hybridfree/eevblog-posts huggingface dataset:
Anemometer pinout - Page 1
Forum section: electronics / beginners

author: fabiodl
author_rank: Frequent Contributor
timestamp: May 22, 2022, 02:27:51 pm
content: I have this anemometerhttp://www.tuifa.cn/detail/4720182394.htmldoes anyone know the pinout? I tried to open it, but it seems glued.

author: MikeK
author_rank: Super Contributor
timestamp: May 22, 2022, 06:42:47 pm
content: Is it three pins? I would guess Vcc, Gnd, and Data (pulse).

author: ledtester
author_rank: Super Contributor
timestamp: May 22, 2022, 06:57:04 pm
content: Using Google Translate on the page yields this:QuoteSo it is very likely there is a data line that outputs pulses. It's also likely that line is an open collector output:https://forum.digikey.com/t/what-does-open-collector-mean/715

author: fabiodl
author_rank: Frequent Contributor
timestamp: May 23, 2022, 03:51:37 am
content: It has four pins,marked 1,2,3 and 4, placed in a square configuration.

author: tepalia02
author_rank: Regular Contributor
timestamp: May 29, 2022, 10:48:16 am
content: You can cross-check with this one:https://wiki.dfrobot.com/Wind_Speed_Sensor_Voltage_Type_0-5V__SKU_SEN0170Maybe you can find similarity.

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 29, 2022, 07:04:36 pm
content: Most anemometers I've seen have 16 switches (22.5º steps) toggling different resistor divider ratios, with analog output.Depending on the voltage, you know the position.But it could be any interface type: rs-232, 4-20mA, PWM...Better you check what's inside!

author: fabiodl
author_rank: Frequent Contributor
timestamp: May 31, 2022, 10:26:45 am
content: It's sealed, so if possible I'd like to leave it waterproof. I would try the dfrobot signals, but I am worried in applying voltage to the pins randomly and let the magic smoke escape

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 31, 2022, 10:47:27 pm
content: Connect power with a limiting resistor, so it doesn't draw more than 50mA, shouldn't damage anything.What are the wire colours?Don't worry, as you say, it's sealed, the magic smoke won't come out

author: james_s
author_rank: Super Contributor
timestamp: May 31, 2022, 11:16:32 pm
content: Quote from: DavidAlfa on May 29, 2022, 07:04:36 pmYou're describing a wind vane, a device that measures the direction of wind. An anemometer is a device that measures the velocity of wind and will have only one output, typically a digital pulse train. I have seen them use a reed switch with a rotating magnet, a coil with a rotating magnet, or an optical sensor with a rotating interruptor. Going by what somebody else said above it sounds like the anemometer in question uses the latter.

author: DavidAlfa
author_rank: Super Contributor
timestamp: June 01, 2022, 03:00:17 am
content: Opps yes, I had another brain arrestTrue, the anemometer sends n pulses on each rotation...
ANENG 870 TRUE RMS - Page 1
Forum section: electronics / beginners

author: Thepro1991
author_rank: Newbie
timestamp: March 19, 2025, 02:21:59 am
content: Hi , guysi need gudiance for aneng 870 true rms1. i have seen some one edit eeprom file and change counts to a better results.2. i need the light to always be ON.thank you very much , i would accept any resource regarding this issue.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: March 19, 2025, 07:52:45 am
content: This thread may help you troubleshoot the multimeter.https://www.eevblog.com/forum/testgear/calibration-of-an-aneng-an870/
Aneng AN8009 Faulty  - Page 1
Forum section: electronics / beginners

author: hpibmx
author_rank: Regular Contributor
timestamp: September 14, 2022, 02:03:28 am
content: Hi,So I have been using this multimeter as a secondary and it's been a month not reading accurate anymore, is there anyway to calibrate this? or can't be repaired at all,I used to run this with 4.2v batteries and some buck converters, but it seem not accurate anymore, as in diode mode beeps most of time and dcv have always some crazy minimal readings,Thank you.

author: tooki
author_rank: Super Contributor
timestamp: September 15, 2022, 04:21:45 pm
content: I think you’re going to need to describe the problem much more precisely.

author: strawberry
author_rank: Super Contributor
timestamp: September 15, 2022, 07:23:45 pm
content: nothing can do bout it (black blob)check resistors , range switch contacts
Another 555 timer question scraching my head on it. - Page 1
Forum section: electronics / beginners

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: March 06, 2016, 05:17:36 am
content: Okay in advance sorry to annoy you guys with another one of these.So i have been looking over this chip, watching tutorials, and videos, and reading. But it is still not clicking with me. Many of the tutorials just show how they hook it up and what it is doing.any that explain it explain it with over diluted tech terms that to woosh over my head.SO! its leaving me not understanding the WHY?Why dose it blink the light when it had this cap and resistor added this way to it.how dose each pin on the chip truely function, Why dose putting this pin to this pin casue this reactionI need some kind of complete lamen break down of the 555..so that i can know its full potential, for my projects, and future endvors.PS..did anyone you run into this brick wall at some point where something just did not make sense to you?All your guys and gals, help is greatly aprechiated, and welcomed. I thank you all for all the assistance in my persuits to date.

author: Brumby
author_rank: Unknown
timestamp: March 06, 2016, 05:57:38 am
content: You will need to look at an internal block diagram. Here's one example showing the 555 timer inside the dotted box with a couple of components outside to make a simple oscillator.To understand it's function in this role, you only need to consider two states - one when the external capacitor is charging and the other when it is discharging. The transition is controlled by the transistor connected to the 'Discharge' terminal (pin 7) which is driven by the flipflop.

author: Kappes Buur
author_rank: Regular Contributor
timestamp: March 06, 2016, 06:07:47 am
content: http://www.williamson-labs.com/pu-aa-555-timer_med.htm

author: Brumby
author_rank: Unknown
timestamp: March 06, 2016, 06:14:41 am
content: Quote from: Kappes Buur on March 06, 2016, 06:07:47 amNice animation. Well worth looking at.

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: March 06, 2016, 07:08:59 am
content: OH WOW..thank you.best way i am looking at it right now.Is like 2 comparitors, working in conjunction with a flip flop. working with a clock, as voltage is added it kicks one over, and it subtracts off it kicks the other over.all this is in minecraft terms for messing around with redstone for 2 years. but i have been watching the animation for 10 mins now. this is going to help me so very much. this will i belive give me the click i need to get it all.
Open clamper diode outcome? - Page 1
Forum section: electronics / beginners

author: gotwood
author_rank: Contributor
timestamp: February 27, 2013, 07:11:11 pm
content: source--------cap-----------D2FB---------------out| | | |ground D1RB cap 100k| | |G G Gac sourcecan someone explain when D1 diode(normally used for clamping) is missing/open no V appears across outputsimple explanation of how cap is acting would be great

author: Bored@Work
author_rank: Super Contributor
timestamp: February 27, 2013, 07:30:40 pm
content: First of all, learn to write meaningful subject lines instead of this "question needs clarification"crap.

author: gotwood
author_rank: Contributor
timestamp: March 01, 2013, 03:02:36 pm
content: Anything?

author: c4757p
author_rank: Super Contributor
timestamp: March 01, 2013, 03:07:56 pm
content: Unless someone is better than me at deciphering questions, you're going to have to explain better. I'm not really sure what the question is.

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 01, 2013, 03:13:33 pm
content: Download LTspice (it's free), build the circuit and you will see why.(The cap will be charged so that the right side will not raise above 0 volts and D2FB will not conduct.)

author: gotwood
author_rank: Contributor
timestamp: March 01, 2013, 04:27:56 pm
content: What is the cap acting like that the fwd biased diode will not conduct?

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 01, 2013, 08:37:20 pm
content: Quote from: gotwood on March 01, 2013, 04:27:56 pmSee the 2 pictures below.Now think about why this happens.

author: gotwood
author_rank: Contributor
timestamp: March 02, 2013, 02:04:32 am
content: I understand what happens with a clamper....I don't understand how the cap is acting without the diode. Nor do I get the waveform output from the cap on your first illustrationI'm guessing that over the first cycles the cap is building charge from the positive part of the sine wave......
Another Beginners question - Page 1
Forum section: electronics / beginners

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: February 28, 2016, 03:15:35 am
content: What is a good circuit design program for my PC, that i can draw up and test my designs? I heard about one called circuit lab, but checking to see what you guys might add. im trying to get myself really going here too just self teachingthere was a free on i tried, that was crap. casue no matter how i changed cap values or resistor values, the circuit acted the same. then i removed all that all together and it acted right. and i knew that was wrong, becasue a 9v DC souce would burn a LED out without a resistor of the correct ohms.

author: DimitriP
author_rank: Super Contributor
timestamp: February 28, 2016, 05:22:19 am
content: http://www.linear.com/designtools/software/#LTspiceI don't know if it will save you from burning up your virtual LED....

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: February 28, 2016, 06:52:35 am
content: thank you for that. open soourcing my stuff is no big deal, as its all for props, so nothing next gen and world changing.

author: DroneBuster
author_rank: Contributor
timestamp: March 01, 2016, 07:31:36 am
content: You can also try out EveryCircuit on Android/iOS. It got example circuits with physics and formulas explained.

author: Azhar
author_rank: Regular Contributor
timestamp: March 01, 2016, 10:15:59 am
content: Dave made a video about CircuitMaker, it worth a watch before trying the softwarehere is the link:
Another component identification - Page 1
Forum section: electronics / beginners

author: slim
author_rank: Contributor
timestamp: May 02, 2015, 11:40:56 am
content: Hello All,Could anybody tell me what this component is?it has a black oval on one side and a large gold dot on the other besides the colored dots seen here.Thanks

author: Psi
author_rank: Super Contributor
timestamp: May 02, 2015, 12:11:55 pm
content: its either a cap or an inductor.

author: Cliff Matthews
author_rank: Unknown
timestamp: May 02, 2015, 12:17:43 pm
content: Perhaps it's a dipped tantalum... Googling capacitor dipped dot code helped.http://www.dutchforce.com/~eforum/index.php?s=3247216f9725ef0a8499a5e1c0a4af85&showtopic=17840

author: Cliff Matthews
author_rank: Unknown
timestamp: May 02, 2015, 12:26:22 pm
content: Nope, that's an inductor. I reached into similar ones I have and tested 0.10 mH (2.4 ohms) on a component tester.Mine have brown (gold?) on the side and black brown on top.The image below may help (fromhttp://www.sentex.ca/~mec1995/gadgets/coils/coils.html)

author: slim
author_rank: Contributor
timestamp: May 02, 2015, 11:14:58 pm
content: Quote from: Cliff Matthews on May 02, 2015, 12:26:22 pmThanks!
Another Dick Smith Q-1280 Oscilloscope.  Need Help. - Page 1
Forum section: electronics / beginners

author: Hammer_651
author_rank: Newbie
timestamp: November 21, 2024, 01:09:02 am
content: HI all. I would like to ask the forum if anyone knows about these dick smith oscilloscopes. Yes i have one and i really like it but, two things are different.1) The POT-R215-5KB on the MPCB from the Horizontal Gain as shown in the schematic has been replaced with a POT on the front panel.2) There is also a small PCB on the back inside of the panel top RHS above the transformer. This has Blk and Red banana plugs and a small POT connected to it. There is a small coaxialcable coming from it goingwhich is floating at the back of the horizontal gain pot previously mentioned. There no indication of this PCB or connections on the scopes schematic. I have no clue what this PCB cctdoes.Can anyone help with this please?Thanks.Hammer_651

author: wilfred
author_rank: Super Contributor
timestamp: November 24, 2024, 08:04:39 am
content: It looks like a DIY addition to me. I did find a picture of the rear panel of another example at this website. Scroll across to the third picture.https://www.radiomuseum.org/r/dicksmithe_65mhz_single_channel_oscilloscope_q_1280.htmlBut as to what the modifications do I wouldn't even try to guess.

author: Hammer_651
author_rank: Newbie
timestamp: December 15, 2024, 04:12:45 am
content: Thanks for your help.

author: floobydust
author_rank: Super Contributor
timestamp: December 15, 2024, 05:13:29 am
content: To me, that looks like someone was building-in a I-V curve tracer into the scope. Sort of a poor man's Huntron tracker.But these require a dedicated say 6VAC power transformer. You can't use the one in the scope without trouble and this might be why it was abandonedLook up "octopus curve tracer" to see the circuit, it is very simple and needs the scope's H and V inputs.edit: added a typical schematic. The pots might be another addition.
Another Homemade Flashlight - Page 1
Forum section: electronics / beginners

author: joeqsmith
author_rank: Super Contributor
timestamp: September 21, 2020, 01:33:38 am
content: I had made a video some time ago showing this Cree LED mounted to green heatsink, with no lens compared with some of our flashlights. It's pretty bright.Saved a couple of dead house LED bulbs from the trash along with a laptop battery pack that I gutted and sorted for good cells. Taking apart the bulbs, the supplies had failed, but the LEDs were still fine. So I mounted them to a heatsink.The reflector is the clear packing from a set of 4 D energizer cells. I cut it in half and taped the two ends together. The face cover is the clear plastic packing from some weed whacker parts. Using a small boost switcher to drive it. A 9V transistor battery will drive it.....

author: joeqsmith
author_rank: Super Contributor
timestamp: September 21, 2020, 01:46:09 am
content: So here's the results of the trash picked flashlight held together with electrical tape....Ambient is showing the camera pointed up into a tree with no lights. Flashlights were ran left to right.FL1 is one of my first LED flashlights. Amazed at how the LEDs have changed in such a short time.
another interview with W2AEW - great oscilloscope info - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: September 16, 2016, 06:58:45 pm
content: I stumbled onto a two part interview with Alan Wolke and listened to part one today.lots of information about oscilloscopeshttp://hamradio360.com/index.php/2016/08/30/ham-radio-workbench-5-oscilloscopes-part-1/http://hamradio360.com/index.php/2016/09/13/ham-radio-workbench-6-oscilloscopes-part-2/

author: Back2Volts
author_rank: Unknown
timestamp: September 17, 2016, 09:55:46 pm
content: I tried to get to it but seems it requires login to view

author: w2aew
author_rank: Super Contributor
timestamp: September 18, 2016, 02:53:23 am
content: Quote from: Back2Volts on September 17, 2016, 09:55:46 pmHmm, really? I didn't see anywhere where it required a login.

author: Back2Volts
author_rank: Unknown
timestamp: September 18, 2016, 06:07:58 am
content: Now I can get in with no problem. I must have use the wrong link once in the page. What can I say !Thanks
Another LM338 related question - Page 1
Forum section: electronics / beginners

author: the_eagle
author_rank: Contributor
timestamp: July 14, 2021, 12:25:29 pm
content: I am adventuring myself in the design of a 28VDC linear power supply (for the other specs of the power supply I am using as reference MIL-STD-704F).AC mains (UK) is rectified from a 100VA transformer which gives an unregulated voltage of about 52VDC.Because 52-28=24V, the continuous output current of the LM338 is limited to only 2A. Therefore I am thinking to shift the unregulated DC output from 0/52VDC to -17/35VDC such that Vout-Vin of the LM338 is less than 10V.I have drawn a circuit in LTSpice which seems to give 28VDC output voltage, but when I add a load of 10 Ohm, the output voltage drops to 300mV. Why is this happening?I am more than happy to do a complete change of the initial designEDIT: confused Peak-to-Peak with Peak voltage. Removed transformer secondary voltage

author: Circlotron
author_rank: Super Contributor
timestamp: July 14, 2021, 12:34:24 pm
content: As soon as you apply your load the voltage drop across R3 and R4 causes the input voltage to the regulator to drop to a very low value. Also, an 18VAC transformer should give you about 25.4V, varying somewhat with load.

author: the_eagle
author_rank: Contributor
timestamp: July 14, 2021, 12:49:31 pm
content: I was doing automatic conversions from rms to peak voltage but I didn't notice the result was peak-to-peak instead of Peak voltage.Thank you for the explanation. What can I use as an alternative to the resistors?

author: Circlotron
author_rank: Super Contributor
timestamp: July 14, 2021, 01:07:35 pm
content: I’d say use a 25vac transformer and no resistors.
another mystery part - Page 1
Forum section: electronics / beginners

author: Dan Moos
author_rank: Frequent Contributor
timestamp: July 04, 2023, 11:06:51 pm
content: Its cherry read in real life. My camera lit it poorly.

author: ledtester
author_rank: Super Contributor
timestamp: July 04, 2023, 11:50:49 pm
content: When I click on the image I see a black capacitor...which I guess is a 1nF 100V capacitor. K means +/- 10%.

author: Dan Moos
author_rank: Frequent Contributor
timestamp: July 05, 2023, 01:09:55 am
content: man, Thats wierd. That pic is from another post I made. I'll try again

author: Dan Moos
author_rank: Frequent Contributor
timestamp: July 05, 2023, 01:10:52 am
content: Here's the pic again. Hope it works

author: RJSV
author_rank: Super Contributor
timestamp: July 05, 2023, 01:38:24 am
content: Dan:My smartphone on forum gets me the 'bottlecap' image when I click on the smaller image.Obviously a different photo, maybe related to some problems lately, with getting EVERY mobile to work uniformly. Better to use laptop, I've heard here.

author: RJSV
author_rank: Super Contributor
timestamp: July 05, 2023, 01:41:42 am
content: I'd start thinking maybe a thermistor, can be checked out with an ohmmeter.If it's a cap, try make a reading, if your multlmeter has capacitance range.

author: RJSV
author_rank: Super Contributor
timestamp: July 05, 2023, 01:43:20 am
content: Second posted picture clicks out to look correct.

author: srb1954
author_rank: Super Contributor
timestamp: July 05, 2023, 06:37:11 am
content: Quote from: Dan Moos on July 05, 2023, 01:10:52 amA ceramic plate capacitor. The dots are a colour code similar to resistor colour code except that it is measured in pF rather than.brown/black/red = 10x102= 1000pF.

author: Gyro
author_rank: Super Contributor
timestamp: July 05, 2023, 08:03:03 am
content: Rather than starting a new thread for each component, we already have a sticky thread specifically for component identification...https://www.eevblog.com/forum/chat/what_s-this-please-(component-advice)/
Another newbie oscilloscope question, dual timebases? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: January 07, 2012, 11:03:50 pm
content: Newbie question again, sorry. From my automotive background I have thought of a potential issue with using a dual or quad channel scope on signals of different frequencies. Let's say I want to use channel one to scope the crank position sensor output which is reading a trigger wheel with 36 less one teeth on an engine turning at 8000 RPM. that's about 4800 Hz I think?On channel two I want to watch the output of the O2 sensor which cycles a voltage of around 0.9 to 0.1 volts about once second. Would you need a scope with two time bases to see anything worthwhile of both outputs at the same time, or am I misunderstanding it? Is that what dual timebase scopes allow, the watching of two sources of very different frequencies at the same time? Do any USB scopes allow this? Thanks.

author: Lightages
author_rank: Unknown
timestamp: January 07, 2012, 11:44:08 pm
content: Yes you are right. There are dual trace scopes and dual channel scopes. They differ quite a bit in price.

author: amspire
author_rank: Super Contributor
timestamp: January 07, 2012, 11:58:03 pm
content: This is where long memory comes in. You slow the scope down to be able to capture the slowest waveform. Once the waveform is captured, you can zoom into the trigger wheel waveform at any point of the 02sensor cycle. The bigger the capture memory, the more samples can be captured giving you more high frequency resolution.For example, with the Rigol DS1052E, if you set the timebase to 200mS/div, and enable long capture memory, then with 2 channels, it is sampling at a bit under 5uS per sample. So that means there will still be about 40 samples per 4800Hz waveform, so that is pretty good. With long memory disabled, the scope would only be sampling at about 3KHz which is useless for the 4800 Hz waveform.There is also delayed sweep. This is where you trigger off the O2sensor waveform, but the scope is set to only show, say, a 1mS window. With the delayed sweep, you can move this 1mS windows backwards and forwards in time so you can investigate both waveforms at any part of the O2cycle. This method doesn't need the long memory, but you can still use it. The delayed sweep will give you the best resolution, but you are only able to see one slice at a time.Richard.

author: IanB
author_rank: Super Contributor
timestamp: January 08, 2012, 01:34:48 am
content: Quote from: amspire on January 07, 2012, 11:58:03 pmI've just made a post about these features in the other thread:https://www.eevblog.com/forum/index.php?topic=6239.msg81551#msg81551I was finding out how they work and thought that others might benefit from some pictures.
another noob wants to build a tesla coil... - Page 1
Forum section: electronics / beginners

author: Pirateguy
author_rank: Regular Contributor
timestamp: August 23, 2018, 02:57:45 pm
content: So i'm doing some preliminary research and acquisition work for a future tesla coil project andi am somewhat overwhelmed by the volume of info out there.The scope of the project is 2-fold:i want to make one desktop sized coil with a secondary of around >=6" tall.and i want to see how small a coil i can make that still is capable of significant discharge.both will be optimized for visual effect.for the desktop one i am looking for about this effect:and for the tiny ones as close as i can get to that.what kind of specs should i be shooting for?any recommendations for a particular type of coil?and can anyone recommend any good links for a noob?
Another what is this SMD? - Page 1
Forum section: electronics / beginners

author: Rick Law
author_rank: Super Contributor
timestamp: May 11, 2021, 05:44:29 am
content: I am trying to figure out what this SMD is.I had them in a project box I put away but forgot it existed a few years ago. I purchased > 20 of these on a cut tape, so I must have found it useful at the time -- but I can recall what the heck it may be.The ruler markings are mm.Thanks for any help.

author: Slh
author_rank: Regular Contributor
timestamp: May 11, 2021, 05:55:32 am
content: Some sort of diode. Probably silicon but could be Schottky.Measure it with the diode setting on your multimeter. Silicon is closer to 0.6V and Schottky more like 0.4V.If Schottky then the maximum reverse bias voltage might only be 40V but silicon is likely be much higher (80V+).If silicon it could be a variant of 1n4148.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: May 11, 2021, 06:18:01 am
content: See search results below:https://www.google.com/search?q=B2+diode&rlz=1C1CHFX_enUS697US697&sxsrf=ALeKk02E1GnAyTUAH2Pos5xmwDnonYbqZw:1620713809359&tbm=isch&source=iu&ictx=1&fir=0J5NjBbe57ttdM%252C-auIwUg-ZMhcnM%252C_&vet=1&usg=AI4_-kSC-1ZSGl6jZIjOMGyXttruAhtibQ&sa=X&ved=2ahUKEwivkI63_cDwAhWrQTABHZvbD44Q9QF6BAgVEAE#imgrc=0J5NjBbe57ttdM

author: Rick Law
author_rank: Super Contributor
timestamp: May 11, 2021, 05:46:13 pm
content: Thanks, guys!I kept looking for 82 instead of B2, what a blind dummy I was....
ANRITSU VNA 37397D - Page 1
Forum section: electronics / beginners

author: ELIAHOU
author_rank: Newbie
timestamp: December 04, 2015, 01:26:11 pm
content: I HAVE THIS ERROR ON ANRITSU VNA 37397D - PHS LOCK ERROR 6024i need to sell this equipment but i have to repair it

author: KJDS
author_rank: Super Contributor
timestamp: December 04, 2015, 02:26:02 pm
content: The maintenance manual is here, I suggest you spend a good while patiently workout out which module is faulty and replace it.https://d3fdwrtpsinh7j.cloudfront.net/Docs/document/10410-00264.pdf
Antenna driven element? - Page 1
Forum section: electronics / beginners

author: Cubbie
author_rank: Contributor
timestamp: October 25, 2022, 04:28:20 am
content: 850 MHZ 9 element GMS yagi antenna. I'm using it for P25 police scanner reception.It broke in a wind storm so, putting it back together. The driven element appears to be a folded dipole but, it makes no sense to me the way it is configured. Maybe this is not called a folded dipole? Appreciate any insight. Thanks.

author: Faranight
author_rank: Unknown
timestamp: October 25, 2022, 10:15:25 am
content: I think I've seen some yagi active element configurations like this that use the coax through half of the folded-dipole element as a balun.https://ham.stackexchange.com/questions/14713/feeding-a-folded-dipole
Antenna extender for sim900a module - Page 1
Forum section: electronics / beginners

author: A2
author_rank: Contributor
timestamp: August 11, 2014, 02:49:26 pm
content: Hi,I am using sim900A module, for sending SMS , similiar to this:http://www.aliexpress.com/store/product/Dual-frequency-sim900a-replace-Sim900-module-development-board-gprs-module-gsm-learning-board-better-than-sim300/835168_1328189947.html1. problem is there is no datasheet available, all are either from china or taiwan2. The antenna is very small. I have to increase the antenna length by 1m, is there antenna expander which I can use without losing the signal strength.
Antennas - Page 1
Forum section: electronics / beginners

author: olsenn
author_rank: Frequent Contributor
timestamp: July 31, 2012, 05:19:09 pm
content: Just thought I'd share this reference I found for helping to understand the basic types and operating principles on antennas. It uses the minimum amount of math and it seems to cover a very broad range of related topics.Here's the site:http://www.antenna-theory.com/On a side note: does anyone know of any places to find a high quality VSWR bridge; preferably with N-type connectors (BNC or SMA would also work)? I recently got into HAM radio, and I would like to use my spectrum analyzer to measure some different antennas to visualize their performance.

author: JackOfVA
author_rank: Unknown
timestamp: August 01, 2012, 12:46:08 am
content: Check Mini-Circuits for bi-directional couplers. (I assume you will use this with a tracking generator, not a transmitter.)Mini-Circuits' model ZFBD-61HP for example is 1-60 MHz, rated at 25 watts main branch power, 20 dB coupling loss. Price with your choice of SMA or N connectors is $67 plus a few bucks for shipping.Or, you can make your own.

author: olsenn
author_rank: Frequent Contributor
timestamp: August 01, 2012, 01:29:05 am
content: Thanks. Haha, yes; I do plan on using the TG of the spectrum analyzer, not my transmitter. As for your recommendation, I would like something that can go to much higher frequencies than 60MHz. I mainly use VHF/UHF and I would like to use the full range of my SA which is 1.5GHz. I'm willing to spend a few hundred dollars on this if it's neccesary.

author: kg4arn
author_rank: Unknown
timestamp: August 01, 2012, 04:39:16 pm
content: You can use the SA with a Tracking Generator and a Return Loss Bridge. The SWR relates to the return loss and there are many published tables. I keep the table from Minicircuits on my work bench.If you are careful you could build your own Return Loss bridge with good directivity up to the gigahertz range. But this requires some experience (and skill). I have built my own (HF) and I also use one from Amtronix (1.2GHz). it is $189 and has good (40dB directivity) at lower frequencies and 35 dB.http://www.amtronix.com/sw1200n.htmYou need to be aware that as the SWR measurement errors increase as the SWR gets closer to 1.0 (higher return loss). There is a web site by Sam Wetterlinhttp://www.wetterlin.org/sam/,somewhere on it he has some articles that explain the errors that are inherent with these measurements. If you are interested I can send send you a plot of the measurement uncertainty vs the directivity of the Return Loss Bridge.
Another What's this component question - Page 1
Forum section: electronics / beginners

author: ketil b
author_rank: Regular Contributor
timestamp: June 30, 2015, 05:53:47 am
content: Hi allI'm currently trying to fix a bit of test gear that is too noisy, I thinks that I have track it down to the voltage ref or the filtering on it output.The Vref is a LT1021-7 in a negative output configuration with a 100nF ceramic and the unknown cap in the pics, the marking are 10M8 16VFAm I correct in thinking that this is a 10uF 16V Solid Tantalum?thanksKetil

author: PICmonster
author_rank: Regular Contributor
timestamp: June 30, 2015, 01:49:38 pm
content: That sounds reasonable, did you try and check the capacitor with an LCR meter?

author: ketil b
author_rank: Regular Contributor
timestamp: July 02, 2015, 03:59:17 am
content: HiI finally got some batteries for my DE5000 and yes it is 10uF.Just needed to double check because i haven't seen that formfactor befor.thanksketil
Anti-interference shield purpose - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: January 18, 2021, 03:56:21 pm
content: Hi, I have smart screen with dual core 200Mhz CPU chip. The screen does not fit in tight spot slightly, so I want to remove anti-interference shield of CPU.What is the purpose of this shield?Does it protect only from other electronic components interference nearby or even from board components itself?Is this shield only needed if its close to other electronic components? ~30cm away?

author: TimNJ
author_rank: Super Contributor
timestamp: January 18, 2021, 06:42:23 pm
content: Faraday shield goes both ways. EM field cannot get through from outside, and EM field cannot exit from inside. So...it could be both?Touch screens can be quite sensitive to noise, and controllers require relatively high SNR to achieve accurate sensing. If you remove the shield, you should check that the reliability of the screen is still acceptable. Check with battery operation and with power adapter operation (if applicable).
Anti Static (ESD) Work Clothes (Lab Coat) -  Will It Help? - Page 1
Forum section: electronics / beginners

author: Steve Wayne
author_rank: Contributor
timestamp: April 28, 2017, 12:27:32 am
content: I recently moved to a region with possibly the highest level of self generated static electricity I've ever experienced. Will an Anti Static (ESD) lab coat or other ESD clothing aid in reducing the charge buildup and discharge to items under test, repair or exam at my workbench?

author: FlyingSquirrel
author_rank: Contributor
timestamp: April 28, 2017, 12:49:46 am
content: afaik ESD clothing will just not build up a charge, usually cotton clothes will do the trick too as far as your not dealing with very sensitive componentsopposed to synthetic (ie polyester) clothes that will attract them electrons like crap attracts fliesdo you maybe have a synthetic carpet that could be building up the electricity?an anti static wrist strap connected to an adapter to your mains earth should generally do the trick (just make sure it has a resistor built in)or when i have to fiddle in spots i cant reach very well with a wrist strap pulling on my hand, i usually make sure to wear cotton and just discharge myself on the adapter before i crawl into the hole - which obviously isnt 100% safe, but hasnt failed me so far

author: German_EE
author_rank: Super Contributor
timestamp: April 29, 2017, 08:18:56 am
content: A humidifier in your work room should help as well.

author: AndyC_772
author_rank: Super Contributor
timestamp: April 29, 2017, 08:47:30 am
content: Start with a dissipative bench mat, and always wear your wrist strap.Choose cotton or other natural fibres, rather than synthetic fabrics, and wear short sleeves when you're handling sensitive components.
Anti-static glove - Page 1
Forum section: electronics / beginners

author: fishandchips
author_rank: Regular Contributor
timestamp: January 27, 2022, 06:37:07 pm
content: Hi, in Winter, my place has static electricity issue. Recently, a lot of time when I touch equipment, static electricity is generated and caused malfunctioning even I touched the plastic part. If I wear a pair of anti-static gloves, will I be able to avoid such problem? Any good product recommendation?

author: electr_peter
author_rank: Unknown
timestamp: January 27, 2022, 07:49:18 pm
content: Pair of gloves would not be a good solution (it may be even worse, because you may not feel static anymore, but equipment will). You should look at static as a bigger problem and manage it with higher humidity, dissipative surfaces, potential bonding, removal of static generating materials (carpets, chairs, insulated boots), etc.There were several discussions on static issues in low humidity weather (like in heated homes in winter), search for it on forum.
Anti-static wristband newbie. - Page 1
Forum section: electronics / beginners

author: giovimonto
author_rank: Newbie
timestamp: January 26, 2016, 05:26:21 pm
content: Why there is a 1M? resistor in an anti-static wristband?Shouldn't the current be able to quickly leave my body?

author: bitslice
author_rank: Frequent Contributor
timestamp: January 26, 2016, 05:31:25 pm
content: Zaps are unpleasant, dissipating it more slowly is preferred.Besides, it is just there to stop the static building up, not dumping a potential out of nowhereAnd it's handy to be able to measure a defined value when testing to see if the strap is still functional

author: Ian.M
author_rank: Super Contributor
timestamp: January 26, 2016, 05:49:27 pm
content: More to the point, its there for your safety. Shock currents in excess of 10mA through the skin are generally regarded as hazardous. Assuming you aren't working on anything above 360V (the bus voltage in a EU SMPSU under high mains conditions), the 1Meg resistor will limit the current to 0.36mA, which is extremely unlikely to cause any injury.

author: bitslice
author_rank: Frequent Contributor
timestamp: January 26, 2016, 06:17:23 pm
content: ^Isn't that assuming the person isn't earthed by some other route?I'd assume the bench RCB would deal with any ground current issue, but yeh, fair point.

author: Ian.M
author_rank: Super Contributor
timestamp: January 26, 2016, 06:24:21 pm
content: If you are earthed by another route, the wrist strap manufacturer isn't liable

author: c4757p
author_rank: Super Contributor
timestamp: January 26, 2016, 06:50:40 pm
content: It isnotonly there for your safety, it is absolutely essential to the operation of the wristband. The termESDexists for a reason. Electrostaticdischarge- it's not the voltage/charge that's a problem, it's the current that flows when you discharge it. If you were solidly grounded, and touched a part that had picked up charge, you'd discharge it very quickly and kill it.

author: Ian.M
author_rank: Super Contributor
timestamp: January 26, 2016, 07:09:03 pm
content: I beg to differ slightly. Due to the human body's capacitance to ground, you can still kill a highly charged, very ESD sensitive device just by touching it, even with a 1Meg resistor in your wrist strap. It does however decrease the risk for less sensitive devices.

author: c4757p
author_rank: Super Contributor
timestamp: January 26, 2016, 09:13:34 pm
content: Well, yes, I never said it was perfect...

author: xwarp
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:38:04 am
content: I prefer applying ESD as if I were doing an EKG........
Anti static ? - Page 1
Forum section: electronics / beginners

author: AmirTheGreat
author_rank: Unknown
timestamp: March 11, 2013, 07:35:49 pm
content: Hey guys,Today I got my Real Time Clock ICs in the mail and they came in the anti static foam wrapped in Saran Wrap. I'm wondering if wrapping the thing up defeats the purpose of the foam.the inside of the package itself was lined with bubblewrap as well

author: knarf.be
author_rank: Contributor
timestamp: March 11, 2013, 07:49:46 pm
content: So far I got shipped only a few items with this technique from ebay. Never gave me any problems.Mostly they ship it to me withouth any type of antistatic foam etc. And also those come in undamaged. I even once had atmega's shipped packaged by pushing them in a piece of carton.Davd has a vid about this and its that ping stuf which doesn't generate static, but wont block it so I will have to answer NO.
Antistatic - Page 1
Forum section: electronics / beginners

author: banedon
author_rank: Regular Contributor
timestamp: April 18, 2015, 10:37:13 am
content: Hi guysBit of a noob question, but are the standard plastic tubes that DIP ICs come in antistatic? I've never thought so, but I have a guy who's sent me a CPU in one of these cellotaped to a bit of paper.

author: banedon
author_rank: Regular Contributor
timestamp: April 18, 2015, 11:59:27 am
content: Anyone at all?

author: GreyWoolfe
author_rank: Unknown
timestamp: April 18, 2015, 12:01:14 pm
content: They are safe for static sensitive components.

author: sleemanj
author_rank: Super Contributor
timestamp: April 18, 2015, 12:18:39 pm
content: Probably dissipative, if they hve any sort of conductive layer I don't know. The plastic is quite thick, so maybe that is deemed sufficient to prevent zapping through it as long as it is dissipative. Personally, i assume tubes and smd tape to be mechanically protective, they then go into conductive bags for static protection.

author: erolsansolo
author_rank: Contributor
timestamp: April 18, 2015, 01:08:19 pm
content: Extruded or injection molded plastic formulations (pe,pp,pet,ps,abs...) can easily be made sufficiently conductive (couple of Mohms) for ESD protection.

author: kolonelkadat
author_rank: Regular Contributor
timestamp: April 18, 2015, 04:05:28 pm
content: dave did a video or two on this.

author: Cherry
author_rank: Contributor
timestamp: April 20, 2015, 11:48:28 am
content: Anything else?
Any advantage to powering WS2812 leds at lower than 5V? - Page 1
Forum section: electronics / beginners

author: desertgreg
author_rank: Contributor
timestamp: April 28, 2023, 08:21:53 pm
content: Most projects I see power their WS2812 leds using a 5V power rail. Internally there are 3 separate LEDs and the blue led only needs (I think) 3.5V. My thought is, would there be an advantage if I tuned my buck converter powering the LEDs to output something closer to 3.5V instead of just using 5V? It seems like this would allow the individual leds to do a smaller step-down to the LED voltage (though I don't know how ws2812's work internally). Obviously if I get too close to the min voltage for the blue led, then it would stop working correcly.TLDR: Would my device gain efficiency if it powers its ws2812 leds at 4V instead of 5V?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 28, 2023, 08:25:12 pm
content: Yes it would be more efficient ( assuming your power supply is a switcher whose draw is proportional to output power, not output current. - reduce voltage until you see a drop in current draw, then increase a little. I've run short LED strips at 3.3v, though we didn't need blue in that jobJust make sure you allow for voltage drop, especially when using LED tape

author: Benta
author_rank: Super Contributor
timestamp: April 28, 2023, 09:00:05 pm
content: None at all.Read and respect the datasheet. The 5 V is for the internal logic/drive and interface.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 28, 2023, 09:15:42 pm
content: Quote from: Benta on April 28, 2023, 09:00:05 pmApart from saving up to 25% power, which may or may not matterQuoteThe datasheet says 3.7-5.3v supply

author: Benta
author_rank: Super Contributor
timestamp: April 28, 2023, 09:58:27 pm
content: Quote from: mikeselectricstuff on April 28, 2023, 09:15:42 pmGood.Then continue your project with the OP on running them at 3.5 V.

author: qtbits
author_rank: Newbie
timestamp: March 01, 2024, 07:38:25 am
content: Rather late to the conversation... but heat would be another reason to test on lower voltages... I have a tight 10x10 grid of 2020s and at 5V and full brightness - it gets too hot to touch.

author: baldurn
author_rank: Regular Contributor
timestamp: March 03, 2024, 08:36:39 pm
content: Quote from: mikeselectricstuff on April 28, 2023, 09:15:42 pmThat should probably be measured at the far end of the LED chain. There is going to be a voltage drop.
Any benfits from a bipolar OpAmp w/o internal ESD protection? - Page 1
Forum section: electronics / beginners

author: RoGeorge
author_rank: Super Contributor
timestamp: March 25, 2022, 07:27:03 pm
content: While searching for some generic bipolar OpAmps through my scrap boxes, I've noticed that Motorola has had two versions of the 2902:- LMT2902withoutinternal internal ESD protection (stated so in the datasheet)- and "normal" LM2902 with ESD clamping protection diodes includedWhy so? Why having two different dies for the same OpAmp? Is there any benefit for having a non-ESD OpAmp?

author: TimFox
author_rank: Super Contributor
timestamp: March 25, 2022, 08:43:30 pm
content: The internal diodes add extra capacitance between the two inputs, which can degrade high-frequency performance.Of course, blowing up the input devices will degrade the performance further.

author: RoGeorge
author_rank: Super Contributor
timestamp: March 26, 2022, 02:21:52 am
content: Could be. Not sure if that would make a difference in a low speed OpAmp (1MHz unity gain bandwidth), unfortunately the datasheet I found for LMT2902 has no AC specs. DC specs are identical between LMT and LM versions.I wonder how much extra die area is needed to add ESD protection diodes. Maybe they just wanted to fit more chips on a wafer, only to realize later that the ESD resilience is preferred over a slightly cheaper IC.

author: magic
author_rank: Super Contributor
timestamp: March 26, 2022, 07:57:53 am
content: Actually, I don't think I have seen anything special in LM358/324. There are TI versions on zeptobars.com and ST's TS321 and there used to be ST's LM358 on vintageteardown.com too but that site went down recently.Except for some of the Chinese ones, which appear to have a second PNP similar to the input one but with grounded emitter.
any common/cheap stepper motors smaller than the 28 byj-48? - Page 1
Forum section: electronics / beginners

author: engineheat
author_rank: Frequent Contributor
timestamp: July 28, 2017, 02:35:55 pm
content: Hello.I've been using the 28 BYJ-48 for a project and while it's quiet and offers the torque I need. The size/weight is a bit much for the space available. Does anyone know of any common/mass produced stepper motors that are tad smaller than the 28 byj-48 but still offers torque within the same order of magnitude? Something like the "24 byj-48" (if exisits).Thanks
Any CPLD-like thing with analog? - Page 1
Forum section: electronics / beginners

author: madshaman
author_rank: Frequent Contributor
timestamp: August 22, 2013, 09:05:47 pm
content: Anyone know of a CPLD or FPGA-like device that does mixed signal stuff where I can configure analog building blocks as well as logic?

author: free_electron
author_rank: Super Contributor
timestamp: August 22, 2013, 09:16:58 pm
content: Silego

author: tanstaafl
author_rank: Contributor
timestamp: August 22, 2013, 09:22:35 pm
content: http://www.microsemi.com/products/fpga-soc/fpga/fusion

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 22, 2013, 09:26:17 pm
content: Cypress Psoc

author: madshaman
author_rank: Frequent Contributor
timestamp: August 23, 2013, 01:30:56 pm
content: Thanks guys! Perfect leads :-)
any differences between pic 18Fxxxx?? - Page 1
Forum section: electronics / beginners

author: christos
author_rank: Regular Contributor
timestamp: January 30, 2017, 08:00:30 pm
content: hello,,does the PIC 18F4550 have any difference with the 18F2220?by that i mean ,the way to program it,,do they all have the same commands? for the 18F only

author: Buriedcode
author_rank: Super Contributor
timestamp: January 30, 2017, 10:14:56 pm
content: For the most part, I believe they share the same instruction set, although they are obviously different microelectronics, both 18F, and a quick skin over the datasheet leads me to believe that you can treat them as the same (save the difference maximum clock frequency, and different peripherals).Most code in 'C' these days which means one doesn't really have to know the instruction set, I'm surprised if you were using assembly for it.
Any "experts" care to chime-in on this power supply refinery problem?  - Page 1
Forum section: electronics / beginners

author: wuddadid
author_rank: Newbie
timestamp: May 18, 2021, 02:15:29 pm
content: This is my first post so apologies in advance if I broke some rules.I thought you guys would probably be able to solve this problem in a minute or two.A youtuber called sreetips who refines gold & silver is having problems with his silver crystal generator cell. You can watch the video but essentially he is using a cheapo power supply to form silver in an electrolyte cell.The problem is that the voltage on the power supply is not the voltage going into the cell. There is a voltage drop somewhere. I am thinking the connections are dodge but I also have been known to be a complete f#$king moron so...Anyway, here's the link!

author: mikerj
author_rank: Super Contributor
timestamp: May 18, 2021, 02:34:00 pm
content: I put a comment on there. He's clearly got a voltage drop in one or both of the cables he's connecting the silver cell to the PSU with. My immediate suspicion would be that inline fuse holder, I've seen these melt into a blob of plastic due to a high resistance between the internal contact and the fuse.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 18, 2021, 02:35:55 pm
content: wire seems to thin and too long ?? it create current losses, and by the voltage differece how much it is ?

author: tooki
author_rank: Super Contributor
timestamp: May 19, 2021, 12:11:46 am
content: And the update:https://youtu.be/NmaNVKlp9Wc

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 21, 2021, 06:29:11 pm
content: The wires look reasonably thick, and it's only an amp and a half, so even though the wires are quite long, loosing a volt is still quite much.But there is a weird yellow piece grafted in, and something that may look like a fuse and that can have a significant voltage drop. It also looks like a decent power supply with adjustable current limiting, so adding a fuse is not needed at all.Switching power supplies can be noisy, and often are. I am not sur if that is relevant for electrolysis though.You could measure the AC output of the power supply, but most DMM''s do not have sufficient bandwith to give a sensible measurement.