hybridfree/eevblog-posts huggingface dataset:
Difficulty soldering pin header to LCD - Page 1
Forum section: electronics / beginners

author: SpareFag
author_rank: Contributor
timestamp: June 27, 2022, 05:13:18 pm
content: Hello,I'm trying to use a 60W soldering iron to solder a pin header to a LCD, but I can't manage to melt the solder. When the solder is in direct contact with the soldering iron, it has no problem melting, but when I heat the pin and the "hole", then apply the solder without touching the iron, nothing melts, no matter how long I heat.I followed many video tutorials, including Dave's, but maybe I'm missing something. Does the iron have to be in contact with the solder during the procedure?

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2022, 07:39:00 pm
content: Watch this video series, it’s hands down the best soldering tutorial I’ve ever found, and is well worth the time:https://youtube.com/playlist?list=PL926EC0F1F93C1837In electronics soldering, we basically always operate at the very brink of the melting point. The idea is: “iron in, solder in, solder out, iron out” in that order, within 2 or 3 seconds for a typical joint. The timing takes practice. The videos above demonstrate it beautifully.Assuming your iron is set to the right temperature, and you’re using a tip that’s appropriately sized for the job, my hunch is that your tip is too “dry”: you still want it to have a little tiny cushion of molten solder on it, which acts as a thermal bridge. Without that, it’s extremely hard to get good thermal conductivity to the joint.

author: SpareFag
author_rank: Contributor
timestamp: June 27, 2022, 07:44:28 pm
content: I forgot to mention that I melt some solder onto the tip beforehand, and I follow the “iron in, solder in, solder out, iron out” tempo, but still, the solder won't melt unless it's in direct contact with the iron, and even then, it sticks to the iron without covering the pinhole.

author: MikeK
author_rank: Super Contributor
timestamp: June 27, 2022, 07:45:25 pm
content: As mentioned, a little bit of solder on the tip - as well as using flux - will help with heat transfer. If what you're heating up has a lot of mass your iron may not be able to heat it up enough to melt solder...though unlikely if it's just a header and a pad. Check for anything pulling heat out of your joint.

author: MikeK
author_rank: Super Contributor
timestamp: June 27, 2022, 07:46:12 pm
content: A photo of your sitution may help.

author: Ian.M
author_rank: Super Contributor
timestamp: June 27, 2022, 08:03:19 pm
content: + a close up photo of your soldering iron bit (tip). *MOST* hand soldering problems here seem to be due to bits without enough copper CSA to give a good thermal path to the working face, or in poor condition so the solder doesn't wet them to form a thermal bridge to the joint.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 27, 2022, 09:08:50 pm
content: The OP said it is a 60W iron. My slightly larger 80W iron can be used for soldering tinned ducts with leaded solder.I do agree a picture would help. Although the iron may melt the solder,does its tipwetwith the solder?
digi-key  - Page 1
Forum section: electronics / beginners

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: February 10, 2014, 04:31:08 pm
content: uh noob here againi am purchasing from digi-key how do i do that what's this standard -extended price thing i just want to make sure (sorry)http://www.digikey.com/product-detail/en/C503B-BCN-CV0Z0461/C503B-BCN-CV0Z0461-ND/1922945

author: Falcon69
author_rank: Super Contributor
timestamp: February 10, 2014, 04:34:18 pm
content: it just means that if you order 100,000 pieces, then the extended price is what is the total cost for all of those, but you have shipping on top of that.The unit price is given so you can see what price break per unit you will receive when ordering in the quantity to the left of it.

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: February 10, 2014, 04:36:52 pm
content: oh ok i thought extended would mean shipping (lol) thanks you so much

author: casinada
author_rank: Frequent Contributor
timestamp: February 10, 2014, 04:50:25 pm
content: Depending on the quantity you want to purchase the price will change. In your case I assume you want to buy small quantities (less than 1000 LEDs)so the price is $0.21 per LED. If you buy 1000 to 49999 LEDs, the price per LED will drop to $0.162, etcMake sure you make a decent size order otherwise the cost of shipping + tax will make the cost of the LED more expensive than to buy it at Radio Shack.

author: electronics man
author_rank: Frequent Contributor
timestamp: February 10, 2014, 06:09:44 pm
content: its something you probably dont need to worry about

author: Rerouter
author_rank: Super Contributor
timestamp: February 11, 2014, 01:46:25 am
content: equally if your buying passives in bulk it will likely be cheaper to use element 14 (farnell) as for a few of my projects its been 10+cents on digikey and 1-3c on element 14though active devices and capacitor brands are better on digikey, which lead to my last project being only 13c cheaper on digikey for a 60 part long BOM,

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 11, 2014, 04:47:05 am
content: Quantity x Price = Extended priceone look at the those columns should make that pretty obvious
Digikey wont  sort inductors by dotted/undotted? - Page 1
Forum section: electronics / beginners

author: Faringdon
author_rank: Super Contributor
timestamp: July 19, 2021, 05:40:28 pm
content: Hi,Why wont digikey allow sorting of offtheshelf inductors as dotted/undotted?ie, the dot to indicate which end to connect the switching node of an SMPS. (to reduce radiated emissions)

author: Terry Bites
author_rank: Super Contributor
timestamp: July 19, 2021, 05:58:15 pm
content: Why? Because its up to the manufacturers to mark their products.So refer to datasheet. Or trial ane error.It only affects the directional component of the EM interference so its more about your PCB layout than the particular polarity.
Digilent AD3 and Righol DHO804 reading I2C easy on AD3 challenging on DHO804 - Page 1
Forum section: electronics / beginners

author: glenmann
author_rank: Newbie
timestamp: July 08, 2024, 02:51:36 pm
content: Dave J. did a great job convincing me to invest in Digilent's AD3 and Rigol's DHO804 for my son's new EE lab at home. Both are outstanding value IMHO.To guide my "EE in training", I decided I2C would be a fun way to introduce him to board level communications.The issue I am having is the AD3 does an excellent job of generating/decoding I2C right off the start. The Rigol, is a head scratcher. I know it can be done because this post shows me what I am trying to arrive at.https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/450/Can someone direct me to an article/video on how to setup the Rigol DHO804 to decode the I2C? I know I have good I2C signals, because the AD3 shows me the self generated signals and I can connect it to an Arduino we set up to populate a 4x20 LCD with I2C. I even put 4.7K pull up resistors on the Arduino I2C to ensure I have sufficient signal, but the Rigol refuses to reveal the I2C decoded signal from the AD3 generated I2C or the Arduino.Thanks in advance.Cheers, Glen

author: rstofer
author_rank: Super Contributor
timestamp: July 08, 2024, 07:52:08 pm
content: I2C is a tough protocol mainly because of the Start condition and this is what you need to trigger on. The scope will do the work if you get all the parameters correct and the manual gives a step-by-step example. Try their approach first...https://www.batronix.com/files/Rigol/Oszilloskope/DHO800/Manual/DHO800_UserGuide_EN.pdfDocument page 177, pdf page 191 and onward...

author: RogerG
author_rank: Regular Contributor
timestamp: July 24, 2024, 01:53:34 pm
content: @glenmann:Please be aware that there's a bug at serial decoding at DHO800/900. You always have to set a 1x probe multiplier for both used I2C channels, even when your probes are at 10x (what they normally should be). Maybe this helps to solve your problem.We all hope that Rigol is coming soon with a big FW update to solve (most of) the pending problems.
digilent digital discovery high speed logic probe - Page 1
Forum section: electronics / beginners

author: metebalci
author_rank: Frequent Contributor
timestamp: January 05, 2022, 05:39:22 pm
content: The high speed logic probes (1) have a 100 ohm resistor in series in signal line. What is the purpose of that ?1)https://digilent.com/reference/_media/reference/test-and-measurement/digital-discovery/250-104_dp_2.54_3.pdf
Digistump - Page 1
Forum section: electronics / beginners

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 22, 2017, 04:19:52 am
content: Wasn't sure how to repost it so shared link hope that is okayDigistumphttps://r.tapatalk.com/shareLink?share_type=t&share_fid=25658&share_tid=97237&url=http%3A%2F%2Fwww%2Eeevblog%2Ecom%2Fforum%2Findex%2Ephp%3Ftopic%3D97237Sent from my iPhone using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: October 22, 2017, 05:05:25 am
content: <expletive> tapatalk!I've seldom seen a link as badly FUBARed.I *THINK* you were trying to link to your posthttps://www.eevblog.com/forum/repair/digistump/. You'd be better off typing links manually using BBCODE url tags rather than letting tapatalk mangle them through a redirect.;While we are discussing what could be done better, *PLEASE* use a plain white background (e.g. a sheet of paper) when photographing boards etc. A patterned background significantly increases the image file size with no benefits to anyone. Normally I'd say crop the extraneous background, but that can be difficult on a mobile device, so at least make sure you've used macro mode and zoom to get the board filling as much of the frame as possible without getting so close its out of focus.

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 22, 2017, 05:09:22 am
content: Thank you so much I appreciate your feedback I'll update pics nowSent from my iPhone using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: October 22, 2017, 05:55:59 am
content: Back off a little - you are getting some blur and the distortion and clipping in the corners is excessive. Its pretty hard to tell on a phone so maybe have a practice session when you can view the result fullscreen on a PC. However otherwise its a good effort and the new pics are immediately usable without having to open them in a new tab and zoom in on them.
Digital Ammeter from Ebay? - Page 1
Forum section: electronics / beginners

author: geratheg
author_rank: Regular Contributor
timestamp: December 16, 2014, 02:24:51 am
content: Hello does anyone have experience with digital ammeters from ebay?I'm thinking about getting one like this:Digital AmmeterWill it be appropriate for it to be powered by the same power source that powers the circuit from which this ammeter will be measuring?If anyone has experience I hope you can throw some tips in on use and calibration and such.Thanks!

author: cpt.charlie
author_rank: Contributor
timestamp: December 16, 2014, 10:37:50 pm
content: Most cheap digital ammeters need a separate power supply.

author: liquibyte
author_rank: Frequent Contributor
timestamp: December 17, 2014, 12:52:22 am
content: I just ordered two that are similar to this (0-100V 0-10A). You have to power them from a separate source, 4-30V in my case but these look exactly the same except for the current shunt.

author: G7PSK
author_rank: Super Contributor
timestamp: December 17, 2014, 09:22:10 am
content: As long as the voltage of the circuit is within the rated voltage of the meter you can power them from the same circuit. I have done this on my wife's power chair so that I have an idea of how the batteries are performing not sure how accurate they are for a check on a couple of 50 Amp hour lead acid batteries they are more than good enough reading within a 100th of a volt of each other and a couple of 100ths of a volt of my test meters.
Digital Chirp signal BW - Page 1
Forum section: electronics / beginners

author: mr_byte31
author_rank: Regular Contributor
timestamp: July 19, 2024, 05:35:21 pm
content: Hi Folks,I have a pulsed signal and I would like to measure the BW of the high power frequencies in it as shown in figure below. The shortest pulse shall be in 100 us.I will build a circuit and will use a microcontroller for that.The signal looks like a chirp signal but somehow in digital fashion with DC offset. I can see the frequency of the signal increase with time so I called it digital chirp signal. I don't know if it has a scientific name or not !I thought of the following techniques:collect samples via ADC and use FFT to figure out the high power frequencies and measure the BW.use pulse discriminator to figure out the positive edges and measure the time between themuse zero crossing circuit and measure the time as point aboveuse PLL and measure the voltage before the VCO to figure out the frequency rangesis there a simpler or more recommended solution for such problem statement ?

author: radiolistener
author_rank: Super Contributor
timestamp: July 19, 2024, 06:07:32 pm
content: You can measure rise or fall time (which is more fast) with oscilloscope and then calculate bandwidth:BW_MHz = 350 / rise_time_nsBut oscilloscope needs to have high enough bandwidth, otherwise oscilloscope bandwidth will limit your measurements.
Digital Circuit Simulator - Page 1
Forum section: electronics / beginners

author: bearded_badger
author_rank: Contributor
timestamp: May 06, 2016, 10:38:48 am
content: Hi forum, I was wondering what a currently developed digital circuit simulator software for Windows (for a beginner) would be? I started using CEDAR but it crashes with a simple circuit.

author: danadak
author_rank: Super Contributor
timestamp: May 06, 2016, 01:47:59 pm
content: The FPGA guys offer low end versions of Modelsim in their basic tools, like Altera, Xilinx.But learning curve not simple to get setup and running for first time user.Regards, Dana.

author: Lee Leduc
author_rank: Regular Contributor
timestamp: May 06, 2016, 02:58:20 pm
content: Have a look at Logisim. To quote the web page, "Logisim is an educational tool for designing and simulating digital logic circuits."It' free and available athttp://www.cburch.com/logisim/You can download a Beginners tutorial and the documentation to see if it's what your after.http://www.cburch.com/logisim/docs.html

author: bearded_badger
author_rank: Contributor
timestamp: May 06, 2016, 11:30:12 pm
content: Thanks I'll look into both.

author: dentaku
author_rank: Frequent Contributor
timestamp: May 07, 2016, 01:18:59 am
content: Yes, Logism is the nicest free logic simulator I have used.If you're looking for a simple non-free program, I like using Circuit Wizard for simulating circuits with logic chips (7400 and 4000 series stuff).http://www.new-wave-concepts.com/products.html

author: Raj
author_rank: Frequent Contributor
timestamp: May 14, 2016, 12:21:22 pm
content: alun_davies software? its a good logic gate sim

author: roblkc3
author_rank: Contributor
timestamp: May 15, 2016, 07:12:21 am
content: Quote from: dentaku on May 07, 2016, 01:18:59 amHello,We've been developing an improved version of Logisim (since the original version is not developed anymore), check it out here:https://github.com/reds-heig/logisim-evolutionCheers,Rob

author: tautech
author_rank: Super Contributor
timestamp: May 15, 2016, 07:41:26 am
content: Here's one that I go to when I get(that's often)https://tams.informatik.uni-hamburg.de/applets/hades/webdemos/00-intro/00-welcome/chapter.html

author: Gyro
author_rank: Super Contributor
timestamp: May 15, 2016, 12:14:11 pm
content: You might want to try LogicCircuit. It's free and looks easy to use and pretty comprehensive (check out the sample circuit for the calculator):http://www.logiccircuit.org/EDIT: If you check this post on their forum, someone has written a complete 74xx parts library for it:http://www.logiccircuit.org/forum/viewtopic.php?f=3&t=9628
digital clock - Page 1
Forum section: electronics / beginners

author: delta75
author_rank: Contributor
timestamp: October 20, 2012, 04:16:45 pm
content: Hi All,I am trying to make a digital 12hr clock, I have it working sort of right. Its working more like a 12 hr timer right now,what i would like to know is how can i set the time do i need to use some memory chips, i am a beginner and am trying to learn by building.i am using 4 seven seg leds, 4511 decoders and have tried using various counters 4518, 4510I am trying to make this without micros as i think i will learn more about the basics of electronics

author: johnboxall
author_rank: Unknown
timestamp: October 21, 2012, 12:02:12 am
content: Here's a few projects that may of interest:http://code.google.com/p/74clock/http://geekness.eu/content/4000-series-cmos-24-hour-clock

author: delta75
author_rank: Contributor
timestamp: October 21, 2012, 12:00:56 pm
content: thanks for the links tronixstuff
digital communication materials - Page 1
Forum section: electronics / beginners

author: rakeshm55
author_rank: Regular Contributor
timestamp: April 20, 2016, 11:26:14 am
content: I have been out of touch with digital communication for a long time 12years.....now I want to refresh this field...is there course materials available which is less math intensive and intuive....I would like to catch up with basics ask fsk Pak msk qam etc....I hav tried materials but they are so intensive on math side I could not follow the meat.... :scared.any help is appreciated....thank you all

author: coppice
author_rank: Super Contributor
timestamp: April 20, 2016, 12:49:38 pm
content: I don't know of any material on communications that is better than superficial, and yet keeps the maths simple. I don't really know how you could even achieve that. I just flicked though a copy of John Proakis's Digital Communications book, and couldn't find a page with less than 2 equations on it. Its a rather mathematical topic. If you can handle the maths there is an excellent digital comms course amongst the MIT courseware, although its getting a little dated now. It misses some of the more recent coding techniques, and I don't think there's anything about OFDM or MIMO in there. Its a good grounding, though.

author: Syntax_Error
author_rank: Regular Contributor
timestamp: April 20, 2016, 07:32:48 pm
content: I don't know if you're in the U.S.A. or not, but check your local library for a copy of the ARRL Handbook. It's got a fair amount of math in it, but nothing too deep.

author: coppice
author_rank: Super Contributor
timestamp: April 26, 2016, 07:14:03 am
content: I just noticed that David Fourney, who presents the MIT courseware lectures on communications I referred to above, has just won the 2016 IEEE Medal of Honorhttp://spectrum.ieee.org/computing/hardware/david-forney-the-man-who-launched-a-million-modems
Digital dual power supply unstable amps on channel two - Page 1
Forum section: electronics / beginners

author: SydLynx
author_rank: Newbie
timestamp: April 14, 2023, 06:44:20 pm
content: Hi folks, I bought a replacement for my defective, now returned, linear dual voltage power supply, and tested it today.It's an Aim TTi EX354RD 280W digital dual power supply (I believe it's most commonly knows as switching power supply).Anyway, as soon as I switched it on, I noticed that the CC led light of the right-hand channel did not come on, at zero current setting, as the left-hand side one did.Thus, on the left-hand side display, the current sits at zero amps, stable zero digit, whilst on the right-hand side the last digit on the CC display keeps fluctuating between zero and one, hence the CC led not coming on, because there's some current flow (inside the power source? maybe a short?), although there's nothing connected to the terminals outside, and all the pots are turned all the way left, to zero. I believe it might be defective?Otherwise, measuring the voltage, it seems quite accurate, to mVolts. On both channels.I bought it off eBay, at the stupid price of £295 (I saw it on Farnell at around £600 new). Seller said it's never been used, he bought it for a project that never reached fruition. And it does look new, no signs of previous use tbh.Should that amp level fluctuation be the reason why he sold it?Thanks for any helpful opinions!Edit: After I finished formulating my question here, I switched the power source on again, and... now both channels fluctuate, between the digits zero and one, on the CC display, both pot levels left and right all the way to minimum, but now happily, and strangely, both CC leds are also on. Right-hand side still didn't come on at first when I powered it on. It took it about three seconds to come on, without my doing nothing, just looking at it.Probably has something to do with the inner components needing some time to.. warm up, or the capacitors to... I don't know.. get some charge? I probably sound extremely dumb, but I'm miles away from real electronics, I'm just learning the thing.

author: pqass
author_rank: Super Contributor
timestamp: April 14, 2023, 09:02:30 pm
content: Without anything connected at the terminals...if you set the voltage knob to, say 5V, then slowly adjust the current knob downward to 0A, you will find that before you reach full counter clockwise that the CC LED will kick-in and the voltage display goes to 0V. That's what I see on my HP E3611A.If my PS was off for a couple of days, the CC LED kicks-in at 100mA but after 20 minutes warmup, turning the knob CCW, CC kicks-in at 10mA (the E3611A only has 2 decimal digits display for current). I attribute that to the internal voltage reference warming up and the CC comparator isn't precisely calibrated at the very bottom. It's not expected that these lab supplies have the sensitivity to limit single-digit mA loads.
Digital input on DAC? (datasheet confusion MP7531JN) - Page 1
Forum section: electronics / beginners

author: SArepairman
author_rank: Frequent Contributor
timestamp: July 15, 2013, 10:01:55 am
content: http://www.datasheetarchive.com/MP7531JN-datasheet.htmlI am testing this DAC and It says on the first page that Logical 1 at digital input steers current to Iout1.I set the dac up with a IV converter op-amp using Rref and the Iout1 works fine, but I have no idea how to activate Iout2.What do they mean by digital input? When I leave it as it is and measure Iout2 it goes from 12-14 volts.... did they forget to add a pin?I thought it might have meant that Floating-Ground = output 2 and vdd-ground = output one but I tried it and it does not work.I also tried grounding and vdding Iout1 and it does not change Iout2, where the steps change it from 12 to 14

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 15, 2013, 12:58:59 pm
content: Another multiplying DAC:http://www.ti.com/lit/ds/slas061d/slas061d.pdfStrat reading from page 5 how these things work, you are supposed to use both outputs.About the "Logical 1 at digital input steers current to Iout1" see the diagram on the first page of the document you linked, the inputs control the switches.

author: SArepairman
author_rank: Frequent Contributor
timestamp: July 15, 2013, 05:25:09 pm
content: I realized that in the schematic the second output is grounded so I don't think I will even bother to test it, I can't imagine they need to use an abnormal dac for generating a sweep wave form.There is just a buffered voltage reference for vref and a IV converter+Pi RC filter for Iout1 and Iout2 is grounded, I don't think its doing anything odd.I guess the multiplication feature is kind of odd ball... I don't believe its used here.Maybe the company bought 50,000 of them and they decided to use it instead of a traditional dac?

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 15, 2013, 06:19:49 pm
content: I had a broken MP7528 in my Marconi 2022 signal generator, which was there to tune the output notch filter. I suddenly noticed a lot of spurious in the signal and it turned out to be this DAC.That one is a dual multiplying 8 bit dac, where the second half is used for jitter control. I never found out if they are using the multiplying function in there, but after replacing the DAC everything was fine again.
Digital IO – PIR Sensor – Arduino for Beginners - Page 1
Forum section: electronics / beginners

author: mahendaran R
author_rank: Newbie
timestamp: November 22, 2014, 06:43:23 am
content: In the below mentioned link the PIR used for motion detection.....what is the range of motion detected by PIR Sensor….http://www.ingenstech.com/6-digital-io-pir-sensor-arduino-beginners/

author: Azhar
author_rank: Regular Contributor
timestamp: November 23, 2014, 06:52:06 am
content: The maximum sensing distance is 7. 7 meters according to the datasheet in the link belowbut in ideal situations it can be more than 10mI built a similar circuit before and was happy with the resultsdatasheet:http://www.mpja.com/download/31227sc.pdf
digital i/o protection - Page 1
Forum section: electronics / beginners

author: alireza7
author_rank: Regular Contributor
timestamp: March 02, 2018, 11:26:32 am
content: hii want to connect digital io of my micro controller to a digital ic which it's input capacitance is 15_25 pF ;do i need any protection here? like simply connecting my io's througha series resistor to the ic to prevent sudden current surge ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 02, 2018, 11:31:45 am
content: That is not normally a problem, most ic's have that sort of input capacitance.

author: danadak
author_rank: Super Contributor
timestamp: March 02, 2018, 01:18:54 pm
content: If the UP is running at 5V, the IC at 3.3, then a series R is advised.That's because of the parasitic scr problem in CMOS -https://en.wikipedia.org/wiki/Latch-uphttps://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwiSndO53M3ZAhXKct8KHTKTDVIQFgg6MAE&url=https%3A%2F%2Fwww.fairchildsemi.com%2Fapplication-notes%2FAN%2FAN-339.pdf&usg=AOvVaw0N7NnjfjppHF0Vl4H16wJmNote in this case a series R degrades speed, so if you need to maintainfast rise/fall times then use a logic level translator, many variants fromOn Semi, Fairchild, NXP, TI....Regards, Dana.
Digital Logic signal boosting. - Page 1
Forum section: electronics / beginners

author: cpuchip
author_rank: Contributor
timestamp: December 10, 2020, 06:15:26 pm
content: I am trying to boost the signal coming off of a WS2811 pixel for a longer wire run, A lot like the F-Amp's by Falconhttps://www.pixelcontroller.com/store/index.php?id_product=53&controller=productI ran out of those, and thought it'd be fun to make my own, but I'm running into issues.A few constraints I'm working with. All I have on hand are mosfets 2n7000 or the FQP30N06L N-channel enhancement Mosfets.I have 10 volts coming in, but can easily drop that down to 5v for logic level work. but I really don't know what the input signal voltage level will be, somewhere from 3 volts to 5vI'm trying to bread board a circuit to boost the signal like this one linked below, but tying the Low Voltage and High Voltage lines together since they "should" be the same level but That doesn't boost the voltage out. This does not need to be bi-directional. my input clock rate is 800KHz and I have an oscilloscope and function generator to check that a clean squarewave makes it through in that configuration, but I cannot get it to amplify the voltage back up to 5v logic levels. What am I missing.https://www.pololu.com/blog/343/new-product-logic-level-shifter-4-channel-bidirectional

author: cpuchip
author_rank: Contributor
timestamp: December 11, 2020, 11:36:35 pm
content: Does anybody have experience making a spi/i2c signal booster? NOT a logic level translator, I'm not really going from 3.3v to 5v I'm just trying to repeat the digital signal along the wire.

author: oPossum
author_rank: Super Contributor
timestamp: December 11, 2020, 11:51:25 pm
content: A pair of SN75176A or similar (there are many pin compatible alternatives available). Use one as the transmitter with DE & RE tied high. Use another as the receiver with DE & RE tied low.

author: cpuchip
author_rank: Contributor
timestamp: December 14, 2020, 06:46:20 am
content: Quote from: oPossum on December 11, 2020, 11:51:25 pmOkay! so basically any RS-485 chip? I sadly don't have any of those.but I think I might have figured it out with a BS170 mosfet. I needed a stronger 5v output resistor since the 10k wasn't pulling it up to 5v fast enough for above 100KHzSince I'm not worried about by directional IO just low voltage to higher voltage it should be alright.
Digital Oscilloscope Bandwidth and Logic Analyzer  - Page 1
Forum section: electronics / beginners

author: Detailz
author_rank: Newbie
timestamp: March 09, 2016, 04:09:57 am
content: I have been reading for a few days now and still have some unanswered questions lolIm looking to get a Oscilloscope and or LA but was unclear as to what i should get.At this point in time I dont have a "Clock speed" in mind but I did see a chart somewhere referencing *Common Clock speeds* and recommended scopes.Of course, my biggest fear is buying a Digital Scope less than capable of doing what I need so I am looking for REAL WORLD application examples to reference if possible.What would a 200mhz do that a 100mhz wont?I would like to play around with some hardware hacks such as this here.https://youtu.be/BUvFGTxZBG8Or reverse engineer some household electronic.Im also having a hard time finding info on choosing a Logic Analyzer. Im considering the Saleae 8 channel or PRO 8 channel but is it worth it to go PRO for modern applications?Im sorry if this has been done to death but I cannot find the info Im looking for.Budget: Prefer to keep it below $800, however, if there is something of greater value for more ....Im interested.

author: 8of10
author_rank: Newbie
timestamp: March 09, 2016, 11:21:24 am
content: Why don't you go for the Rigol1054zI have the same one, it's a 4 Channel 50 MHzOsci with hacking capabilities (100 MHz, and various communicationProtocol decoding capabilitys , spi,i2c, and so on )I'm very happy with mine . And for under 500 $And for house hold stuff it's more than enough.Best regards

author: danadak
author_rank: Super Contributor
timestamp: March 09, 2016, 04:28:01 pm
content: The 1054Z will decode serial busses. And its hackable to 100 Mhz as a scope. Plus youcan look at an analog stream while decoding a serial buss.A real cheap but very capable LA is something likehttp://www.ebay.com/itm/USB-Logic-Analyzer-Device-Set-USB-Cable-24MHz-8CH-24MHz-for-ARM-FPGA-M100-/201450276552?hash=item2ee75f46c8:g:8mUAAOSwl9BWIMdLThe inputs are not protected, so either you add the clamps externally or stay in the LV scheme of things like embedded micros.saleae logic analyzer software is the software you download for free and use with the pod.They say they are 24 Mhz, I got reliable captures up to 5 Mhz.Scope, 100 Mhz vs 200 Mhz, the 1054Z analog BW is actually around 140 Mhz or something like that. Someone did a test on youtube as Irecall. What is equally important is sampling rate. 1054Z has a total sampling rate of 1 Gs/s, 1 channel, 500 Ms/s 2 channels, 250 Ms/s 4 channels.Quite a lot of embedded parts 100 Mhz fine for most work.Regards, Dana.
digital output not outputting to base of transistor - Page 1
Forum section: electronics / beginners

author: AH1234
author_rank: Contributor
timestamp: May 18, 2020, 11:55:39 pm
content: I am working on a night light project, one aspect of my project gives an digital output signal when it is dark and motion is detected, this part of my circuit is working fine but I am having issues with trying to transfer this to a transistor to drive it into saturation with Tinkercad as the simulator. With a relay it's fine but I'm hoping to use a transistor with the load at the collector, the base current is non-existant since I switched from a relay to a transistor, I could debug further if the current was low but I'm not sure how to debug further. Please find attached some images alongside a schematic.

author: Tom45
author_rank: Frequent Contributor
timestamp: May 19, 2020, 12:01:55 am
content: Connect the two grounds together. i.e., connect the Arduino's ground to the 9 volt battery - terminal.

author: AH1234
author_rank: Contributor
timestamp: May 19, 2020, 10:41:37 pm
content: Emitter doesn't seem to be outputting anything, base resistor is eating up all the voltage

author: Nerull
author_rank: Frequent Contributor
timestamp: May 19, 2020, 11:44:42 pm
content: Your diodes are backwards.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 20, 2020, 03:54:15 am
content: Yes, the base resistor is ‘eating up all the voltage’ because the resistor is too high in value.You want to saturate the transistor and the rule of thumb is to apply about 10% of the expected collector current in the base. I don’t know what current your load is but 10k will give you approximately 400 ua of base current which when multiplied by 10 says you can’t get more than about 4 ma load out of the transistor. I’d say that’s probably too low by an order of magnitude so lower your base resistor to 1K and you should be able to drive about 50 ma of load.The actual calculation is (drive voltage - 0.7V) / load current.

author: Nerull
author_rank: Frequent Contributor
timestamp: May 20, 2020, 08:29:22 pm
content: The circuit operates just fine if the diodes are connected in forward bias.

author: AH1234
author_rank: Contributor
timestamp: May 21, 2020, 07:23:46 pm
content: Reversing the diodes seemed to fix the issue, I must have got muddled up, thanks guys.
Digital Phosphor Oscilloscope - DPO Explained? - Page 1
Forum section: electronics / beginners

author: Time
author_rank: Frequent Contributor
timestamp: May 06, 2011, 08:01:37 pm
content: So I was curious as to what the difference between a DPO and a DSO are.When would you want to use a DPO over a DSO? Does a DPO only offer superior waveform update rates over a conventional DSO? What makes a DPO different from a DSO? Is the difference in sampling rate?How do the Tektronix DPOs match up against these new generation Agilent scopes that dave recently reviewed?

author: Unknown
author_rank: Unknown
timestamp: May 06, 2011, 09:31:08 pm
content: DPO (and competing technologies from Agilent and Lecroy) is about getting the performance of a DSO (a DPO is still a digital sampling oscilloscope, fancy marketing names notwithstanding) closer to analog scopes. An early DSO (or the current bottom end) had a low refresh rate, and only displays one acquisition at a time (unless you enable persistence, which is useless for anything but simple, constant signals). Many of them have/had a refresh rate in the order of 10Hz. An analog scope can easily exceed thousands of updates per second an fast sweep speeds. The idea of DPO was to increase the refresh rate and use a variable persistence display with intensity grading based on frequency (basically a 2D histogram with color for frequency), just like a real phosphor does.
Digital pod on Oscilloscope - Page 1
Forum section: electronics / beginners

author: Shocked
author_rank: Newbie
timestamp: February 23, 2012, 10:52:54 pm
content: Hi, Newb question.I'm looking to buy a cheap scope and found an old agilent 54xxx series but it supposedly works but the "digital pod" is broken. The seller hasn't responded and I am unable to determine what he means buy this. All I want is that an oscilliscope that can proprely display waveforms on a couple of channels. Is this pod a separate input on the oscilliscope that shows digital highs and lows?

author: Unknown
author_rank: Unknown
timestamp: February 23, 2012, 11:07:31 pm
content: All scopes have analog channels, usually somewhere between one and four. Some scopes also have 8-32 digital channels, which can only show high or low. Since that many BNC connectors would take up way too much space and would be too cumbersome, they usually use pods that connect to the scope with some sort of ribbon cable and that have short flying leads or special connectors for connecting them to the DUT.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 23, 2012, 11:17:24 pm
content: AFAIK, with all Agilent scopes that have digital inputs, e.g.54645D, the physical digital probe pods are just passive, so can be improvised/repaired if necessary.However if the inputs themselves have died it could be a problem as they use custom chips for the digital inputs..
Digital Potentiometer  - Page 1
Forum section: electronics / beginners

author: poojadholam
author_rank: Newbie
timestamp: July 28, 2021, 01:51:23 pm
content: Hello All,I need help related to digital potentiometer.As you can see in the attached image, I have used digital pot (AD8403) to adjust output voltage of Step Down Converter.I would like to connect digi pot as per given figure B (it is must be connected given way).I have two questions:1. The way I have connected digi pot is it same as figure B? I am new to this subject, so I want to be sure.2. If reset is performed on the digi pot, the output of the step down converter should not change or it should be approx same. In this case terminal W will connected to Terminal A or B ? Why?

author: 4kruby
author_rank: Contributor
timestamp: July 28, 2021, 02:08:19 pm
content: Hello,First, aPotentiometeris generally represented by 3 pins. I see only 2 pins in your diagram (figure B) and the wiper is missing in your figure B.If you meant to connect end to end (10K) then you should consider only A and B terminal on the IC.As per the datasheet of the digipot, if reset, the wiper will come to the middle position (might read 5k from both A to W and W to B)

author: poojadholam
author_rank: Newbie
timestamp: July 28, 2021, 02:16:06 pm
content: Thank you for reply.The Figure B and AD8403 is given to me and told that it should be connected in that way and i should determine w terminal should connect to A or B as per the condition given in the second question.
Digital Potentiometer DS1802 - limit upper range - Page 1
Forum section: electronics / beginners

author: irq99
author_rank: Newbie
timestamp: September 15, 2017, 11:49:48 am
content: Hi,maybe someone can give me an hint with this problem.Since there seem to be nearly no 5k digipots with pushbutton control available i am curious if i can use a DS1802 (10k) and limit its upper range somehow? The Datasheets dont really provide any useful information about this (at least for me).Can i just parallel 2 of those to half its Range?https://datasheets.maximintegrated.com/en/ds/DS1802.pdfThanks!Juergen

author: danadak
author_rank: Super Contributor
timestamp: September 15, 2017, 02:18:15 pm
content: Paralleling not a good idea. First the chip to chip ladder variation is quitelarge. Second its log so variation effect is aggravated by curvature of response.Regards, Dana.

author: Zero999
author_rank: Super Contributor
timestamp: September 16, 2017, 07:32:59 pm
content: If the potentiometers are both on the same IC, then I would have thought they'd be fairly closely matched.Why does it need to be 5k? Can't you modify the circuit so it works with a 10k potentiometer? Please post a schematic.

author: danadak
author_rank: Super Contributor
timestamp: September 16, 2017, 11:36:49 pm
content: Actually that is a good point, there is an inter channel matching spec,but not a spec on absolute ladder R matching. Eg. the matching isin db attenuation, a ratiometric spec. But maybe all things being equalthe ladders themselves are also matched.Contact Maxim and pose the question and ask if the ladders will meetyour requirement.Regards, Dana.
Digital potentiometer with 256 steps Up/Down - Page 1
Forum section: electronics / beginners

author: aless2056
author_rank: Contributor
timestamp: May 24, 2021, 09:30:04 pm
content: Guys, I would like to exchange an X9C104 (100K) that has 100 steps for one that has more steps. I found the MAX5455 and MAX5389, can you get another one compatible with the X9C104, but with more steps and up / down?

author: ledtester
author_rank: Super Contributor
timestamp: May 24, 2021, 09:43:10 pm
content: There are a lot of digital pots with 1024 steps. Both Mouser and Digikey (and others) allow you to search for devices based on resistance, number of steps, communication protocol, package, etc.
Digital pots - Page 1
Forum section: electronics / beginners

author: elki
author_rank: Regular Contributor
timestamp: April 12, 2024, 11:01:30 am
content: Is there a way to reduce the ringing when using digital pot instead of the usual one? I am feeding a short pulse to a divider made with a pot to reduce the voltage from 5V to small values of the order of 20mV. Please see the screenshots below. I guess nothing to be done, since there is always an intrinsic capacitance associated with the digital pot? The voltage is taken from 22 Ohm going to ground from the wiper.

author: jwet
author_rank: Frequent Contributor
timestamp: April 12, 2024, 02:35:14 pm
content: Loading any digital pot with a 22 ohm load won't work well. You'll get a high pass type response as you've seen. Something else is going on in that circuit- I suspect that the 22 ohm load is drawing too much current intially. The wiper current of digital pots is limited- see abs maxes. Also there own wiper resistance is likely larger than 22 ohms so this won't work anyway.Here are a few things you can try:Use the lowest impedance post device you can find.If you're always attenuating by large values, put a fixed 10:1 upstream or downstream. Upstream with the pot feeding a reasonable divider. You might want to ac compensate the divider (see below).For an AC voltage divider you can put equivalent capacitive reactance across your divider like 10:1 scope probes do. The variability of a pot make this tougher but you can experiment over the range you need to attenuate.A 40 ns square pulse is a very high frequency signal, this might not be a good application for a digital pot. You might consider an RF VCA (voltage controlled amplifier) with the control driven by your digital pot.Another possibility is a monolithic RF step attenuator- you could get something with a 30 db range in 1 db steps. If you look at Dave's o'scope tear downs, you'll see these kind of things in front ends.Good Luck

author: aliarifat794
author_rank: Regular Contributor
timestamp: April 12, 2024, 03:11:51 pm
content: Place decoupling capacitors across the power supply pins of the digital potentiometer. These capacitors can help stabilize the power supply and reduce noise and ringing.

author: elki
author_rank: Regular Contributor
timestamp: April 12, 2024, 06:22:40 pm
content: Thanks a lot. These are all good ideas.Quote from: jwet on April 12, 2024, 02:35:14 pm

author: MarkT
author_rank: Frequent Contributor
timestamp: April 13, 2024, 08:29:48 am
content: Quote from: elki on April 12, 2024, 11:01:30 amLike all pots, digipots are designed for low loading on the wiper. 22 ohms is a massive load!
Digital Power Supply, Interface Arduino-PC - Page 1
Forum section: electronics / beginners

author: r_guillermo0
author_rank: Newbie
timestamp: September 24, 2012, 11:22:56 pm
content: hi i want to make a Digital Power Supply with uncommon specs, for example,the power supply has to be adjustable 0-15 v, wiht pc control, interface Arduino, my problem is the current, the power supply has to control 10 amp.if you can help me with a schematic i would appreciate.i am not shure where i have to put the PWM.?my email is r_guillermo0@yahoo.com.mx

author: free_electron
author_rank: Super Contributor
timestamp: September 24, 2012, 11:44:30 pm
content: Design the regulator system first. Slap on the hardwhino later ...Have you figured out yet what regulator topology you will use ? linear ? pwm fiollowed by linear ?Work on that part first.what about current limitation ?From the way you wask your question i fear you may have experience with an arduino only... and that is not exactly 'electronics'.... which is what you will need to design a decent supply.

author: mariush
author_rank: Super Contributor
timestamp: September 25, 2012, 03:52:46 am
content: This smells like one of those"please email me the codes"threads.If you want to do it smps style, then I'd suggest getting a book about smps power supplies. A book likeSwitching Power Supply Design, 3rd Edis well worth the money.A half-bridge design or something equally simple can be done fast and cheap.If you want to just do something fast and without worrying about efficiency, get a nice 2x10-12v x 12A transformer, a bridge rectifier, a bunch of big capacitors and you have either 10-12v DC @ 10-12A or 20-24v @ 12A... switch between them with a relayThen regulate to the desired voltage by using something like 2 linked LT1083 .. each can do 7.5A by itself but they can be made to work together (see page 14) . One or a couple of i2c 1kohm digital potentiometers instead of that 2k adjustable resistor solves the adjusting by arduino...But you'll need a big heatsink with a nice fan to cool it down when it dissipates 50-90 watts into the heatsink.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 25, 2012, 05:44:03 am
content: Arduino? Sure. Why do you kids think that slapping an Arduino onto something makes it a new and unique design? Somewhere I have a 40 year old application note describing how to build a digitaly adjustable power supply. Complete with isolation (of a parallel bus ...). Nothing new under the sun.

author: r_guillermo0
author_rank: Newbie
timestamp: September 26, 2012, 11:35:43 pm
content: your reviews are right, i know only the basics in PWM, i will see in the commercial shops about the LT1083.thanks.