hybridfree/eevblog-posts huggingface dataset:
Diy Textronix TDS 1002 extension module - Page 1
Forum section: electronics / beginners

author: nunolopez
author_rank: Newbie
timestamp: December 11, 2024, 03:32:29 am
content: Hi everyone, I’m new here, so apologies if this isn’t the right place to post this.I was wondering if anyone has successfully created a DIY extension module for the Tektronix TDS 1002 oscilloscope. The original TDS2CMA module, which provides RS-232 and GPIB communication, seems quite overpriced on eBay for what it offersI have read this topic from another person that created a diy module for the TDS2CM the issue is this person never shared any schematics or gerber fileshttps://www.eevblog.com/forum/testgear/reverse-engineering-tds2cmtds2mm/

author: MathWizard
author_rank: Super Contributor
timestamp: December 13, 2024, 05:51:56 pm
content: Did you try messaging the OP ? I have an old Tektronix DSO, also with some old style com port I've never used. But for a challenge maybe this winter, I should try and get some serial communication to a PC. Price and time wise it's not worth it, but some day I might try and replace the CRT w/ some modern screen.

author: Simon
author_rank: Unknown
timestamp: December 15, 2024, 08:19:33 am
content: See:https://www.eevblog.com/forum/beginners/is-the-tds2cm-module-compatible-with-the-tektronix-tds1002-oscilloscope/msg5745615/#msg5745615
diy thermal imaging camera - Page 1
Forum section: electronics / beginners

author: p.larner
author_rank: Frequent Contributor
timestamp: February 24, 2024, 06:40:47 pm
content: Is there any thermal imaging camera moduas on the market cheap to homebrew said camera?.All the thermal imaging cameras i see on the market have prices akin to a telephone number,is it posst to homebrew one on the cheap?.

author: Andy Chee
author_rank: Super Contributor
timestamp: February 24, 2024, 07:17:28 pm
content: The big expense is in the glass lens optics.Basically you can't use normal glass, because normal glass is a heat insulator, thus preventing thermal "light" reaching the imaging sensor.I don't know of a DIY source of these lenses, but would probably cost the same as a thermal camera anyway!

author: Andy Chee
author_rank: Super Contributor
timestamp: February 25, 2024, 05:43:21 am
content: I did a google and found some IR lenses:https://www.edmundoptics.com/c/ir-lenses/655/#But like I said, the prices are comparable with a complete thermal camera unit.

author: LinuxHata
author_rank: Frequent Contributor
timestamp: February 25, 2024, 11:58:24 am
content: There is absolutely no need to pay huge fees for lenses.You can use readily available lenses for CO2 laser cutters - they can be bought under $20 each.Basically, you need two of these with different focal distance.Say, one with 75mm and another with say, 50mm focal distance.This will give you 1.5x magnification.I've experimented with cheapest, 12mm ones and they were quite good.The main issue is the sensor itself.You can use single sensor, like that used in IR thermometers, mount it on gimbal and do X-Y scan mechanically, while accumulating data.Extreme resolutions can be obtained, but almost unusable for anything that might move or change it's temperature.

author: JXstaystonight
author_rank: Contributor
timestamp: February 27, 2024, 02:57:28 am
content: Not sure what you are trying to use it for. But actually, many cell phone thermal cameras are not that expensive these days. They are very small inserts, and if the measurement requirements are not high, I think they are perfectly adequate.I recently got one, it's not expensive, over 200 bucks, and it still works great.I'm personally too lazy to bother with it myself though.
DIY transformer - component naming, and where to get them - Page 1
Forum section: electronics / beginners

author: andybrandi
author_rank: Contributor
timestamp: October 01, 2019, 06:17:22 pm
content: Hi. I'm planning to build my own transformers. (Of course I could use off-the-shelf ones or just salvage, but that would be no fun.) In this video:https://youtu.be/s6NyTprQCBI?t=898you can see the guy using a plastic transformer "skeleton", as well as iron sheets for the core.Could anyone tell me the proper names of the above parts, and possibly a place to get them from for reasonable prices? (AliExpress isn't helping, and Google only gets me lots ofTransformerstoys, but maybe that is because I don't know what to search for.)Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 01, 2019, 06:19:12 pm
content: Bobbin / former.Tim

author: strawberry
author_rank: Super Contributor
timestamp: October 02, 2019, 07:06:20 pm
content: https://www.alibaba.com/showroom/transformer-lamination-e-core.htmlthere are other fancy core shapes as well.bobbin can be made out of FR4 (clean no copper) or electrical cardboard

author: andybrandi
author_rank: Contributor
timestamp: October 02, 2019, 08:47:05 pm
content: Thanks everyone, that clarifies the terminology!As for buying the laminates/iron sheets, these seem to be quite abundant on Alibaba (thanks @strawberry for the link!), but only in integer multiples of 1 metric ton... guess I'll have to look somewhere else. At least I know what to google for now.

author: strawberry
author_rank: Super Contributor
timestamp: October 02, 2019, 10:28:32 pm
content: try Indel , Hammond mfg , or other tube transformer makers who could helpout with some raw materialthere are some skilled tube amplifier transformer winders out there on youtube as well

author: johnkenyon
author_rank: Regular Contributor
timestamp: October 03, 2019, 11:33:05 am
content: Quote from: blueskull on October 02, 2019, 07:48:52 pmThe iron sheet forms "laminations" (a pointer, just in case a search doesn't throw up what you want/need)

author: scatterandfocus
author_rank: Regular Contributor
timestamp: October 03, 2019, 12:34:32 pm
content: Applied Science made an informative video on some basics of magnetics, which is very relative to making a transformer:

author: andy3055
author_rank: Super Contributor
timestamp: October 05, 2019, 05:53:33 pm
content: Quote from: blueskull on October 02, 2019, 09:02:19 pmI hope you are not toying with the idea of buying iron sheets. If so, you will need to buy a machine to cut them in to the required size/shape as well unless you plan on doing it as a business.

author: james_s
author_rank: Super Contributor
timestamp: October 06, 2019, 05:43:59 am
content: I've bought cores and bobbins from Bridgeport Magnetics, they will sell small quantities and have various core styles.
Diy transistor curve tracer? - Page 1
Forum section: electronics / beginners

author: peps1
author_rank: Regular Contributor
timestamp: April 19, 2013, 07:15:10 am
content: Hello guys,Just saw a really cool video about the Octopus Curve Tracer by w2aew, and was just wondering if its possible to make a DIY transistor curve tracer to plug into my oscilloscope for matching up JFET's for audio phaser projects?Had a look on google, but just found lots of VERY expensive bits of kit.

author: branadic
author_rank: Super Contributor
timestamp: April 19, 2013, 07:21:48 am
content: http://www.dl4jal.eu/kls/kls.htmland related:http://www.qrpforum.de/index.php?page=Thread&threadID=6289

author: peps1
author_rank: Regular Contributor
timestamp: April 19, 2013, 10:51:06 am
content: Thanks branadic.But, looking for something a little more analog and less German.

author: Unknown
author_rank: Unknown
timestamp: April 19, 2013, 12:36:22 pm
content: This might be what your looking for ? go down the page for circuit and info...http://www.extremecircuits.net/2010/06/curve-tracer-adaptor_17.htmlAlso here's a V/I tracer that might be of interest...http://www.techlib.com/electronics/curvetrace.html

author: peps1
author_rank: Regular Contributor
timestamp: April 19, 2013, 07:02:57 pm
content: Quote from: vlf3 on April 19, 2013, 12:36:22 pmThanks vlf3Quote from: Aurora on April 19, 2013, 05:08:49 pmAt that price Id be a fool not to grab one........now iv just got to learn how to use a transistor curve tracer!
DIY Ultrasonic Welding - Page 1
Forum section: electronics / beginners

author: Chiliyago
author_rank: Newbie
timestamp: June 06, 2015, 02:38:54 pm
content: I am trying to research the feasability of building a DIY Ultrasonic Welding device for welding 3D Printer filament.Here is what I have learned so far in the following link.http://www.plastemart.com/upload/literature/Frequency-in-ultrasonic-plastic-welding-machines-applications-limitations.asp"An ultrasonic welding machine comprises four main components: a power supply, a converter, an amplitude modifying device (commonly called a Booster) and an acoustic tool known as the horn (or sonotrode). "I would like to know how to build such a circuit to generate the 20,30 or 40khz and if an off-the shelf "horn" is available somewhere or if it can be made easily.Thanks for any input you can provide.(Pardon the open ended nature of this question)

author: harii07@gmail.com
author_rank: Newbie
timestamp: October 27, 2017, 04:55:17 am
content: I can help for designing power source for ultrasonic frequency. Shall we start fabricating one of this.

author: meehan8381
author_rank: Newbie
timestamp: November 05, 2017, 06:59:14 am
content: https://www.facebook.com/quantatxink/thanks eevblog

author: Raj
author_rank: Frequent Contributor
timestamp: November 05, 2017, 09:08:45 am
content: Sounds like a problem similar to this-https://youtu.be/aKhPj7uFD0YBasically, you'll have to make a high power high frequency compatible h bridge
DIY VU meter - Page 1
Forum section: electronics / beginners

author: ezalb98
author_rank: Contributor
timestamp: February 05, 2024, 05:12:25 pm
content: Hello everyone, i'm new here and i'm also new in to eletronics!I was wondering if this circuit that i made will work.So, the project is an analog VU-Meter. Not an accurate professional thing, just a bouncing meter.I'll put this circuit in the speaker out that goes to the speakers of my stereo.Don't mind about the generator (i just had to simulate an AC current) and also about the voltmeter at the end, there i'll connect the meter.Thanks to anyone who will help me!

author: Andy Chee
author_rank: Super Contributor
timestamp: February 05, 2024, 05:19:01 pm
content: If this VU meter is to be connected to your speaker level output, you may need signal attenuation.How powerful is your speaker output? 5W? 50W?

author: coromonadalix
author_rank: Super Contributor
timestamp: February 05, 2024, 06:13:04 pm
content: normally you measure in parallel of say 2, 4, 8 ohms load etc ...

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 05, 2024, 08:55:00 pm
content: You are going to use a digital panel meter? You wouldn't be able to read anything.

author: ezalb98
author_rank: Contributor
timestamp: February 06, 2024, 06:40:49 pm
content: Quote from: Andy Chee on February 05, 2024, 05:19:01 pmFrom the manual:Rated Input Power 5WMax. Input Power 10W

author: ezalb98
author_rank: Contributor
timestamp: February 06, 2024, 06:42:14 pm
content: Quote from: BeBuLamar on February 05, 2024, 08:55:00 pmSomething like this:https://www.amazon.it/JZK-Amperometro-Pannello-Current-Corrente/dp/B09VXSDMD3/ref=sr_1_5?__mk_it_IT=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=36ZFA9J8XBYBB&keywords=analog+meter&qid=1707244897&s=tools&sprefix=analog+mete%2Cdiy%2C349&sr=1-5

author: Manul
author_rank: Super Contributor
timestamp: February 06, 2024, 08:23:54 pm
content: It might cause slight audio distortion. I would add some series resistance before or after the diode bridge to minimize non linear loading.

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 06, 2024, 09:22:25 pm
content: You need to find out the impedance of the meter.
Django Question! - Page 1
Forum section: electronics / beginners

author: ankitdixit
author_rank: Newbie
timestamp: June 29, 2019, 08:09:02 am
content: Hello All, I am looking for Django interview questions resource or want to know which type of question will put during a technical interview. Any Django expert is available here?I have to go through some like to read technical questions -http://techgeekbuzz.com/django-interview-questions/Check this one also, Is it enough to crack the interview?
DL187T leads/probes - Page 1
Forum section: electronics / beginners

author: schneiderbecket
author_rank: Newbie
timestamp: March 02, 2019, 04:13:07 am
content: I have a seemingly rare noname multimeter with the model number DL187T that apparently still works perfectly great and it's owner misses it, but unfortunately it's leads/probes were broken. I don't have enough experience with old meters to know which name brand leads should be compatible. I hope someone on here can point me to a pair of leads that should work, if not I have a some digital calipers to take measurements with.Cheers, thanks for atleast reading!

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 02, 2019, 07:37:23 pm
content: That meter has some crazy large inner shrouds on the banana jacks, so standard shrouded leads won't fit. You'll have to use leads with unshrouded 4mm banana plugs, or cut the shrouds off of some leads, or a nice safe solution would be to have leads with "retractable" shrouds likethese Probemaster Softies (8018S option).
DMM adjusting or calibration questions - Page 1
Forum section: electronics / beginners

author: mikem
author_rank: Contributor
timestamp: February 07, 2014, 03:46:42 am
content: hello to all of you.my questions will no doubt expose my lack of knowledge in this field of electronics.my name is Mike, and i am 58 years old. have been in hobbies all my life.........mainly the building and flying Free Flight competition airplanes....picture attached here to give you an idea.i have always wanted to become more involved with electronics, and recently became in need of a good DMM.this led to of course the study and referencing of what to buy and also led to a device that i'm sure you all are aware of.....the DMMCheck Plus.watching a video of the use of this tool was intriguing to say the least. while this is just a start for me, i am very interested and figuring out what can and cannot be done to a piece of test equipment and so on.while i can understand what the DMMCheck is all about, i would like to ask, are there trim pots inside the average DMM that a user can adjust to bring a value into spec?by that i mean, if checking a meter for a 5v readout, and the meter is off + or -, is this adjustable inside the meter?or is this something that a calibration would be needed to acquire accuracy and so on.

author: Fsck
author_rank: Super Contributor
timestamp: February 07, 2014, 03:57:19 am
content: for anything reasonably high end = no, they're closed case calibrations.low end = highly likely as it's an easy as hell way to trim at the factory.

author: mikem
author_rank: Contributor
timestamp: February 07, 2014, 05:01:50 am
content: thank you for the answer.i believe i will be buying top end DMM, but thought it would be fun to experiment with a couple cheapies to learn from.i wasn't sure if each function that has an adjustment pot was affected by the other.nothing worse than making an adjustment only to find that all the other pots would need to be reset to a spec i can't possibly do as a DIY'er.i will be looking into a course this year to really get into this field further.i find reading here so fulfilling.Dave's videos are really educating me, and i love the way he says it like it is.

author: retiredcaps
author_rank: Super Contributor
timestamp: February 07, 2014, 07:30:52 am
content: Quote from: mikem on February 07, 2014, 05:01:50 amA top end multimeter will likely be closed case and you won't be able to DIY calibrate.You can likely adjust DCV on a low end multimeter, but adjusting it for just one voltage (say 5.000V DC) doesn't guarantee linearity. That is, you can tweak the pot so the meter reads 5.00, but it may be off at 400mV range or 40V range.If you are buying a cheapie to play, learn and experiment on low voltage and current (< 30V and < 1A), then get one of those Harbour Freight $2.99 jobs. Accuracy is hit or miss (one is barely within spec while the other is "bang on" for 5V). Seehttp://mrmodemhead.com/blog/gallery/cen-tech-92020-dmm/Marting has some videos on DMMCheck
DMM auto-shutoff questions - Page 1
Forum section: electronics / beginners

author: Electro Fan
author_rank: Super Contributor
timestamp: February 04, 2015, 05:05:54 am
content: When a DMM goes into auto-shutoff how much drain is on a battery? Or said another way, if hypothetically a battery (shelf-life?) lasted a year in DMM that was fully turned off, would the same battery last a year in sleep mode after auto-shutoff or something less? If less is it negligible, or something significantly less? Or, net, net: if you have auto-shutoff on a DMM is it worth turning the DMM fully off, or is it ok to just let it go into sleep mode? (How much of these answers is DMM model dependent?)

author: mij59
author_rank: Frequent Contributor
timestamp: February 04, 2015, 05:18:44 am
content: The Fluke 87V has about 50uA in "auto-shutoff " mode, so its better to switch the meter off.

author: retiredcaps
author_rank: Super Contributor
timestamp: February 04, 2015, 07:33:01 am
content: The answer will vary from meter to meter, but in my findings, auto-shutoff or sleep mode will always draw some current whereas turning it off usually draws 0.0 mA.If you use poor quality batteries or batteries that are prone to leak, leaving it in auto shutoff mode will probably cause battery leakage and ruin your potentially expensive multimeter. I use Eneloops or equivalents whenever I can.
DMM base dt0660 and dt1106EN - Page 1
Forum section: electronics / beginners

author: rafik23
author_rank: Newbie
timestamp: December 18, 2019, 07:09:12 pm
content: hiplease can any one has idea about hacking eeprom DT1106EN and for manual range ? examplein data 80H and BFh i found some function what is 2Xh and 3Xh and more DCA and ACA 6 60 600 6000A , i try to anlyse this dumpOffset 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F===============================================00000080: 00 00 24 01 00 22 1A 19 09 0A 0B 21 0C 31 29 2A00000090: 06 05 04 2E 03 30 2C 2B 18 17 16 15 14 1F 1C 1D000000A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000000B0: 00 00 00 00 00 00 00 00 00 00 00 001320 00 1Eit for pm18C manual range only HZ/% , Capacitor and temperature are in auto ranging , i compare it to bside adm08a without temperature mesuring i see that the 13 at BCh is remplaced by 00h and replace at adresse 9EhOffset 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F===============================================00000080: 05 00 00 24 01 00 22 1A 19 09 0A 0B 21 0C 31 2900000090: 2A 06 05 04 2E 03 30 2C 2B 18 17 16 15 14131C000000A0: 1D 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000000B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00is there another functions implemented ? or with new algo to formating data in range 80h BFh ?this pic for rotating range for both DMMpm18Chttps://drive.google.com/file/d/1SKqT1JZbKe3bTTXyYgXGC5H1dWYPdEfY/view?usp=sharingbside adm08Ahttps://drive.google.com/file/d/1UPUMSLIMj5l0WFClw-wjnHH2DK_VWLpI/view?usp=sharingthxs
DMM  Closed Calibration - Page 1
Forum section: electronics / beginners

author: Tel007
author_rank: Newbie
timestamp: December 14, 2022, 04:58:33 pm
content: Hello Guys, I have a MORPILOT 108C DMM that is reading 0.2 V DC high so was looking at recalibrating. I decided to tear down the DMM and have ago at adjusting but found no trimmers so it is as I now understand a closed system. I found open contacts on the pcb marked CAL SW1. I bridged this reassembled and powered up. This obviously put it in calibration mode. When switched to ohm/resistance CAL was displayed and then stepped through values starting at 8 and ending at 92. After this it displayed ER3 which is a common error code so assume it was exoecting an input. If the orange SELECT button was pressed during or after the step sequence the display went to 0000 mV. Any help or info to progress this would be much appreciated... pics attached for info
DMM Diode Test - What exactly? - Page 1
Forum section: electronics / beginners

author: dav
author_rank: Regular Contributor
timestamp: March 09, 2017, 05:20:45 pm
content: I measured a red LED with my 87V and I got 1.830V.I added another meter in series to measure the current and I read 0.98mA so I thought ok, the 87V estabilishes enough voltage to force 1mA in the diode and returns that value.Then I tested a second LED (white) and here what I got: 2.667V 0.85mAso my previous hypothesis is wrong.Moreover I tried same LEDs with another meter, now using the 87V as an ammeter.Here the measurements:red LED 1.805V 0.67mAwhite LED 2.580V 0.31mASo what does the meter exactly measure in diode test?

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: March 09, 2017, 06:47:55 pm
content: If you read the manuel it usually tells you the ohmic resistance applied. I think different meters use different ohmic resistance. Whats more your battery may have something to do with it.

author: TimFox
author_rank: Super Contributor
timestamp: March 09, 2017, 07:35:11 pm
content: The normal diode test in a DMM applies a constant current (value varies with model) to the DUT and measures the voltage across it. The maximum voltage is limited, so it may not work well with a (reverse-biased) zener diode or sometimes with a high-voltage LED.

author: Seekonk
author_rank: Super Contributor
timestamp: March 09, 2017, 10:06:17 pm
content: I measured a meter on ohms and OC voltage was 2.97, so you are likely bumping at the edge of some meters providing a constant current. Your test tells you something, but not much.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 10, 2017, 05:33:45 am
content: Most meters use aconstantcurrent of about 1mA for the diode test (the chosen current is usually in the range of 0.4mA to 2mA). The voltage across the diode or LED is then displayed.LED datasheets use a current of 20mA to characterize the forward voltage drop.Open circuit voltage varies from as low as 1.8V for some meters, up to 15V for a few others.All of them can measure the drop out voltage of a normal diode (0.6V). Few are designed to light up a LED and measure its drop out voltage.Connecting a current shunt in series in the test circuit to measure the constant current makes things even more difficult for the meter, increasing total drop out voltage.As an example, testing a diode, gives a drop out voltage of 0.6V. With another meter introduced in the circuit to measure current, the displayed drop out voltage becomes 1.6V.With a white LED, the drop out voltage is a lot higher (2.6V). Compliance voltage can be exceeded and the meter's constant current source cannot maintain the required 1mA.I suggest you go and read about constant current sources.
DMM max allowable common mode voltage ? - Page 1
Forum section: electronics / beginners

author: Cyclone1
author_rank: Newbie
timestamp: June 05, 2020, 10:05:05 am
content: Does DMM or DAQ have max common mode voltage rating before it blows up? Let's take the attached image for an example, is there a cap of how high V2 can be before it causes problem to the DMM?Just wondering what would happen if it is exceeded, would v2 get shorted out ? What component in the DMM/DAQ dictate this limit? Is it clamping device, transformer or etc?

author: Kleinstein
author_rank: Super Contributor
timestamp: June 05, 2020, 10:46:22 am
content: There is a limit to the common mode voltage. Normally this limit should be listed somewhere in the specs, though one may not find it with battery operated ones.The limiting parts can be the case (with battery operated ones), the transformer or some DC/DC converter or opto-coupler. In most cases there would be no defined clamping but just a chance to see arc over or isolation failure from some point on. Once an arc starts the voltage can drop relatively far.
DMM Showing Current without Current Source - Page 1
Forum section: electronics / beginners

author: lothian
author_rank: Newbie
timestamp: August 31, 2021, 03:50:09 pm
content: I am attempting to use my DMM to identify a parasitic drain in my car's electrical system using a Chinaseum-brand DMM with an amp clamp.After I set the thing to DC amps and before I clamp it to the target conductor, it displays a range between 0.1A and .22A. This makes t'shooting with this tool impossible. I can't figure out how to "zero" it within this mode; nor can I determine if--like voltage measurements--extraneous ambient readings are normal. The user manual is useless,Thoughts? Suggestions?

author: David Hess
author_rank: Super Contributor
timestamp: August 31, 2021, 04:21:18 pm
content: DC clamp meters almost always rely on hall effect sensors which means they suffer from high DC offset and drift, so what you are observing is normal; they are not suitable for measuring low currents.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 31, 2021, 06:56:53 pm
content: Use a regular DVM or Good old analog.

author: Gyro
author_rank: Super Contributor
timestamp: August 31, 2021, 07:28:41 pm
content: Quote from: Terry Bites on August 31, 2021, 06:56:53 pmNot so easy to measure parasitic current with modern cars these days - they take a while to shut down with some systems taking significant power before they finally go to sleep (more than enough to blow a mA range fuse!).Some hints in this thread irrc...https://eevblog.com/forum/beginners/measuring-car-battery-dc-current-with-uni-t-ut139c-multimeter/

author: jeroen79
author_rank: Frequent Contributor
timestamp: September 04, 2021, 02:28:50 am
content: Going by themanualthe 'Z/F' button will zero the meter in AC current mode.The procedure would be to to hold the jaws closed near the wire you want to measure, zero the meter, snap the jaws around the wire and take a reading.You can also measure the voltage across the fuses to determine how much current is going through them.If you google you may find conversion tables for various types of fuses from car manufacturers. (VAG I think)This will not be accurate but once you find which fuse is passing a lot of current you can do an in-line measurement.For that you could rig up something where you can first bypass the meter with a high current switch during the car's switch off period and then open the switch to send the current through the meter.

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 06, 2021, 03:25:49 am
content: Yes, DC clamp meters always have a 'zeroing' button.
DMM useage for us real beginners. A HKJ 5 min block of instruction - Page 1
Forum section: electronics / beginners

author: bc888
author_rank: Regular Contributor
timestamp: December 13, 2018, 02:55:15 am
content: Poster HKJ is known for his excellent flashlight, charger and multimeter reviews. He just put up a very good tutorial on the basics of using the Multimeter to measure or check various components. There is also a link on this tutorial for measuring and checking LED flashlights, it's all good stuff. Bonus points is you can accurately guess (the total) how many different meters he uses to test various things. Much like a Dave video without the sword Dave uses to open his packages ...or a video as well. Good stuff!https://lygte-info.dk/info/DMMComponentTesting%20UK.html

author: xrunner
author_rank: Super Contributor
timestamp: December 13, 2018, 02:58:31 am
content: I think that is useful for beginners. To see the DMM reading along side the component being tested. Quite useful for beginners.
DMM Voltage Reference  - Page 1
Forum section: electronics / beginners

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:57:07 pm
content: I am looking to building a voltage reference to check the calibration of my multi meters.. I am not sure what voltage but I was thinking of using a single voltage and using a calibrated chip since I don't have a high count meter.. My best meter is a series II Fluke 87.. I was think about using a 9v battery as the supply or use a lipo or wallwart.. Do you guys have any suggestions or ideas or built something similarThanks

author: Gyro
author_rank: Super Contributor
timestamp: December 14, 2015, 11:59:15 am
content: There are actually a lot of threads on this subject, both for 'average' meter calibration and for higher precision. I suggest a forum search for 'voltage reference'.
DMMs Model Grading - Page 1
Forum section: electronics / beginners

author: teslafan
author_rank: Regular Contributor
timestamp: January 12, 2015, 05:10:44 am
content: Watching a YouTube video on DMMs abt a UNI-T UT61E & a UT61C, I got the impression maybe we think different here than in China, maybe backwards from their point of view? I tend to think each US model from A-Z gets more features than the previous. So, model Z would be the US' flagship model? Do the Chinese grade their models from Z-A. A being their flagship model?

author: devanno
author_rank: Regular Contributor
timestamp: January 12, 2015, 05:34:27 am
content: Quote from: teslafan on January 12, 2015, 05:10:44 amNo, not really. DMMs and other test gear are designed with different uses in mind. Fluke may have one meter that is designed for electronics work, and one with a higher number may be less capable for electronics, but aimed at the industrial electrician... I recently looked at DC Electronic Loads and one firm used a suffix on a load that indicated that the highest voltage rating on it was 500VDC vs 150VDC, but at the same time, the current rating on the higher voltage model dropped below what the 150VDC model could handle... both models had the same basic model number. You just have to read the specifications and find the unit that meets your needs. For a while this plethora of model numbers (and the UniT DMMs definitely qualify here) gave me headaches trying to figure out which unit I needed. That's where sites that let you compare specs can be very helpful. I often look athttp://tequipment.netbecause they do have comparison capability for the items that they carry.

author: teslafan
author_rank: Regular Contributor
timestamp: January 12, 2015, 06:02:49 am
content: Thanks, I'll try that feature at their site, appreciate it.
Do all 5630 SMD LEDs have the same characteristics?  - Page 1
Forum section: electronics / beginners

author: Shadow351
author_rank: Newbie
timestamp: July 18, 2015, 02:35:47 am
content: Hello, I am working on a lighting project for my garage. I currently have 4x, 2 bulb (T-12) Shop Lights rated 34W and 2325lm per Bulb. The ballast went out of one of the fixtures and cost more to replace then the fixture so I thought I would give LED's a try. I purchased a 5M roll of 5630 Cold White LED Strip. When it arrived I cut it into strips of 23 segemts (3 series LEDs each) and stuck them to the metal case of the old fixture, wired them up to a 12V power brick and powered it up, and it was not as bright as I expected (hoping for on par with or a little brighter than current florescent fixtures or about 5000lm which the 5630 at a min of 29lm per the datasheet *276 LEDs > 8000lm should be able to achieve). I measured the current draw and it was less then 3.5A at 12V. The datasheet I have for a 5630 LED is Lumichip (found with a google search), and the "optimal" forward current listed is 120mA which would equate to a little over 11A for all 92 sets of LEDS (23 *4). I decided to dig a little deeper and cut 1 section of 3 LEDs out of the remaining strip, and measured a forward current of 48.9mA (ok so maybe they were worried about heat and limited the current accordingly) but then I measured the forward voltage of the LEDs to be 3.34V, According to the data sheet the forward Voltage at 50mA should be closer to 2.9-3.0V. Is there this much difference between manufactures of LEDs with the 5630 number, or did the manufacture of this strip falsely label the LEDs hoping nobody would know? I de-soldered one LED and I see no identification markings, Is there any way to tell? I would like to go to LED's because in the winter the florescent lights protest being turned on (it hit -20F last winter thats -29C) and I also intend to build a PWM circuit so I could dim the LED lights when I didn't need full intensity.Thanks-Brad

author: 8086
author_rank: Super Contributor
timestamp: July 18, 2015, 02:40:05 am
content: 5630 is only the physical package size, and tells you little to nothing about the actual LEDs' characteristics.Where did you buy your LEDs?

author: Shadow351
author_rank: Newbie
timestamp: July 18, 2015, 02:42:32 am
content: Quote from: 8086 on July 18, 2015, 02:40:05 amGood to know.Amazon.comhttp://www.amazon.com/5630-Waterproof-Fleixbe-supply-Brighter/dp/B00D86DZZA/ref=sr_1_2?ie=UTF8&qid=1437187314&sr=8-2&keywords=5630+led+stripThanks
Do-all function generator - Page 1
Forum section: electronics / beginners

author: malch
author_rank: Regular Contributor
timestamp: February 08, 2015, 04:19:01 pm
content: I saw this on ebay:http://www.ebay.com/itm/HP-3314A-Function-Generator-OPT01-Working-condition-/120770596384?pt=LH_DefaultDomain_0&hash=item1c1e7d0e20Is this a good jenny to inject sweep signals to trouble-shoot analog problems?And align 455 IF if I come across something like that?note the 100$ shipping - hits all Canucks.The revered Rigol DS1054Z is over 600 cad.Trying to build up a small repair center on a fixed living budget.Tried USB and no- junk.P.S. Seems to me a beginner needs a generator that displays the frequency and waveform rather than guessing with your scope while trouble-shooting .

author: mij59
author_rank: Frequent Contributor
timestamp: February 08, 2015, 05:35:18 pm
content: I think this function generator is way to expensive, what makes it so special ?For that kind a money you can buy a new Rigol or Siglent.Also on eBay are a lot of HP 3314A for less.

author: c4757p
author_rank: Super Contributor
timestamp: February 08, 2015, 05:41:09 pm
content: These old HP function generators - all the "digitally controlled analog" ones - areincrediblygood function generators; I have yet to find any other that comes so close to doingexactlywhat it says on the tin with few non-ideal nasties like distortion and phase noise. These are, in my opinion, the ideal function generators for anybody who doesn't need AWG.However, that'swaytoo damn much for one. I'd pay a bee's dick over $100 if I were desperate for a function generator.

author: rdl
author_rank: Super Contributor
timestamp: February 08, 2015, 05:42:48 pm
content: Yes, I agree that having a frequency counter built in is good, and the HP 33214 is a nice bit of equipment. However, I think you can do just as well for much cheaper with a bit of looking.867-5309

author: malch
author_rank: Regular Contributor
timestamp: February 08, 2015, 06:58:28 pm
content: All is too expensive! Whiner mode

author: KJDS
author_rank: Super Contributor
timestamp: February 08, 2015, 07:27:31 pm
content: I can do you an HP3310A including shipping to Canada for £93

author: rf-loop
author_rank: Super Contributor
timestamp: February 08, 2015, 07:59:01 pm
content: I have very Good condition HP3314AIt is good and very handy in use. And it have some nice features and of course also well known eastern egg...And btw, it is also (early generation) Arb.But, this link to eBay show something what I do not touch even with long wooden stick. And its price. It looks like collected from waste station (yes it IS propably collected from waste container shipped for metal recycle in China). And if it do not work... well of course all can repair but...
Do Analog Multiplexers need a GND connection - Page 1
Forum section: electronics / beginners

author: Arznei
author_rank: Contributor
timestamp: October 20, 2018, 06:49:54 pm
content: Hello,I am having a hard time getting this straight in my head. I am trying to have an analog test signal pass through an unknown impedance that could have a voltage source inside it. So my plan was to have the impedance decoupled with capacitors like shown in the attached schematic. First of all: I am not even sure this works, so if you can give me some input on that I would appreciate it.Now on top of that i would like to switch between different outputs, for example the external impedance under test and a known calibration one. I figured it would be best to have the path selection after C1. However I am not sure if an analog multiplexer like ADG739 would work in that instance? I mean the output behind C1 is not really tied to GND, so will it pass through an analog switch without problems?Thank you for any advice!

author: MasterT
author_rank: Frequent Contributor
timestamp: October 20, 2018, 09:46:14 pm
content: Something is not right with your schematic,https://www.eecs.tufts.edu/~dsculley/tutorial/opamps/opamps5.htmlMUX better to put at the OPA output, than you always would know DC bias point, and control it if it's necessary.
[SOLVED]Do capacitors dry out faster when they are not used? - Page 1
Forum section: electronics / beginners

author: Stori
author_rank: Contributor
timestamp: July 29, 2018, 10:37:38 pm
content: Hello good people,I've been searching for an answer but didn't find anything usefulDo electrolytic capacitors dry out faster when they are just laying around unused? (in comparison with an electrolytic capacitor that is built into a curcuit and is being used at least once every 1/2 weeks within it's specs)What about other type of capacitors?Background: Some "wiseguys" in a car forum always claim that if you store your car for a long time you will get problems with dry capacitors. IF you never move/use it that is. Those guys are no electronic experts...I know that a capacitor is always going to break down at some point no matter what, but do they really dry out faster when not used? It sounds like BS imho, urban myth?Thx

author: james_s
author_rank: Super Contributor
timestamp: July 29, 2018, 10:41:13 pm
content: I don't think they dry out if not used, but very old electrolytics may need to be re-formed if they have sat for a long time. Personally I just replace electrolytics with modern parts, they are what I consider to be consumables.Surely with cars there are lots of other things that deteriorate when sitting. Seals dry up, fuel turns to varnish, rubber parts rot, but capacitors? Maybe if you let the car sit for 50 years but by then you'll have other problems.

author: Stori
author_rank: Contributor
timestamp: July 29, 2018, 11:19:15 pm
content: Thanks for your confirmation that it's not true

author: Lee Leduc
author_rank: Regular Contributor
timestamp: July 30, 2018, 12:48:25 am
content: Here's a presentation titled "Long-Term Storage of Aluminum Electrolytic Capacitors".https://www.dfrsolutions.com/hubfs/Resources/services/Long-Term-Storage-of-Al-E-Capacitors.pdf?t=1528744207492
Do delta-sigma ADC average a fast changing signal? - Page 1
Forum section: electronics / beginners

author: atwoz
author_rank: Regular Contributor
timestamp: September 26, 2014, 02:35:06 pm
content: I have been looking at some delta sigma ADC IC's, I need a 24bit delta sigma to get the average voltage of a signal that changes faster than the output rate of the delta sigma. Most delta sigmas have output rates of 100's of samples per second.My question is: If my signal is a 10kHz sine wave, and I use a 24bit delta sigma that outputs 100 samples per second, will the delta sigma average the 10kHz sine wave so that in the output I will have the real average of the wave even when I'm only getting 100 samples per second?Thanks!

author: Dago
author_rank: Frequent Contributor
timestamp: September 26, 2014, 03:05:34 pm
content: Edit: wrong information. I retract my answer

author: David Hess
author_rank: Super Contributor
timestamp: September 26, 2014, 03:08:17 pm
content: Quote from: atwoz on September 26, 2014, 02:35:06 pmNoise consideration means that they will be slower than that when delivering high resolution results. Often the sample rate is a submultiple of 50 or 60 Hz (or both) so power line noise is rejected.QuoteThat is exactly what will happen. Delta-sigma converters are a type of integrating converter and average their inputs over the sample period. This is in contrast to sampling converters which acquire a sample at one specific point in time.

author: atwoz
author_rank: Regular Contributor
timestamp: September 27, 2014, 05:36:27 am
content: Thanks a lot David! I have another question. After a Delta-Sigma ADC outputs a sample (averaged) does the integrator reset for the next set of readings or will the next sample gets averaged along with the past readings?

author: David Hess
author_rank: Super Contributor
timestamp: September 27, 2014, 05:46:57 am
content: Quote from: atwoz on September 27, 2014, 05:36:27 amThis depends on the details of the converter. Linear Technology makes "no latency" delta-sigma ADCs where every sample is independent. Some other delta-sigma converters have a pipeline latency of like 3 samples making them more difficult to use with a multiplexor if you wanted to do that.
Do dual mosfets max VDS doubled, in the back to back connection as a switch ? - Page 1
Forum section: electronics / beginners

author: BravoV
author_rank: Super Contributor
timestamp: December 19, 2018, 06:57:20 am
content: With identical mosfets, does the maximum VDSdoubled at the switched line ?For e.g. each max breakdown VDS= 100V, with this configuration will it become 200V ?Assuming the gate driver is fully isolated, like using photovoltaic MOSFET driver.

author: capt bullshot
author_rank: Super Contributor
timestamp: December 19, 2018, 06:59:33 am
content: No, it does not.One of the MOSFETs is reverse biased in this configuration, so its internal diode is conducting and pushing all the voltage drop to the other one.

author: BravoV
author_rank: Super Contributor
timestamp: December 19, 2018, 07:15:57 am
content: Quote from: capt bullshot on December 19, 2018, 06:59:33 amAh, thanks, forgot the body diodes at both fets.So the max breakdown simply = (A single VDS) + (Single body diode VF) ?Back to drawing board to find suitable MOSFETs.

author: capt bullshot
author_rank: Super Contributor
timestamp: December 19, 2018, 07:22:09 am
content: Or even simpler just the single VDS, since the body diode VF usually is significantly lower than the breakdown voltage, especially as long as it isn't carrying current.

author: BravoV
author_rank: Super Contributor
timestamp: December 19, 2018, 07:23:24 am
content: Yeah, noted, as the VF is minuscule compared to VDS, again, thanks.
Do hz matter in a soldering station? - Page 1
Forum section: electronics / beginners

author: 32kms
author_rank: Newbie
timestamp: October 31, 2022, 09:42:19 am
content: I just bought my first soldering station (Weller we1010na) through Amazon USA and it tells me that it uses 120v, in my country we use 220v/50hz. here is the question, do I need to change from 50hz to 60hz? or only from 220v to 120v?Weller does not provide much information about the station's hz, it only says 120v.sorry if there are grammatical problems, use google translate.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 31, 2022, 09:50:00 am
content: Hi 32kms,welcome to the forum.Normally the 50/60hz would not be a problem. Only for devices that base a date/time clock on the main frequency it matters (Or televisions from the early days)The weller site does mention it to be 120V and that might mean that you need a transformer to get your 220V down to 120V.

author: jonpaul
author_rank: Super Contributor
timestamp: October 31, 2022, 10:18:42 am
content: The shipping, import tax's and duties will be very high cost.Suggest to cancel the Amazon USA and use the local distrib or Amazon/ebay in Chile.Then you get the correct line V etc.We use old Hakko analog 926/936 irons and our design the Metcal Smartheat SP-200Better than the new digital Wellers.Jon

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 31, 2022, 10:42:23 am
content: To save money, Weller may use a 60hz transformer which might overheat at 50hz. The manual for the WE 1 (does that include WE 1010?) lists three versions, presumably with different transformers, for Europe, North America and Japan.

author: 32kms
author_rank: Newbie
timestamp: October 31, 2022, 11:11:52 am
content: thanks for your comments, in the end I canceled the purchase and will wait for an offer from 'we1' at 230v/50/60hz
Do I have DC here ? Or does this cap prevents it ? - Page 1
Forum section: electronics / beginners

author: Frederico Acardi
author_rank: Contributor
timestamp: August 16, 2021, 02:30:19 pm
content: Hello, the question is in the imageThank you.

author: rsjsouza
author_rank: Super Contributor
timestamp: August 16, 2021, 02:38:04 pm
content: No DC there if V2 is an ideal sinewave generator with no DC offset.In the real world you might have some DC depending on the generator and if it has decoupling on its output.

author: Frederico Acardi
author_rank: Contributor
timestamp: August 16, 2021, 02:53:30 pm
content: It's not an ideal generator, but suppose I have a DC offset, it will still be present after the pot at this node ?

author: rsjsouza
author_rank: Super Contributor
timestamp: August 16, 2021, 03:00:47 pm
content: Quote from: Frederico Acardi on August 16, 2021, 02:53:30 pmYes, but proportional to the position of the cursor of R2 - in other words, R2 is a voltage divider where the output voltage is proportional to the relationship between the lower pin and the cursor and the upper pin and the cursor.Question 9 of the reference below contains a nice description of this scenariohttps://www.allaboutcircuits.com/worksheets/potentiometers/

author: Frederico Acardi
author_rank: Contributor
timestamp: August 16, 2021, 03:31:40 pm
content: Thank you !
Do I have it right? | Efficient powering of small ASIC cluster - Page 1
Forum section: electronics / beginners

author: NLM
author_rank: Newbie
timestamp: February 12, 2024, 01:36:46 pm
content: Hi All,I am building a cluster of small ASIC miners and looking for a more efficient way to power them. The ASICs come with a 120W laptop style charger, for power (stock speeds) they require 100W at 16v-19v. Now for 2 or 3 this is ok but more than that it is not very efficientor clean to have a bunch of laptop chargers and using tons of outlets.I have some 1200W server PSU that I would like to use, problem is they are 12v, so what I was thinking is:Server PSU > Breakout board > ATX 6 pin off breakout to voltage step-up > to ASIC which accepts 2.5*5.5mm DC jack.I will be running these ASIC overclocked which increases power to about 160W.In theory I should be able to power 6 ASIC per 1200w server PSU, it would be much cleaner and efficient / cheaper.This all sounds good in my head, and I think should work. BUT I am new to doing mods like this and looking for any advice or things I should be watching out for.Cheers,NLM

author: Ian.M
author_rank: Super Contributor
timestamp: February 12, 2024, 03:18:06 pm
content: Sounds like a PITA. The boost converters will kill your efficiency and cost a fair bit as you need 10A ones to have some margin. A 1000W 18V PSU can support six 160W loads direct, with much simpler wiring. Maybe derate to five loads to have some margin.N.B. 2.5x5.5mm barrel jacks are *not* trustworthy at high currents.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: February 12, 2024, 03:37:59 pm
content: https://www.meanwell.com/productSeries.aspx#The PSPA-1000-15 (can be adjusted to 17V output voltage) should suit your needs.