hybridfree/eevblog-posts huggingface dataset:
0.5x auxiliary Barlow lens - Page 1
Forum section: electronics / beginners

author: Slydder
author_rank: Newbie
timestamp: September 23, 2017, 02:58:29 pm
content: Hey all,I just bought a used Euromex scope (60 Euro). The following specs are all I know of atmWF10X S Oculars1x and 3x Objectives33mm diameter threaded auxiliary opening in the turretI am in need of a 0.5x Barlow that will fit the auxiliary opening and have absolutely NO idea what size I should buy.Does anyone have time to give a bit of info on this?Thanks folks,Chuck
0-60 VDC POWER SUPPLY CONTROLLED BY PIC 0-5VDC - Page 1
Forum section: electronics / beginners

author: chuzkin
author_rank: Newbie
timestamp: April 22, 2014, 10:18:59 pm
content: Hi friends.I think i should give more detailed information.What I need is to uso a PIC microcontroller, so using 2 push-buttons, I can increase / decrease the voltage level from 0VDC to 60VDC. The PIC output range is 0-5VDC, so I need an interface to convert this signal to 0-60VDC.Current output needed 2.5 or 3A. Load is a magnet, with the following voltage/current measured:40V - 2.08A34.8V - 1.85A30.3V - 1.26A24.5V - 0.69A18.4V - 0.12A17V - 0.01AThe idea is to replace actual boards to get 50 or 60VDC in order to achieve a stronger magnetic force.Thanks!Best regards.

author: valentinc
author_rank: Regular Contributor
timestamp: April 22, 2014, 10:35:13 pm
content: Hi,In order to produce an analog voltage output with a PIC microcontroller you need a digital to analog converter (or a microcontroller which has one integrated)... You also need an amplifier, a voltage reference and a power transistor...What is the input voltage of your system ?

author: Psi
author_rank: Super Contributor
timestamp: April 22, 2014, 10:38:24 pm
content: If you're just controlling a magnet you can simply do PWM on the PIC from a 60VDC source.eg..75% duty cycle 60V pwm = power into magnet equivalent to a 45V DC source50% duty cycle 60V pwm = power into magnet equivalent to a 30V DC source25% duty cycle 60V pwm = power into magnet equivalent to a 15V DC source(Note this is not strictly true but close enough, if you're over-driving the magnet past its rated voltage the efficiency goes down)You just need- a N-channel logic level mosfet- 100R resistor between PIC output and mosfet GATE- Generic diode that can handle 2A placed across the magnet for backEMF protection (arrow pointing towards the 60V)Mosfet SOURCE to GND, mosfet DRAIN to magnet, other magnet terminal to 60VDC(Same circuit you will find everywhere for driving a relay from a 5V logic signal)
0.8mm Pitch connector - Page 1
Forum section: electronics / beginners

author: e8ghtmileshigh
author_rank: Newbie
timestamp: August 03, 2025, 11:24:55 pm
content: Hello. I'm looking for a 1 to 2 female on all ends adaptor for this particular pin.Also where can I get more of these pins.They looks like this (pic 1)The housings look like this (pic 2)
0603 resistor pad smaller than physical resistor  - Page 1
Forum section: electronics / beginners

author: DroneBuster
author_rank: Contributor
timestamp: July 05, 2016, 07:41:52 pm
content: Hi,Is it normal that high density pads are narrower than resistor (footprints generated with Altium IPC compliant footprint wizard)Pictures attached

author: Christe4nM
author_rank: Unknown
timestamp: July 06, 2016, 07:47:54 am
content: No that seems wrong to me. The pad must be at least as wide as the terminal. If I remember correctly, a tiny bit wider even for IPC "least" (i.e. high density) footprints.A quick search gave me this IPC calculator at their official site, it might help:http://www.ipc.org/ContentPage.aspx?pageid=Land-Pattern-CalculatorBut do check if you entered the right dimensions into Altium's calculator. And also check if your 3D body has the right dimensions. Just to make sure you're not chasing the wrong error

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 06, 2016, 09:36:18 am
content: Side fillet can be -0.03mm.Tim
0R ferrite beads ... are they real ?? - Page 1
Forum section: electronics / beginners

author: softfoot
author_rank: Contributor
timestamp: July 27, 2020, 07:33:54 am
content: I've been in electronics for some years but I was looking at a design that called for a 0R ferrite bead in a power supply line.Zero ohm impeadanceYou can buy them on eBay for example but are they an inductor at all ??It strikes me that they are in essence a wire link rather like the 0R resistors you often find in a schematic to facilitate testing or controlling options.Have I got the wrong end of the stick hereTIA,Confused Dave

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 27, 2020, 07:58:52 am
content: They have some resistanse of cause. It can be about 5-20 mOhm (+-) depends on wire size, look at datasheet (I'm talking abou wired ferrite beards). They have inductance too - it is about 0.5-1.0 uH (at 100 kHz).And there is a type without wires - just small ferrite tubes.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 27, 2020, 07:59:51 am
content: I guess something like a BL01/BL02/BL03 ferrite jumper (e.g. BL01RN1A1D2B) is implied.

author: brabus
author_rank: Frequent Contributor
timestamp: July 27, 2020, 09:12:39 am
content: They act as a short circuit in DC, but significantly increase their impedance in certain frequency bands, specified in the datasheet. Be careful though: they do not work as inductors, as they dissipate the energy rather than storing it.This exact behavior is desired in order to dampen any disturbance in the target band.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 27, 2020, 10:13:40 am
content: It's a completely meaningless specification.The designer meant something, but wrote down something else. You can only ask the designer.Ferrite beads are different and they should be specified with part numbers, or at least with the basic stack of parameters like impedance @ 100MHz, DC resistance, and maximum current. Saturation current would be necessary as well but as the manufacturers fail to provide that, designers can't specify it either.
0V-15V to -5V|+5V question - Page 1
Forum section: electronics / beginners

author: MegaWatt
author_rank: Contributor
timestamp: August 11, 2013, 07:23:31 pm
content: Hello everybody, I have designed a circuit to convert a 0-15V power supply to a -5V|+5V supply. You can see it on this picture:The voltages that I have written there are the voltages I measured when I built the circuit. Obviously this is not correct and I cannot find why, I would expect the inputs of the voltage regulators to be at +/-7.5V and the output at +/-5V, but that is not the case. I have already disconnected the diodes to check if they were causing problems but the result was the same. Can anybody see what I might be doing wrong? Thanks in advance!

author: Dave
author_rank: Super Contributor
timestamp: August 11, 2013, 07:48:04 pm
content: The way I see it, you only have 2 input connections, right?You need to provide an unregulated positive supply rail, negative rail, AND ground. Just connecting 15V between positive and negative rail won't cut it.If your load doesn't require much power, you could try using asupply rail splitter. I said low power, because this circuit isn't too efficient.

author: MegaWatt
author_rank: Contributor
timestamp: August 11, 2013, 08:00:40 pm
content: Yes you are right, I see my mistake, very stupid. Thanks a lot!

author: Dave
author_rank: Super Contributor
timestamp: August 11, 2013, 08:29:27 pm
content: Hey, you make mistakes and you learn from them. Don't worry about it.You are welcome.

author: hlavac
author_rank: Frequent Contributor
timestamp: August 13, 2013, 05:18:12 pm
content: As to why it does not work, see which way does the current have to go to charge each input cap,you will find it needs to go thru the opposite side regulator and load...Read up on the concept of "virtual ground". You need a way for current to bypass the side that requires less current.Fix could be as simple as putting two ~8V zeners across the input caps to bypass the other side unloaded regulator. Make sure that together the zener voltages are slightly higher than your supply voltage.

author: Zero999
author_rank: Super Contributor
timestamp: August 13, 2013, 08:38:13 pm
content: How much current do you need? 15V doesn't give you much headroom for the dropout voltage.The zeners are probably the simplest option but transistors would enable it to work from a wider voltage range.http://www.learningelectronics.net/circuits/discrete-virtual-ground-circuit.html
1-15V to 3.3-5V converter for one LED - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: February 19, 2023, 10:26:16 am
content: Hi, my car has factory ambient lighting which is very dim so I would like it to shine always at brightest setting, but I cant set it to brightest setting because it also changes instrument cluster brighness to max which I don't want to be at max.Current supply source changes depending on "brightness setting/engine running" from 1-15V. So I would like to convert 1-15V to 5V or 3.3V for one LED maybe 60mah max power, is there a simple board converter which I could buy for this purpose?

author: tooki
author_rank: Super Contributor
timestamp: February 19, 2023, 12:21:02 pm
content: Converters that will start at 1V and still handle 15V is a tall order. Maybe it exists, but I wouldn’t count on it.Additionally, if the LED driver is a constant-current source (rather than a voltage source), then you have that layer of complexity to deal with, too.Wouldn’t it be easier to just use the fixed 12V supply and then a MOSFET or transistor to switch the enable pin of the DC-DC converter?Also, be aware that automotive electrical systems are extremely “dirty”, with lots of spikes and noise, so you need to provide robust input protection to everything.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: February 19, 2023, 02:27:43 pm
content: How did you measure that 1-15V? I suspect the LED power is being pulse width modulated (where the voltage is always 15V, but pulsed on/off for a varying regular period depending on brightness desired), but when you're measuring it you're just seeing the average voltage level.

author: wasedadoc
author_rank: Super Contributor
timestamp: February 19, 2023, 02:56:35 pm
content: Quote from: HwAoRrDk on February 19, 2023, 02:27:43 pmIndeed that is a very reasonable suspicion given that LEDs that give useful light output from 1 Volt are as rare as rocking hor.......

author: symbianas
author_rank: Regular Contributor
timestamp: February 19, 2023, 05:44:45 pm
content: Quote from: HwAoRrDk on February 19, 2023, 02:27:43 pmYes, I was using simple multimeter so it might be average voltage level. Do voltage regulators like "step down" work on this pulse width modulated power source?Quote from: tooki on February 19, 2023, 12:21:02 pmI might end up doing that...
1.27mm Dupont connectors ? - Page 1
Forum section: electronics / beginners

author: michaeliv
author_rank: Frequent Contributor
timestamp: September 21, 2015, 07:58:24 am
content: Hi,Are there any Dupont connectors for 1.27mm pitch headers :http://www.aliexpress.com/item/200pcs-lot-1-27mm-1X40-Single-Row-Male-Pin-Header-Strip-Gold-plated-Connector-Plastic-in/1572815748.htmlIt's easy to find 2.54mm ones - here is what I mean:http://www.aliexpress.com/item/Free-Shipping-20cm-40P-1P-1P-Female-to-Male-DuPont-Line-Wire-Cable-for-Arduino-FZ0261/1542521528.htmlWhat solutions are there for connecting individual wires to 1.27mm pitch headers ?Thanks!

author: mauroh
author_rank: Frequent Contributor
timestamp: September 21, 2015, 10:10:49 am
content: The pitch between the wires in the "dupont" connector you linked is already 1.27mm, you can easily cut the connectors and solder your own 1.27mm female strip to the wires.Or you can find a 1.27 connector like this:http://www.elechouse.com/elechouse/images/product/1.27mm10p.jpgMauro

author: michaeliv
author_rank: Frequent Contributor
timestamp: September 21, 2015, 10:33:51 pm
content: I am looking for single-pin connectors, that can be connected individually on to the 1.27mm pin headers. I guess there may not be such a thing ... only full connectors.

author: mauroh
author_rank: Frequent Contributor
timestamp: September 22, 2015, 08:05:30 am
content: http://www.ebay.com/itm/10pcs-50-Pin-50P-1-27MM-Gold-Plated-Single-Row-Straight-Female-Pin-Header-Strip-/381374578531?hash=item58cbb23f63I meant: you can cut individual pins from strips ad solder your single wires.Mauro
1.2V LVCMOS to 3.3V LVTTL level shifter - Page 1
Forum section: electronics / beginners

author: twitzelbos
author_rank: Contributor
timestamp: February 07, 2023, 08:26:54 pm
content: Hello all,I'm in need of an 8 Bit unidirectional level shifter that takes 1.2V LVCMOS input signals and turns them into 3.3V TTL output signals. There are a gazillion ICs out there, but I don't seem to be able to confidently select one with the search function in Digikey or on manufacturer websites. The data rate would be roughly 50 Mbps.Can someone please recommend an IC that will work for this application?Thank you,Thomas

author: Benta
author_rank: Super Contributor
timestamp: February 07, 2023, 09:11:20 pm
content: LCMOS to TTL at 50 Mbps? Are you sure? Or do you mean LVCMOS?Ah! I see you fixed the OP. Gotcha.

author: twitzelbos
author_rank: Contributor
timestamp: February 07, 2023, 09:14:26 pm
content: Yep, we have this working at 3.3V routinely, but now we have a FPGA board that only outputs 1.2V on this port. We are operating SPI near its limits on this (actually mostly 39.5 Mbps, but occasionally higher).Thomas

author: langwadt
author_rank: Super Contributor
timestamp: February 07, 2023, 09:35:22 pm
content: there's numerous dual supply 74xxx245 like;https://www.nexperia.com/products/analog-logic-ics/voltage-translators-level-shifters/74AVC8T245PW.htmlthat should work

author: twitzelbos
author_rank: Contributor
timestamp: February 07, 2023, 11:24:51 pm
content: Thank you. Do I read the datasheet correctly, that I would then supply Vcc_A with 1.2V as this is the logical level I'd have on the input, and Vcc_B with 3.3V?Thanks again,Thomas

author: langwadt
author_rank: Super Contributor
timestamp: February 07, 2023, 11:41:42 pm
content: Quote from: twitzelbos on February 07, 2023, 11:24:51 pmyes

author: twitzelbos
author_rank: Contributor
timestamp: February 08, 2023, 02:01:36 am
content: Thank you!!
1.3V as voltage drop of a blue LED? - Page 1
Forum section: electronics / beginners

author: bitwelder
author_rank: Super Contributor
timestamp: August 12, 2023, 05:57:58 pm
content: I'm checking an issue with the blue power LED of my desktop computer.I noticed that lately it's much less bright, so first I checked the contacts but it looks ok.Then I checked what voltage comes from the motherboard when the computer is on: 5VThen I measure with a multimeter the voltage drop of the LED: 1.33V which looks suspiciously lowIn fact if I get a fresh 3mm blue LED from by my bins and do the same measurement: 2.53VSo, is the LED failing?

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 12, 2023, 06:24:43 pm
content: At 1.5V it shouldn't shine at all. That's the drop of a red led!Maybe it's not DC, but high frequency pulses?

author: bitwelder
author_rank: Super Contributor
timestamp: August 13, 2023, 04:44:49 am
content: In fact it doesn't shine while testing it.In the last days it had a weird behavior, most of the time it was so dim that it was visible only in a dark room,but sometime was returning to its original brightness, but only for ~30 minutes.I'm curious about the LED failure mode.I'm not sure how the LED is driven by the motherboard, whether in DC or in pulses,but I'll add anyway a ~220 Ohm resistor to my replacement LED.

author: Faranight
author_rank: Unknown
timestamp: August 13, 2023, 05:33:25 am
content: I've had something like this happen on a green LED in my custom RGB Christmas decoration string where one LED would suddenly lose luminosity down to like 20% and maybe flicker a little.But after an hour or so it would light up back to normal for a while, and then the phenomenon would repeat. No idea what caused it, the contacts were all good. Must have been a faulty LED.

author: bitwelder
author_rank: Super Contributor
timestamp: August 13, 2023, 06:02:56 am
content: Anyway, problem solved by replacing the blue LED with a new one, with a 390 Ohm resistor in series(it's a little less than full brightness, but on the other side it's only a signaling LED, and this way it's not disturbingly bright in a dark room)As I had the computer front panel open, I thought about applying a similar treatment to the red HDD LED, but meh,after all it's a mostly-off, or shortly blinking LED, so let it stay as it is.
1.5 volt electric motor inductance - Page 1
Forum section: electronics / beginners

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 12, 2013, 02:24:06 pm
content: Hi,The motor is now on the 7 volts battery. the shema is :https://www.eevblog.com/forum/beginners/dc-motor-kicker-capacitor/15/If I have a 150 Omhs resistor and it takes .200 A to start then it continue at .070 A, can I find the inductance of the motor with E/di/dt = L ?If I put a L meter on the black and red wire I have jumping readings from 7 mH to 0 mH.Thanks for your concern,JP

author: hlavac
author_rank: Frequent Contributor
timestamp: April 13, 2013, 03:46:18 pm
content: It makes not much sense to talk about motor inductance in a commutated DC motor like that.There are multiple windings inside (usually 3) that are switched in and out by mechanical contacts and brushes as the rotor rotates.Any movement of the rotor will cause EMI that will put reverse voltage across the motor power leads.That is throwing off your measurement...

author: 6502nop
author_rank: Regular Contributor
timestamp: April 13, 2013, 06:18:00 pm
content: If I may add...That looks like a bog-standard Mabuchi motor used in toys and such. So as not to go about re-inventing the wheel, why not point you to all the info you need, right from the horse's mouth:http://www.mabuchi-motor.co.jp/en_US/technic/index.htmlI'm wondering, though, why you wouldn't just use a fan? The contraption shown would be "torque-challenged" and unbalanced, both problems which make motors very unhappy. A simple thermal switch (as used in coffee makers) attached to the heatsink, wired to the fan, and Robert's one of your parent's siblings. Or just leave it running. There's no such thing as having a heatsink "too cool" (Josephson junctions not withstanding).nop

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 13, 2013, 07:43:45 pm
content: Thank you very much.>"I'm wondering, though, why you wouldn't just use a fan?"To spare the battery.>"Robert's one of your parent's siblings"I dont understand.)>"Or just leave it running"Indeed.JP

author: c4757p
author_rank: Super Contributor
timestamp: April 13, 2013, 07:48:41 pm
content: Quote from: J4e8a16n on April 13, 2013, 07:43:45 pm"Bob's your uncle"...

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 10, 2014, 04:29:07 pm
content: Quote from: J4e8a16n on April 13, 2013, 07:43:45 pmThey are all too big. I build a small helice for the motor. It is balanced.
1 Hz Low Pass Filter - Page 1
Forum section: electronics / beginners

author: fourierpwn
author_rank: Regular Contributor
timestamp: August 24, 2017, 06:43:18 am
content: Hi all,A typical measurement setup used to measure 1/f noise is to use a 1 Hz low pass filter in order to filter out any noise that is present on the DC bias voltages from a given SMU and obtain "clean" DC.All attempts at building a simple RC filter have not yielded results that seem correct. This filter is not specific to the type of measurements it is being used for, so essentially I am just after a ? 1Hz LPF to clean up some DC voltages. Sounds simple enough (probably is, I'm just too noob) but I would appreciate as far as practical designs.

author: Benta
author_rank: Super Contributor
timestamp: August 24, 2017, 07:39:15 am
content: At frequencies that low, component values get so large that it's practically unmanageable and you get into all sorts of leakage and other parasitic problems.If at all possible, I'd recommend an active filter, but even there you'll have to watch out for parasitics.

author: bson
author_rank: Unknown
timestamp: August 24, 2017, 04:01:45 pm
content: Use an active filter for such low frequencies!

author: eliocor
author_rank: Unknown
timestamp: August 24, 2017, 04:25:54 pm
content: Switched capacitor filters?https://www.maximintegrated.com/en/products/analog/analog-filters.htmlhttp://www.linear.com/product/LTC1059http://www.linear.com/parametric/Filter_Building_Blockshttp://uk.farnell.com/c/semiconductors-ics/filters-active/switched-capacitor-filters @Benta: sorry, I was in a hurry and I didn't take care of the requirement for 1/f measurements!!!

author: Benta
author_rank: Super Contributor
timestamp: August 24, 2017, 06:52:09 pm
content: If you read the OP, the goal is to measure 1/f noise. I'd expect any kind of switched filter to counteract that goal. Just sayin'

author: jpanhalt
author_rank: Super Contributor
timestamp: August 24, 2017, 08:40:47 pm
content: How about lead-acid batteries? We ran our Beckman DU spectrometers from them.
1 MHz crystal options - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: July 21, 2024, 03:57:18 pm
content: HiI need a 1 MHz crystal for use with a SFC96364 VDU chip.The only easy / cheap options seem to be either oscillator modules or ceramic resonators.I'm thinking that you can't just put the two output pins of a module across the crystal pins on the IC. Right ?Would a ceramic resonator be good enough ?Thanks

author: ledtester
author_rank: Super Contributor
timestamp: July 21, 2024, 04:41:55 pm
content: Quote from: netdudeuk on July 21, 2024, 03:57:18 pmIt might be possible to feed the oscillator module output into one of the crystal pins.Figure 2 and 3 in this article:https://www.analog.com/en/resources/technical-articles/replacing-crystals-and-ceramic-resonators-with-silicon-oscillators.htmlshows the basic idea. Using an oscillator you just feed the output into one of the crystal pins and leave the other one open.It might matter which one you feed the signal into.

author: wasedadoc
author_rank: Super Contributor
timestamp: July 21, 2024, 04:46:58 pm
content: It certainly will matter. Feed oscillator into pin 1.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: July 21, 2024, 05:47:51 pm
content: Thanks both.@ledtester, I really appreciate that article you linked to. I shall read it now.
1% or better precision resistor combo pack? - Page 1
Forum section: electronics / beginners

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: August 21, 2015, 12:03:45 am
content: I was wondering if someone knows of a decent precision through hole resistor kit? Radio shack has a nice package but there 5% and the "1%" blue resistors I bought on ebay are a joke..... is the best idea to just order a bunch from mouser or digikey?
1 to1 voltage regulator with external power ind - Page 1
Forum section: electronics / beginners

author: bwinddk
author_rank: Newbie
timestamp: January 12, 2020, 07:46:54 am
content: Hello good people :-) i hope this is a simple question, have a 3dprinter but because of chines cheap engineering the mosfet of the fan control is stuck at 6v i am getting a new motherboard, but want to remove the strain of the mosfet with a external board, but cant fore the love of my life find out what it is called. the range is 0-12v under 1A need a board that regulate one to one ( 5v in 5v out, 12v in 12v out) but with a external power in... does something like this exist??Just need the name of something like this, ore a link so i can find something to search for :-) want to do the work but hard when you don´t know what to search for :-/ :-)Hope you guys can help med :-DThanks in advancekind regards Brian

author: ZaphodBeeblebrox
author_rank: Contributor
timestamp: January 12, 2020, 02:06:34 pm
content: So, you have a regulator that regulates the voltage of a fan in the range of 0-12V, with a maximum current draw of 1A at 12V? You noticed a MOSFET of said regulator is deffective because it "is stuck at 6V". What do you mean by the latter? When a MOSFET goes to the eternal silicium fields, it shorts out most of the time...Could you either:[li}Provide the schematic of the regulator, so we know what is going on? Maybe it's easier to just take the input of the regulator an feed it to a more powerfull regulator, but to know that, schamatics are required.Confirm that you in fact need an analog/digital (which of the two?) power amplifier that takes an input signal of 0-12V and outputs the same voltage but with more current capacity?

author: bwinddk
author_rank: Newbie
timestamp: January 20, 2020, 07:20:52 am
content: Hi thx for the replyi got a Anycubic i3 mega S 3dprinter and people warn that the main board i a bit small for the loads, so modding it with external relays to not burn out the main board for the hot end and heated build plate, but min is stuck a 6.1V on a fan output and it cant adjust anymore and it is not software, the fan runs as soon as i give the printer power, but there is a small start up on the main board so normal no fans runs before this is done. Anycube is sending a new main board, i can´t do anything to the main board i don´t got schematics on it just need to find a external solution. i got the error on a other forum other has this problem but nobody got a solution except a new mainboard. i am thinking i can make one out of a arduino but i am thinking something like this must exist??? i am still just a noob :-/Kind regards Brian
1 Uart In -> 16 Uart_Out - Page 1
Forum section: electronics / beginners

author: ElectricGuy
author_rank: Regular Contributor
timestamp: April 20, 2015, 02:55:02 am
content: Hi;I did the attached circuit. It is supose to acept one TX Uart from a micro and provide 16 outputs so i can connect 16 devices.They all are close, 30cm away maximum, and it has to me Uart, so I2C, SPI or 485, its out of question.What do you think about the circuit, it will work?Thank you.

author: matseng
author_rank: Frequent Contributor
timestamp: April 20, 2015, 03:10:11 am
content: If all your devices doesn't load the signal too much (like if it goes more or less directly into a microcontroller made after the 70'ies) then I'd guess you really don't need any circuitry at all. A fanout of 16 on a slow signal like an uart sounds more than reasonable to me.But if you really want to have something between the uart and the receivers then your schematics seems just fine.

author: ElectricGuy
author_rank: Regular Contributor
timestamp: April 20, 2015, 08:15:02 am
content: Quote from: matseng on April 20, 2015, 03:10:11 amThank you for your answer.Actually it's based on recent PIC micro.

author: daqq
author_rank: Super Contributor
timestamp: April 20, 2015, 08:33:42 am
content: QuoteThe extra buffer might provide some protection for the USART - if one device fails in a shorting way, then this is better - one dies, the rest still live. But yeah, if you don't mind that and are not running at some obscene frequencies, then a direct connection should be OK.By the way, you have 16 bit wide ICs like this (of most 74xx bus like logic), seehttp://www.nxp.com/documents/data_sheet/74LVC_LVCH16245A.pdf

author: ElectricGuy
author_rank: Regular Contributor
timestamp: April 20, 2015, 08:35:26 am
content: Quote from: daqq on April 20, 2015, 08:33:42 amThank You for your advice!
1-Wire bus - ESD & surge protection - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: May 31, 2022, 06:15:27 pm
content: HiI want to use a 1-Wire bus for an outdoor application over a cable with 20m length.Now I want to protect the bus from ESD surges.I saw that Bourns utilizes a TBU for current limiting and an TVS diode for voltage limiting for a rs485 bus, but also a GDT on the front.I'm ok to use a TBU-CA085-050-WH (850V and triggers at 50mA) and an STS321050B100 5V 350W 30kV 1.5pF TVS diode.The problem is that I don't have space to put the GDT 90V on the board.Do you think it's necessary or is the TBU+TVS enough?Thank you

author: jwet
author_rank: Frequent Contributor
timestamp: July 15, 2022, 02:37:55 am
content: Maxim/Dallas has a good app note on running one wire in bad environments. Worth a read. A TVS give you a lot. Add a little R if you can, even 10 ohms can help. The peak currents in ESD spikes are BIG.Maxim PDF Format TUTORIALS 148: Guidelines for Reliable Long Line 1-Wire Networks

author: MarkL
author_rank: Unknown
timestamp: July 15, 2022, 02:20:56 pm
content: You might also want to consider the DS9503. It's specifically designed for 1-wire ESD protection, and has integral resistors:https://www.maximintegrated.com/en/products/interface/signal-line-protection-ics/esd-protection-diodes/DS9503.htmlMouser has them in stock, US$1.46 (qty 1).
1-Wire bus, ground reference & common mode filter - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: June 10, 2022, 08:43:26 am
content: HelloI need to power a PCB over a cable of several meters. I will use 24VDC but also a 1-Wire bus to communicate with a microcontroller.I need to use a common mode and differential mode filter on the input of the board.But now I have those 2 questions:1. What about the ground reference and the 1-Wire bus? Is the common mode filter on the 24V/GND line a problem? Will I need to decouple the 1-Wire signal also with an isolator?2. How do I trace the 1-Wire bus on the PCB since there is a ground plane "discontinuity" because of the common mode choke?Thanks
10.000 EUR for small scalle cell phone production line? - Page 1
Forum section: electronics / beginners

author: dds737
author_rank: Contributor
timestamp: May 20, 2015, 06:03:31 pm
content: While reading this blog:http://blog.p2pfoundation.net/business-models-for-open-hardware/2011/03/19I've read this: "Significantly, the Shanzai companies are almost universally bootstrapped on minimal capital with almost no additional financing: Mitchell Tseng reported that 10.000 € are enough to start such a company, and it may eventually scale to over 50 million € revenue per year within a couple years."Could this be a possibility elsewhere, or only in China?What kind machines are needed to let's say, small scale cell phone production? (Off course with Mediatek Chipset)

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 21, 2015, 05:19:59 am
content: To actually produce smartphones all on your own you'll need several 100k$. SMD production line, plastic moulding,...So with a budget of 10k$ you'll be looking at outsourcing most or all of it. Of course, the 10k$ iscapital. That doesn't mean you can't buy stuff (such as a production line) on credit.

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 21, 2015, 06:49:24 am
content: Would love to see a link for the MTK stuff, but I guess it's something likehttp://neoden.eu/en/smt-production-line-bundle?That's nice and dandy for a few prototypes and low volume stuff but for actual volume? And in addition to that, most of these cheapo placers crap out at 0402 which would kinda suck for mobile phones. And I would imagine that the rest of the packages would be out of their league as well...

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 21, 2015, 07:09:31 am
content: Oh, with "MTK sells entire solutions you mean they sell chips and offer schematics, BOM, SW a complete DK for 10k$? I figured you wanted to start a SMD production line on a 10k$ budget
100 ohms differential pairs impedance matching + length matching - Page 1
Forum section: electronics / beginners

author: VEGETA
author_rank: Super Contributor
timestamp: September 25, 2021, 12:47:55 pm
content: Hello,I want to route high speed digital signals of 600 mhz and 6 ghz. datasheets and design guides strictly says it should be 100 ohms differential impedance. I also want to length matching them. I am using KiCAD, can't\won't use any other package.I used 0.1 trace width and 0.2 spacing (i though it is 0.3 but it is actually 0.2). my PCB vendor is AllPCB and their 4-layer stackup shows pre-prep is 0.122mm of heighthttps://www.allpcb.com/4_layer_pcb.htmlI plugged these numbers in Kicad calculator and it showed like in attached picture.I already routed these signals, was very tiresome to length match them!please inform me what to do to achieve the requirements... and what is the best approach professional designers use in order to do it.I mean, you don't design the board multiple times to be able to fit all PCB manufacturers with their different stackups right? or do you specify a custom stackup all the time if you are doing it for professional job.. and is it really much expensive?does length matching has to do with this?I had to put vias (0.3mm size) for nearly half of these diff. pairs... will this affect anything?for your kind help!NOTE: attached picture was for 0.3 gap which is not correct, correct one is 0.2mm. for 0.2mm kicad says Zodd= 68 ohms which is not going to be 100 ohms diff... i need it to be 50 ohms.EDIT: I achieved 50 ohms Zodd by making 0.15mm width and 0.1mm spacing, but i feel these are too close and too small... is this correct to choose?thanks!

author: VEGETA
author_rank: Super Contributor
timestamp: September 25, 2021, 01:11:44 pm
content: reference board has this:width of trace: 0.1 mmspacing: 0.2 mm (= actual space between the 2 tracks, not from track center to track center).which is like mine.but their stackup specs are the following:prepreg height: 60 um.copper height: 18 um. (mine is standard 35).I plugged them on kicad calculator and it turns out to have around 51.75 ohms Zodd. seems about correct right?___I might be wrong about reference stackup, therefore I attached the sheet showing its details. please correct me

author: VEGETA
author_rank: Super Contributor
timestamp: September 25, 2021, 05:10:03 pm
content: I looked around and found that I used 0.1mm trace with 0.2mm gap + 0.122mm prepreg thickness and 35um copper thickness... both kicad and saturn pcb tool showed around 100-103 ohms differential which is nice! also, all signals are length matched with help of 0.3mm vias. is there anything else i need to worry about? please inform me.Now for single signals (not differential), there are 60 of them which needs to be 50 ohms. kicad shows 0.2mm to be suitable (=51.1 ohms) while saturn shows around 0.19mm (50.1 ohms). gonna go with saturn calculations and modify the tracks.what do you think or recommend?
100M Resistor 4th B. white. - Page 1
Forum section: electronics / beginners

author: Vtile
author_rank: Super Contributor
timestamp: January 22, 2017, 12:35:57 pm
content: I have this 100Megaohm resistor, deep purple to brownish body. It is 100 megs since it divides 10V to 5V series with my 100Meg Multitester and so says also the colorcode: brown-black-purple-whiteNow what is the White??? I have no source/reference that it even should exist in that place as a 4th band. I'm just curious.. Anyone have any information what is this presumaply nonstandard marking.I have no idea of the age of this as it is salvaged part from random electronics in the past (late 90s when it did end to my box of resistors).

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 22, 2017, 03:03:54 pm
content: For very high values, which will often be used at high voltages, you don't want a metallic ink like gold or silver, so white is probably used as non-shiny silver.These VR68 high-voltage resistors use yellow instead of goldFrom the datasheethttp://www.vishay.com/docs/28907/vr25vr37vr68.pdfQuote

author: Vtile
author_rank: Super Contributor
timestamp: January 22, 2017, 03:19:06 pm
content: Oh, really nice. Thx.It might indeed be the explanation, since it does have good technical reasoning.The resistor I have also do have this hard enamel shine on it so it might indeed be a highvoltage range. Something over the typical jellybean dip to paint range anyway.
100V DC @ 10 Amps regulated power supply? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: October 16, 2015, 10:35:21 pm
content: Self build or commercial, what are my options? Currently struggling with a toroidal transformer and a full wave bridge, unregulated. Voltage drops to circa 65 / 70V DC under load. Would prefer to steer away from a SMPS, especially self built, too complex. Thanks. Mains available here is 230V AC, 50Hz, about 60 Amps

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2015, 11:21:43 pm
content: if it drops to 65V under load your transformer AC output voltage is too low for 100VDC.The problem with regulation at this current and voltage difference is you either have a massive heatsink or go switchmode. Your looking at 40-50V difference between noload and fullload DC output which is 50V*10A = 500WThere are a few more specialized options, such as a servo controlled variac with feedback from the DC output after the bridge. But this is obviously slow to respond so is only useful in limited situations.Best option is to just look for something on ebay. Or perhaps multiple units that can be wired in series to give you 100V. (Since 100V isnt going to be very common for a single unit) Two 48V 10A units might be easier to find and could be tweaked to output 50V easy enough with some understanding of how switchmode psu feedback works.

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2015, 11:34:09 pm
content: I'm not saying you should get this, i cant figure out if its compatible with being wired in series but.. Two these might work and would be under US$100http://www.aliexpress.com/item/led-power-supply-switch-600W-48v-12-5A-ac-dc-converter-Input-220V-S-600w-48v/2026109253.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4I'm pretty sure this will have a pot to make tweaking the output to 50V dead simple.Cheaper onehttp://www.aliexpress.com/item/New-model-48V-10A-480W-Switching-Power-Supply-Driver-for-LED-Strip-AC-100-240V-Input/32345061556.html?ws_ab_test=searchweb201556_7,searchweb201527_2_71_72_73_74_75,searchweb201560_4Of course this is relatively cheap china stuff, so quality is a bit unpredictable.

author: Simon
author_rank: Unknown
timestamp: October 17, 2015, 07:40:58 am
content: Quote from: AcHmed99 on October 16, 2015, 11:27:51 pmNo here in the UK we are terribly good at taking a source of heat, wastefully turning it into electricity by burning it miles away and loosing 60+% of it's heating power, then channaling it all the way to our homes so that we can use electricity to..... make heatMany houses still have electric cookers and heating, these may be deemed to be safer for elderly people etc but many of us are now on gas.
100W constant current load to test my power supply - Page 1
Forum section: electronics / beginners

author: Spikee
author_rank: Frequent Contributor
timestamp: August 13, 2012, 03:16:43 pm
content: My new powersupply will arrive in a few days (ELV.de pps5330)http://www.elv.de/prozessor-netzteil-pps-5330-komplettbausatz.htmlAnd to test it and compare it to my own noobish power supply i want to build a constant current load that is capable of 100w (30V 3A) .The heatsink i will use is 0.4 c /w (has small fan on it).So here is the first attempt:https://docs.google.com/open?id=0BwczAtgmsNqIakhQeW5PN05MQmcI just used the lm324n because i have them at home , but this is probably not the ideal opamp .But i was not sure which other one is better. I also have the TI OPA2336 opamp wit rail to rail output capability.The current readout is not added yet ...What i want it to be capable of:100W dummy loadso i can test my 30V 3A power supply and my diy power supplies.Thanks to everyone that will help =) .Trying to do an ltspice simulation now ...

author: kripton2035
author_rank: Super Contributor
timestamp: August 13, 2012, 03:31:43 pm
content: this is an old elv kit for a 100w dummy load model EL7000.good readings !

author: Spikee
author_rank: Frequent Contributor
timestamp: August 13, 2012, 03:48:38 pm
content: It's kinda the same principle.But its hard to read technical German

author: T4P
author_rank: Super Contributor
timestamp: August 13, 2012, 03:54:59 pm
content: Low offset opamp. That's the sort of opamp you needalso a chopper amp would be good

author: Spikee
author_rank: Frequent Contributor
timestamp: August 13, 2012, 04:03:30 pm
content: so the OPA4251 would be good ?http://www.ti.com/product/opa4251
1013d oscilloscope - Page 1
Forum section: electronics / beginners

author: Mal
author_rank: Newbie
timestamp: February 04, 2022, 02:03:21 pm
content: hi everyone, i have a 1013d oscilloscope, the inner screen is broken, ive looked everywhere for a replacment but could not find one. the manufacturer fnirsi wont help at al . is there anyone who has replaced a screen in one of these that could proide me with a screen number, the number on the screen back is hz-tft070ie001 is there an equivalent screen to the one thats in it. any replies i will be grateful for it

author: bob91343
author_rank: Super Contributor
timestamp: February 04, 2022, 05:18:49 pm
content: What is a 1013d oscilloscope?

author: tunk
author_rank: Super Contributor
timestamp: February 04, 2022, 05:50:32 pm
content: You did get a reply from one of your other posts - did you look into that?Maybe you could take it apart and post some photos?

author: ledtester
author_rank: Super Contributor
timestamp: February 06, 2022, 04:19:41 am
content: Quote from: bob91343 on February 04, 2022, 05:18:49 pmIt's a tablet style scope made by FNIRSI:http://www.fnirsi.cn/productinfo/419011.htmlYou'll find quite a bit of discussion about it on the forum here.

author: bob91343
author_rank: Super Contributor
timestamp: February 06, 2022, 04:36:45 am
content: Thank you for the clarification. However, I read this:

author: Mal
author_rank: Newbie
timestamp: February 06, 2022, 05:42:57 pm
content: i have emailed them so i will see what they say ,thankyou for the info
105 SMD resistor  tolerance - Page 1
Forum section: electronics / beginners

author: Agony
author_rank: Contributor
timestamp: May 12, 2013, 07:51:27 pm
content: so i "salvaged" a led ring/strip and looked at the resistors.There are some 105-s, that look like 0.06W range, really tiny.measured i get 720-730k ohms.105 is rated at 1M ohm.is that huge tolerance normal? thats around 27% less.

author: David_AVD
author_rank: Super Contributor
timestamp: May 12, 2013, 09:29:18 pm
content: Maybe you fried them during removal?

author: Agony
author_rank: Contributor
timestamp: May 12, 2013, 11:25:15 pm
content: didnt remove them, in circuit testing. .. too small to even bother removing.https://www.circuitlab.com/circuit/fhp5xv/led-ring/

author: Psi
author_rank: Super Contributor
timestamp: May 12, 2013, 11:33:58 pm
content: They probably are 1M but other components in the circuit are skewing the measurement.Or maybe your DMM is a cheapish brand and has a flat battery (cheap meters read wrong when getting flat)Most likely the former.

author: Skimask
author_rank: Super Contributor
timestamp: May 12, 2013, 11:34:45 pm
content: No, but if you look at your schematic, you've got resistances in parallel, and if you're trying to measure those 105 resistors in circuit, assuming all of those resistors are actually 1M and they are right on the mark for tolerance, you should read about 750K. Factor in a bit of tolerance, and 720K-730K isn't that far out.

author: Agony
author_rank: Contributor
timestamp: May 13, 2013, 12:34:53 am
content: the R3,R4,R5,R6 - they all were marked as "105" - 105 should be 1M.But when i did some measuring - had a unregulated DC supply (17.6V under load) - the current was very close - 7mA.Thats what simulation gets me with 720k ohm resistors. With 1m ones the simulation suggested a 11mA - way mroe then it actually measured.

author: David_AVD
author_rank: Super Contributor
timestamp: May 13, 2013, 02:09:08 am
content: Measure the resistors out of circuit and tell us what they read.

author: Skimask
author_rank: Super Contributor
timestamp: May 13, 2013, 02:42:22 am
content: Quote from: Agony on May 13, 2013, 12:34:53 amYou're not listening and/or reading...You can't measure the value of those resistors "in-circuit". There's too much other stuff going on.And an unregulated 17.6v. Who knows what kind of wave garbage is coming out of that thing...

author: metalphreak
author_rank: Frequent Contributor
timestamp: May 13, 2013, 02:38:02 pm
content: You should look up how a voltmeter works. Also understanding that taking a measurement at two points is between two "nodes", so anything connected between those two nodes is measured. It might give you some clarity as to why you're getting the result you are.The multimeter is putting out a small test voltage, the current from this is travelling through all the resistors in the circuit. What you are measuring is the combination of all the resistors at once in that configuration. You pretty much have to remove most components from a circuit if you want to test their values.
1070Ti "Please connect power" - connected - Page 1
Forum section: electronics / beginners

author: elior77
author_rank: Newbie
timestamp: May 14, 2020, 07:00:47 am
content: Hey !I got this ASUS 1070 Ti, when I turn it on I get "Please power down and connect the PCIe power cable..."The back side of the card was very dirty and has some signs of corrosion, I work at an Electronic factory so I have every thing needed for repairs, I got the card cleaned and re-soldered any bad pads found.I understand the the INA 3221 chip is responsible for voltage monitor on the card, I replaced it - still the same.btw, all the voltages I expect to see are there, mem,gpu,pcie,5v,1.8v ...I would love some help here, as I understand it the the card does not start normal start up for some reason.Thanks !Elior

author: ConKbot
author_rank: Super Contributor
timestamp: May 15, 2020, 02:53:26 pm
content: Is it an 8-pin PCI-E power connector? Given that its the same number of power pins as a 6-pin, and just 2 extra grounds, see if one of the ground pins is being used to sense the 8-pin plug being connected, and if there is a faulty joint, or visible cracked trace. No specific guidance on how to diagnose, as I'm not sure what a typical implementation is for them, but I do know at least some cards can tell if a 6 or 8 pin is plugged in.

author: elior77
author_rank: Newbie
timestamp: May 19, 2020, 07:06:21 am
content: It has 1x8pin PCI-E power connector, there no cracks, the card is like new on the gpu side, it is just the back side that suffer from liquid attack...I source reason for the problem is the liquid that got spilled on the back, I tried to take care of all the visible corrosion but I something is still not right.