hybridfree/eevblog-posts huggingface dataset:
+-15V isolated DC-DC converter module with LDO output low noise PCB mounted - Page 1
Forum section: electronics / projects

author: mnni
author_rank: Newbie
timestamp: January 20, 2021, 11:37:22 am
content: I am looking for inputs to select a low noise +-15V isolated DC-DC converter module, for a low noise <1MHz analogue circuitisolations i needed to break ground loops/avoid them.Requirements:Input voltage: 5V ( but others voltage can do as i have not settle on the main PSU)PCB mounted1Watt will doIsolating 500V is okLow EMI as i will have near by connectors and PCB's i want to avoid coupling toif LDO output not included a good candidate for that is also highly well-come - I prefer my output voltage being +-15V but my circuit will work down to +-12Vthanks

author: Benta
author_rank: Super Contributor
timestamp: January 20, 2021, 06:14:59 pm
content: The best I've worked with are from Traco Power.https://www.tracopower.com/de/dc-dc-convertersBut they're not the cheapest.No affiliation.

author: mnni
author_rank: Newbie
timestamp: January 21, 2021, 08:47:22 am
content: already had a look on Traco and found this onehttps://docs.rs-online.com/8145/0900766b816ed6f1.pdfwith low noisebut its kind of expensive! and i do not need that much currenti may consider taking a cheaper one and add an LDO but there is still the emi but may be just fine with a good EN 55032 rating

author: Berni
author_rank: Super Contributor
timestamp: January 21, 2021, 08:54:59 am
content: Quote from: mnni on January 21, 2021, 08:47:22 amThat is the price you pay for taking modular power solution shortcuts. Little PCB mount switcher modules tend to usually be significantly more expensive than making your own application specific optimized solution.Also careful with common mode noise on isolated switcher modules like this. The sharp switching edges love to jump across parasitic capacitance of transformers (switcher modules have to contend with this too as they contain the same transformers inside).

author: strawberry
author_rank: Super Contributor
timestamp: January 22, 2021, 12:29:59 pm
content: SN6505A
16 bit console confusing audio circuit - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: June 20, 2022, 06:44:08 pm
content: I did my best to reverse engineer it, but trying to do that on a 3 layer board is already a nightmare.[ Attachment Invalid Or Does Not Exist ]the audio signal gets taken from the negative side of C22; C47 and C48 connect to the expansion card slot which the audio is fine without it; C32 connects to pin 1 of a CXK58257M-12L static RAM chip which is Input adress 14C34, C31, C92 dont seem to connect anywhereC39 connects to the game cartridge slot pin 3 on the front side from the left. calledQuotemaybe you see what they're doing here... the quad op amp is TA75324P, I get a big audio signal from pin 8 (as expected), and 2 smaller level audio signals from pin 1 and 14, I get just noise from pin 7.pin 14 seems to have more noise too. but the signal gain is about the same as from pin 1

author: Terry Bites
author_rank: Super Contributor
timestamp: June 22, 2022, 12:31:18 pm
content: Its chaos but you can guess that its just a gain block with some gentle HF roll-off. The big caps from 4k7s to ground suggest that there are three or four very similar stages. Non inverting single supply stages with a common split rail supplied by R79, R80. egA general pupose mixer input would have about 70dB of gain.I wouldnt reverse engineer it, just build something to replace it. Peferably with much lower noise parts than the dinosaur opamps they used.If you know the gain of this circuit and the ADC sample rate its a very simple job. Connection to RAM? Probaly a power common, it cant be signal related. 3 layers? Cool.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 22, 2022, 06:01:40 pm
content: That is a differential reciever (of sorts) with summed inputs.Well, how wrong I was.They've used R29 etc and opamp as a power on reset. Many modern opamps won't be happy used as comparators and they may oscillate with a capacitive load. Put a 100R beween pin 7 and C10.
16 Pin LFCSP soldering on a proto PCB - Page 1
Forum section: electronics / projects

author: eurofox
author_rank: Unknown
timestamp: September 04, 2013, 05:03:52 pm
content: Hi,I would like to find a proto PCB adapter to solder a 16 Pin LFCSP and be able to do some testing. Those chips are so smallSomebody know where I get get it?eurofox

author: eurofox
author_rank: Unknown
timestamp: September 06, 2013, 10:58:53 am
content: Nobody?The only solution is to glue the chip with connection up on a proto PCB and wire it this way.eurofox

author: Marco
author_rank: Super Contributor
timestamp: September 06, 2013, 12:36:17 pm
content: Wouldn't a QFN breakout board (of which there are many) work for LFCSP?

author: eurofox
author_rank: Unknown
timestamp: September 06, 2013, 02:41:10 pm
content: Quote from: Marco on September 06, 2013, 12:36:17 pmThanks Marco, you are right it look the same and many available on ebay.eurofox

author: eurofox
author_rank: Unknown
timestamp: September 11, 2013, 07:47:41 pm
content: Got my proto PCB today and work perfect, again a litle bit wisereurofox
164 and 595 shift registers - Page 1
Forum section: electronics / projects

author: Stonent
author_rank: Super Contributor
timestamp: October 21, 2013, 08:04:55 pm
content: I just watched this video, I was aware of the 595 but not the 164 until I saw one for sale and googled the differenceThe 595 is latched and he said that's why the LEDs don't flicker when transitioning, but he also said the 164 has a NAND gate on it. My thoughts were, what if you triggered a false on the NAND gate between transitions, could that eliminate the flickering?Or if you connected VCC to a pin on the AVR and brought it high then sent your serial data and then brought it low to power down the 164?Or would the flickering still happen because it's just something that happens during the data loading into the 164?

author: mariush
author_rank: Super Contributor
timestamp: October 21, 2013, 09:01:44 pm
content: The 595 has the latch feature, but in this video he doesn't use it. As soon as he shifts the bits in, the leds light up, that's why you see the leds blinking ever so slightly as the active led moves around.edit: nevermind, ignore what i said... i only watched a part of the video and I assumed the chip in the first part is 595 but it was actually the 164 one.

author: Hideki
author_rank: Frequent Contributor
timestamp: October 21, 2013, 09:04:59 pm
content: You can certainly blank out all LEDs while shifting in new data, but it might still be visible as a slight flicker in the ones that should stay lit instead of a flicker in all of them.Just use the 595 and make sure the outputs are latched before shifting in new data. After shifting in all 8 bits, let the new data through the latch and all LEDs will update at the same time.

author: Stonent
author_rank: Super Contributor
timestamp: October 21, 2013, 11:59:40 pm
content: Well I figured I'd learn about both because I never know when I might encounter a 164. Now that I got to thinking about it I guess on a 164 I could put a transistor on the ground line running to the LEDs and flip it on after the bits have shifted and then flip it off afterwards.
16x2 LCD Display PC Board too wide - Page 1
Forum section: electronics / projects

author: wb3fsr
author_rank: Contributor
timestamp: April 10, 2013, 07:34:34 am
content: I'm building an esR meter and ran into a problem with the Displaytech 162B LCD 16x2 display pc board width.My enclosure is a Teko slope faced box model 690D.5 and the internal width is 78 mm, my new digital caliper shows the display pc board is 82 mm !Has anyone ground the edges of one of these 16x2 units ~ 1 to 2 mm per side?Regards,PeterV

author: dr_p
author_rank: Frequent Contributor
timestamp: April 10, 2013, 09:28:08 am
content: Hold the LCD board against some powerfull light source. It should be clearly visible if the edge is free from traces. If so, good luck with the file/grinder.I once filed a 2x3mm rectangle out of a DDR2 DIMM for some cables to pass over itIt's somewhere in this project:http://mixitraieste.blogspot.ro/

author: hlavac
author_rank: Frequent Contributor
timestamp: April 10, 2013, 08:36:30 pm
content: I think the edges are sealed to keep the LCD liquid inside between two glass panels, if you grind that away it may leak out

author: MikeK
author_rank: Super Contributor
timestamp: April 10, 2013, 09:35:30 pm
content: I looked at a handful of LCDs I have sitting around and none of them can be whittled down to the dimension you want. And I think the mounting hole dimensions are standard so I would think you need a bigger boat...err, enclosure.

author: dr_p
author_rank: Frequent Contributor
timestamp: April 10, 2013, 09:58:59 pm
content: Quote from: hlavac on April 10, 2013, 08:36:30 pmI think he wants to grind the PCB of the LCD

author: wb3fsr
author_rank: Contributor
timestamp: April 10, 2013, 11:47:27 pm
content: Yes that is correct - shave the edges of the PC Board...TnxPeterV WB3FSR
16x24 Wireless full color matrix in picture frame - Page 1
Forum section: electronics / projects

author: ledfreak3d
author_rank: Newbie
timestamp: August 18, 2015, 11:35:42 am
content: Hey GuysJust joined the forum after several years of watching the EEV BLOG.Thought I would share my latest projectIts completely driven by a Esp8266 running the tmp2net ws2812 driver software.And created a nice 16x24 full color wifi controlled picture frame with it that can do all kinds of awesome stuffsee videos belowlink to topic on esp8266 forum and links the github are in there tohttp://www.esp8266.com/viewtopic.php?f=6&t=1441

author: ledfreak3d
author_rank: Newbie
timestamp: August 18, 2015, 02:30:04 pm
content: for now max amount of leds controllable is 512 but might be able to go as high as 1024

author: ledfreak3d
author_rank: Newbie
timestamp: August 19, 2015, 05:21:22 am
content: Common guys any sugestions tips ?
170 Vdc, 3A/1A/250mA cc supply - Page 1
Forum section: electronics / projects

author: dcoig1
author_rank: Newbie
timestamp: April 02, 2011, 12:00:07 pm
content: I'm trying to build a charger like this:http://99mpg.com/Data/resources/downloads/gridchargerstuff/dual_stage_grid_charger1.pdfbut... i would prefer to build the supply as a single unit and not use so many separate 48v supplies, add a higher 3a initial charge, and adjust the trickle current to250mAinstead of 350mA.The charger is for a honda insight nimh 144v battery pack which charges fully to ~170v. There are 120 1.2v nom 6.5ah 'd' cells in series.I am an electrician not an engineer so putting the charger together as prescribed is tempting, but something in me says there is a better way.The goal is to top off the pack occasionally since the factory bms never charges the pack beyond 80%. I can use either 110 or220v. I would like to keep as efficient as possible, but it is not a daily charger.I need some helprectifyingthe situation, please help, all is appreciated!
17670 NI-MH Batteries - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: July 15, 2019, 12:01:01 pm
content: Hi everyone,I unpacked a 17670 NI-MH battery pack from an electronic device. As you can see from the picture attached there is a series component (with red leads and something like a black bulb) on the negative side.What is this component and what its purpose? Furthermore why there are two paraller negative cables?Thanks in advance

author: capt bullshot
author_rank: Super Contributor
timestamp: July 15, 2019, 12:13:47 pm
content: That component most probably is some kind of a thermistor, so the charger can stop charging if the temperature of the battery is too high or too low.Paralleled wires increase the current capability (by lowering the resistance), this is the most common reason for having paralleled wires.

author: Nikos A.
author_rank: Regular Contributor
timestamp: July 15, 2019, 12:25:55 pm
content: Thank you for your promt reply,Is there any reason that places in paraller negative side instead of positive?

author: capt bullshot
author_rank: Super Contributor
timestamp: July 15, 2019, 01:06:10 pm
content: Normally, one would use parallel wires on both sides if one wanted to increase the current capability.Here, it just might be done to compensate for the longer run of the black wire in comparison to the red one. But you'll never know without knowing the complete design or asking the original designer.

author: Psi
author_rank: Super Contributor
timestamp: July 15, 2019, 01:12:11 pm
content: Sometimes you also see a thermal fuse.

author: mikerj
author_rank: Super Contributor
timestamp: July 15, 2019, 02:53:30 pm
content: The additionally ground wire is likely to prevent battery charge/discharge current causing errors with the thermistor measurement, effectively a Kelvin connection.

author: Nikos A.
author_rank: Regular Contributor
timestamp: July 15, 2019, 08:03:30 pm
content: Thank you guys!!Quote from: mikerj on July 15, 2019, 02:53:30 pmYou are right, after searching I found that this is actually a 3 wire RTD (Resistance Temperature Detector) configuration. Actually it doesn't matter which one is the double wire (negative or positive). The key point is to maintain equal lenght in order to achieve equal resistance among the wires.This site was helpfullhttps://www.omega.com/en-us/resources/rtd-2-3-4-wire-connections
1800's half abacus - Page 1
Forum section: electronics / projects

author: ranch varment
author_rank: Regular Contributor
timestamp: June 16, 2015, 10:54:31 pm
content: 1800's mechanical switched 3 bit incremental differential. (+1)This kind of machine could have been around for ages, it has special switches that put current in the opposite bit selection, then it fires the leds on all but the valid response.In this way, one can cheat having and gates, by relying apon the ands being on the part of the circuit that has no current in it, the rest has, as if one wants both bit values valid, either of the opposite firing means it is false, so current can be used for even the selective process of an and, as long as all the inputs are powered. But transistors didnt exist, so it was a matter of switching it for it, and looking for off rather than on, like a half abacus.

author: amyk
author_rank: Super Contributor
timestamp: June 17, 2015, 03:57:22 am
content: Please, for the sake of everyone, including yourself,learn how to draw a proper schematic!!

author: matseng
author_rank: Frequent Contributor
timestamp: June 17, 2015, 04:23:27 am
content: Are those cigs laced with THC?

author: RJFreeman
author_rank: Regular Contributor
timestamp: June 17, 2015, 04:29:39 am
content: you talk about making circuits without a Transistor, but then you mention using a NOT (or Inverter) which is implemented using a Transistor....but then as matseng asked, are you stoned??

author: nitro2k01
author_rank: Frequent Contributor
timestamp: June 17, 2015, 05:24:16 am
content: Mr Superior here again... If I'm getting what you're saying correctly, you want to use all AND gates and then a NOT at the end. It doesn't work that way. You need NOT in arbitrary places to be able to create arbitrary logical nets. It's well known and formalized theory which basic gates you need to create arbitrary nets. And yeah, it's also well known that (NOT A) AND (NOT B) = NOT (A OR B). It's called de Morgan's theorem and was formalized something like 150 years ago, long before anyone even knew what to use it for. These are things I learned in the intro to digital electronics course long ago. These are not exactly new revelations to the world.As an aside, I have actually experienced discussing digital electronics while I was stoned, and even though I was pretty out of it, I'd like to think I made more sense doing it than you are atm. Assuming you are even stoned.

author: matseng
author_rank: Frequent Contributor
timestamp: June 17, 2015, 06:12:23 am
content: Quote from: nitro2k01 on June 17, 2015, 05:24:16 amI've tried coding while drunk - it didn't turn out too well. :-)

author: Simon
author_rank: Unknown
timestamp: June 17, 2015, 06:52:46 am
content: Topic locked, I've never heard anything so incoherent in my life, I hope he gets help or stops playing us, Either way I have only to press the big button on him.
18650 - Page 1
Forum section: electronics / projects

author: Ugur
author_rank: Regular Contributor
timestamp: June 10, 2022, 05:58:02 am
content: Hello,I will feed a peltier with an 18650 battery, but I want the current to pass through the battery to be limited to 1A. Is there a ready circuit for this?With 18650 3S connection, 12V will be applied to the Peltier.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 10, 2022, 06:17:29 am
content: Peltiers are so resistive (basically, Ohm's law applies) that you can control current by just finding correct voltage. I would try with single 18650 (or 3p pack) first, depending on the size of Peltier, you might be close to 1A to begin with. 1-cell configuration would also make battery management easier.

author: Ugur
author_rank: Regular Contributor
timestamp: June 10, 2022, 06:53:12 am
content: Hello,Is Peltier's resistance constant?Won't the peltier resistance change when the temperature changes?Peltier TEC1-12715 (231W) I bought from the local marketIf too much current flows, the other side of the peltier will get very hot, so cooling it will be a big problem.I plan to try it tonight.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 10, 2022, 08:05:02 am
content: Not constant but good enough, try it first.Cooling the Peltier requires quite some effort, either water cooling or truly massive and well designed fan cooled heatsink.

author: Ugur
author_rank: Regular Contributor
timestamp: June 13, 2022, 05:51:12 am
content: Hello,Yes, you are right, when I try with a single battery, a maximum current of 1A passes.It's at 750mA if the cooling isn't good.If the cooling is done well, a current of 0.9 - 1A passes.Thank you for giving a time.
[Re-written]18650 batteries with BMS starts for a 1sec and stops - Page 1
Forum section: electronics / projects

author: sdancer75
author_rank: Frequent Contributor
timestamp: June 09, 2021, 06:04:19 am
content: Hi,I connected in series 4 batteries 18650 3.7v with the attached photo 4s BMS. Checking the voltage of batteries at the -B and +B pins I get ~15V.The vacuum cleaner drill (14.4V)starts for a second, and then it stops. The BMS says that it can handle a peak of 30A.Is the PCB the problem or the batteries themselves?Regards,
18650 batterypack design software - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: September 28, 2020, 09:02:02 am
content: Hi all,im trying to build a 16s/5p pack to fit inside a triangle bag,does anyone know of any software that can plan the layout of the cells etc?,thanks in advance.

author: Nusa
author_rank: Super Contributor
timestamp: September 28, 2020, 10:09:14 am
content: You can play with this to see if it fits the space you've got:https://e4bike.ru/page/battery-shape-configurator?c=31800501605162201600200561455

author: m3vuv
author_rank: Super Contributor
timestamp: September 28, 2020, 11:21:54 am
content: ive already seen that but doesent help with the interconnections between the groups of cells!,thanks anyway.
18650 soldering iron - Page 1
Forum section: electronics / projects

author: daniel444
author_rank: Regular Contributor
timestamp: November 20, 2019, 12:47:41 pm
content: soldering iron builduses ngk glow plug , silicon nitride ceramic tip , 3mm tip , top of the line glow plug25A momentary microswitch , beer keg stainless tube surroundfits a weller tip after being drilled out with 1/8 drill bit , then uses a small offcut of pyrolitic graphite thermal pad to hold it on by frictionswitch needs to be held on about 1/3 of the time for lead solderpictured is a spare glow plug and a Chinese nitride glow plug i bought , the Chinese version wont fit the weller tips at 4.4mm but is cheaper and more readily availabledraws about 10 amps , im NOT using the high drain 18650s if i were it might be to powerful maybe

author: fmkit
author_rank: Contributor
timestamp: November 20, 2019, 01:28:10 pm
content: mine also looks crude, unlike original temp.is contrlled w/MT3608 DC step_up,as well 18650 is under-voltage protected.

author: ElectricPower
author_rank: Frequent Contributor
timestamp: November 20, 2019, 01:45:28 pm
content: I found out yesterday that i'm not a REAL man when i saw the soldering iron this guy used. Take å look from (08:34) in this video

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 20, 2019, 02:42:39 pm
content: Quote from: ElectricPower on November 20, 2019, 01:45:28 pmOhhh damm, my sides!!!

author: daniel444
author_rank: Regular Contributor
timestamp: November 20, 2019, 02:59:40 pm
content: Quote from: CJay on November 20, 2019, 02:36:45 pm

author: mikerj
author_rank: Super Contributor
timestamp: November 20, 2019, 05:28:31 pm
content: Just need to add a PWM controller. I'm wondering if it would be possible to derive the temperature by taking current & voltage measurement during the on period to calculate heater resistance..

author: mikerj
author_rank: Super Contributor
timestamp: November 21, 2019, 12:36:53 pm
content: Quote from: CJay on November 20, 2019, 07:34:58 pmA possible snag with many modern glowplugs is they integrate some kind of regulating element (presumably some kind of PTC) in series with the heater element. This may not be a problem since a soldering iron would be operating well below the normal regulated temperature.

author: KL27x
author_rank: Super Contributor
timestamp: November 23, 2019, 02:01:14 am
content: https://youtu.be/en8bh60K7m8?t=110This is probably 12 years old. I just checked it. It still works. Microcontroller, PWM standy and autoshutoff. Single button interface.
19 inch tv vector conversion - Page 1
Forum section: electronics / projects

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: March 09, 2018, 10:43:07 pm
content: Alright, I recently acquired a samsung CXD1942 - it's a 19 inch crt tv. I think it would be a cool project to convert it into a vector display and play old atari vector games on it. Unfortunately I have previous HV experience, but that's about it. I don't have experience in arcade games or vector displays. I don't have the money and resources to buy a real arcade board. That leaves it to using emulation and specialized vector generators. I know the yoke needs to be rewound, but what will be driving it? What about color control? Can someone point me in the right direction? Thanks.

author: james_s
author_rank: Super Contributor
timestamp: March 09, 2018, 10:58:56 pm
content: I would suggest starting by studying the schematics for the Amplifone and Wells-Gardner 19K6100 monitors, the manuals for these are readily available online.In a nutshell since the yoke is inductive and the beam position is proportional to the current through the yoke, you need a voltage to current amplifier. If you look at the circuit you'll see that it resembles an op-amp, very high open loop gain which is tamed by negative feedback. Unlike a typical amplifier, the negative feedback comes not from the output voltage, but from the output *current* picked off the top of a sense resistor between the other end of the yoke and ground.There is a guy I know named Fred Kono who designed a modern deflection board and pioneered the concept of rewinding raster yokes to make them suitable for vector displays. At one point he was selling kits for his boards so you could google his name and ask if he still has any. I have built a small vector deflection board for my 5" B&W vector monitor but I have not tried scaling it up.Oh and don't neglect the spot killer, it's not absolutely needed for a little 5" tube but with a larger tube the beam needs to be hot enough that if you lose deflection it will instantly burn a hole in the phosphor. Anything from around 9" and up a spot killer circuit is mandatory.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: March 10, 2018, 09:55:31 pm
content: I touched a screwdriver to the tube pins PCB after it was turned off and saw a little flash of light. Now the tv turns off quickly after it turns on and repeats. Perhaps a shorted capacitor?

author: james_s
author_rank: Super Contributor
timestamp: March 10, 2018, 10:43:06 pm
content: I'd be more inclined to suspect a shorted semiconductor but it's hard to say. Generally shorting pins shortly after it has been on is not a good idea, as you've now found out why. Discharging the anode under the suction cup looking terminal is a good idea though before poking around inside.
1951 Bell Telephone Laboratories Transistor Symposium - Page 1
Forum section: electronics / projects

author: RonFred2
author_rank: Contributor
timestamp: December 19, 2022, 06:09:48 am
content: Biophysics Lab has just scanned and made freely available a rare book from 1951 called "The Transistor" - selected papers from Bell Lab's first symposium on the transistor.Perhaps some of the EEVBlog readers would be interested in downloading this book...https://www.biophysicslab.com/2022/12/18/1951-bell-telephone-laboratories-transistor-symposium/

author: moffy
author_rank: Super Contributor
timestamp: December 19, 2022, 08:03:01 am
content: Truly pioneering days. Bell labs was one of the great scientific institutions.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 19, 2022, 08:43:18 am
content: Wow, that's a lot of pages, will be a great joy to read through the scanned book during this holiday, thank you!

author: mawyatt
author_rank: Super Contributor
timestamp: December 19, 2022, 02:21:59 pm
content: What a wonderful and historic book, must read and study for anyone interesting in semiconductors and transistors.What an effort to photocopy each and every page, so hats off to youThanks for the copying effort, and sharingBest,

author: niconiconi
author_rank: Frequent Contributor
timestamp: December 19, 2022, 04:52:58 pm
content: What a coincidence. I was just made aware of its existence by an article a few days earlier and today the book itself shows up online!Computer History Museum describes this book as "Ma Bell's Cookbook" and "the bible of the dynamic semiconductor industry that emerged in the 1950s".Quotehttps://www.computerhistory.org/siliconengine/bell-labs-licenses-transistor-technology/

author: Terry Bites
author_rank: Super Contributor
timestamp: December 19, 2022, 06:23:12 pm
content: Does it mention what a b*stard William Shockley was to the transistor's co-inventors. He was a racist who agreed with hitler about the application of eugenics.A real charmer!

author: mawyatt
author_rank: Super Contributor
timestamp: December 19, 2022, 06:43:34 pm
content: And the Trairorous Eight at Shockley Semiconductor Labs of which Moore, Noyce and Hoerni were 3 of the 8!!https://en.wikipedia.org/wiki/Traitorous_eightBest,

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: December 19, 2022, 07:14:41 pm
content: Thanks! What a fantastic book. I wasn't aware of just how much was known in 1951 and how many of those concepts we still use today.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 19, 2022, 07:50:33 pm
content: Quote from: Terry Bites on December 19, 2022, 06:23:12 pmPropaganda must be very high with you, since you needed to scream "Hitler bad" and "racism" in a topic about an electronic book from 70 years ago.Is that all you have to say about the effort to scan and post a book for free, from a seminar that used to be $25000/attendee and with historical value?Shockley didn't come to the seminar, as per this link in the blog references:Quote
1959 Gibson Gibsonette repair - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: July 09, 2016, 03:50:02 pm
content: This documents the Repair I did on a 1959 Gibsonette where a Bad filter Cap finally took out a few components and brought the AMP to a NON-op state.Restoration VideoTest RunCapacitor Post Mortem

author: calexanian
author_rank: Super Contributor
timestamp: July 09, 2016, 06:34:30 pm
content: Those took the idea of how do we make a better amp than a champ? Add a second output tube!

author: jcrubin
author_rank: Frequent Contributor
timestamp: July 10, 2016, 12:37:24 pm
content: And its a single ended setup!

author: jcrubin
author_rank: Frequent Contributor
timestamp: September 01, 2016, 02:03:13 am
content: The 59 Gibsonette ends up back in the shop with the mechanical failure of a capacitor which I was able to demonstrate in the genrad 1650AIf you like these video's subscribe and provide feedback so I gauge who / what /where with regard to the viewing
1960 Danelectro Centurion Model 272 Series E repair  - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: July 09, 2016, 03:57:54 pm
content: This AMP arrived in a NON-operating condition and there is no known schematic for it, though one exists for the series F all of the values are different and the series F has Reverb circuitry as well as different DC plate voltage setup for obvious reasons.The AMP was even brand new of such low quality that pieces fell apart as you worked on it and almost everything required reflow work.At best, completely unsafe, the only ground between the top and bottom chassis is through the signal line shield for the 260vDC for the 12AX7 Plate feed. If the RCA jack got disconnected and there was a short, the only path to ground would be through the guitar!

author: calexanian
author_rank: Super Contributor
timestamp: July 09, 2016, 06:31:06 pm
content: They are out there. They are very reminiscent of Valco/National amps of that era. May even be made by the same people. They also made many of the Supro amps and practically anything sold as a combo with a lap steel.
1972 Swtpc Function generator (Wayback Wednesday) even tho its thursday - Page 1
Forum section: electronics / projects

author: Kilroywashere
author_rank: Regular Contributor
timestamp: March 14, 2019, 11:35:58 pm
content: Hey Got this a bit ago.... I dunno if its working right .. i mean it is older than me ..... maybe the caps are gone....The pic shows the Ramp I think it looks off... and the offset pull does not work?I just thought you guys would think this is cool here is some pics and stuff...Maybe if you guys can help me find out if its working right ... i have two scopes so i otta be able tohttp://www.swtpc.com/mholley/RadioElectronics/Sep1972/RE_Sep1972.htmLet me know what you would do to check if this works right( the ramp is at time div .5 us ampl/div .1 v )

author: Kilroywashere
author_rank: Regular Contributor
timestamp: March 15, 2019, 02:49:02 am
content: This pic shows the ramp stops but on my scope the ramp kinna trails off.... what do you think the issue is?

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 15, 2019, 03:05:25 am
content: Wow, that was my first signal generator. I don't remember much, but it might well need some new electrolytics by now. I do remember the output opamp was an LM318 in a metal can, and I blew several. Nothing else works quite right. I may have adapted in a DIP8 at some point. Do you have a manual? Not sure if I still have a copy, but sold the generator long ago.

author: Kilroywashere
author_rank: Regular Contributor
timestamp: March 15, 2019, 03:30:14 am
content: I found schematics even! This was apparently a kit you could buy, i don't physically have the manual but this link has a lot of info prolly build one with it ...http://www.swtpc.com/mholley/RadioElectronics/Sep1972/RE_Sep1972.htmThe Ramp looks alot different than when i put it on my scope .... the rest seem to work fine tho....But i don't really know how i would start to find out if it works properly.... I mean i would like to use it but im sad that i would have to replace the caps ... kina cool they are older than me HAHA

author: duak
author_rank: Super Contributor
timestamp: March 15, 2019, 04:55:32 am
content: I remember when that article came out. I was in high school and didn't have any money for the kit or even for the Exar function generator chip so I made up the basic oscillator using unmarked discrete transistors from a grab bag (U test n' save!) and whatever reused junk I had. It was an emitter coupled oscillator and the voltage waveform on one side of the timing caps is supposed to look like that. If you look at both sides of the timing caps with a differential amplifier you get a triangle wave. If you round the points off of that with a non-linear amplifier you get a sine wave.A few years later when I had more money, I built a function generator with an Intersil 8038 function gen chip. I still have that somewhere & it might even still work.
1980s Elta/Realistic 8971 Car EQ and 4 channel amp schematic! - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: August 21, 2023, 08:15:35 pm
content: Seems to be quite a rare piece. It uses very cool looking Push button switches, when you push on the add buttons it rocks over to the next position, sliding over to that place for the potentiometers, as well as sliding over to connect the corresponding LED. It's got 11 bar LED's in the middle, and a button on the top and bottom. Too bad they don't make any switches like this, looks quite neat!The id's on the switches are: "ALPS Japan" "740H" for the volume or "739H" for everything else, and "20KAX2" or "20KWX2"The EQ sounds great (tapping off the "DEFEAT" switch right after the preamp). but the output amps are meh, typical 80s class AB car radio output pizza oven IC sound.It's very cool how it's wired so when you turn it off, it bypasses itself and passes the speaker inputs from an car radio to the speakers. when you turn it on, it uses the speaker inputs as the signal input.It lists the power as:70W + 70W MAX front outputs.130W + 130W MAX rear outputs.As it's using the ~20W IC's for the front, you could assume the real output of the rear channels is more like 35W. And the heatsinks are about the right size for that power rating.It seems to be designed so you can hard wire the VCC supply to the battery for the rear channel outputs, since when the power is off the output transistors should be totally off. Although they for some reason added an 18k resistor to the bias supply from VCC. Didn't even label it, it's right next to the other "R56?" resistor so I couldn't tell which one was the R56 since there was only one label.I'm using it just for the EQ tapping off the defeat switch, I turn the fader all the way to the rear and just don't supply VCC so it doesn't waste a ton of power for no reason. So the only wasted power is the idle current of the TA7250BP'sThe colored wires in the schematic are all the wires in the amp, instead of traces which are the dark green.Yes it is a rats nest of wires.
Mystery 1985 vintage "HBATD1" and "3550 TD1" evaluation boards - Page 1
Forum section: electronics / projects

author: `
author_rank: Newbie
timestamp: January 22, 2016, 12:46:58 am
content: Presented just for interest, there's two variations on the sales counter at Weird Stuff in California.Datecode is barely visible in pen on the PCB "7/13/1985". Logo isAMD.

author: xrunner
author_rank: Super Contributor
timestamp: January 22, 2016, 01:00:26 am
content: Pretty (hand drawn?) traces.

author: crispy_tofu
author_rank: Super Contributor
timestamp: January 22, 2016, 01:14:50 am
content: Very cool!

author: xrunner
author_rank: Super Contributor
timestamp: January 22, 2016, 01:39:46 am
content: Well the logo on the board is for AMD.

author: Vgkid
author_rank: Super Contributor
timestamp: January 22, 2016, 01:59:14 am
content: What are the non bnc connectors? They look like large smb connectors.

author: calexanian
author_rank: Super Contributor
timestamp: January 22, 2016, 06:51:18 am
content: Wow. "Serious" business there. Bet those were not cheap when new!

author: Kalvin
author_rank: Super Contributor
timestamp: January 22, 2016, 08:57:17 am
content: Might be an eval/test board for the AMD Am3550 ECL/TTL mask-programmable gate array.http://www.datasheetarchive.com/dl/Scans-000/Scans-006350.pdf

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 22, 2016, 12:52:27 pm
content: Quote from: Vgkid on January 22, 2016, 01:59:14 amMy guess is scope probe.

author: AF6LJ
author_rank: Unknown
timestamp: January 22, 2016, 01:00:36 pm
content: The first one looks like it was made for testing an old AMD K-6 processor.Looks like they tried to keep the traces to the socket the same lenght.Nicely done.

author: `
author_rank: Newbie
timestamp: January 22, 2016, 04:31:32 pm
content: Quote from: Kalvin on January 22, 2016, 08:57:17 amPlausible, the date on the board matches as a pre-production development.
1990's Beady Computer - Page 1
Forum section: electronics / projects

author: picitup
author_rank: Regular Contributor
timestamp: December 27, 2015, 11:40:32 am
content: Hi All I hope you enjoyed the xmas break if you took one.I worked for a computer dealer in the '90s and my mate, who was not into electronics, called all components 'beady things' and if a board had gone faulty he'd say that one of the beads had probably broken.So I built him a beady computer. If you squeeze the two chrome blazer buttons on the left, it would play a tune. I think I got the music electronics from a pair of xmas socks I owned.Any road up, here's a pic:Keep Smilin'Steve

author: AF6LJ
author_rank: Unknown
timestamp: December 27, 2015, 12:20:45 pm
content: That's very Cool

author: MagicSmoker
author_rank: Super Contributor
timestamp: December 27, 2015, 12:50:24 pm
content: Comedic gold!

author: picitup
author_rank: Regular Contributor
timestamp: December 27, 2015, 02:45:23 pm
content: Thanks :-)

author: SL4P
author_rank: Super Contributor
timestamp: December 27, 2015, 10:06:21 pm
content: That could be a really good teardown.
1990s Panasonic Camcorder viewfinder issues  - Page 1
Forum section: electronics / projects

author: valley001
author_rank: Frequent Contributor
timestamp: August 03, 2020, 12:57:48 am
content: Hello all,I am having some fun with an old Panasonic palmcorder, thinking the viewfinder might be useful for a project.I was surprised to find a composite video input in the viewfinder wiring bundle. Further investigation revealed inputs for power +15 and +5v, ground plus a number of other wires I assumed were associated with the playback controls located on the viewfinder housing. I was able in inject a video source into the viewfinder composite input and got it to display in the viewfinder (this is with it still mostly attached the the rest of the camera). I then proceeded to remove (cut) the wiring I assumed was not associated with the LCD/backlight/video input and was rewarded with a dead screen. I replaced said wiring and the screen came back.Hooking the suspect wires to my DSO reveals a series of pulses when power is applied to the camera, this is followed the display lighting up. If I remove one of these wires while the display is on, it will turn off.I assume these are some sort of control pulses coming from the main board on the camera. Is it possible to read and then replicate these pulses so the viewfinder will activate? Perhaps this is not possible at all? I am not familiar with programming outside my awareness of things like raspberry pi and such. Hoping for a simple solution/ideas. Thanks all!

author: dmendesf
author_rank: Frequent Contributor
timestamp: August 03, 2020, 02:03:36 am
content: Probably can be done with a cheap microcontroller (arduino level). Are they just 0/5V waves?

author: valley001
author_rank: Frequent Contributor
timestamp: August 03, 2020, 03:43:14 am
content: So far as I can tell they are +5v pulses.
1997 Buick VAT Bypass Circuit - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: August 19, 2019, 02:28:53 am
content: I have a question about the old "security" feature that uses a resistor in the key; I think it's called VAT.Anyway, due to resistor tolerance, keys with the same resistor value can differ slightly.Does anyone know what the tolerance of the resistor pellet? Also, I assume the car uses a comparitor circuit to compare a set value. How does it handle both upper and lower limits of the tolerance values?I'm thinking maybe it's not hardware like a comparitor, but maybe software that handles a range of values to handle the variations.

author: bdunham7
author_rank: Super Contributor
timestamp: August 19, 2019, 03:27:42 am
content: 3% according to this source. I remember bypassing them (no, I'm not a car thief...) and using cheapo resistors that were probably 5% tolerance at best and not having issues. The resistances were far enough apart that tolerances didn't matter too much--you just had to select the right key. And I never had a key not work for being out of tolerance, although I rarely if ever measured the NEW keys.https://www.lockmasters.com/site/pdfs/TT4002%20Vats%20Overview%20Article.pdf

author: bostonman
author_rank: Super Contributor
timestamp: August 19, 2019, 12:52:00 pm
content: QuoteI had an old car where this system died and then had the whole key assembly replaced. Months later the system went bad again, and, not realizing how simple the system was, returned to the mechanic. He found the resistor pellet went bad, either because it went out of tolerance or opened. Unfortunately I don't know what happened, but know the second time it was just the key.Now I have an old car and decided to by pass the resistor pellet because I sense it will eventually fail. To match the value, and having a limited amount of resistor values, I used two in parallel with one in in series. It's about a 20 milli-ohm difference using 1% resistors.I was a bit concerned working around the yellow air bag wire because I don't know what it takes to trigger it, but have read banging the wire isn't good. I had the battery disconnected, but remained cautious regardless.Wish I didn't get intimidated by the "high tech" security system because I blew a chunk of time/money having the mechanic fix it for me. I don't remember the cost, but paid for a tow (this was before AAA), paid for the repair, and then months later got stuck in downtown Boston late night. Since the repair was still under warranty, got the car towed to his shop (which he paid for), but wasted a whole night trying to get home. For the cost of a few resistors, I could have saved time/money.

author: amyk
author_rank: Super Contributor
timestamp: August 20, 2019, 01:10:02 am
content: The title of this thread reads far more curiously to someone from Britain... I was expecting something less legal
1DZ61 replacement - Page 1
Forum section: electronics / projects

author: jeffjmr
author_rank: Regular Contributor
timestamp: May 28, 2021, 01:46:22 pm
content: Hope this is the right place.I can’t find anything online about the apparently obsolete 1DZ61 rectifying diodes, other than 1 amp and 200 volts.Would a conventional 1N4002 or 1N4007 be a suitable replacement or is there something special about the 1DZ61 I am missing?Thanks,Jeff

author: RayRay
author_rank: Frequent Contributor
timestamp: May 28, 2021, 02:46:09 pm
content: 200V,1A and 1.2V max voltage forward. Anyhow, I'd say this would be your best bet:https://www.mouser.com/ProductDetail/Vishay-General-Semiconductor/1N4935GP-E3-54?qs=7w0fSgRKp91yzOtE7QwFEQ%3D%3D

author: coromonadalix
author_rank: Super Contributor
timestamp: May 28, 2021, 05:17:01 pm
content: 1n4003 and up can do fine since you need 200v
1/f noise of PWM -> RC filter *thought experiment not really practical* - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 06, 2014, 05:19:58 am
content: I was wondering what the 1/f noise will look like for a PWM signal that is sent through a RC filter.Does the 1/f noise of the resistor dominate the circuit? Does the capacitor cause anything?how about a really big LC filter?

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 06, 2014, 06:35:47 pm
content: I ask this because I need a null voltage circuit, I have a PWM output that I don't need... I was wondering if I used a big transformer and a capacitor could I get a nice "nuller"

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 06, 2014, 08:04:37 pm
content: Nulling what, just a low bandwidth (a few Hz) DC signal to read off a galvanometer?I'd be way more concerned about the supply stability (your PWM digital output buffer is being used as a 1-bit DAC) and switching speed (and stability) than 1/f noise from a resistor. Which, if this is for nulling...will carry zero DC current anyway, so what's the 1/f noise coming from?If this is more about, like, nulling on a scope, then you'll probably want more attenuation than just a few stages of RC or LC filtering can provide. Just to get the ripple down, nothing to do with noise.Noise is more of a microvolts thing, what are you doing that you need that kind of precision? Is there a better way to do it? If it's that precise, it's probably best done in analog in the first place, leave the MCU out of it. Is that an option?Tim

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 06, 2014, 08:33:09 pm
content: well im 99.9% likely to implement this using a DAC, I am just wondering what the filtered signal would look like on a FFT in a DSA.its not a practical solution considering that highly stable dacs are available.its just difficult to imagine for me what it would look like.I imagine that a LC filter changing would just cause the ripple voltage to drift ( as when the cut off frequency changes the attenuation @ ripple frequency will change by some miniscule amount).,.but what about 1/f?like, if you took the output signal of the RC/LC filter and put it into a 1Hz cutoff preamplifier filter connected to a digital signal analyzer and nulled out the error from the amplifier to get accurate 1/f information about the DUT.

author: GK
author_rank: Super Contributor
timestamp: April 07, 2014, 02:08:11 am
content: Quote from: SArepairman on April 06, 2014, 05:19:58 amI couldn't imagine the thermal noise voltage of the resistor being anywhere near the amplitude of the raw PWM, let alone any flicker (1/f) noise that the resistor may have.