hybridfree/eevblog-posts huggingface dataset:
XOR, XNOR logic, question. - Page 1
Forum section: electronics / beginners

author: firewalker
author_rank: Super Contributor
timestamp: September 25, 2014, 01:06:14 pm
content: When do we say that a digital circuit verifies the "XOR logic" or the "XNOR logic". Does a digital circuit with functionY=A+B+ABverify any of the above logic?http://en.wikipedia.org/wiki/Exclusive_orhttp://en.wikipedia.org/wiki/Logical_equalityAlexander.

author: Dave
author_rank: Super Contributor
timestamp: September 25, 2014, 02:57:39 pm
content: Y = A + B + AB is just an ordinary OR function. The AB part of the equation is redundant.XOR: Y = AB' + A'B (the ' symbols are the negations)XNOR: Y = AB + A'B'

author: firewalker
author_rank: Super Contributor
timestamp: September 25, 2014, 03:01:58 pm
content: So the question is (once again) wrong. You must select XOR logic or XNOR logic.Alexander.

author: DJohn
author_rank: Regular Contributor
timestamp: September 25, 2014, 03:22:12 pm
content: "Verify" is a strange word to use. A circuit can realise some logic function (make it real), and you can verify that it does. But what they mean by the circuit verifying the function, I don't know.If someone claims that Y = A + B + AB is equivalent to XOR or XNOR, it's easy to check with a little truth table:A B | Y XOR XNOR0 0 | 0 0 10 1 | 1 1 01 0 | 1 1 01 1 | 1 0 1The Y column isn't the same as either XOR or XNOR, so it's something different. As Dave says, it's equivalent to OR: Y = A + B.But that might not be what the original question is asking. Do you have a bit more context?

author: firewalker
author_rank: Super Contributor
timestamp: September 25, 2014, 03:34:34 pm
content: An exact translation (from Greek) of the question is:QuoteThe syntax is also wrong in Greek. The question "Verifying the EXOR logic or the EXNOR logic?" makes more scene as "Does it verify the EXOR logic or the EXNOR logic?".And also, who writes XOR as EXOR and XNOR as EXNOR?Alexander.

author: DJohn
author_rank: Regular Contributor
timestamp: September 25, 2014, 04:27:43 pm
content: That makes a bit more sense. This circuit is !(!(A+B))(!AB)) = A+B + AB, as you said. I guess they're asking if it's XOR or XNOR, but it's neither.If you turn the NOR gate into an OR, then you get !((A+B)(!AB)) = !(A+B) + AB, which is an XNOR. Perhaps you should offer to proof-read for them. For a suitably high fee, of course, to compensate for the inevitable loss of sanity.I've not seen EXOR before, but the 6502 did have an EOR instruction (for 'exclusive or').
XR2206 timing current formula - Page 1
Forum section: electronics / beginners

author: marekpasek
author_rank: Contributor
timestamp: June 25, 2018, 07:37:39 pm
content: Hello, I have a problem deriving the formula which would descripe the relationship between Vin and output frequency on xr2206.The datasheet says that f =1/RC, where C mean the timing capacity and R means the resistance between pins 3 and 12. Therefore I derived that f = dVin/3RC, where dVin means the voltage difference across resistor with given resistance R and C mean timing capacity.Nevertheless the datasheet also says that f = 320000I/C.Certainly both formulae cannot be correct therefore... where is the mistakeThanks

author: ledtester
author_rank: Super Contributor
timestamp: June 26, 2018, 06:37:05 pm
content: Well, dVin/R = I, right?So the only difference is in the constant - you have 1/3 and the datasheet has 3200000.How are you deriving your 1/3? Could it just be you are using different units? Note that 1/3 = .333333... which is close to 320000 if you multiply by 10^6.

author: marekpasek
author_rank: Contributor
timestamp: June 27, 2018, 07:57:44 pm
content: Correct. The voltage on pin 7 (sorry, I was misled and I thought it was pin 3) with reference to pin 12 equals 3v and is constant. Therefore 1/V equals 0.33333. There is a difference only in that. Nevertheless it makes a serious variance in the output frequency. I want to construct a device on whose precision I could rely, so I need to be capable of predicting the output frequency accurately.

author: ledtester
author_rank: Super Contributor
timestamp: June 28, 2018, 01:38:45 pm
content: Two things...1. If you want to have an RC timing circuit produce a specific fixed frequency you need to make one of the components adjustable (i.e. either a variable resistor or variable capacitor) and use a frequency counter to tune that component to the desired frequency.2. Below is the formula I found in the XR2206 datasheet. Note that "I measured in mA" is I*1000 and "C measured in microfarads" is C*1000000, so the frequency formula is:Code:f = 320 * (I*1000) / (C * 1000000) = 0.320 * I / CXR2206 datasheet:https://www.sparkfun.com/datasheets/Kits/XR2206_104_020808.pdf

author: schmitt trigger
author_rank: Super Contributor
timestamp: June 28, 2018, 01:51:44 pm
content: If you are building your own XR2206 based generator, I would suggest to watch this very informative video:
XS3868 / OVC3860 5sec idle noise. Help needed - Page 1
Forum section: electronics / beginners

author: ESXi
author_rank: Regular Contributor
timestamp: August 04, 2017, 04:58:35 pm
content: Hi,I don't want to copy paste my problem.http://www.diyaudio.com/forums/car-audio/310717-xs3868-ver-3-0-bluetooth-stereo-audio-noise-5-idle.htmlThis is the issue I have.Here is a video of it :https://youtu.be/9YBVj6Cl-cEHere is the diagram (shown in the video on the prototype board)I have tried to hook it up to another amp, same problem. I tried headphones and those work without the buzzing sound after 5 seconds! I don't understand why.. Soms people say it's a fault on the board (gnd and audio gnd being the same. I don't know. I used the diagram provided by the DS).

author: danadak
author_rank: Super Contributor
timestamp: August 05, 2017, 11:03:00 am
content: This is a longshot but datasheet does not show specifically asystem ground connection between car 12V chassis and thebluetooth batteries common. So try it without a commonground......Although chip does have a Li battery chargingcapability, but in your schematic does not appear to beconnected.Datasheet very poor on unterminated connections, like VPOW,and a lot of others. Maybe their website has a FAQ section orforum where you can post.Regards, Dana.

author: ESXi
author_rank: Regular Contributor
timestamp: August 05, 2017, 04:26:30 pm
content: Hi Dana,Thanks for your response. I have my OVC3860 powered by common and vbat pin. It is powered for testing now by USB 5 volt to a LM2596S buck convertor or DC DC step down set to 3.8volt.With headphones (without amp) I never hear this noise. After 5 seconds when using headphones nothing can be heard in the headphones after 5 seconds idle. Not even a tiny little RF noise (which is normal). So I tried another small amp instead of the car amp I used in the video. And the result was the same.Best regards,ESXi

author: ESXi
author_rank: Regular Contributor
timestamp: August 09, 2017, 12:38:41 am
content: It was a design fault..I fixed the problem by adding a 4.7uF cap to pin 20 of the OVC3860 (VMID) to I believe pin 16 A0M (audio ground).If I change 4.7uf to 100uf almost all of the HF crosstalk is filtered out but at the cost of the audio quality.. The pcb design still has some flaws. It has been improved over ver.2.0 but still.. Add a small wire to the antenna this will lower the noise as well. So far I'm happy now. For this price can't really complain, but the developer could improve software button debounce a bit. The board needed some tweaks but hey, it works and was only 2 dollars!
Xtal without MCU? - Page 1
Forum section: electronics / beginners

author: kfitch42
author_rank: Frequent Contributor
timestamp: March 08, 2013, 08:10:26 pm
content: Mostly out of curiosity I was wondering how one would use a crystal oscillator(resonator?) without a microcontroller. In just about every microcontroller datasheet you see something similar to the attached image. What magic lives on the other side of those xtal pins? Is it something a noob like me could actually breadboard?

author: mrflibble
author_rank: Super Contributor
timestamp: March 08, 2013, 08:25:44 pm
content: See for examplehttp://en.wikipedia.org/wiki/Pierce_oscillator

author: TerminalJack505
author_rank: Super Contributor
timestamp: March 08, 2013, 08:42:24 pm
content: Yes, this is something you can breadboard quite easily. (High frequencies might be a problem on a breadboard, however.)There are a few ways to go about it but most circuits use, in addition to the crystal, just a couple of inverters, a few resistors and a few capacitors. Do a Google image search on "crystal oscillator circuit" to see some examples.They make ICs specifically made for this too.For example. Notice (page 7) that all that IC really does is package-up the inverters. You still need to provide the capacitors, resistors and crystal.Finally, in case you aren't aware, they package the whole crystal and other necessary components up into a single package an call it a crystal oscillator.

author: Bloch
author_rank: Unknown
timestamp: March 08, 2013, 09:33:46 pm
content: My first was with 74xx and 40xx IC´ssome thing like this look okhttp://www.z80.info/uexosc.htm

author: jimmc
author_rank: Frequent Contributor
timestamp: March 08, 2013, 09:41:37 pm
content: Try looking at crystal manufacturers application notes for ideas.e.g.http://www.euroquartz.co.uk/Portals/0/pdf/tech-notes.pdf(practical circuits start on page 5).Jim

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 09, 2013, 12:36:28 am
content: Spot the mistake.edit: It's from the above tech sheet, which was actually interesting for a Xtal noob such as myself.

author: c4757p
author_rank: Super Contributor
timestamp: March 09, 2013, 12:49:25 am
content: Quote from: HackedFridgeMagnet on March 09, 2013, 12:36:28 amC1is an inductor and L1is a capacitor.

author: marshallh
author_rank: Unknown
timestamp: March 09, 2013, 06:58:50 am
content: 74HCU04 + xtal is a common setuphttp://www.nxp.com/documents/data_sheet/74HCU04.pdfSee page 8

author: pspgeek
author_rank: Contributor
timestamp: March 14, 2013, 02:40:52 am
content: Thanks. I was also looking to use a crystal to replace a (transistor + capacitor + etc) oscillator.
Xytronic 968 insides - Page 1
Forum section: electronics / beginners

author: Noidzoid
author_rank: Regular Contributor
timestamp: July 07, 2018, 12:58:56 pm
content: Not much out there on these it seems. So incase anyone is interested here is the interior of mine, and to my untrained eye it looks pretty solid.

author: Noidzoid
author_rank: Regular Contributor
timestamp: July 07, 2018, 04:04:50 pm
content: Quote from: wilfred on July 07, 2018, 01:15:26 pmGood to know. Thanks
Xytronic LF3200 pinout - Page 1
Forum section: electronics / beginners

author: Vorskin
author_rank: Newbie
timestamp: October 09, 2021, 12:11:52 am
content: Hello. Me new here. I just wonder if I can modify some standard soldering handle for my beloved Xytronic LF3200 model with this 6-pin pinout. Goal being getting tips for lower price in Europe by changin handle to modified Hakko handle. I cannot say I understand too much of it but I was able to hack pinout. And Hakko has same pinout except number 6 which is in the middle. In hakko it is not connected but in LF3200 it is second white wire. I wonder what kind of function it is part of. Could you please tell me some suggestion how to track it or better if you really know about it already.One thing to mention is that iron has dual function in standby.1.Something like at 10 minutes without use LF3200 goes to waiting state where display starts to show 100 .2 For added safety after 25 minutes or so it goes off and must be restarted from switch to get function back. Switch must be off 5 seconds or so to get it running again.3. When it is in initial standby waiting state just touching the brass shavings will make it heat back to full power.Would that extra middle pin 6 have something to do with that recover mode from 100 to full power?

author: Paroidia
author_rank: Contributor
timestamp: December 22, 2021, 08:43:39 am
content: Quote from: Vorskin on October 09, 2021, 12:11:52 amIf you mean Hakko FX888D type tips it won't work, they use two completely different methods of heating. the FX888D uses a ceramic heater and the LF-3200 uses high frequency induction heating, basically it runs 36v 400khz AC though a coil around the tip and heats it by induction.Try looking for Quick 200 tips (Ebay has lots of them) they are the same design as the Xytronic high frequency tips and will work in the HF90 handset that the LF-3200 uses.

author: Vorskin
author_rank: Newbie
timestamp: December 23, 2021, 06:28:13 pm
content: Ok. Thanks.

author: Paroidia
author_rank: Contributor
timestamp: December 24, 2021, 03:25:35 am
content: Quote from: Vorskin on December 23, 2021, 06:28:13 pmYou can also get some sizes and shapes in the "off brand" tips that Xytronic doesn't make like a 5mm chisel. Unlike third party Hakko tips these actually work well, induction irons don't care about air gap. They're using high frequency AC to directly heat the metal in the tip so exact tolerances aren't critical because the air gap is irrelevant.
Help needed - YAATXPS  Yet another atx power supply - Page 1
Forum section: electronics / beginners

author: opicaretasoueu
author_rank: Newbie
timestamp: September 04, 2018, 10:25:23 pm
content: Hey fellas, how ya doing?I'm building my very first atx power supply and already got the 3.3v 5v 12v binding posts and a USB port on the 5vsb line. It's working fine so farI'm planning to add a power and stand-by led indicators and a step-up and step-down modules so I can get some more interesting voltages going on.I'm about to add the two modules and see what voltages i'm getting with the V/A meter thing and as a final step put everything into a laser cut enclosure.Can I get away with the plan shown below?Here are some pics:PS.: excuse my nasty workbenchcheers,Fernando

author: xani
author_rank: Frequent Contributor
timestamp: September 07, 2018, 03:40:40 pm
content: PleaseADD FUSES. Resettable polyfuse (preferably on lines going from atx supply directly, before your electronics) will save you a lot of trouble if something goes wrongATX power supplies can supply a LOT of amps and even tho they generally are over-current protected.Like even 250W one can usually put ~20A on 5V line and often more than 10-20A on 12V, which means if you fuck something up you can even evaporate some component or trace on target device before ATX limits even trigger.While fuse is not an 100% sure protection (it has delay, so there will still be a power spike, power regulator with current limit will be much faster than fuse), it helps to at least limit the damage
Yaesu FT-902 boat anchor losing TX power after long powered on periods in RX? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: June 03, 2012, 04:08:45 pm
content: I was falsely blaming my laptop for reduced audio drive to my FT-902DMwhen running USB digital, but having now seen it do the same from aproper PC, with a different interface, and seeing as it's gettingworse, I need to check it out. I am thinking it's time or temperaturerelated as it's fine in a m morning after being turned off all night.But after a few hours of being left on, TX output power has dropped toabout 5 to 10 watts even with plenty of audio drive in digi modes.Pressing the "Tune" knob gives more output, but nothing like enougheven with everything plate and loaded, and trimmed up properly, withfull carrier. It seems fine when cool, and gives its 100 watts OK.Without more testing I can't say if this happens if I leave the tubeheaters off until such time as I want to transmit, and I am not sureif I should be running it at all for prolonged periods. Only whoopsieis I blew the main fuse (which has always been fast blow, 3Amps),three times when my ATU had an internal issue and I couldn'tload the set up properly. It ran fine for some long period ( a coupleof weeks or so) after these dramas, so not sure if it's relevant. Cananyone suggest some tests I can perform to see what's happening, andis leaving it on, in receive, to see if the heaters being on or not isrelevant, a good idea? All PS caps were changed a good while ago (4months or so) except the two very big ones in the middle of the case,I didn't have to time to ferret them out. I have new ones for itthough. I have changed the notorious very high voltage ceramic for thepower tubes though, I forget its number designation.I have a decent scope, a Wattmeter, signal gen and frequency counter,as well as decent bench meters, but as yet am at a very low level inthe learning curve. I am aware of the high voltages present in thesethings, and residual in the caps, and how to preserve myself for alittle longerThanks.

author: vk6zgo
author_rank: Super Contributor
timestamp: June 05, 2012, 04:48:16 am
content: Chris,do you have a dummy load?If so, the best thing I can think of is to leave the Radio running continuously keyed in CW mode,& see if the power drops after a while.You probably won't be able to do this for long,as most dummy loads aren't up to really long periods of full power.If you don't have the problem with continuous carrier,the fault is probably in your SSB generator,or some other circuit which is used for SSB,but not CW.If it is in low power stages,you may be able to monitor it with your Oscilloscope.I don't really know the FT-902DM,so can't help much more.Have you tried asking on QRZ.com.or eHam?There are some very knowledgeable people on this forum,but few of them are Hams,so you may do better on those forums.73,VK6ZGO
Yamaha PSS590 repair: bad IC ? - Page 1
Forum section: electronics / beginners

author: ratatax
author_rank: Regular Contributor
timestamp: August 23, 2020, 07:13:39 pm
content: Hi,I'm trying to repair a PSS-590 keyboard, it worked well a few months ago but today it keeps creating random noises and random display when I power it on.So opened it up then I reworked all the solders. Now it starts with the right display ("000" on the 7 digit displays) but no sound and the interface doesn't respond at all (pressing any key does nothing).I also noticed two leds randomly flickers with varying intensity while they should be completely on or off.Power supply is OK (+5V), the sound amplifier part too. The keyboard scans the button matrix I see the pulses. But I noticed that some 8-bit communication between two IC's YM7138 (sound chip) <=> XH748A0 (mask rom I think) is totally weird, see what I probed with my scope (attached pic)It's the same on all the 8 data lines. Random levels instead of clean 0/5V pulses.I'm not very experienced in repairs but does that mean the IC went bad (for no apparent reason)? I'm short of ideas, I probably could remove some caps to test them for high ESR (although they look perfect) but if you have more ideas to try let me know

author: gnif
author_rank: Unknown
timestamp: February 07, 2022, 10:39:39 pm
content: Quote from: melohoca on February 06, 2022, 08:20:58 amThis is an English forum, please reply in english.

author: sashko
author_rank: Newbie
timestamp: April 07, 2024, 01:00:02 pm
content: Hi,I know it's been a while but... I guess I've found the issue.I recently encountered the same symptoms with my Yamaha PSS-595.None of the buttons and keys are working. Both displays show "0".The power amplifier looks good.All electrolytic capacitors that showed high ESR and rather low capacity were replaced.After some poking around with oscillograph and multimeter I've come to a conclusion, that the System ROM chip (IC5) is a faulty one.It wasn't hard to find a dedicated firmware dump for that EEPROM IC and the programmer for flashing it, but getting a replacement EEPROM chip is a tough one (no luck yet).

author: aliarifat794
author_rank: Regular Contributor
timestamp: April 07, 2024, 02:57:27 pm
content: Make sure there are no short circuits on the PCB, especially around the ICs you've mentioned. Also, check for continuity on all the traces connected to these ICs to ensure there are no breaks or damaged traces.

author: xvr
author_rank: Frequent Contributor
timestamp: April 07, 2024, 06:15:43 pm
content: > But I noticed that some 8-bit communication between two IC's YM7138 (sound chip) <=> XH748A0 (mask rom I think) is totally weird, see what I probed with my scope (attached pic)Looks like ROM chip is out of orderJust in case - try to check power pins with oscilloscope on both chips.
Yaskawa/Omron V1000 VFD - Max. freq. locked - Page 1
Forum section: electronics / beginners

author: cs.dk
author_rank: Unknown
timestamp: June 16, 2013, 09:44:53 am
content: Hi,I've installed/programmed several (used) Omron V1000s, but this one is giving me a headache. Max. frequency parameter is for some reason locked.I started with Initialization;Parameter O2-03 = 2 (Clear all)Parameter A1-03 = 2220 (2 wire installation) (default when shipped)But for some reason I can't edit E1-04 Max. frequency output.Parameter A1-01 (Access Level) is set to full access.Any ideas?

author: edm68
author_rank: Newbie
timestamp: June 16, 2013, 07:18:45 pm
content: I'm not familiar with the V1000, but on the Z1000 there is a parameter D2-01 that needs to be changed for the max frequency. It needs to be stopped to change it.Edit:My mistake, it looks like for E1-04 thru E1-14 to be changed from their default values E1-03 needs to be set to F.I was able to find a V1000 manual here:http://yaskawa.com/site/dmdrive.nsf/(DocID)/MHAL-7JSLMA/$File/SIEPC71060618.pdf

author: cs.dk
author_rank: Unknown
timestamp: June 17, 2013, 07:34:25 pm
content: You are absolutely right - Today I match all menues up with my other V1000's, and E1-03 was the only thing being different.. It is not mentioned in the quick-start guide, only in the full manual. Thanks alot for your replyI just don't understand, I set the VFD to factory-default (i guess) - This parameter should be defaulted to?
FIXED: Yes another rotten homemade PSU - I think I'm loosing my marbles - Page 1
Forum section: electronics / beginners

author: tron9000
author_rank: Frequent Contributor
timestamp: May 02, 2016, 04:13:48 pm
content: right I really don't understand what's happen here, I think I'm seriously am loosing my marbles so please bear with me.Here is my circuit:Its a 20V 1A adjustable PSU, yes I know its another one of those designs based on Daves PSU tutorial. I know there are better designs, I know I can buy my own off banggood or whatever, this is my project and its going to cost me less than a tenner in parts, I'm trying to prove you can build your own kit using scavenged parts without having to raid your piggy bank.Anyway the problem is the current limiting control circuit. Without R8 connected to the base of Q2, the output of IC1B works as it should: you set the current limit pot (it'll be on pads8, 9 & 10 with the wiper on pad 9), connect a load to the output between pads 4 & 5 (in this case 44R) and turn up the voltage and as the current increases the output of IC1B switches high (25V = V+)Yet when you connect R8 to Q2 and do the same thing, it doesn't work as expected. The voltage at pin 7 on IC1B slow ramps up to 0.6V as the output voltage is increased and the current just keeps climbing past the set point.I know there is something here I'm not seeing, and can't find out what, I think I'm loosing my marbles a bit, which is worrying.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 02, 2016, 04:22:36 pm
content: well having a blown Q2 doesn't help - marbles found! please ignore and thanks for looking.

author: Martini
author_rank: Regular Contributor
timestamp: May 02, 2016, 04:53:30 pm
content: Dumb question....what are the pads?

author: GreyWoolfe
author_rank: Unknown
timestamp: May 02, 2016, 09:11:58 pm
content: Methinks it's the solder pads.
Yet Another ATX Power Supply Idea - Page 1
Forum section: electronics / beginners

author: ruku
author_rank: Contributor
timestamp: April 18, 2011, 06:18:35 am
content: So I'm looking for a practical project to build, and a bench power supply seems to be like a sane thing. I started out with a LM317, went to a LM338, then to a few transistor based ideas, and then an ATX... ...and back all over again.I could go whole hog on the design, but I really liked the idea of a single transistor power supply. Its simple enough that I don't get bogged down, but complex enough that I have to learn a few things.Based off of this design,http://tuxgraphics.org/electronics/201005/bench-power-supply-v3.shtmlThe TL;DR here is he's using a BJT power transistor as a voltage follower, and using an AVR microcontroller to generate the buffer levels. Since the BJT's base terminal has a low impedance (and thus requires amplification), I was thinking of using a MOSFET power transistor. My understanding is they have high input impedance, which means a voltage buffer would be more simple.I'd like to be able to source 0 - 12 V at around 2 amps max (...25 Watt transistor?) from an ATX power supply. I've heard they can be noisy, so I figured stack the 12 V and a 5 V line together and feed it through my regulator, then use a cleaned up 5 V line to run the uC and supporting hardware. Maybe use a relay to switch between the 12/5 line and the 5/3.3 line so not so much power is wasted...ANYWAYS. I come to my point. I'm fairly set on my single transistor design, unless there's a significantly simpler and better way of doing this. However, I haven't decided on my transistor (BJT, MOSFET, JFET?) or its characteristics. I'm also not entirely sure how to analyze my circuit... there seem to be a few ways to lay out a voltage buffer, and I'm unable to decide which is the best. Any help would be muchly appreciated!

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: April 18, 2011, 12:57:51 pm
content: Quote from: ruku on April 18, 2011, 06:18:35 amIf by stack, you mean connect the 12V and 5V supplies in series to get a 17 volt supply, it won't work. They have a common ground.

author: House91320
author_rank: Regular Contributor
timestamp: April 25, 2011, 01:06:25 am
content: Do all the rails in a pc power supply share a ground our are they isolated.

author: PeterG
author_rank: Frequent Contributor
timestamp: April 25, 2011, 04:35:22 am
content: PC PSUs are all Common Ground from what i have seen.Regards
Yet another beginners soldering iron topic - Page 1
Forum section: electronics / beginners

author: eevdude
author_rank: Contributor
timestamp: November 20, 2020, 10:16:32 am
content: Hey guys - i've seen the other posts about soldering irons and problems and i have to say i have found the same. I used to solder at college and home many many years ago, with pretty basic kit, but the soldering irons and solder of old were pretty good to whats available these days.I didn't want to spend too much, but get useable equipment - so i did some research, and eventually went with a recommendation of a Saike 220V 909D+ by a popular drone builder youtuber. I ordered one for £70 with a load of rubbish tools and solder/flux that i will never use, and what turned up was a HANDSKIT branded device, which when i asked the seller they said it was the same thing (and when i checked back on youtube theirs also had that branding) - weird.It's not great. The temperatures are way out, you have to be +50 higher than you really should be, and the range of temperature depending on your ambient temperature is terrible. The air gun? has been useful a couple of times, but i really should have bought a separate air soldering iron.So then after doing a lot of research i was stuck between getting a ksger T12 for £30 or a T80 for £70. I went with the ksger and some tips after reading about the hold-ability for longer periods of the T80. The ksger is a lot better, temperatures are better, but the tips are terrible, going black after one use, only having one small part of the tip producing heat.I totally understand with people posting why i can't solder at the temperatures some of the pros tell you too. I think my set is okish now, i'm not sure i'd spend >£100 on the big brand soldering irons, because their seems to be issues with new versions of those, until you go upto pro levels.Anyway just wanted to share my thoughts for other people looking to purchase a setup, any comments/thoughts would be great from other owners of reasonable priced equipmentD

author: ataradov
author_rank: Super Contributor
timestamp: November 20, 2020, 05:40:03 pm
content: All those cheapo combined stations are about the same. You can fight the seller on that, of course, but what you will get with the other one would likely be very similar.Temperature indication accuracy does not matter that much. Just adjust the temperature until solder comfortably melts, but the flux does not burn instantly.Ksger T12 is an excellent soldering iron for the price.

author: uli12us
author_rank: Contributor
timestamp: November 26, 2020, 02:58:41 pm
content: And try to get a leaded solder wire instead of that leadfree crap, you often get with some DIY-Sets.Maybe its not so good for the tips, but these tips are really cheap (4-5$) and the one, you get with the iron at buyis nearly unuseable. Better use a horseshoe or a chisel shaped type, the Knife Type is also good for some works,
Yet another bench power supply design - Page 1
Forum section: electronics / beginners

author: mayor
author_rank: Regular Contributor
timestamp: May 15, 2014, 08:35:15 pm
content: Hello! First post here. As a learning experience, I've decided to build a current and voltage adjustable power supply. I know many others have done so :-)My requirements aren't as strict as Dave's in his power supply series (starting at eevblog #221), in that minimum voltage isn't a critical issue.I have designed the following in TI Tina (similar to LTSpice), and it checks out in the simulator. Don't get hung on the component selection (especially since I'm using theoretical op amps!). What I am looking for are comments on the overall design. As I said, plenty to learn here. I will add protection circuitry (but will need to read up on that - please feel free to comment on the how and why, too!)The idea is to control current and voltage from a microcontroller, where 0-1V will adjust current from 0 to 1A (notwithstanding the LM317/1117 or whatever other regulator's physical limitations), and 0-1V from another pin to adjust voltage from ~1.25V to 5V. I could easily change the voltage and current ranges in software using the same divider and sense resistor.Anyway, thanks for any suggestions! See attached image.

author: pipe
author_rank: Contributor
timestamp: May 16, 2014, 12:23:24 pm
content: Won't the regulation suffer when you have the current sense resistor after the regulator? The LM317 will try to make the output about 1.25 volts above the input, but when your load draws a variable amount of current, the regulator won't "see" the voltage drop appearing across the sense resistor and it can't do anything about it.Oh, and while you're doing this, I suggest that you make the voltage range a little higher, maybe aim for at least 15 volts. That way you'll get a much more usable bench supply!

author: IO390
author_rank: Regular Contributor
timestamp: May 16, 2014, 12:35:22 pm
content: I've built a power supply using very similar current regulation. The sense resistor used was 20mOhm, so the drop at 1A (max limit) was only 20mV, so pretty much bugger all. Then all you need to do is switch between the voltage going into the opamp for the limit and the top of the sense resistor, amplify it by whatever and display it on a voltage readout.That way you can see the max limit when the output is off (on the switch), then when you turn the output on it will display the current draw.As for the voltage drop, a possible remedy would be to take the voltage drop off of the resistor and add it to the adj pin of the LM317. That way it will compensate for the drop, although there might be some issues with oscillation, I'm not sure though.Oh and you won't be able to get the current limit down to 0 in this config. You'll need to get the output of the opamp down to zero, adding a negative rail would solve that.

author: mayor
author_rank: Regular Contributor
timestamp: May 16, 2014, 06:01:08 pm
content: Good points. Max voltage is a resistor change away. I will see about a change to include current limiting accounted for. Thanks!
Yet another component to be identified - Page 1
Forum section: electronics / beginners

author: giosif
author_rank: Frequent Contributor
timestamp: January 07, 2017, 11:03:39 pm
content: Ok, got a quick answer to my previous call for help on identifying a component.So, I am hoping to up the game with this one.Anyone any guesses?Thanks!

author: Benta
author_rank: Super Contributor
timestamp: January 07, 2017, 11:18:06 pm
content: Signal transformers, TX/RX pair. Which interface type is not clear.

author: giosif
author_rank: Frequent Contributor
timestamp: January 08, 2017, 11:16:56 pm
content: Quote from: Benta on January 07, 2017, 11:18:06 pmAmmm... Ok...Thanks for that!Have to admit, I am not any much more clear on what these are doing on the board I have (part of a Solartron 7060 multimeter).

author: Benta
author_rank: Super Contributor
timestamp: January 08, 2017, 11:45:51 pm
content: What's up here?A question with incomplete data just for fun? Bye.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 09, 2017, 01:48:05 am
content: Quote from: giosif on January 08, 2017, 11:16:56 pmAs standard for nearly all bench DVM design, the grounded digital control circuitry is electrically isolated to the floating analogue circuitry. These two interfaces can exchange data/control signals optically via optocoupler or magnetically via signal transformer.

author: giosif
author_rank: Frequent Contributor
timestamp: January 15, 2017, 10:59:42 pm
content: Quote from: Benta on January 08, 2017, 11:45:51 pmSorry, my intention with my reply was meant to reflect how "much" knowledge and understanding on electronics I have.i.e. I had never heard of signal transformers before.

author: giosif
author_rank: Frequent Contributor
timestamp: January 15, 2017, 11:00:49 pm
content: Quote from: eblc1388 on January 09, 2017, 01:48:05 amThank you for the explanation!I understand now.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 16, 2017, 01:06:25 am
content: Here is a typical drawing showing the two interfaces, communicating via signal transformer. It is taken from an age old Datron 1051 bench DVM schematic.The analogue section uses +/-15V while the digital section uses 5V. They do not share a common ground. Therefore if one connects 500V to the DVM input during a measurement, then there could be 500V between the two sections.

author: giosif
author_rank: Frequent Contributor
timestamp: January 16, 2017, 10:46:10 pm
content: Quote from: eblc1388 on January 16, 2017, 01:06:25 amOk, it is clear now.Thank you again!
Yet Another Electronics Primer - Page 1
Forum section: electronics / beginners

author: Dumpsterholic
author_rank: Regular Contributor
timestamp: November 07, 2023, 04:37:00 pm
content: Hi all: I recently unpacked myAnalog Discovery 2device and started searching for any teaching materials associated with it. Feel free to laugh at me for buying the thing, but it has a lot of useful features and is quite well documented and supported, even though a new, upgraded device, theAnalog Discovery 3, has been out for some time.Anyway, in the process of my search, I came across a nicely put together lab manual-cum-reference guide which I find does a very good job of explaining basic concepts in electronics, and also sets forth a variety of experiments. While the guideisaimed at users of theAD2, the explanations are concise, and the experiments can be carried out using the "real" test equipment theAD2is supposed to replace--DMM, oscilloscope, waveform generator, et cetera. At the time of this writing, the whole schmeer, running to 688 pages, can be downloaded for free in .pdf form at the link below; also, individual chapters can be downloaded separately. Needless to say, I have no relations, commercial or otherwise, with Analog Devices, Digilent, or any of their partners.https://digilent.com/reference/learn/courses/real-analog/start

author: JJ_023
author_rank: Frequent Contributor
timestamp: November 07, 2023, 10:47:26 pm
content: Seems pretty neat. I'll have to check it out. Thank you.
Yet another ESD-storage question - Page 1
Forum section: electronics / beginners

author: ollihd
author_rank: Regular Contributor
timestamp: May 03, 2016, 08:40:37 pm
content: Hi everyone!I just had a stroke of luck getting my hands on some ESD-storage dirt cheap from an old Nokia repair shop that closed. I got some ESD storage containers (http://www.treston.fi/sites/default/files/294esd_0.jpg) that have a plate on the bottom to connect them to the ground and some ESD storage boxes.The containers i have connected to each other and the last one to ground. My ground plug has a built in 1M resistor. The boxes however are just on my shelf.My question is: can I just cover my shelves with conductive material, for example aluminum tape strips, and then connect the that conductive material to the same ground as the containers (the plug has multiple inputs). Would this be the right way to go? I'm guessing that the boxes are meant to be places on a ESD-workbench which would be connected to ground. So basically in my case the boxes would be sitting on conductive material connected to ground.I have also attached two pictures of the gear i scored if someone is interested. Can only fit about 50% in my "lab" though

author: ollihd
author_rank: Regular Contributor
timestamp: May 07, 2016, 08:26:59 am
content: Anyone?

author: mcinque
author_rank: Unknown
timestamp: May 07, 2016, 09:50:46 pm
content: I guess that yes, it will do the job.

author: KL27x
author_rank: Super Contributor
timestamp: May 08, 2016, 12:58:34 am
content: You don't have to ground your storage containers, as long as you don't go out of your way to insert/remove components without touching the container... While the container is levitating.Any empty cookie tin is an ESD safe container. Also a faraday cage to protect against EMP devices and massive solar flares.
Yet another LM317 design - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: September 14, 2020, 06:40:48 am
content: So there's this "LM317 Kit Build Speed Run" contest going on on Youtube. The goal is to clock the fastest build time of a simple LM317 power supply kit.Here's the schematic for this particular kit (fromhttp://www.icstation.com/lm317-adjustable-step-down-module-125v-acdc-power-supply-module-p-2713.html)I was wondering about the role of Q1. It seems that during normal operation it wouldn't be on. My guess is that it is used to discharge C5 when the transformer power is disconnected. Comparing it to the reference implementation in the LM317 datasheet, it seems it would serve the same role as the protection diode D2. If so, does it offer any advantages over the D2 diode approach?

author: magic
author_rank: Super Contributor
timestamp: September 14, 2020, 07:30:02 am
content: Its base is shorted to the emitter by the pot. You can fiddle with the transformer all day long and it won't discharge anything.It discharges C5 when the pot loses connection.IIRC, diode D2 may or may not be required, depending on output voltage and capacitance. See the datasheet for details.

author: hugo
author_rank: Regular Contributor
timestamp: September 14, 2020, 06:02:58 pm
content: First of all C4 is way too big and is killing the regulation... I would use a 100uF (max 220uF) for C4.Let's say the adj pin of the regulator is wired to a potentiometer and to the ground.When there is a break between the ground and potentiometer (that could happen on some potentiometers at the ends) the load will see ~(Vin-3) volts which is something not desirable.Q1 will prevent that situation to occur, e.g. wiper is disconnected then Q1 turns on and Vout will be reduced to ~ 2.1 volts only.

author: David Hess
author_rank: Super Contributor
timestamp: September 14, 2020, 11:52:04 pm
content: Quote from: magic on September 14, 2020, 07:30:02 amExactly but it does more than that. Q1 pulls the regulator's adjustment pin low if the wiper on the poteniometer fails so that the output voltage falls to a minimum, about 1.25 volts + 1*Vbe or 2 volts, instead of rising to maximum which could damage the load. It protects against an open wiper which is the most common failure of a potentiometer.
Yet another transistor question - Page 1
Forum section: electronics / beginners

author: SteigsdB
author_rank: Contributor
timestamp: February 03, 2013, 06:01:47 am
content: Hi folks,Long time listener, first time caller.I put this circuit together on a breadboard (minus the relay and associated diode):Everything worked as expected until I swapped out the LED for a lighted switch.I now get a low glow from the LED in the switch when output Q is low.I've been googling around for a while trying to figure out what's going on with no success.I'm guessing largely due to not searching with the correct terminology.Anyhow, the best I can garner is that I need to pull Vb to ground somehow to deal with stray current at Vce?I'm not sure that's entirely correct, although some information I found that somewhat parallels my scenario suggested that.As I only have a limited number of these switches, I'd rather not fry them while playing around with too many options, so I thought I'd come here and ask people smarter than myself about such things.The original LED was a garden variety from a grab bag, so I don't know the exact specs for it.The LED in the switch is rated for 2.1v @ 20mA. This is a 12v circuit and I changed the LED ballast resistor to 1/2w 470 Ohm to match the new LED.Any advice appreciated. Thanks!

author: amyk
author_rank: Super Contributor
timestamp: February 03, 2013, 01:29:14 pm
content: LEDs can light atverylow currents (uA), and the transistor will amplify an even lower current flowing into its base; how long is the wire from the base of Q1 to the IC? It could be acting as an antenna.
Yet another update - Page 1
Forum section: electronics / beginners

author: zerorisers
author_rank: Regular Contributor
timestamp: June 06, 2015, 02:26:35 am
content: Hello everybody, I finished up my last day of school and just might have some more time to finish a few projects. I went to the keysight core bench lab in Richardson and am being allowed to demo 2 prices of equipment for a week. The fieldfox microwave analizer, and the MSO-X 4104A.I will include pictures below. And thought you might like the selfie nature of them.(Images are mirrored)

author: tautech
author_rank: Super Contributor
timestamp: June 06, 2015, 03:17:30 am
content: Interesting form factor, what do you think of the UI on the left?

author: zerorisers
author_rank: Regular Contributor
timestamp: June 06, 2015, 05:04:21 pm
content: Quote from: tautech on June 06, 2015, 03:17:30 amBoth images seem to be mirrored. but the user interface on both are quite nice. having trouble finding FFT on the oscilloscope though. the touch screen is very nice as I can access quite a bit easily. Also starting from yesterday for all this year i believe all software options on any keysight oscilloscope are enabled by default. So I will definitely try to figure out a payment plan with them for one of the lower end oscilloscopes. this one is too high end for me. (doesn't have high bandwidth enabled by default in software btw. 1GHz.Been Using the field fox microwave analyzer for its not so intended purpose (listening to the radio)But I have been getting more used to the equipment's intended purpose and have certification from keysight saying I can use the equipment.fieldfox N9917A microwave analyzer 18GHzInfiniVision MSO-X 4104A 1GHz 5GS/s

author: tautech
author_rank: Super Contributor
timestamp: June 06, 2015, 08:10:05 pm
content: Quote from: zerorisers on June 06, 2015, 05:04:21 pmChange them, it's very misleading/confusing.All the worlds lefties will be rushing out to buy one.
Yet another video on practical understanding of opamp circuits - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: January 28, 2013, 05:19:42 am
content: Several of my YouTube subscribers asked me to do a tutorial about opamps. While my video doesn't go into all of the background and analysis details in the other videos posted here and elsewhere, it does discuss a practical way for you to be able to understand the basic operation of most opamp circuits.

author: robrenz
author_rank: Super Contributor
timestamp: January 28, 2013, 11:57:32 am
content: I always learn something from your videos

author: nicknails
author_rank: Regular Contributor
timestamp: January 28, 2013, 05:28:34 pm
content: Very nice video. Illustrates a nice simple analysis technique.

author: FenderBender
author_rank: Super Contributor
timestamp: January 29, 2013, 03:10:40 am
content: Very nice very nice.

author: w2aew
author_rank: Super Contributor
timestamp: January 29, 2013, 11:05:41 pm
content: Thanks for your nice comments guys! Always appreciated!

author: Chasm
author_rank: Regular Contributor
timestamp: January 30, 2013, 02:21:03 am
content: And now the same for op-amps vs. phase shift.It always takes a while to wrap my head around it.

author: funk1980
author_rank: Contributor
timestamp: January 30, 2013, 12:49:40 pm
content: Opamp buffer with a gain of 1. My favorite piece of circuitry.Very clear and pratical video. I wasn't familier with the square to saw application, so thanks for that.
YH-995D Vs YH-898D+ ??? - Page 1
Forum section: electronics / beginners

author: peps1
author_rank: Regular Contributor
timestamp: May 11, 2013, 02:53:45 pm
content: Hey guys,Looking for a entry level SMD station and seen a fair bit on here and other sites about the value YH-898D+ so was ready to pick one up this weekend, but then spotted the YH-995D, is this just the same unit with a big LCD???

author: peps1
author_rank: Regular Contributor
timestamp: May 21, 2013, 12:27:26 pm
content: BUMP

author: tarmogr
author_rank: Newbie
timestamp: May 25, 2013, 10:59:29 am
content: Hi995D has all the features of 898D+ and 899D+. It means you can program the sleep time (time after the soldering iron is not touched the temperature will fall to 200 deg C. I have 899D+ and this feature is very handy. it saves tip and heater. 898D+ dosn't have this feature.But in addition for 995D you can also digitally calibrate the hot air gun and iron temperature +-50 C. if you wanted to calibrate 898D+ you would need to open the station in order to access the trim pots.it also has a celsius/Fahrenheit unit conversion.manufaturer also claims it's temperature stability to be +-1C which is pretty good, and more powerful soldering iron (70W)Overall I think 995D is superior over 898D+ in many ways.I would take 995D over 898D+ although my 899D+ has served me well last...3 years I think

author: zimzia
author_rank: Newbie
timestamp: August 15, 2013, 05:52:26 pm
content: Hello how to calibrate 898D +?, who trim pots I see two ?"tarmogrcalibrate 898D+ you would need to open the station in order to access the trim pots."