Without the subtraction of R*I value, the V channel will bring unclear values, not exactly what one may expect from I-V tracer.

author: smpowell
author_rank: Contributor
timestamp: August 06, 2015, 11:37:03 pm
content: >Could using sine, square, or saw wave make a difference?Use a sine wave. A square wave will not work and a saw wave will distort the results if the DUT has capacitance or inductance,Also check to make sure the ground on your test circuit is connected to the scope's ground.However, I suggest that you try the original version of the octopus circuit instead of the one you found. Look at the classic circuit at the top of my old web page:http://web.archive.org/web/20070909022650/http://octopus.freeyellow.com/octopus.htmlReplace T1, R1, and R2 with your sine wave generator.Back in the old days, transformers were common and the only cheap source of sine waves. Now you could use a sine wave generator, MP3 player, or tone generator program on a computer to get whatever frequency sine waves you want to play with.As far as explaining the results, I like an old 1975 magazine article. It starts at page 70 here:http://www.americanradiohistory.com/Archive-Poptronics/70s/1975/Poptronics-1975-08.pdfAlso see:http://www.qsl.net/kd7rem/pdf/octopus.pdf

author: J4e8a16n
author_rank: Regular Contributor
timestamp: August 07, 2015, 02:24:37 am
content: Thank you.https://www.eevblog.com/forum/Smileys/default/clap.gif
Owon SDS7102: How do I use slope trigger? - Page 1
Forum section: electronics / beginners

author: AndrejaKo
author_rank: Frequent Contributor
timestamp: August 24, 2013, 12:27:04 pm
content: Hi!I'm trying to understand how slope triggering works on this oscilloscope (examples for other units are also welcome!).I can't really understand what the manual says about the slope trigger, because it only says the names of the controls and that's about it.From settings, I have basically two important menus:When menu:In it I can select rising or falling slope. Further, I have 3 options marked with > = and <. There's a time value for every option which I can adjust. Now my understanding is that when I select the >, I set the scope to trigger when it takes more than written amount of time to move the signal from the lower value to the upper value. When I select =, it means that it takes that much time exactly and when I select <, it takes less than written amount of time.Threshold&SlewRate menu:I have a High level (T1 on screen) and a Low level (T2 on screen) options to set the voltage. If I understand how this works correctly, this is the place to set the levels which will be used to measure the time set in the When menu.Now my problem: I'm trying to use slew rate trigger with the attached wave. The section I'd like to trigger on rises from -980 mV to 900 mV, so I set the levels in Threshold menu to -980 mV and 900 mV. Next, the time it takes for the wave to rise is 5.6 ns. I don't have that low option, so I choose less than 30 ns in the When menu.Next, I let the scope run and it stays in auto trigger. Single/normal mode will result in to trigger at all.So I switched it from < 30 ns mode to > 30 ns mode and then it triggered on a falling edge of a wave with a very small amplitude! When I switched it from rising to falling edge, it triggered on a rising edge.So did I get the theoretical part correctly and am having a buggy scope or is the problem between keyboard and chair?
Owon SPE3103 on 120V/60Hz - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: February 13, 2025, 07:16:02 am
content: This PSU is for 220V, it says so on the back. I wonder if it can work just fine on 120 volts in the U.S.A.?This is an Owon SPE3103

author: xvr
author_rank: Frequent Contributor
timestamp: February 13, 2025, 11:20:42 am
content: According to manufacturer specification it can't -https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/2884/SPE%20Series.pdfOWON make this PSU in 2 different versions - for 110V and 220V

author: coromonadalix
author_rank: Super Contributor
timestamp: February 13, 2025, 11:23:39 am
content: because some of the input parts are changed to fit 120 or 220 240 vac usage ... unless you do see an ac voltage switch ... or universal ac input modelsyou simple choice would be to add an step down transformer 220-240 to 120 ac, and if the psu dont sync or anything on the ac frequency ?

author: benj38
author_rank: Frequent Contributor
timestamp: February 13, 2025, 08:09:13 pm
content: @coromonadalix, I think you reversed things by mistake. He needs a 120V to 200-240V step-up transformer.Frequency is not an issue since the label on the PSU clearly states 50-60Hz.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 14, 2025, 01:52:38 am
content: my bad loll on some xformer just reverse the connection
Owon VDS 1022i - Page 1
Forum section: electronics / beginners

author: shobo
author_rank: Regular Contributor
timestamp: September 07, 2021, 01:45:57 pm
content: i would like to buy a scope for some light hobby use.Since i'm a sub for Mike Harrison(mikeselectricstuff) i have seen that he took apart a VDS series scope and he didn't seem put off by it.Is it worth the money?currently 78 euros on amazon DE, but i have a 30 euro gift code from work, so basically 48.

author: Gyro
author_rank: Super Contributor
timestamp: September 07, 2021, 09:54:36 pm
content: Here's the 'main' VDS1022(i) thread. Hopefully it will give you all you want to know to make a decision...https://www.eevblog.com/forum/testgear/owon-vds1022i-quick-teardown-(versus-the-hantek-6022be)/At 48 eur it's probably a no-brainer.
Owon VDS1022i Max Input Voltage  - Page 1
Forum section: electronics / beginners

author: ksat44
author_rank: Contributor
timestamp: July 07, 2022, 03:42:11 am
content: Just picked up this USB scope isolated model and noticed in the specs (see screenshot) it says the max input is 400V peak to peak. Does this mean it can handle that amount on the 1X attenuation?

author: rsjsouza
author_rank: Super Contributor
timestamp: July 07, 2022, 07:29:50 am
content: Despite the specifications mention the 400V peak-to-peak, they are only attainable with a 10x probe (this is clarified on the help document of the BDS_C2 software).Also, the software only has a 5V/div on 1x attenuation, thus measuring only up to 40V on the input.Just keep in mind the inputs are not isolated between them, so be extra careful if measuring anything higher.

author: ksat44
author_rank: Contributor
timestamp: July 08, 2022, 08:35:11 am
content: Thank you very much for the replyCould you expound a bit on what you said regarding the non-isolated inputs of the VDS1022i. As I understand the term, this means there's a common ground (continuity) between the 2 channels and therefore when using both channels simultaneously, both test lead probe grounds should be at the same potential when taking a measurement.

author: rsjsouza
author_rank: Super Contributor
timestamp: July 08, 2022, 10:48:25 am
content: Yes, you are absolutely correct. Always keep the same potential on the ground leads of the probes.
Owon, Victor, Multicomp Pro (perhaps others?) - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: May 23, 2023, 01:59:12 pm
content: I was looking at this oscilloscope Owon HDS2202S and I come across similar oscilloscopes one by Victor and another one by Multicomp Pro.They are apperantly the same thing, more or less. Victor has crappier specs tho.Here is the question.What is the main company and who are clones?

author: tunk
author_rank: Super Contributor
timestamp: May 23, 2023, 02:24:06 pm
content: Owon makes these.There's also the Hanmatek HO102 and HO52 which probably are Owons in a new case.

author: barshatriplee
author_rank: Regular Contributor
timestamp: May 23, 2023, 02:24:51 pm
content: Owon is a good brand. Victor sells cheaper meters.
Oxygen 61 v1 Slider problems - Page 1
Forum section: electronics / beginners

author: SEGACDX
author_rank: Newbie
timestamp: November 12, 2012, 02:41:15 pm
content: So I picked up an Oxygen 61 V1 Midi keyboard for 50 bucks off of craigslist quite the deal.But the catch was it had a sustain pedal problem, but on further inspection I found out that the F1 Slider was not working.I don’t really need a sustain pedal at this point but I don’t think it’s really broken I think the F1 Slider was causing an interference with the midi inputs.When I turn it on it goes from 127 to 64 then stops I thought it was the sustain pedal but later not realize this is the F1 slider causing the problem.When you move the slider nothing happens I can seem to get any response from it.Poking around with a very sketchy DIY meter I made told me that there is not voltage going to it and every other one that work had voltage I don’t know how much since I have such a basic meter it only tells me if there is any voltage flow.I thought if I replaced the ceramic cap and F 104 it would fix the problem but it did not.I’ll upload some Images of the board that I’m trying to fix and maybe someone could give me an opinion on what may be the problem.I’m sorry this is so long and drawn out but I am very tired and have spent a long night fiddling with electronics.Here is a link to those images of the board.http://www.mediafire.com/?k5k659cvxi1vxjlAfter a bit more poking around I found out that the slider was the problem so not I have to find a replacement for it.Its model number is 822c-10KB.Here are some images of the sliderhttp://www.mediafire.com/?1rxkuci1378rh8eDoes anyone know where I would be able to find a replacement part online or anywhere for that matter?

author: marinedalek
author_rank: Contributor
timestamp: November 13, 2012, 06:30:26 pm
content: After a quick look at google, it seems most people contact M-Audio and purchase spares direct from them. On the other hand it may be possible to locate a compatible replacement. 10KB means that the pot has a maximum resistance of 10k? and has a linear taper (i.e. when the slider is in the centre position, the resistance between the centre tap and either end measures 5k?). To find a replacement a few measurements (in mm) would be useful:1. The travel of the slider. This is the distance between the middle of the slider knob at its lowest setting, and the middle of the knob at its highest setting.2. The pin pitch. This is the distance between the pins at opposite ends, and between the two pins at one end.2. The size of the metal lever. This is the thickness of the metal as well as the width and height of the lower and upper sections (notice how it is split in half with a narrower section on top).
P 203 trimpot - Page 1
Forum section: electronics / beginners

author: RacerDave
author_rank: Newbie
timestamp: January 07, 2020, 06:27:50 pm
content: I am trying to find a alternative potentiometer to the p203. I need it to be a direct replacement as far as size and hookup but needs a shaft on it for knob. I was going to modify them by adding a shaft but would rather find them made the way I need them as there is a lot of them and they have to not break off. If anyone can help it would be greatly appreciated before I start to modify these.Thanks,Dave

author: wraper
author_rank: Unknown
timestamp: January 07, 2020, 06:30:26 pm
content: No info whatsoever on what original trimpot is or what is that mysterious p203 to begin with.

author: RacerDave
author_rank: Newbie
timestamp: January 07, 2020, 06:35:53 pm
content: I found a p103 that may work in its place.

author: wraper
author_rank: Unknown
timestamp: January 07, 2020, 06:43:45 pm
content: Quote from: RacerDave on January 07, 2020, 06:35:53 pmDid you mean P203 as resistance marking? in that case you want to replace 20k with 10k.
P-Ch E MOSFET replacement - Page 1
Forum section: electronics / beginners

author: trondl
author_rank: Regular Contributor
timestamp: September 07, 2023, 10:14:19 am
content: Hi!I'm a noob when it comes to finding transistor equivalents / replacements.We have a light fixture where the Gobo (effects) card has two shorted transistors:One NPN ZXTN2010 where I found the exact same and a MOSFET ZXMP6A16.I only found a ZXMP6A18available.The CAN bus communicating circuit is used to control some "smaller" step motors and reading optical sensors with an on board MCU.Is the ZXMP6A18 just a newer beefier version of ZXMP6A16 and is in this case a drop in replacement?Datasheets included.Thanks in advance!

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 07, 2023, 11:05:45 am
content: It's slighly slower and has higher capacitance, but will probably work just fine.Do you know what these fets do in the circuit?

author: trondl
author_rank: Regular Contributor
timestamp: September 07, 2023, 01:01:17 pm
content: There is only one of them on this PCB, and the PCB is referred to as "Motor driver low power".It is controlling 8 step motors through DRV8844 drivers, 8 sensors, CAN bus and 2 blower fans of smaller size.The board is fed 24V DC, and it has very low resistance from the +24V to the Sink pin.Should the capacitance cause concern?

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 07, 2023, 01:07:15 pm
content: Only if switching at very high speeds, which doesn't seem the case.I'd try them right away.

author: CaptDon
author_rank: Super Contributor
timestamp: September 07, 2023, 01:10:09 pm
content: I noticed you said CAN Bus control. Do the mega expensive pro lights use CAN as opposed to DMX control? I've been involved with some pro gear but it was all DMX. I did locomotive control circuits for years and I hated CANBUS. It never worked well on locomotives. CAN features some data rates of a few MHz but we had trouble with capacitance and cable lengths even at 500KHz. It was unstable in 65 foot cable runs. Ethernet just worked better. Fiber optic at the time suffered degradation from the sulfur in the diesel fuel and wasn't allowed on locomotives.

author: trondl
author_rank: Regular Contributor
timestamp: September 07, 2023, 01:33:01 pm
content: Quote from: CaptDon on September 07, 2023, 01:10:09 pmInternal communication between the modules is CAN, DMX is from main MCU to external although Ethernet is in this case also an option.DMX is the default protocol when it comes to lights and such.

author: trondl
author_rank: Regular Contributor
timestamp: September 08, 2023, 10:56:21 am
content: Quote from: DavidAlfa on September 07, 2023, 01:07:15 pmIt worked perfectly!Thanks a bunch for the guidance.Only the long run tests in real situations remain.
P Channel Mosfet - Page 1
Forum section: electronics / beginners

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 03, 2020, 12:24:21 pm
content: Hi everyone,Could someone explain me how the P channel Mosfet at this circuit works?When it is supposed to be ON and when it is supposed to be OFF?I suppose that this is to distinguish and prioritize the two voltage domains VBUS and VBAT but I cannot see how it is works.Thanks in advanceNick

author: dietert1
author_rank: Super Contributor
timestamp: June 03, 2020, 01:25:54 pm
content: First of all the mosfet is a diode, so the input can receive current from both the bus and the battery. When the bus has no/low voltage, the p-channel mosfet will turn on and shorten out the diode voltage drop. When the bus has voltage comparable or higher than battery, the mosfet and its diode will both be off.Regards, Dieter

author: Peabody
author_rank: Super Contributor
timestamp: June 03, 2020, 02:08:53 pm
content: This is a standard "load sharing" circuit. If USB is not plugged in, the gate pulldown resistor will bring the gate low, and that turns on the mosfet so the battery can provide power to the regulator. But if USB is active, it will bring the gate high, which turns off the mosfet. The orientation of the mosfet permits its body diode to block current from flowing from VBUS back into the battery, which would overcharge it. D1 is there to block the battery from trying to power whatever else might be connected to VBUS, such as a battery charger. In fact, you could have an upstream battery charger powered by VBUS, and this circuit would let VBUS charge the battery to termination while also powering the load.When VBUS is active the mosfet's body diode will not pass current from the battery because the voltage at its source terminal is greater than the battery's voltage, so the diode is reverse biased.With this circuit, VBUS will always power the regulator when it's plugged in. When it isn't, the battery will take over, and the voltage drop though the mosfet will be very small, which maximizes battery life. You could just have another diode there in place of the mosfet, and that would work the same way (the highest voltage input source would always power the load), but there would be a voltage drop across the battery diode. The mosfet just eliminates almost all of the voltage drop so you don't waste battery power generating heat.

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 03, 2020, 03:38:45 pm
content: Thank you guys!! Now I can see clearly how it works!!Quote from: Peabody on June 03, 2020, 02:08:53 pmGreat explanation, thanks!!
P-Channel Mosfet Gate Drive - Page 1
Forum section: electronics / beginners

author: smssk
author_rank: Newbie
timestamp: January 10, 2024, 12:35:18 am
content: Mosfets are fairly new to me. Will it be ok driving a DMP3125L-7 directly from 12v? I am trying to automatically switch +MCU_V between the buck converters 3.2v output and a lipo when +12v is connected. I will be drawing less than 100ma from +MCU_V.Also does anyone see any other issues with my circuit? Is 100K a reasonable value as a gate pulldown?The TPS560200DBVR datasheet does specify to leave EN floating to Enable.DMP3125L-7 Max\Min RDS ON According to digikey: 4.5V, 10Vhttps://www.diodes.com/assets/Datasheets/DMP3125L.pdf

author: inse
author_rank: Super Contributor
timestamp: January 10, 2024, 05:52:56 am
content: Flip drain and source of the FET, don’t exceed 20V gate/source and everything should be fine

author: eTobey
author_rank: Super Contributor
timestamp: January 10, 2024, 06:39:23 am
content: Here is something to play around with to learn:http://www.falstad.com/circuit/

author: smssk
author_rank: Newbie
timestamp: January 10, 2024, 10:22:11 am
content: Quote from: inse on January 10, 2024, 05:52:56 amThanks. Swapping the source and drain makes sense to me but I may still be misunderstanding some fundamentals.I keep finding examples where the source and drain appear to be swapped. Is there an error in the attached schematic or am I missing something? Is the battery connected to drain in this example?

author: liaifat85
author_rank: Regular Contributor
timestamp: January 10, 2024, 10:27:35 am
content: I can see that the Gate-Source Voltage is ±20 V. So, 12V direct input shouldn't be a problem.https://www.diodes.com/assets/Datasheets/DMP3125L.pdf

author: RFDx
author_rank: Regular Contributor
timestamp: January 10, 2024, 02:14:17 pm
content: Quote from: smssk on January 10, 2024, 10:22:11 amYes, the battery is connected to the drain of the PMOSFET because, contrary to your circuit, the voltage of the USB power supply is higher than the battery voltage.Without 5V from USB, the transistor gate is grounded, the PMOS is switched on (ideal diode) and the load is supplied from the battery. With USB connected, the PMOS transistor is off and the load is supplied with ~4.6V (5V minus the voltage drop of a Schottky diode). The body diode of the PMOSFET is not conducting because the output voltage (~4.6V) exceeds the voltage of the (fully charged) battery.

author: Peabody
author_rank: Super Contributor
timestamp: January 10, 2024, 03:24:34 pm
content: +1. If the mosfet were oriented "normally", the high external voltage could pass through the body diode back to the battery, which you defintely don't want. The orientation used in load sharing prevents that. But the mosfet still functions properly as a switch because, as @RFDx says, the body diode is reverse biased when the high voltage is present, so no current flows through it.Here's an app note:http://ww1.microchip.com/downloads/en/AppNotes/01149c.pdf
P-Channel mosfet gate zener clamp protection - Page 1
Forum section: electronics / beginners

author: Heisen
author_rank: Contributor
timestamp: June 24, 2023, 06:07:42 pm
content: Hello everybody,Based on this appnote from TI.https://www.ti.com/lit/an/snva717/snva717.pdfI want to understand how does the gate clamp protection works here, or most importantly why is it needed in this case?As I understand it, the voltage at gate in this case is always going to be slightly lower than the voltage at source of the P-FET, even in overvoltage condition. It is never going to exceed the typical +/- 20V maximum gate to source voltage. So why they added zener diode as gate clamp?Obviously I am missing something here.Attaching the LTspice simulation.I tested with various input voltages, the D3 is never clamping anything because the voltage at gate is never going beyond the zener voltage.Thanks.

author: ledtester
author_rank: Super Contributor
timestamp: June 24, 2023, 07:48:12 pm
content: It is very helpful to the rest of us to also post the LTspice .asc file.(Edit: OK - I just had trouble myself uploading an .asc file - had to change it to a .txt file.)I reconstructed your test circuit and determined that D3 does clamp for a small range of input voltages but then the over-voltage protection diode D2 takes over. This is because both zeners have the same breakdown voltage. See the attached I(D3) vs I(D2) graph below.I guess the point is this... D3 should be selected to protect the P-FET, ie it is selected based on the max Vgs of the P-FET. D2 is selected to provide the application specific overvoltage protection limit.

author: Heisen
author_rank: Contributor
timestamp: June 24, 2023, 09:05:35 pm
content: Quote from: ledtester on June 24, 2023, 07:48:12 pmThis is it, you are spot on, I changed the D3 to 12v zener and the D2 remain 16v zener as overvoltage setpoint and while the input voltage was between 12v to 16v the Vgs remained clamped at 12v.So I guess it's suffice to say that when the overvoltage set point is below the max Vgs of the P-FET, the D3 zener is not needed. Correct?

author: ArdWar
author_rank: Frequent Contributor
timestamp: June 26, 2023, 03:39:17 am
content: Quote from: dobsonr741 on June 26, 2023, 03:32:49 amNot really.You connect the PMOS in "forward" direction if you want an ideal diode or polarity protectionYou connect in "reverse" direction if you want a load switch or surge limiter/disconnect, which is the case here. This is typical ISO 7637-2 surge limiter.
P-channel mosfet to switch power to Lolin/Wemos D1 Mini - Page 1
Forum section: electronics / beginners

author: Peabody
author_rank: Super Contributor
timestamp: October 31, 2019, 05:30:26 pm
content: I'm doing my first WiFi project. It's a mailbox notifier using the ESP8266 Wemos D1 Mini. The power circuit (see pic) uses a magnetic reed switch to ground the gate of a P-channel mosfet when the door is opened, then the processor brings GPIO pin D2 high to turn on an NPN transistor, which continues to ground the mosfet gate after the door is closed. Then when the notification has been sent, the Mini switches its power off.During transmit there are pretty large current spikes - well over 100mA. I know the regulator in the D1 Mini will have trouble supplying those spikes, so per a video by Andreas Spiess on powering the ESP8266, I've added a 1000µF cap to the 3.3V pin.But in testing out the circuit, I connected my battery powered scope across the switching mosfet, and found that the voltage across it reaches as high as 0.4V during the spikes. The LM0701 I'm using has a couple ohms RDSon, which I think is clearly too much for this situation. So I'm looking for a replacement with much better RDS values. I've been unable to find anything in a TO-92, but in surface mount I've found the IRLML6401. This is the 12V version of the 20V IRLML6402 that seems to be popular, with a bit better gate threshhold and RDS numbers than the 6402. Power is coming from either an 18650 or three AAs, so 12V should be plenty.Would this be a good choice? Does a better one come to mind? The only thing that's unusual about this project is that it will be subject to temperature extremes. The circuit will turn on for only about 20 seconds twice a day, and the power will be off the rest of the time. But, you know, it could be pretty hot, or cold, in the mailbox.The other issue is how to deal with the brick-enclosed mailbox as far as WiFi is concerned. But I probably should ask about that in another thread.
P-Channel MOSFET - Page 1
Forum section: electronics / beginners

author: Savetheday
author_rank: Regular Contributor
timestamp: January 13, 2016, 09:21:56 pm
content: Hi everyoneI was trying to fix my tft Philips 190v7 screen but I blowed with accidentally component (Q405) AO3401L SOT23. Instead of AO3401L What kind of P-Channel MOSFET can I also put it same place?http://linfotech.co.uk/schematics/Philips/Philips%20190v7.pdfhttp://doc.chipfind.ru/pdf/aosmd/ao3401l.pdfThanks.

author: mich41
author_rank: Regular Contributor
timestamp: January 14, 2016, 12:11:24 pm
content: I think TO92 wouldn't be that hard to solder in place of SOT23 if you are desperate

author: Ian.M
author_rank: Super Contributor
timestamp: January 14, 2016, 12:53:38 pm
content: The L suffix is lead-free, not important for a DIY repair.Digikey stocks theAO3401A, which has a compatible pinout and near enough the same specs.

author: Savetheday
author_rank: Regular Contributor
timestamp: January 15, 2016, 03:40:27 am
content: I checked ebay for thatI found with near specificationsSI2301 DS-T1, P-Ch. MOSFET 20V/2.8A, SOT-23(E0928)IRLML2502 International Rectifier MOSFET 20V 4,2A 1,25W 0,045R SOT-23 8557055 IRF7316 International Rectifier MOSFET Transistor 30V 4,9A 2,0W 0,058R 8541882 x IRLML2803 N-channel SMD Power MOSFET 30V Internati SOT-23 2pcsWould it be any differents? Which one do I have to choice? What is the differents between N and P channel ? And I mean this 12v provided tft screen.Why should I need 30V and 4A current?By the way I have some old boards and I think There is some kind of smd transistor on it.But transistors dont have that much informations on it.Is there any easy way to figurout what kind of component are they. May I take picture and put it here?Thanks

author: Savetheday
author_rank: Regular Contributor
timestamp: January 18, 2016, 11:08:35 pm
content: Here are they
P-I-D Controller from a data set. - Page 1
Forum section: electronics / beginners

author: firewalker
author_rank: Super Contributor
timestamp: October 17, 2018, 08:24:08 pm
content: Is there an easy way to select the gross values for a PID controller from a data set? The following data are from a soldering iron. Degrees Celsius vs Time in seconds.Alexander.

author: CM800
author_rank: Frequent Contributor
timestamp: October 17, 2018, 08:27:55 pm
content: Have a look here:https://en.wikipedia.org/wiki/PID_controller#Manual_tuningThis should provide you all the information you need to know on how to do so!
P-MOSFET reverse polarity protection - Page 1
Forum section: electronics / beginners

author: PerranOak
author_rank: Frequent Contributor
timestamp: September 14, 2018, 11:49:50 am
content: I've just seen a YouTube vid (Afrotechmods) using a p-channel MOSFET as a reverse polarity protector.The theory being that, in the forward mode, the power loss is less than any diode.I was going to use a Zener as both a reverse polarity protector and an over-voltage protector (when the power is connected the right way).Is there a way to use a "device" to do the job of the Zener but with the low power dissipation of the MOSFET?Thanks.

author: cbc02009
author_rank: Regular Contributor
timestamp: September 14, 2018, 12:05:41 pm
content: Quote from: PerranOak on September 14, 2018, 11:49:50 amIf you're looking for a MOSFET solution specifically, I've seen MOSFET controllers like the LTC4365 that drive a mosfet (or a pair of them) to protect against over voltage. You set the voltage limits with a resistor divider.

author: PerranOak
author_rank: Frequent Contributor
timestamp: September 14, 2018, 02:16:12 pm
content: Cheers.No, anything will do just with cheap parts and without wasting loads of power.
P to P measurements with an RMS meter? - Page 1
Forum section: electronics / beginners

author: Axtman
author_rank: Regular Contributor
timestamp: March 13, 2014, 03:48:04 am
content: How can I measure peak to peak voltage with an RMS multimeter?

author: w2aew
author_rank: Super Contributor
timestamp: March 13, 2014, 12:14:48 pm
content: The answer is - you really can't. IF the signal you are measuring is a sinewave that is within the frequency range of your RMS voltmeter, then you can calculate the peak to peak value by multiplying the RMS voltage by 2.828.

author: ConKbot
author_rank: Super Contributor
timestamp: March 13, 2014, 12:15:51 pm
content: If its a sine wave youre measuring, mulitply by 2*sqrt(2), or 2.8284. For RMS to Vpeak its RMS*sqrt(2) but since you want peak-peak, its 2x that.If its not a sine wave, then make a voltage doubler,(the transformer in the image is the AC source, substitute with whatever you want to measure) and add ~0.6 to 1V for the voltage dropped over the diodes. The drop would nominally be 1.4V for the 2 diodes, but with no load being drawn, then the Vf of the diodes will drop a lot.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 13, 2014, 12:25:31 pm
content: Some true RMS multimeters have a 'Peak" feature, giving you peak to peak values.Here is an example: (the 71B meter on the left was defective)

author: ttp
author_rank: Regular Contributor
timestamp: March 14, 2014, 05:45:13 am
content: Nice to know, I got 71D.
Pace ads200 or Hakko fm- 2032 micro pencil? - Page 1
Forum section: electronics / beginners

author: wadmancpu
author_rank: Contributor
timestamp: September 05, 2019, 04:43:26 am
content: Hello, I currently have the pace ads200, which I love, but I'm windering if getting a hakko station with the fm-2032 micro pencil would be better for microsoldering. Is the fm-2032 really any better than the iron that comes with the ads200? Thanks!

author: Cliff Matthews
author_rank: Unknown
timestamp: September 05, 2019, 06:41:33 pm
content: Here's 10-cents.. Pace tips are low cost, last longer, you have short grip-to-tip, and you'll be able to use the MT-200 tweezers with the base unit.

author: wadmancpu
author_rank: Contributor
timestamp: September 05, 2019, 07:13:34 pm
content: Thanks Cliff. I appreciate the input and after some further research I completely agree. I do have the hakko mini parallel tweezers and I love em although like most hakko stuff it was overpriced. I considered the pace tweezers but decided the hakko would be a better fit for me. At this point I don't see any advantage at spending the cash on the hakko micro pencil.
Pace soldering iron compatible handpiece - Page 1
Forum section: electronics / beginners

author: Mad Professor
author_rank: Regular Contributor
timestamp: September 18, 2016, 10:47:22 am
content: Hi All.I have recently acquired a freePace 30E Soldering Base Station.I only have the Base Station, I do not have any of the accessories, eg, handpiece, stand, tips (cartridges), etc.Looking on sites, such as RS and Farnell, it seems that the Pace TD-100 handpiece costs in excess of £100.The tips (cartridges) are from as little as £6.00Can anyone advice if they know of any TD-100 compatible handpiece's that are cheaper?Thanks for your time.

author: chris_leyson
author_rank: Super Contributor
timestamp: September 18, 2016, 12:01:07 pm
content: Never seen a cloned Pace handpiece, I think the one you were looking at may come with a stand as well at that price. The standard tips don't seem to be that good with lead free solder and I've had much better wetting performance with the diamond loaded tips.