hybridfree/eevblog-posts huggingface dataset:
id a tcxo  - Page 1
Forum section: electronics / beginners

author: longpole001
author_rank: Contributor
timestamp: September 24, 2016, 08:39:32 am
content: hi guys i am trying to identify the manufacture and find datasheet for the part picturedfrom what i can see it 16.368mhz tcxo , but from the logo i cant find who makes it and it ppm rate ,it is in 3220 packageny help would be good finding further detailsregardssheldon

author: Koen
author_rank: Frequent Contributor
timestamp: September 24, 2016, 09:12:56 am
content: Hello, the manufacturer logo is Kyocera.

author: longpole001
author_rank: Contributor
timestamp: September 24, 2016, 11:08:26 pm
content: thanks , i will contact them for further detailstheir markings on part is very hard to work outi have spent a lot of time looking at their current and discontinued spec sheets , and most show only ordering information not how the markings relate on the componenthttp://www.kyocera-crystal.jp/eng/prdct/list/tcxo/
ID Component - Page 1
Forum section: electronics / beginners

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 21, 2017, 06:00:13 am
content: Trying to ID these chips so I can proceed with testing- they read:L1213817 BWThe L is leaning to the right towards the 1 (top line)Did search Google with numerous strings. One result was a photocoupler and the other a voltage regulator. Sorry I can't discern....I'm learningThanks for any help.Here is a photo of the four-legged monsters:

author: helius
author_rank: Super Contributor
timestamp: March 21, 2017, 06:15:03 am
content: Lite-On LTV-817 optoisolator

author: JoeN
author_rank: Frequent Contributor
timestamp: March 21, 2017, 06:17:53 am
content: You can tell it is an optocoupler just by that packaging. I don't know anything else that gets put into that package. Is this a power supply? Optocouplers are very common to connect signals from the high voltage to low voltage side.

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 21, 2017, 06:36:30 am
content: Thank you both a lot !Joe, yes a power supply for PC (https://www.eevblog.com/forum/repair/atx-power-supply-dead/msg1166236/#msg1166236).

author: DTJ
author_rank: Super Contributor
timestamp: March 21, 2017, 06:57:10 am
content: Maybe one of these:https://img.ozdisan.com/ETicaret_Dosya/28512_2166956.pdf

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 21, 2017, 07:19:23 am
content: Whichever, can terminals 1 and 2 (anode cathode) be tested with a simple diode test on DMM?

author: DTJ
author_rank: Super Contributor
timestamp: March 21, 2017, 09:56:05 am
content: Quote from: OpenCircuit on March 21, 2017, 07:19:23 amYes, see data sheet page 2.Vf = 1.25V typ up to 1.6V max.I'm assuming your power supply has failed?Perhaps look at the electrolytic caps, input rectifier and switching semis.

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 21, 2017, 04:46:35 pm
content: Quote from: DTJ on March 21, 2017, 09:56:05 amDTJ, here is a link:https://www.eevblog.com/forum/repair/atx-power-supply-dead/msg1166236/#msg1166236
I'd like to understand how telecommunications work - Page 1
Forum section: electronics / beginners

author: Connecteur
author_rank: Frequent Contributor
timestamp: March 12, 2022, 05:50:45 pm
content: I find it a bit frustrating that most explanations for how high-speed communication works goes far beyond the level of a novice, which I am. I'd like to find a simple explanation of how they manage to convey so much data over limited bandwidth. Are there some good learning resources for this subject?

author: PartialDischarge
author_rank: Super Contributor
timestamp: March 12, 2022, 06:04:18 pm
content: The reason is that the bandwidth is shared among many channels while they are separable. Understanding this however requires understanding math, spectrums, phases and frequencies.In simpler modulations like QAM, the vertical axis is ortogonal to the horizontal carrier because sine and cosines are ortogonal.You could start by understanding OFDM,https://www.techtarget.com/searchnetworking/definition/orthogonal-frequency-division-multiplexinghttps://www.electronics-notes.com/articles/radio/multicarrier-modulation/ofdm-orthogonal-frequency-division-multiplexing-what-is-tutorial-basics.phpI have to point out that before modulation there is a huge signal processing work to compress the signals and these methods vary a lot depending on if they are lossless or not, realtime or not, bitrate, audio/video/images....

author: Terry Bites
author_rank: Super Contributor
timestamp: March 12, 2022, 06:49:21 pm
content: This is a massive subject to cover in a blog response. The time, amplitude, phase and frequency can all be use to convey data- often in very complex combinations of the latter. Data compression is also an important part of many systems.Complex systems of modulation have evolved. This is where you need to delve into the maths. There's no way around that.This ebook seems to give a simple introduction to data coms conceptshttps://ebookreading.net/view/book/EB9781118995624_7.html
ID Please - Page 1
Forum section: electronics / beginners

author: queennikki1972
author_rank: Regular Contributor
timestamp: April 30, 2019, 12:19:36 am
content: I don't mind reading about them but not sure what to look for?https://anfamily.cloud/question.jpg

author: oPossum
author_rank: Super Contributor
timestamp: April 30, 2019, 12:21:27 am
content: Possibly IF (intermediate frequency) transformers for a radio.

author: Mickster
author_rank: Contributor
timestamp: April 30, 2019, 12:29:10 am
content: Google hits here:https://www.google.com/search?q=if+transformer&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiq-Yq0x_bhAhVvhuAKHTQeCDEQ_AUIDigB&biw=1350&bih=608

author: queennikki1972
author_rank: Regular Contributor
timestamp: April 30, 2019, 12:38:39 am
content: yes from radio equipment and looks like that is it. Thank you

author: Andy Watson
author_rank: Super Contributor
timestamp: April 30, 2019, 12:40:50 am
content: I agree, they're probably IF "cans" or just tunable inductors. Like these:http://www.webshed.org/wiki/TOKO_10K_Series

author: radiolistener
author_rank: Super Contributor
timestamp: April 30, 2019, 08:02:28 am
content: this is variable inductor/transformer for radio frequency. It has screw core, which allows to tune it's inductance.It can consist of single coil (variable inductor) or several coils (RF transformer).
ID this connector? - Page 1
Forum section: electronics / beginners

author: djacobow
author_rank: Super Contributor
timestamp: December 12, 2016, 11:46:32 pm
content: Can anybody help me ID this connector. I mean, it's mate. This is the DC jack on a GMRS radio.

author: RJFreeman
author_rank: Regular Contributor
timestamp: December 13, 2016, 12:34:50 am
content: I thought of it as a version of a Molex connector, but it looks like a variant of what is known colloquially (and more commonly) as a 'large Tamiya connector'

author: djacobow
author_rank: Super Contributor
timestamp: December 13, 2016, 04:36:07 pm
content: Thanks! Seems like a strange choice for a radio, but, hey, at least you can get them on Amazon!
ID this diode? - Page 1
Forum section: electronics / beginners

author: chuho
author_rank: Newbie
timestamp: February 13, 2024, 01:46:42 am
content: Are the square components here diodes? Dimensions are 50mm x 50mm. They have no markings I can find.I'm trying to get an old benchtop power supply working. There are four of these and based on their location in the circuit they should be rectifying the AC.If they really are diodes, the two shown here are shot. The two on the other side have a fwd bias voltage between 0.25 and 0.35 V.

author: wraper
author_rank: Unknown
timestamp: February 13, 2024, 02:30:20 am
content: Look like selenium rectifiers.

author: amyk
author_rank: Super Contributor
timestamp: February 13, 2024, 02:38:54 am
content: Could be selenium or copper oxide.
ID this over heated component - Page 1
Forum section: electronics / beginners

author: Degreaser
author_rank: Newbie
timestamp: November 01, 2022, 09:31:05 am
content: HiI was wondering what this is, it came from a paper shreader that turned itself on all night due to a clogged sensor it was still running in the morning and the room was filled with white smoke, the tech said this was the only damaged part, what are the grey bits oozing out

author: Psi
author_rank: Super Contributor
timestamp: November 01, 2022, 09:33:26 am
content: Probably the motor start capacitor.
IDC 64 pin connector  - Page 1
Forum section: electronics / beginners

author: AGRAIL
author_rank: Contributor
timestamp: April 22, 2017, 06:25:40 am
content: Hi All ,Can anybody know alternate connector for this one :http://uk.farnell.com/3m/3695-0000/plug-idc-din41612-64way/dp/972927?ost=972927&scope=partnumberlookahead&exaMfpn=true&searchref=searchlookahead&searchView=table&iscrfnonsku=false&ddkey=http%3Aen-GB%2FElement14_United_Kingdom%2Fw%2FsearchIt`s not manufactured by 3M any more but I have many projects where spare parts required .Is there some alternate manufacturer for this type of connector ?Thanks in advance.

author: ebclr
author_rank: Super Contributor
timestamp: April 23, 2017, 01:49:55 am
content: https://world.taobao.com/item/548303299901.htm?spm=a312a.7700714.0.0.T3ldtw#detail

author: AGRAIL
author_rank: Contributor
timestamp: April 24, 2017, 11:08:43 am
content: Thanks for link , but there are only THI .Is there any IDC type ?

author: MagicSmoker
author_rank: Super Contributor
timestamp: April 24, 2017, 12:23:39 pm
content: Quote from: AGRAIL on April 22, 2017, 06:25:40 amDirectly terminating ribbon cable to a board with an insulation displacement connector fell out of favor over 20 years ago. A much better yet physically compatible solution would be to use something like Omron XG4M sockets on the ribbon cables and XG4A plugs on the boards. See, for example, this selection of 64 pin connectors at Digikey:https://www.digikey.com/products/en/connectors-interconnects/rectangular-connectors-free-hanging-panel-mount/316?k=&pkeyword=&pv88=63&FV=ffe80a69&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25Don't forget you'll need a special tool for compressing the ribbon cable onto the IDC sockets (or you could use a bench vise, I suppose).

author: tooki
author_rank: Super Contributor
timestamp: April 24, 2017, 07:11:25 pm
content: Quote from: MagicSmoker on April 24, 2017, 12:23:39 pmI don't think that's what the OP's connector is. It's a DIN 41612plug, which mates into the board-mounted female DIN 41612socket.I thought DIN 41612 was still widely used. DigiKey and Mouser both show a wide selection of DIN 41612 parts, including IDC connectors. AGRAIL, what makes you think your part is discontinued??

author: MagicSmoker
author_rank: Super Contributor
timestamp: April 24, 2017, 07:26:46 pm
content: Quote from: tooki on April 24, 2017, 07:11:25 pmYou might be right on that, but there was something else I got wrong and that is the spacing between parallel rows. On the OP's connector it is 0.2" while the Omron series I suggested is 0.1".

author: tooki
author_rank: Super Contributor
timestamp: April 24, 2017, 07:30:12 pm
content: Quote from: MagicSmoker on April 24, 2017, 07:26:46 pmWell, only because the middle row is not populated. DIN 41612 plugs are a 0.1" grid. I'm sure some alternative 0.1" plug would work in a pinch, I just doubt that a workaround is needed, since I thought these things were still widespread for industrial use. (It's the plug for Eurocard backplane systems.)
IDC cable -separating individual strands - Page 1
Forum section: electronics / beginners

author: analogix
author_rank: Frequent Contributor
timestamp: December 07, 2017, 01:29:28 pm
content: Is there a smart way to separate the individual strands apart from an IDC flat ribbon cable?I've tried using a sharp knife, fingernails etc. but no matter what I do I always end up with a few strands where the insulation has been torn past their sides. And every time this happens I have to cut off a whole section of the cable and start all over againI'm trying to fix a broken membrane connector by super-glueing a pre-stripped IDC cable on top, attaching the individual wire ends to the membrane tracks with electrically conductive glue (possibly pre-tinned first if that would provide a better connection) and finally soldering the other end (also separated, stripped and tinned individually) to the device's multi-pin connector which (in theory at least) should provide a new, fixed connection.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 07, 2017, 01:40:57 pm
content: A good pair of long scissors. Hold the cable loosely so it self-guides the blade into the valley between the cores. Once you get the hang of it, you can do one core a second.

author: UsefulTechStuff
author_rank: Newbie
timestamp: August 07, 2025, 06:31:01 am
content: Excellent suggestion. Thank you, it worked a treat. Believe me, I tried everything else before I saw this post. I even tried heating the cable in the hope that it would make splitting it easier. Nope!

author: reodor
author_rank: Contributor
timestamp: August 07, 2025, 07:22:33 am
content: I have had good luck with small, sharp side cutters. They tend to be naturally guided to the narrowest point.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 09, 2025, 06:05:57 am
content: I use side cutters or scissors (or even a knife if that's closest, but you have to be careful) and then use it to get the separation started. Once over 5mm is separated you can usually just pull them apart, but that may depend on the brand of cable you have.

author: jmelson
author_rank: Super Contributor
timestamp: August 09, 2025, 05:19:59 pm
content: One method I have used is to lay the cable on a flat surface. Place an Xacto knife in the groove between conductors, with the point of the knife toward the other end of the cable. Press the knife through the cable, and then pull the cable away from the knife. It takes a little technique to keep the cable straight, but this will slit the conductors apart quite easily.Jon
Idea for a beginner helper circuit. - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: November 14, 2017, 08:38:51 pm
content: This is probably something a beginner could build themselves, though I'm not quite sure how to yet.I imagine a device which has various input connectors (USB, Round, Headers) and various output connectors (USB, Headers, Breadboard pins).It would have a jumper or switch which can be either 0.5A or 1A.Should the current through the device exceed that current a buzzer sounds and an LED lights.It sounds completely mickey mouse, but it would instantly point out to the a newbie that:a) they have a short circuitb) they are pulling too much power from the wall wart PSU.If you could package this (if it doesn't exist) into a simple off the shelf component I think it would be really useful.Anything pulling enough amps to heat stuff up will sound the buzzer the instant they connect it or turn the power on.EDIT: I'm pretty sure it's just an op amp with a current shunt or sense resistor type thing.

author: jaromir
author_rank: Unknown
timestamp: November 14, 2017, 09:11:52 pm
content: Yes, you need shunt and comparator, perhaps amplifier after the shunt, possible inspiration is herehttp://www.electronicdesign.com/sites/electronicdesign.com/files/uploads/2014/05/0714_POV_harmon_F2.gifVery very crude way of indicating overload may be based on something like thishttps://snag.gy/miAchB.jpgR1 determines the current "limit", it happens when the voltage drop is roughly equal to 0,7V.This circuit is temperature dependant (cca 2mV/K of BE voltage, at 1R resistor it means 2mA/K), has significant voltage drop (0,7V at current of power limit) and the current "limit" indication isn't straight bi-stable, but it's brain-dead simple andsometimesdoes the job. Variants of this circuit were common decades ago, often with thyristor instead of transistor - then the overcurrent indicator doesn't go off until power supply is interrupted, what may be desirable sometimes.The sense resistor and comparator is technically better way of doing this task, basically eliminating all of the problems of this simple circuit, at marginally higher cost and complexity.

author: Ian.M
author_rank: Super Contributor
timestamp: November 14, 2017, 09:26:13 pm
content: Polyfuse and a P channel MOSFET. Source to PSU side of MOSFET, gate to load side and buzzer and indicator lamp between drain and Gnd. Jumper in a second polyfuse to double the current limit.
Idea needed: Led indicator for wide voltage ranges. - Page 1
Forum section: electronics / beginners

author: Khakimov
author_rank: Newbie
timestamp: March 11, 2019, 09:55:13 pm
content: Hello!Given: A lot of fuses that protects some power electronics (transformers, incandescent lamps, relays). Sometimes a fuse blows and it needs to be spotted and replaced. But it is very hard to carefully look through a lots of fuses and inspect each thin melting wire. So I need some indication device of a blown fuse that connects to fuse itself.This indication device needs to be:1. Simple2. Small3. Working on AC/DC 12..220V ranges.My first thought was "Hey, let's just choose a proper resistor!":But in order to LED be nearly visible on 12V in case of 220V resistor will dissipate a lot of heat, so it needs to be huge.Well... let's add power-limiting capacitor!:But in this case indicator looses an ability to work on DC voltages.Now I am thinking of using resistor + blinking leds with ICs inside them to reduce current consumption and thus a power dissipation on resistor. Most of blinking leds have a 50% duty cycle and there is not much of power saving. I am trying to find SMD blinking led with duty cycle of about 10% (100 msec on, 1 sec off) but still no success with that.1. Any advices of how to find leds with small duty cycle will be appreciated (maybe they are not existing at all?).2. Perhaps I am missing another ways to make simple blown-fuse indication...Thanks =)

author: Benta
author_rank: Super Contributor
timestamp: March 11, 2019, 10:00:30 pm
content: For 100...230 VAC, the simplest is a neon lamp + resistor. Small, simple, inexpensive.

author: Zero999
author_rank: Super Contributor
timestamp: March 12, 2019, 09:59:12 am
content: I think he wants something which will work over a wide voltage range.A flashing LED won't work at such a high voltage because when it goes off, it will be exposed to the full voltage. It's theoretically possible to design a transistor constant current source which will draw say 1mA, over a very wide voltage range, but it's not compact.The attached circuit has a negative temperature coefficient. The series pairs of D2 & D3 and D4 & D5 can each be replaced with a 6.2V zener diode and R1 and R2 increased to 10k, for better temperature stability, but the minimum operating voltage will increase to over 12V.
ideal diode (precion rectifier) with voltage follower in feedback? - Page 1
Forum section: electronics / beginners

author: SArepairman
author_rank: Frequent Contributor
timestamp: July 19, 2013, 01:40:51 am
content: What is the point of adding a voltage follower into the feedback loop of a precision rectifier?Output -> Diode -> Voltage follower (buffer op amp) > negative opamp terminalDoes this have something to do with improving the response time of the circuit?http://upload.wikimedia.org/wikipedia/commons/6/60/Op-Amp_Precision_Rectifier.svgwith a buffer in the feedback loop after the diodethe diode is a 1n4248does this allow you to use a crap diode at the expense of an amplifier?

author: Odysseus
author_rank: Regular Contributor
timestamp: July 20, 2013, 07:21:23 am
content: Is the attached schematic what you're thinking of?If so, I don't think it's going to improve the transient response of the amplifier since the first op-amp is still going to go open loop and enter saturation.The only benefit I can see is the prevention of any subsequent circuitry from offsetting the voltage at which it rectifies.

author: KJDS
author_rank: Super Contributor
timestamp: July 20, 2013, 09:13:50 am
content: Dave did one of his videos on this a few weeks ago, might be worth a check.

author: SArepairman
author_rank: Frequent Contributor
timestamp: July 23, 2013, 10:41:12 am
content: so it would remove the offset error created by the next op-amp in line?wont the voltage followers offset cause an offset anyway?

author: Odysseus
author_rank: Regular Contributor
timestamp: July 24, 2013, 03:44:16 am
content: The precision rectifier goes flat when the current in the diode drops to zero. The issue is if your load has a significant bias current. Then the point at which the diode current is zero is no long the same as zero voltage. The extra op-amp is just a buffer to prevent this.This doesn't really explain why the second op-amp is inside the feedback loop of the first. I see no advantage.

author: SArepairman
author_rank: Frequent Contributor
timestamp: July 24, 2013, 07:13:36 am
content: Quote from: Odysseus on July 24, 2013, 03:44:16 amthis is the digitizer circuit on a spectrum analyzers video signal if it makes any difference.looks like a peak detector circuit
Ideal diode bridge. - Page 1
Forum section: electronics / beginners

author: davelectronic
author_rank: Frequent Contributor
timestamp: May 25, 2017, 11:50:07 am
content: I was looking to have a go at building an ideal diode bridge, using the LT4320 and N channel mosfets. My idea was to bread board it first to get it laid out right. There is a couple of things I'm unsure of, i am going to use a dip package. I'm unsure on the mosfet rating, i know i want a working current of 15 Amps maximum, but typically 10 Amps continuous current. I was looking at the IRF540 mosfets, but not sure if these are suitable. Another thing I'm unsure of is cooling of the mosfets, and if heatsinks are required. My input voltage would be 14.80 Volts AC, and I'm using an LM2940CT-12 low drop out voltage regulator. Any advise on the ideal diode bridge appreciated.

author: digsys
author_rank: Unknown
timestamp: May 25, 2017, 12:04:45 pm
content: Hiya. There are at least 2 huge threads on this subject, with all the questions answered. In my replies I have even included part #s and temp figures.I have PCBs that I run to 25A cont / 30A ave without a heatsink, just 4+4oz copper. There's too much info to re-post, so try a search first. LT4320

author: davelectronic
author_rank: Frequent Contributor
timestamp: May 25, 2017, 06:13:07 pm
content: Many thanks Digsys I will look it up.
Ideal Diode Controller - Page 1
Forum section: electronics / beginners

author: Christopher
author_rank: Frequent Contributor
timestamp: October 15, 2014, 06:09:06 pm
content: All.I need to switch between a fixed 48V Source (V1, coming from a ACDC PSU) and a variable 20-60V Source (V2, coming from bench supply) at a maximum current of 10A. No high frequency, just manually switching every ~30 seconds at the minimum.I have come up with the following circuit which works! But I need to be able to choose between the sources rather than the standard diode-or configuration.Obviously a Shottky diode is pretty much out of the question (10A*0.6V=6W Loss). A relay and other mechanical devices are also out of the question due to arcing.What is driving the gates of M1&M2 in the LTC4355? Can I reproduce this easily?

author: Christopher
author_rank: Frequent Contributor
timestamp: October 15, 2014, 06:52:37 pm
content: Using a bootstrapped gate seems to be the way to go..This *should* work from my app note reading skills, but LTSpice is reporting a wacky high power dissipation in M1.. Can you spot what it is?EDIT: Seems to work with a resistor instead of a constant current load in ltspice!
Ideal diode MOSFET circuit - Page 1
Forum section: electronics / beginners

author: Barkuti
author_rank: Contributor
timestamp: February 02, 2019, 05:49:54 am
content: Posted it yesterday in BudgetLightForum:Having readA simple and inexpensive ideal-diode MOSFET circuit @ Power Electronic Tips, decided to draw its N-channel counterpart. See images below for comparison. Since I have no formal electronics education, this is to ask the experts if this is right (if I converted it right) and what are its practical limitations:Speaking of low nominal voltage cells I guess a low VGSMOSFET is preferred if used to prevent battery or charger reverse current, isn't it?Cheers and have fun

author: spec
author_rank: Frequent Contributor
timestamp: February 02, 2019, 06:47:39 am
content: Hi Barkuti,Yes, the circuit that you have designed is the full complement of the original circuit, so it will have the same characteristics as the original circuit, except all polarities will be reversed, as you show.About MOSFET gate threshold voltage (VGth): The VGth must be low enough so that the MOSFET turns on fully with a low battery terminal voltage. That is the criteria, rather than back flow. There are many low VGth MOSFETs available, both N and P types. The FDS6575 PMOSFET, in the original schematic, has a VGth of 400mV to 1V5 and turns on to a low drain/source resistance (Rds) of 17mR at 2V5.https://www.onsemi.com/pub/Collateral/FDS6575-D.pdf
Ideal Li-Ion battery cutoff voltage - Page 1
Forum section: electronics / beginners

author: Sigmoid
author_rank: Frequent Contributor
timestamp: February 08, 2017, 01:59:24 pm
content: This question came up in relation to my single-board computer (Banana Pro) I intend to use as a portable network analysis tool. Its power management chip supports Li-Ion cell management by default, however it doesn't have well-behaved ACPI, and since I'll be running Linux, I'd like to do a safe, graceful system shutdown well before the power management IC pulls the plug.I can monitor the battery voltage and current via i2c... So the question is, what should I use as a "software cutoff voltage"? 3 Volts seems to be the industry standard, but I've read in places that 3.3V is probably more appropriate for increasing battery lifetime. There are examples of 2.7V being used, on the other end of the scale... Is there a point in taking current draw into account for battery cutoff (like letting it get away with lower voltages if there's a high current...)

author: KL27x
author_rank: Super Contributor
timestamp: February 08, 2017, 04:31:31 pm
content: ^ Yes, to all of that. (Only part I'm sketchy on, I think 3.3V is super conservative!)Yes, of course I would consider relationship between current draw and internal resistance slash output capacity. Your circuit can't measure the battery's internal voltage drop, directly. And of course this matters. For relatively higher current draw in relations to output capability/ISR of the battery, there is a larger discrepancy between max load voltage and the float voltage. For a relatively large current draw for battery, you would generally want to move your bar closer to 2.7. And for lower draw, move that bar higher.

author: mrrrwhat
author_rank: Contributor
timestamp: February 09, 2017, 03:45:05 pm
content: Depends on which type of Li-ion battery you use, the cut off voltage will be different.For high drain type, the lowest cut off voltage are 2.5v.For high capacity type, the lowest cut off voltage are 2.75v.

author: Seekonk
author_rank: Super Contributor
timestamp: February 09, 2017, 05:09:38 pm
content: 3.3V doesn't seem overly conservative if looking for long life.

author: Audioguru
author_rank: Super Contributor
timestamp: February 09, 2017, 06:22:35 pm
content: The electronics in my radio control model airplanes gives a low voltage warning by pulsing the motor when the Li-Po battery measures 3.15V per cell and completely cuts off the motor (but the receiver and controls still work) when the voltage measures 3.05V per cell. The manufacturer says: "Warning. Repeated operating to low voltage cutoff will damage the battery". The batteries are Very High Drain type.

author: mrrrwhat
author_rank: Contributor
timestamp: February 10, 2017, 01:40:56 am
content: Voltage measures with or without load,the cutoff voltage also will be different
Ideal opamp output voltage - Page 1
Forum section: electronics / beginners

author: zzlong94
author_rank: Contributor
timestamp: November 23, 2017, 10:13:23 am
content: I tried by using OrCad program to simulate the Ideal opamp and check for its output voltage.However, the output of the voltage drifted.Is it because of my circuit construction problem or the wave is correct?any explanation on the output wave?

author: mikerj
author_rank: Super Contributor
timestamp: November 23, 2017, 12:55:36 pm
content: You have no DC feedback to stabilise the operating point. Any slight voltage offset will be continuously integrated, which will cause the effect you are seeing.

author: danadak
author_rank: Super Contributor
timestamp: November 23, 2017, 01:10:02 pm
content: http://www.electronics-tutorial.net/analog-integrated-circuits/op-amp-integrator/practical-integrator/index.htmlRegards, Dana.

author: zzlong94
author_rank: Contributor
timestamp: November 23, 2017, 02:06:08 pm
content: Bro, so u r saying that thr is offset voltage for my opamp?So it shifted my value of output voltage?

author: Audioguru
author_rank: Super Contributor
timestamp: November 23, 2017, 02:34:01 pm
content: Your simulation does not have "an ideal opamp". Instead it has an ordinary TL071 opamp that has an input offset voltage.

author: rstofer
author_rank: Super Contributor
timestamp: November 23, 2017, 06:03:48 pm
content: Adding the feedback resistor moves the integration up to some higher frequency as discussed in the linked article. That simply won't work for analog computing where signals (variables) are slow moving. I want to be able to change 10V is 1 second or if the problem scales to 10x, I need 10V in 0.1 second. AFAICT with my limited knowledge of analog computing, these are the highest frequencies involved. In other words, right down to 0 Hz.With the added resistor, all you have is a fancy low pass filter.Offset voltage can often be nulled out by using the 'trim' pins on the op amp.http://www.analog.com/media/en/training-seminars/tutorials/MT-037.pdfThe next analog computer I build will have the capability of adjusting the offset voltage. I'm generally dealing in volt level signals so I'm not sure how important some number of microvolts really is. It's not like the simulations last very long so there really isn't enough time for the offset voltage to impact the results. And let's face it, I'm not dealing with high resolution. 'About' is good enough. If you have seen one damped harmonic motion, you have pretty much seen them all.
Ideas for fume extractor - Page 1
Forum section: electronics / beginners

author: grevan
author_rank: Contributor
timestamp: December 09, 2016, 07:58:41 pm
content: Hi guys,i´m developing an idea for a fume extractor.For now i have maybe a silly question, which of these two setups do you think would have a stronger air flow power? With the carbon filter in between or before the 2 coolers?Of course i can use just one powerfull cooler, but i´tm thinking of getting not so expensive ones.Thanks

author: BobsURuncle
author_rank: Regular Contributor
timestamp: December 09, 2016, 08:38:19 pm
content: The filter in between the fans I would expect to produce more flow. The back fan will not do much work if it is directly behind the front fan spinning at about the same rpm.

author: Gyro
author_rank: Super Contributor
timestamp: December 09, 2016, 08:47:35 pm
content: You'd be better with the two fans side by side with a filter on the output side of each. Without getting too scientific, fans always 'push' better than they 'pull'.

author: jonovid
author_rank: Super Contributor
timestamp: December 10, 2016, 11:15:29 am
content: you could add a dust filter for a super clean air room.& or maybe port the fan's to reduce fan blade noise.

author: Cliff Matthews
author_rank: Unknown
timestamp: December 10, 2016, 12:36:04 pm
content: Pull or push, I prefer surplus centrifugal compressor-type fans for this task (and mostly, they're quieter too).Mount in box with a circular hole to pull air through a plastic dryer hose, and let it push air through any cheap HEPA filter hot glued on the side.
ideas for make a ultrasonic cleaner  - Page 1
Forum section: electronics / beginners

author: Pcaiman
author_rank: Contributor
timestamp: May 07, 2020, 12:10:43 am
content: Hi forum, i wanna get a ultrasonic cleaner, i see in Alibaba and a supplier make a offer for 1000 usd with this Specs:1) Capacity:108L.2) Frequency:28Khz.3) Tank size:600*450*400mmGreat the problem is the shipping price for me is 1000 usd more, and i wanna know what need for make a ultrasonic cleaner with this specs, i wanna use for clean a small block engine, and only car spare parts.maybe buy a kit like this:https://es.aliexpress.com/item/32967152426.html

author: wilfred
author_rank: Super Contributor
timestamp: October 01, 2020, 10:48:42 pm
content: I also am considering making an ultrasonic cleaner. I found a kit for this Silicon Chip magazine project for boat owners to reduce marine growth on boat hulls.http://archive.siliconchip.com.au/cms/A_112107/article.htmlIt was discontinued on sale in Jaycar for only A$27 so I couldn't resist.The transducer was also pre-assembled and potted as per the project description so that just seemed to make it less work and risk. So even if the transducer assembly was all I could use it seemed fair value. Plus I got a tube of JB weld.However from what I can see SC seem to recycle the driver electronics largely between the anti-fouling and cleaning application.So I've been sitting on it since Feb and yesterday I found whilst shopping at "La Strada" (the street) I found a cooking pot with a perforated insert for free. It seemed a good size at about 200mm diameter and a similar depth and with the insert it seemed ideal. However what I am less confident about is can you fit the transducer to the base which is about 10mm thick. Good and sturdy but is it too thick? I just noticed SC Sept2020 has yet again recycled the ultrasonic cleaner project and they always seem to use relatively thin walled containers.Maybe like me they just use what they think is easily available and inexpensive for readers who want to make one.So does the thick base of the pot make it an unsuitable mounting location for the transducer? The curved sides are, well curved so the base is the only flat surface. And would I need to do something to isolate the insert from the main vessel. The baskets used in commercial cleaners seem to contact the main vessel in very small contact points and not the entire circumference.Another concern is the insert is far more "solid" than the mesh baskets I've seen in commercial cleaners. It has 8mm holes which are fine for draining pasta but the sides may attenuate the ultrasonic waves a bit too much. So I have a few doubts creeping in.I hope someone with experience in a similar project can offer some advice.
Ideas for PCB sprocket for PNP? - Page 1
Forum section: electronics / beginners

author: shai
author_rank: Contributor
timestamp: March 07, 2019, 12:46:49 am
content: I am building a PnP Machine and would like to create the sprocket for my feeder out of PCB. See attached. This sprocket will NOT push the tape, only count steps.I know that PCB is not the best material for a sprocket, etc, etc. I would like to focus on one thing only - how to create a good and cheap encoder for this sprocket. I have a few ideas but perhaps someone with more experience can tell me what would work best and if you have better idea to share?Ideas:1. Drill holes in sprocket and use optical sensor (self explanatory, but I'm afraid this is not very super accurate for PCB material)2. Use two springs that will contact with each pad. Simplest way to do it, just the cycle count might not be high as the sprocket/spring could wear out from physical contact/rotation.3. Use optical encoder that reflects off the pads and make sure the PCB is matte black. (will this work? or will it still reflect off a matte black pcb?)4. Use a Hall effect or similar sensor and detect the pads. (This one I'm not sure, non-lead-free pads? is that a possibility? Can any sort of SMT pad coating type be detectable with a Hall effect sensor? I think they are cheaper than optical encoders? Suggestions here?5. Any other ideas on how to get creative with a PCB sprocket to be used as encoder?https://imgur.com/a/2t7MSwchttps://imgur.com/a/cnNVQra

author: ataradov
author_rank: Super Contributor
timestamp: March 07, 2019, 02:26:25 am
content: Just a thought, not a specific advice - PCB holes are as accurate as alignment of the copper layer. It should be plenty accurate for this use.For solder mask reflection, you are probably better off using just plain openings in the mask and no copper. You will get contrasting color between the mask and PCB material. But mask alignment may be much worse than alignment for the holes.With spring contacts - what do you plan to use for the actual contacts? I'm not aware of anything like that sold as a generic component.Also, what sort of resolution do you expect, and what is the size of the wheel?

author: shai
author_rank: Contributor
timestamp: March 07, 2019, 04:25:06 am
content: The sprocket is 26.4 diameter (not pitch), just measured the diameter itself without teeth. Holes can work, but I think I can get better step resolution with pads. What if I use raw FR4 and no solder mask and only pads? I don't fully understand what you mean in your second bullet point.Springs:https://www.digikey.com/products/en/connectors-interconnects/rectangular-connectors-spring-loaded/408?k=&pkeyword=&sv=0&pv7=2&sf=0&FV=1140003%2Cii2%7C2167%2Cii1%7C2172%2Cffe00198%2C1f140000&quantity=&ColumnSort=1000011&page=1&stock=1&pageSize=500

author: ataradov
author_rank: Super Contributor
timestamp: March 07, 2019, 04:30:57 am
content: Those springs look like they would be too hard, they are designed for permanent contact, not for sliding.I mean use black solder mask, but don't put any copper in the openings, just keep bare PCB material. It is pretty light in color.
Ideas For Reverse Engineering Projects? - Page 1
Forum section: electronics / beginners

author: ryankearney
author_rank: Newbie
timestamp: November 08, 2019, 05:58:35 pm
content: I've been interested in this type of stuff for quite some time and have finally gotten around to pulling the trigger on some hardware purchases to get started. I was wondering if anyone had any ideas reverse engineering? My first project involved many tutorials on getting started with the 6502 CPU which I've fully familiarized myself with so it's no longer a challenge by itself. I'm wondering if anyone has curated a list of engaging projects and challenges to attempt in this area.For starters, I was thinking about taking apart an old Nintendo Entertainment System which also uses a MOS 6502 CPU @ 1.79Mhz which seems plenty slow to analyze with the equipment I have, and since I'm already familiar with the CPU I think it would be a great starting point I think. My goal at that point would be to successfully manipulate the memory on the NES to build my own "gameshark" or something to that effect.Any tips on what the next step might be after the MOS 6502?

author: The Senate
author_rank: Newbie
timestamp: November 08, 2019, 08:09:27 pm
content: You can build clones of old computers/consoles like the Apple 1 without having to reverse engineer them since you can usually find the schematics online.

author: james_s
author_rank: Super Contributor
timestamp: November 08, 2019, 08:48:58 pm
content: The NES doesn't use a MOS 6502, it uses a custom chip with a CPU core that is compatible with the 6502. No need to reverse engineer it though, it has already been done. There are even FPGA implementations of the entire NES.
Ideas for using low voltage high capacitance electrolytic caps?  - Page 1
Forum section: electronics / beginners

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: November 16, 2015, 07:05:07 pm
content: Hi everyone!While searching through some of my stockpile I noticed some 15 to 20 year old caps with anything from 25 volts 45.000µF up to 150.000µF - at 6 Volts DC.... I love to tinker around with old stuff and would like to reuse them for some more or less usefull stuff. But I can't think about anything... I already used some of them (20V 100.000µF) to build an spot welding machine, but I have no idea about what I can do with the others, especialy with the 6 Volt things.I attached a pic with some examples of the spare caps. (by the way, don't we all love those golden Roederstein caps? <3 )Any Ideas?

author: SeanB
author_rank: Super Contributor
timestamp: November 16, 2015, 07:27:39 pm
content: Charge to 3V and put a musical card on it. Should run for a day or so. Or make a low power LEd flasher and use them to power it. LM3909 is not exacvtly low power, you can do a discrete oscillator that is lower power, or use some CMOS inverters.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: November 17, 2015, 01:29:56 pm
content: Hi sean and thanks for your ideas!I actualy used some of the (even higher capacitance) caps already to power my leds outside in combination with a solar panel andna lighting sensor.Yesterday I thought about a low voltage high current psu to use the 6v caps, maybe using 2N3055 as power transistor? Anybody ever built such a thing?The 25v caps can be used in a chip amp with 18v or something like that..
Ideas how to solder wire to tiny chip - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: June 14, 2020, 05:50:52 pm
content: Hi, I need to solder 2 wires (marked red and green) on this tiny chip legs:Any ideas whats the best way to do this? Maybe I could cover other legs with something while soldering to avoid contact with neighbor legs?

author: Ian.M
author_rank: Super Contributor
timestamp: June 14, 2020, 06:05:07 pm
content: Looks like a 0.50mm pitch TQFP. A fine tipped iron and a steady hand are all you need provided the wire is solid core. Pre-tin (heavily) and flux the wire end, and you should be able to simply sweat each wire straight onto the flat of the pin on the pad. If you get it wrong, no big deal - simply remove any bad bridges with desolder braid, then flux and reheat, dragging outwards to fix the neighbouring pin joints.Hint: a blob of bluetack nearby to hold the wires in the correct position to solder will make it a lot easier.

author: janoc
author_rank: Super Contributor
timestamp: June 14, 2020, 06:50:00 pm
content: Another (potentially easier) approach would be to find a track, via or another component those two pins are connected to using a meter, scrape off soldermask, if necessary and solder the wires there.Of course, that assumes those pins are actually used on that board - check the bottom of the board whether there are any vias under the IC.

author: wizard69
author_rank: Super Contributor
timestamp: June 15, 2020, 12:45:38 am
content: This would be my preferred approach. Otherwise I would likely need a good microscope and a perfect set up such that I could rest my arms and body for steadiness. Frankly I'm not even sure that would be enough.Quote from: janoc on June 14, 2020, 06:50:00 pm

author: Habropoda
author_rank: Regular Contributor
timestamp: June 15, 2020, 01:48:10 am
content: If you have never done this before, practice on an old board with chip that has similar pins. That way you won't destroy the good board when you fling the practice board out the window.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 15, 2020, 02:29:14 am
content: https://hackaday.com/2016/10/10/ne555s-smd-prototyping-is-a-work-of-art/

author: Bassman59
author_rank: Super Contributor
timestamp: June 15, 2020, 03:50:47 am
content: Quote from: Doctorandus_P on June 15, 2020, 02:29:14 amThat reminded me of the best rework I ever saw, which was a QFP-208 (or some such) where legs were lifted from the pads and tiny series resistors were installed between the legs and associated pads for series termination.
Idendify SC508738CFU microchip - Page 1
Forum section: electronics / beginners

author: Ehmm
author_rank: Newbie
timestamp: March 20, 2025, 05:21:29 pm
content: Hi all, i am trying to read the data off SC508738CFU microchip but i can not find a datasheet for it. It was recomended to read it as MC68HC912B32 but then i get BKGD high error in UPA USB reader. Can anybody identify this chip for me?Br.Ehmm

author: Benta
author_rank: Super Contributor
timestamp: March 20, 2025, 07:30:32 pm
content: I'd say it's a Motorola/Freescale/NXP mask.programmed microcontroller.Which one I don't know, but try using the mask set code (J38M) to find it. There's a list on the interwebs somewhere.EDIT: seems to be a MC68HC12BE32.

author: u666sa
author_rank: Frequent Contributor
timestamp: March 20, 2025, 09:43:11 pm
content: How about Renesas M30291FCHP?

author: Benta
author_rank: Super Contributor
timestamp: March 21, 2025, 07:30:47 pm
content: Quote from: u666sa on March 20, 2025, 09:43:11 pmWut?

author: fzabkar
author_rank: Super Contributor
timestamp: March 21, 2025, 07:55:28 pm
content: Quote from: u666sa on March 20, 2025, 09:43:11 pmIt doesn't look like it:https://ae-pic-a1.aliexpress-media.com/kf/S95c9306e4ae547ce995e23b6aefc5962t.png

author: fzabkar
author_rank: Super Contributor
timestamp: March 21, 2025, 07:57:35 pm
content: Quote from: Benta on March 20, 2025, 07:30:32 pmOne of the dimples is missing:https://mt.jsdelectronic.com/uploads/202235227/mc68hc912b32cfu817328039027.jpg

author: Benta
author_rank: Super Contributor
timestamp: March 21, 2025, 09:58:47 pm
content: Quote from: fzabkar on March 21, 2025, 07:57:35 pmIndeed. I have a feeling you don't know too much about semiconductor manufacturing (especially packaging).Packaging (epoxy encapsulation) is made at many subcontractors, and can look different from batch to batch.

author: fzabkar
author_rank: Super Contributor
timestamp: March 21, 2025, 10:20:27 pm
content: Quote from: Benta on March 21, 2025, 09:58:47 pmYes, I am ignorant. :-)Thanks for the explanation.

author: Benta
author_rank: Super Contributor
timestamp: March 21, 2025, 10:51:37 pm
content: We're all keen to learn.I just reviewed my phrasing. It was not meant as unfriendly or condescending. Sorry.

author: fzabkar
author_rank: Super Contributor
timestamp: March 21, 2025, 11:02:52 pm
content: Quote from: Benta on March 21, 2025, 10:51:37 pmI interpreted your post as helpful, not unfriendly. "Ignorant" is a term that is widely misinterpreted as being synonymous with "unintelligent". Strictly speaking, it just means that one is lacking in particular knowledge.

author: amyk
author_rank: Super Contributor
timestamp: March 22, 2025, 06:58:08 am
content: Motorola SC prefix parts are custom. Fortunately this one has the mask set ID J38M which leads to it being some variant of a MC68HC12BE32.

author: Ehmm
author_rank: Newbie
timestamp: April 03, 2025, 09:38:56 pm
content: I could read it as MC68HC912B32 whith UPA not sure why the BKGD high error came in the beginning.