hybridfree/eevblog-posts huggingface dataset:
What does the last modifier digit mean in russian germanium transistors? P13V(P) - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: July 31, 2023, 05:06:48 pm
content: I know the first letter after the number is the variant, usually differing in gain. But I've found a few that have an additional letter after that P13VP. Is it like for low noise variants similar to tubes?

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 31, 2023, 05:20:10 pm
content: Two additional letters together 'ВП' in these ancient transistors mean 'military-grade' ('ВП' = 'военная приемка'). It doesn't mean they are 100% really good but there is a good probability that they are better than those without 'ВП'. They were tested at the factory and good ones have 'ВП' marking and are supposed to military customers.There are other codes for military grades (e.g. a rhomb) and several military grades inside military grades (1-9). Grade '9' is a good one that meets all requirements and other 1-8 grades are not good (almost a usual junk).If you have only one letter (А/Б/В/Г) - then it is as you know a usual separation into subtypes under one type (variants, like different hfe or different max voltages, etc.).Upd.:Newer design transistors were marked with another marking standard as 'КТ', 'ГТ', '2Т', '1Т', where 'T' is транзистор/transistor.'1Т' is a military-grade version of 'ГТ' (германий or germanium).'2Т' is a military-grade version of 'КТ' (кремний or silicon/silicium).
What does the marking on a piezo buffer mean HXD/THDZ/HUDZ/XSDZ/XYDZ? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: August 25, 2014, 05:57:08 pm
content: What does the marking on a piezo buffer mean HXD/THDZ/HUDZ/XSDZ/XYDZ? There are many more - does anyone know what the significance of the marking is?
what does the propergation delay in datasheet mean in practise - Page 1
Forum section: electronics / beginners

author: amateur_25
author_rank: Regular Contributor
timestamp: February 06, 2017, 08:27:25 am
content: HiI see in datasheet of 7400 series logic ic's they mension properagation delay and output transistion delays.For example say the output transistion is 25ns, how do I know it'll work reliably if I stick a 1MHZ serial data bus through it?This maybe a stupid question since 1MHZ is propbably not that fast but I want to understand those number instead of guessing and hoping for the best.

author: tggzzz
author_rank: Super Contributor
timestamp: February 06, 2017, 08:36:27 am
content: Look at the diagrams in the datasheet; they will define what the manufacturer is prepared to guarantee. If your device's datasheet doesn't have diagrams, use another manufacturer.Draw a picture of your signal, in this case paying attention to the relative timing of various parts of your signal. Then add the effects specified in your device's datasheet to understand what the output will look like.To determine whether that is sufficient, look at the diagrams in the datasheet of whatever will be receiving the signal.If you are using "long lines" then the connections may affect the signal and you might need to treat them as transmission lines. See "Bogotin's Rules of Thumb" for examples.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 06, 2017, 01:22:01 pm
content: There is usually a diagram explaining what is measured.It is usually the time measured between 50% points of the input and output waveform.The maximum switching, or toggle, or clock, frequency of a device is usually on the order of the propagation delay (i.e., for a 32ns delay, ~32MHz). But it can be greater or lesser, depending on internal design.The very fastest logic is little slower than the speed of light across the package: an internal propagation delay <100ps, yet the delay as measured at the pins is 300ps or more -- because the signal has to propagate along the pins to get there, first! This is one of the more extreme cases, where the clock frequency can be much higher (10s GHz?) than the propagation delay, simply because the propagation delay, as measured at any useful location, is several wavelengths already. (Needless to say, design of digital circuits at those frequencies requires considerable thought in matching up the delays.)Tim
What does the same voltage domain mean? - Page 1
Forum section: electronics / beginners

author: Morgan
author_rank: Newbie
timestamp: December 03, 2018, 09:48:33 am
content: Such as the topic.What does the same voltage domain mean? Thanks

author: capt bullshot
author_rank: Super Contributor
timestamp: December 03, 2018, 09:56:25 am
content: Not enough context given.In general, "same voltage domain" would mean: "parts of a circuit supplied from the same source" or "parts of a circuit supplied by the same regulator" or "parts of a circuit supplied by the same filter" or "parts of a circuit connected to the same GND potential"

author: helius
author_rank: Super Contributor
timestamp: December 03, 2018, 09:58:14 am
content: Typically this concept is applied to VLSI or FPGA design as it relates to different sections of a chip that are supplied with power on separate rails. A mixed-signal design, for instance, may use a +15V to -15V dual-rail voltage domain for its op-amps, while also having a 3.3V domain for digital logic. Bus adapters or voltage converters are used to interface signals between domains.

author: Morgan
author_rank: Newbie
timestamp: January 03, 2019, 05:48:29 am
content: Thank you for your replied.

author: soldar
author_rank: Super Contributor
timestamp: January 03, 2019, 12:22:08 pm
content: Yes, to me "same voltage domain" means points in a circuit which have a common point from which voltages can be measured. Two circuits which are floating with respect to each other are not part of the same voltage domain and you cannot measure voltages between the two circuits.
What does the star mean in a schematic - Page 1
Forum section: electronics / beginners

author: HappyBanana
author_rank: Newbie
timestamp: July 23, 2016, 08:21:00 pm
content: Hello,excuse me if this is a stupid question, but google isn't turning up any helpful results. What does a * mean in a pin number on a schematic? I am looking over a ATSAMD21 board from adafruit (https://cdn-learn.adafruit.com/assets/assets/000/028/801/original/adafruit_products_M0SCHEM.png?1448656357) and both pins 18 and 17 have a star next to them and another number. What is the meaning of this?Thanks,Tyler

author: Monkeh
author_rank: Super Contributor
timestamp: July 23, 2016, 08:23:01 pm
content: This is specific to Eagle. It indicates multiple physical pins or pads are assigned to that pin on the schematic. Most tools won't do this (which is depressing when you have six or more pairs of power and ground pins).

author: HappyBanana
author_rank: Newbie
timestamp: July 23, 2016, 08:32:00 pm
content: Must you connect all the pins then? For example pin 18, 35, and 42 are all ground pins. Would I be fine if I only connected pin 35 to GND? I would think they would be connected internally.

author: Kilrah
author_rank: Unknown
timestamp: July 23, 2016, 08:34:20 pm
content: They may or may not, the chip's datasheet would tell you about that. If in doubt better to connect them all.

author: Signal32
author_rank: Frequent Contributor
timestamp: July 23, 2016, 08:35:52 pm
content: Quote from: Monkeh on July 23, 2016, 08:23:01 pmWhat does this mean exactly?On the schematic you can see 17*2 goes to 3V3. Then on the right 2 goes to the XTAL.

author: Monkeh
author_rank: Super Contributor
timestamp: July 23, 2016, 08:37:41 pm
content: Quote from: HappyBanana on July 23, 2016, 08:32:00 pmYes, you must connect them all.Quote from: Signal32 on July 23, 2016, 08:35:52 pmNot pin 2, 2 pins.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 23, 2016, 11:07:03 pm
content: Quote from: Signal32 on July 23, 2016, 08:35:52 pmthats what it means... some chips have 4 pins or more for GND on all of its edges....

author: bitwelder
author_rank: Super Contributor
timestamp: July 24, 2016, 06:44:16 am
content: Here is the datasheet for SAM D 21, and at paragraph 5.2.1 (page 26) there is the pinout for the SAM D21 G in QFN (as used by Adafruit):http://www.atmel.com/Images/Atmel-42181-SAM-D21_Datasheet.pdfThere are indeed 2 pins on VDDIO (17 and 36), but only 3 are designated as GND (18, 35, 42). Where's the supposed fourth one? (GNDANA at pin 5 is reported separately in the schematic)

author: Monkeh
author_rank: Super Contributor
timestamp: July 24, 2016, 12:00:15 pm
content: Quote from: bitwelder on July 24, 2016, 06:44:16 amIt's a QFN. There's a massive pad on the bottom.
what does these mean in datasheet? - Page 1
Forum section: electronics / beginners

author: navidrct
author_rank: Regular Contributor
timestamp: September 19, 2015, 11:21:54 am
content: hii want to know what exactly does it mean in datasheetwhere they say 250 MHz at -3dbwhere they say .2db at MHzwhat does these mean

author: DimitriP
author_rank: Super Contributor
timestamp: September 19, 2015, 12:38:59 pm
content: -3 db gain: At some frequency the gain has dropped by -3 db (and it's all downhill from there )As for the flattness, unlike the picture above where it's "flat", in real life the gain varies upand down by some value measured in db. if we use 40 db gain as an example, at certain frequencies the gain will be as high as 40.1 db and at others it may be as low as 39.9 db , described as a 0.2 db flattenssThe image below has (about) 12 db of flattness

author: navidrct
author_rank: Regular Contributor
timestamp: September 19, 2015, 12:57:15 pm
content: Quote from: DimitriP on September 19, 2015, 12:38:59 pmthanksthat was helpful
What does this circuit do? - Page 1
Forum section: electronics / beginners

author: Michaelaudio
author_rank: Regular Contributor
timestamp: August 17, 2020, 06:45:43 pm
content: Can someone explain me the left side of this circuit? Its a stby circuit on the 2 resistors the audio signal is applied and when its off the right op switches to high after ~7mins. I dont quite understand the left op. The signal somehow gets amplified with a max of 3.3V if I get it but I want to understand it exactly. The right part is all clean.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 17, 2020, 07:15:25 pm
content: The left side is a full wave rectifier (i.e. like a bridge rectifier) that turns the AC sound signal into a DC voltage. When this voltage becomes higher than about 0.6 volts, transistor Q2 turns on.

author: Michaelaudio
author_rank: Regular Contributor
timestamp: August 17, 2020, 07:59:24 pm
content: So a FBR that doesnt go higher that 3.3V i guess. but why didnt they use 2 zeners? 1n1418 is used for the rectification too then? So if I got his right R64 and R65 together with R66/67 are for the amplification. So across R67 i have the most voltage drop, but then there is the zener in parallel with a resistor in series to the 10u capid like to know exactly what which component does.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 18, 2020, 01:24:20 am
content: I think you are right, it looks more like a half wave rectifier, with an upper limit.Like the top circuit on this page:https://circuitdigest.com/electronic-circuits/half-wave-and-full-wave-precision-rectifier-circuit-using-op-ampHave you tried putting an oscilloscope on it and see what it does?

author: Michaelaudio
author_rank: Regular Contributor
timestamp: August 18, 2020, 07:11:32 am
content: It looks kinda like it but if ur honest, not really. The Resistor ist even between output and neg input like in my circuit. No but thats what im gonna do (but I still hope someone can explain this weird circuit)

author: SilverSolder
author_rank: Super Contributor
timestamp: August 18, 2020, 02:28:52 pm
content: It is a combination of a rectifier and a filter. You'll see it as soon as you connect the scope and some music.
What does this Jfet do? - Page 1
Forum section: electronics / beginners

author: reddish75
author_rank: Regular Contributor
timestamp: August 07, 2022, 02:21:31 pm
content: Could anyone explain what Q401 does in this circuit and is the part anything special as the original is long out of production?

author: David Hess
author_rank: Super Contributor
timestamp: August 07, 2022, 05:31:41 pm
content: JFET Q401 is operating as an amplifier with current feedback to the source. Using a JFET has the advantage of lower input bias current and higher input impedance. It looks to me like it was selected for very low gate cutoff voltage because otherwise it was intended for RF applications.

author: jasonRF
author_rank: Regular Contributor
timestamp: August 07, 2022, 08:22:29 pm
content: If it helps, the big-picture role of q401 is exactly the same as it would be if it was an npn BJT. I am not saying that you can replace it with a BJT without changing anything else about the circuit, but the high-level logic of the design is the same whether it is a JFET or a BJT.I’m sure there are multiple ways to think of it. In my mind, I find it helpful to think of it as a common source (inverting) amplifier for the input signal entering the gate, and a common gate (non-inverting) amplifier for the feedback signal entering the source. So the signal at the drain will be proportional to the difference of those signals.I have built headphone drivers with similar circuits, except using an npn BJT for q401, a Vbe multiplier instead of D401 to bias the push-pull output stage, and a current source instead of R407. This can be a very low distortion topology.By the way, if you build this, you might find that you need a capacitor from base-to-collector on q402 for stability/phase margin reasons. Or maybe not…Jason

author: Terry Bites
author_rank: Super Contributor
timestamp: August 07, 2022, 10:11:04 pm
content: The jfet a common gate stage. As pointed out by JasonRF, they could have used a bipolar transistor here with some minor fiddling.May be it was fun day at Sony. It's a fossil circuit but I think it was probably very cheap to produce. There are easier ways of making an amp with a 100Hz peakiness.Its a good illustration how to use feedback to get the inverse of the filter function.
What does this mean for the BTB16 triac - Page 1
Forum section: electronics / beginners

author: max.wwwang
author_rank: Frequent Contributor
timestamp: April 12, 2020, 04:16:24 am
content: I'm confused by the datasheet of theBTB16triac. What does "V_DSM/V_RSM+100V" mean? I don't think it's 100V - it should be greater than the Peak Repetitive value (600V/800V for -600CW3G and -800CW3G, respectively).Does this mean 600+100V/800+100V, i.e. 700V/900V?Thanks.

author: mikerj
author_rank: Super Contributor
timestamp: April 12, 2020, 09:42:00 am
content: Quote from: max.wwwang on April 12, 2020, 04:16:24 amYes!

author: max.wwwang
author_rank: Frequent Contributor
timestamp: April 12, 2020, 11:23:20 am
content: Quote from: mikerj on April 12, 2020, 09:42:00 amThanks! So it's a typo - should it read "V_DRM/V_RRM+100V" rather than "V_DSM/V_RSM+100V"?

author: mikerj
author_rank: Super Contributor
timestamp: April 12, 2020, 01:07:44 pm
content: Yes, I would say this is an error, since you can not have a value use itself as a reference. Having the non-repetitive surge voltage limit be some fixed amount above the repetitive surge voltage limit makes sense.
what does this mean in part number model? - Page 1
Forum section: electronics / beginners

author: alireza7
author_rank: Regular Contributor
timestamp: March 07, 2018, 04:15:43 pm
content: hii want to order ADR3425 and in it's datasheet there is two model :http://www.analog.com/media/en/technical-documentation/data-sheets/ADR3412_ADR3420_ADR3425_ADR3430_ADR3433_ADR3440_ADR3450.pdfADR3425ARJZ-R2ADR3425ARJZ-R7what does R2 and R7 means? what is the difference of these two models?

author: calmtron
author_rank: Regular Contributor
timestamp: March 07, 2018, 04:30:19 pm
content: AFAIR, the difference is how many devices are delivered per reel as outlined in your table. Small quantity reel vs full reel.

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 07, 2018, 04:32:57 pm
content: Quote from: calmtron on March 07, 2018, 04:30:19 pmAnd even if you don't want the small reel (too many), Mouser (and others I assume) will sell single quantity "cut tape."
What does this mean on a UNI-T multimeter and can it be repaired? - Page 1
Forum section: electronics / beginners

author: epigramx
author_rank: Regular Contributor
timestamp: August 25, 2023, 12:51:05 pm
content: it keeps showing that 'minus' on the top left and an "H" (only the 'dot' changes if the dial-setting is changed).The fuse works and it was replaced to make sure anyway and it's the same on another multimeter-battery.It broke when I went from "20" voltage setting towards OFFwhile it was measuring a car battery while the alternator(car engine) was onand I wonder if it's an easy fix or a whole main chip died that costs more than the multimeter or something (it's my cheap multimeter so I have another to do tests).

author: wasedadoc
author_rank: Super Contributor
timestamp: August 25, 2023, 01:01:37 pm
content: Any change if you release the HOLD function? Toggle the yellow button.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 25, 2023, 01:03:38 pm
content: Good Morning epigramx, my guess is that someone pushed the yellow'Hold' button in the center of the range switch
What does "MKa" mean?  - Page 1
Forum section: electronics / beginners

author: TheBaconWizard
author_rank: Regular Contributor
timestamp: March 07, 2018, 01:51:20 pm
content: I am completely unfamiliar with the designation mkA, does anyone know what it stands for?Here is a link to a datasheet where it is used (English translation immediately under the first picture)https://www.gstube.com/data/2119/Could it be micro-amps per volt?

author: Benta
author_rank: Super Contributor
timestamp: March 07, 2018, 02:04:01 pm
content: I'd say it's the Russian way of writing microampere (uA).

author: daqq
author_rank: Super Contributor
timestamp: March 07, 2018, 02:06:08 pm
content: Would also guess at microamperes. The russian word for "micro" is "mikro", as such "mk" could mean "MiKro".

author: TheBaconWizard
author_rank: Regular Contributor
timestamp: March 07, 2018, 02:32:10 pm
content: Righto, that seems likely. I'll proceed with that assumptionThanks guys.

author: ataradov
author_rank: Super Contributor
timestamp: March 07, 2018, 11:18:09 pm
content: It is the correct assumption

author: Brumby
author_rank: Unknown
timestamp: March 08, 2018, 12:00:06 am
content: Well, I learned something new today.

author: not1xor1
author_rank: Frequent Contributor
timestamp: March 08, 2018, 08:06:53 am
content: That basically means you do not understand the purpose of thesubjectfield.

author: tautech
author_rank: Super Contributor
timestamp: March 08, 2018, 08:13:37 am
content: Quote from: not1xor1 on March 08, 2018, 08:06:53 amErr no!Wilfred understands the importance of having a forum that is easy to search for answers one might seek.OP, put mkA instead of 'this".TIA
What does this Op Amp do in this multimeter circuit ? - Page 1
Forum section: electronics / beginners

author: komrad2236
author_rank: Contributor
timestamp: February 16, 2023, 12:09:30 pm
content: Hi guys, can you tell by looking at this circuit from multimeter, what doesLM358sdual op amp do in this circuit ?What is its job ?

author: MasterT
author_rank: Frequent Contributor
timestamp: February 16, 2023, 01:48:45 pm
content: Very likely OPA is a current sensor amp, with gain 20-50. See big R010, trace connection to the inputs of the IC.

author: MathWizard
author_rank: Super Contributor
timestamp: February 19, 2023, 12:36:15 am
content: I would see what exactly it's attached to, that might require a 2nd DMM. Then just make the op-amp circuit in a simulator. It could just be some buffer, or control circuit even too. Some DMM's like mine have a few op-amps. I traced out part of the schematic, the dial sure makes it a nightmare.

author: Gyro
author_rank: Super Contributor
timestamp: February 19, 2023, 10:08:45 am
content: Quote from: MathWizard on February 19, 2023, 12:36:15 amJust a note that itwouldrequire a second DMM. Nasty things happen if you start probing the internals of a DMM with its own probes. Battery -ve isn't the same as common for instance, there are offsets and internal regulators that get shorted. Even Fluke meters get destroyed by people trying to use them to measure their own battery voltage.
What does this symbol mean ? (car schematics) [solved] - Page 1
Forum section: electronics / beginners

author: tigrou
author_rank: Regular Contributor
timestamp: January 29, 2023, 04:14:23 pm
content: I was looking at car schematics (related to the ECU) and saw this symbol (red arrow) :This is used for sensors (eg: G40 - Camshaft Position Hall Sensor or G28 - Engine Speed).The brown wire is ground, red is VCC and green is connect to the ECU.Some other sensor like G247 (Fuel pressure sensor) or G581 (Turbocharger Boost Control Position Sensor) does not have that symbol.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: January 29, 2023, 09:19:01 pm
content: Quote from: tigrou on January 29, 2023, 04:14:23 pmBase on this, it's a magnetic Hall effect position or speed sensor. The circle with the small square you're pointing to would represent a magnet mounted on a shaft or wheel. The transistor symbol would represent the Hall effect sensor itself.https://en.wikipedia.org/wiki/Hall_effect_sensor

author: coromonadalix
author_rank: Super Contributor
timestamp: January 29, 2023, 09:48:15 pm
content: I would say the samefor sure it's an sensor since you have a transistor as receiver / sensor isolated side
What does transformer do on this condenser mic preamp? - Page 1
Forum section: electronics / beginners

author: dusan
author_rank: Regular Contributor
timestamp: July 05, 2023, 01:46:06 pm
content: In this schematic there is output transformer:http://www.sdiy.org/oid/mics/Neumann_Handheld.GIFWhat does it do? Can it be omitted?

author: rhb
author_rank: Super Contributor
timestamp: July 05, 2023, 02:17:46 pm
content: That is essential. It steps the tube era 48 V phantom power voltage down to what the transistors and op amp require.Reg

author: dusan
author_rank: Regular Contributor
timestamp: July 05, 2023, 02:45:01 pm
content: But why is secondary on the output of the opamp?

author: newbrain
author_rank: Super Contributor
timestamp: July 05, 2023, 02:46:44 pm
content: Because the transformer does nothing of the sort - as it cannot pass DC.The op-amp and associated circuitry directly pick the phantom (common mode) voltage through the two 6.8 kΩ resistor and the 0 V connection.The transformer is rather used to isolate the output of the op-amp from the phantom voltage, letting only the amplified mic signal pass through and not the DC offset at its output.EtA: Why a transformer, one may ask, instead of a simple capacitor? To provide both polarities of the differential signal.The top transistor provides a soft start supply to the op-amp and slightly reduces the voltage (probably the op-amp is a 741, capable of working at ±22 V - be careful if you re-implement this with more modern op-amps), and the bottom one polarizes the + input to about half of the supply, still soft starting.

author: wasedadoc
author_rank: Super Contributor
timestamp: July 05, 2023, 03:13:14 pm
content: The transformer converts the single-ended output of the op-amp to balanced (differential).The op-amp is probably NOT a 741. The input bias current for the inverting input comes through a 470 MOhm resistor. For a 741 that current can be as high as 800 nA. 470E6 times 800E-9 is 376 Volts.

author: newbrain
author_rank: Super Contributor
timestamp: July 05, 2023, 05:04:56 pm
content: Quote from: wasedadoc on July 05, 2023, 03:13:14 pmOops!I did not notice the feedback resistor value, thanks for the correction!
What does X mean as pin state? - Page 1
Forum section: electronics / beginners

author: Oaklander
author_rank: Regular Contributor
timestamp: May 04, 2018, 12:50:34 pm
content: On the 4th page ofLTC1483 datasheetthere is a function table.The state of the RE pin is marked as X when the device is configured to transmitting. What does it mean?I've prototyped the a circuit containing this chip with RE connected to ground and it worked. Now I'm desgining a PCB and don't want to do anything stupid so I'd like to know exactly what the X means.

author: sokoloff
author_rank: Super Contributor
timestamp: May 04, 2018, 12:53:03 pm
content: It means "anything; this pin has no effect on this line"

author: Brumby
author_rank: Unknown
timestamp: May 04, 2018, 12:54:42 pm
content: I was going to say "it doesn't matter".

author: Cerebus
author_rank: Super Contributor
timestamp: May 04, 2018, 12:56:29 pm
content: If it's an output it means "undefined", meaning that you cannot and should not rely on the state of that pin with the device in that mode/state/configuration. If it's an input it is "don't care" and that pin will have no effect (is ignored), no matter what state the pin is in, with the device in that mode/state/configuration.

author: Oaklander
author_rank: Regular Contributor
timestamp: May 04, 2018, 12:57:52 pm
content: Thank you all. That was quick.
What does "X" or a line in the centered vertically means in a logic analyzer ? - Page 1
Forum section: electronics / beginners

author: tigrou
author_rank: Regular Contributor
timestamp: November 06, 2021, 07:38:52 pm
content: Could someone explain me what the "X" character or a line centered vertically (not a 0 or not a 1) means in a logic analyzer, as seen at 0ns in this image ?Does it means there is no clearly defined signal at that time ? (eg: invalid state)In a logic analyzer, when validating some module against a unit test, how does it tell the user that the signal can be "whatever, we don't care" ?For example when a flip flop is not initialized yet the Q0 and Q1 can be anything (until it's cleared out). How is this indicated ? (I ask because I'm a beginner and have very little experience with logic analyzers)

author: ataradov
author_rank: Super Contributor
timestamp: November 06, 2021, 07:49:24 pm
content: That's exactly how undefined state is indicated. This will only happen in behavioral simulation where rules of the language (Verilog/VHDL) are applied literally.Another thing you may see there is Z for high impedance state, but again, this is something that can only happen in simulation in practice, since there are no high-impedance elements inside the FPGAs. It is only possible in I./O buffers.In real life all those elements will default to some defined values. But it is useful to see them in simulation so that you know what is going on logically.There is no "don't care" in simulation. Simulation shows the factual behaviour, it is up to you to interpret if something is acceptable or not. Often having red stuff after a reset signal is a bad sign. In this case you can see that all the signals got initialized on the same cycle as the release of the "areset" signal. This is a very typical behaviour.

author: tigrou
author_rank: Regular Contributor
timestamp: November 06, 2021, 09:06:56 pm
content: Thank you for your answer, it's pretty clear
What drive/buffer can be used for controlling 100 DP1903 by a MCU - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 11, 2018, 06:09:19 am
content: 1. Have to drive DP1903, 100 lights, each of 100leds , in sync as they glowSo that all looks same.2. I tried making different MCU for each individual DP1903 leight(100 led in each). But after sometime they all go bit out of sync. Even if all MCU power is turn on at same time. The difference is low, but noticeable.3. One solution I think if, I drive all DP1903 lights with single MCU. I think what will happen is all will be in sync as they glow, as driving MCU is only one.is ther any buffer/drive available by which it can be done.4. Any other solution

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 12, 2018, 05:52:34 am
content: I think I havent put my query right.Suppose there are 100 individual DP1903. I have to drive them in parallel with a single MCU, so that when data reaches to 100 parallel DP1903, it is sync.What buffer I have to place beteen one MCU out & each input of 100 parallel DP1903
What drives these bulbs - Page 1
Forum section: electronics / beginners

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: September 27, 2019, 07:01:57 pm
content: Is it made for constant current drivers?Filament resistance varies greatly with heat.https://www.aliexpress.com/item/1000007073211.html

author: iMo
author_rank: Super Contributor
timestamp: September 27, 2019, 07:11:48 pm
content: Read the reviews on that page..

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: September 27, 2019, 08:13:51 pm
content: They don't mention driving =>4 bulbs.

author: Jwillis
author_rank: Super Contributor
timestamp: September 28, 2019, 12:40:08 am
content: Got a kick out of the ozone smell complaints. Ultraviolet light disrupts oxygen O2 molecules to create valent oxygen atoms that attach to other oxygen molecules to create O3 or ozone. Just thought it was funny.

author: amyk
author_rank: Super Contributor
timestamp: September 28, 2019, 02:04:09 am
content: bigclivedotcom has a video on these:

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2019, 04:02:21 am
content: They use either a capacitor or a resistor to limit the current. The filament is only used for starting, then the mercury vaporizes and the arc shunts re filament.
What eprom do i have ? for my TL866A - Page 1
Forum section: electronics / beginners

author: janey6152
author_rank: Newbie
timestamp: May 03, 2017, 02:07:04 am
content: Hi everyone. I just got the TL866A V6.50I want to burn a .bin to this eprom. but i dont know what brand is it ? On the Tl866A programmer is there a button that can detect what i have ??It for my Samsung SCX 3405W printer. What i got is C5B i think 25064BS1G, E50643... Under the C5B i see AE 346

author: Kjelt
author_rank: Super Contributor
timestamp: May 03, 2017, 07:30:32 am
content: Difficult to say, you have to deduct this yourself.Look at which pins are Vcc and which are GND.Then probably it is an SPI or I2C eprom so first try to find that out (measuring protocol or deducting from other connected chips on the bus)Than you can try to guess which it is and try it or first try to read out the memory with your own microcontroller so you know which size (2kB, 4kB, etc) it is to make a better guess.As long as you know 100% which is Vcc, Gnd and if it is SPI or I2C and you respect the pinout there is not much you can do wrong.

author: ebclr
author_rank: Super Contributor
timestamp: May 03, 2017, 08:15:33 am
content: You can't handle the toner cartridges prices, right ?1st stepIf your eeprom is still working sniff with a scope or a sigrok and discover if is SPI or I2C and who is who in the pins, This will reduce your set of possibilitieshttp://www.ebay.com/itm/Samsung-Laser-Inkjet-Printer-Copier-MFP-Service-Manual-Choose-from-1000-Models-/231974342277

author: janey6152
author_rank: Newbie
timestamp: May 03, 2017, 06:22:13 pm
content: Its a SPI .. it suppose to be a winbond W25Q32..I tried it but its not working.Maybe cause i'm using the alligator clips. I'm new to using the OKI HCT-900-11 HOT AIR SOLDERING/DESOLDERING SYSTEM.I felt like i was ruining the chip with heat. and it wouldn't budge..Question On 1st Pic the Red line i think is for Pin 1 . Do i have it placed correctly on the TL866 ??2nd pic using the clip and red line cable is on pin 1 the chip has a small dot so that should be pin 1.And yeah the toner cartridges are getting to expensive. Why should i keep purchasing when i can refill for less the fraction.

author: janey6152
author_rank: Newbie
timestamp: May 04, 2017, 12:56:58 am
content: Got it done. Turns out it was GD25Q64And i soldered off the eeprom off and sit onto the SOIC8 ZIF adapter (200 Mil)Worked like a charm..Thankjs everyone for helping...
What ESP32 device is this? - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: November 24, 2024, 11:56:30 pm
content: I've had this random PCB in my junk bin for a number of years, and I have 0 idea where it's from. Recently I had desoldered some of the components, but otherwise the PCB is stock. The micro-USB connection has no data signals; only power. ESP32-WROOM-32D. It had 5x LED's + 2x IR LED's + 1x switch, all that I desoldered. It also has, what I assume, is a temperature/humidity sensor, OR a PIR sensor, with the writing "281R", and it looks similar to the TI HDC1080.I tried to see if I could connect the device to HomeAssistant by messing around with the switch, but the LED indicator did not change at all, and HomeAssistant did not detect it.Can anyone identify the exact product this PCB was pulled from, as well as whether that SMD 6-pin chip is the TI HDC1080 or something else?Thanks___TI HDC1080 =https://www.tindie.com/products/closedcube/hdc1080-high-accuracy-humiditytemperature-sensor/

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: November 24, 2024, 11:57:33 pm
content: PCB backside

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: December 02, 2024, 07:34:51 pm
content: Bump? I guess nobody can identify where the PCB was pulled from, as well as what the mystery 6-pin chip is?

author: fzabkar
author_rank: Super Contributor
timestamp: December 02, 2024, 07:52:11 pm
content: I think your 6-pin IC is indeed an HDC1080. Google Images suggests that the marking code is xx1R. The datasheet simply says "1R".https://d3s5r33r268y59.cloudfront.net/datasheets/7301/2016-05-13-12-01-02/HDC1080.pdfESP32WROOM32D & ESP32WROOM32U Datasheet:https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf
What exactly are these? - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: August 20, 2015, 12:24:27 pm
content: Hey! Found these on the roof of a public toilet, somewhere in Hong Kong. I think they're some kind of LTE transmission system, but I'm not sure. Looks a bit excessive. One even looks like an oversized Xbox 360!Four huge horizontal boxes? Weird.

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 20, 2015, 12:38:02 pm
content: Looks like a typical multi-service cell site. You might find more clues from the appearance of the antennas (directional dishes vs. non-directional, etc.)

author: Unknown
author_rank: Unknown
timestamp: August 20, 2015, 12:45:07 pm
content: Thanks for the reply mate. The cell antennae seemed to be non-directional (instead of a dish, they were a white rectangular box).Any ideas on what the devices specifically are, or what role they play in the transmission system?

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 20, 2015, 02:06:10 pm
content: The entire global network of cellular phones depends on millions of these cell sites. This is a rather small, outdoor installation. It is more common to see larger weather-proof racks with transmitters and receivers bolted inside. And in even larger installations small buildings full of gear. It is rather unusual to see all those individual enclosures out in the weather like that.Google Images for "cell site shelter". You will see a range of installations from individual racks less than 1m tall, to pre-fab buildings as big as a large garage.

author: SeanB
author_rank: Super Contributor
timestamp: August 20, 2015, 07:53:02 pm
content: Outdoor base stations, the boxes strapped together are antenna splitter matcher units, which provide the multiband signals from the antennas to the transceiver unit, and there is active electronics in those along with more in the directional antennas. The whole lot is probably Huawei made. The big rectangular boxes will contain a power supply which supplies 48VDC and which also does battery back up, along with having the fibre transceivers for the backhaul. The antennas are directional, they contain a few separate steerable antenna arrays inside to make multiple sectors to increase traffic density.I have the same layout by me, just all indoor units for lower maintenance, as the whole lot is kept at 24C by dual airconditioners and a management unit.
What exactly do "common negative" and "common positive" mean? - Page 1
Forum section: electronics / beginners

author: lorentzforce
author_rank: Newbie
timestamp: January 30, 2023, 05:34:19 pm
content: Hello, this is my first post, I'm a computer engineering 4th year undergraduate working in sensor monitoring and deployment. Sorry about any mistakes in my post, I've been lurking for a while and I'll try and adhere to the community culture.I'm looking into a solar regulator for a long-term monitoring deployment with a 12V 4P1S battery pack. For the solar regulator's grounding features, a lot of these controllers mention common negatives in their datasheets for their grounding schemes, and I don't really know what that means exactly. I can guess from context that the negatives of the battery pack, solar panels, and load are all connected. But does this have any benefit as opposed to floating voltages, is that how systems are isolated? Are there more benefits or downsides to this type of configuration?Also, on an unrelated sidenote, is it normal/common for solar regulators to use buck-boost conversion for their battery power source voltage regulation?

author: Grandchuck
author_rank: Super Contributor
timestamp: January 30, 2023, 09:44:26 pm
content: Most automobiles are negative ground. The negative battery terminal is connected to the frame or the chassis and that becomes the common or reference point. I am guessing that also applies to solar systems.Oddly, back a while, a few cars were positive ground ... go figure?

author: james_s
author_rank: Super Contributor
timestamp: January 31, 2023, 01:46:23 am
content: The regulation will be on only one leg, the other side will be straight through from the input to the output terminal. Common negative will have this on the ground side and it will regulate the high side. Common positive will regulate the ground side.

author: m k
author_rank: Super Contributor
timestamp: February 05, 2023, 03:46:34 pm
content: Bad exampleCode:--7805-- --7805--| |---+---- --7805--| |--7905-- ---+----
what field? - Page 1
Forum section: electronics / beginners

author: Auggie
author_rank: Contributor
timestamp: February 22, 2010, 12:32:38 am
content: I see that there are many branches and jobs to go in to from electrical engineering. For someone who wants to be out in the field instead of an office what do you all recommend as far as a job title or career branch?

author: EEVblog
author_rank: Unknown
timestamp: February 22, 2010, 01:52:43 am
content: Well, there is always the Sales department! :->Seriously though, it's very often company dependent.If you want to be guaranteed continuously in the field, then being a "field service engineer" is your best bet, but that can often be a glorified technician role (not that there's anything wrong with that).But if you want more design work, then you need to consider an engineering role or company that requires the design to go on-site for various reasons, like design consultation, trials, installation and system testing etc. Power (solar, wind etc) companies are often like this, so getting into power electronics might be worth considering. Many military project also require extensive travel.And then it also comes down to whether you want local or international travel.So it's a bit hard to nail down specific job titles or career branches.Dave.

author: Auggie
author_rank: Contributor
timestamp: February 23, 2010, 07:03:39 am
content: Quote from: EEVblog on February 22, 2010, 01:52:43 amThanks a lot Dave. Very helpful.

author: Neilm
author_rank: Super Contributor
timestamp: February 23, 2010, 07:26:47 pm
content: If you want some general experience look at joining a smaller company. As a newly qualified Electronics Engineer I joined a small company of only 5 people. Second day - go and play with the electronics of a tank turret. Day 3 - design (and draw up) a box to get at all the signals. All in all a rather varied job.
What footprint and connector might this be? - Page 1
Forum section: electronics / beginners

author: brandon.arnold
author_rank: Contributor
timestamp: June 23, 2024, 06:31:22 pm
content: Hi all!Can anyone suggest what kind of connector would have been used in these two unpopulated footprints? I'm assuming it is a connector because it is not labeled with any IC identifier like all other ICs. It isn't labeled with any "CN" identifier like other connectors, for that matter, but I presume this was a production/development convenience for debugging purposes.Year of manufacture: 1995-1999Dimensions of entire footprint, including pins: 29mm x 12mmPin length: 90 milsPin width: 18 milsDistance between the center of two adjacent pins: 32 mils

author: amyk
author_rank: Super Contributor
timestamp: June 23, 2024, 09:36:34 pm
content: Search for "0.8mm 70 pin mezzanine SMT"

author: brandon.arnold
author_rank: Contributor
timestamp: June 23, 2024, 09:57:33 pm
content: Thanks, @amyk. Good selection to compare from here on Mouser, I will look around.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 24, 2024, 01:31:45 am
content: could even be test points ...
What functions can be implemented in a single CLB block of XC4000? - Page 1
Forum section: electronics / beginners

author: r20de20
author_rank: Newbie
timestamp: June 24, 2024, 02:00:04 pm
content: Hi there!School stuff. I try to learn FPGA andknowfew things, but it seems I don't quiteunderstandthem.There is this task:"Can the following logic functions be implemented in a single CLB block of an XC4000 device?"While I know the answers:These are possible:any 5-variable functionany 4-variable function + a specified 5-variable functiona specified 9-variable functionany 4-variable function + a specified 6-variable function2x any 4-variable function + any 3-variable functionThese are not:3x any 4-variable function4x any 2-variable functiona specified 10-variable functionany 6-variable function... I'm not sure of some of them. As per my knowledge, one CLB block of XC4000 consists of 3 LUTs, a mutliplexer and other parts like flip flops, carry. Each LUT has 4 inputs and 1 output.So it is pretty obvious function with 6 variables wouldn't work, because it has 2^6 = 64 different cases, while LUTs support only 3 * 2^4 = 48 cases. But why is "3x any 4-variable function" impossible to implement? For me it is exactly matching the size of inputs we have available, so it is clear I lack knowledge in this topic. I've tried to research it online and used GPT, but I haven't found any information related to this question.I kindly ask you for explanation. Thank you in advance for any tips/rules, which would help me in the future.

author: CaptDon
author_rank: Super Contributor
timestamp: June 24, 2024, 07:20:12 pm
content: Better to move this to the FPGA forum.

author: up8051
author_rank: Frequent Contributor
timestamp: June 24, 2024, 10:14:39 pm
content: http://xilinx.pe.kr/_xilinx/html/ref/fpga4000.htmlTwo LUTs are 4 inputsOne LUT is 3 inputs
What goes into making something hardened - Page 1
Forum section: electronics / beginners

author: lordulrich
author_rank: Newbie
timestamp: March 24, 2014, 11:36:45 pm
content: I have a pretty general question as to what goes into making an electronic device hardened for temperature? At work (Civil Engineer) we buy lots of electronics that cost upwards of 10x of a comparable device that does not meet the temperature spec. I know that this spec is important, but I am curious what is the difference? Is it just higher temperature spec chips? is there a different spec in the circuit boards?Thanks

author: Phaedrus
author_rank: Frequent Contributor
timestamp: March 24, 2014, 11:42:41 pm
content: Devices that meet automotive or military temperature specifications undergo much more thorough testing and validation to ensure that they operate in the temperatures required. For instance, a batch of chips might be "burned in" at 125 degrees Celsius for a number of hours, and if one chip fails the entire batch is deemed unfit for that specification. Likewise for low temperature tests. And by fail, I don't mean burn. I mean violate any important electrical spec, even by a fraction of a percent.The testing varies depending on the component in question, and on the company performing the test. But generally there is a lot more testing and QA involved.

author: tszaboo
author_rank: Super Contributor
timestamp: March 24, 2014, 11:48:35 pm
content: For example ICs usually have ceramic packages, or other hermetically sealed packages. There are less components to chose from, so you cannot just put there your favorite amplifier, you have to chose from something which is actually made for it. Electronics is temperature dependent, so offsets are bigger, errors are bigger, you need more parts to get rid of the errors.Power dissipation must be lower than in normal operation, as it would overheat itself. For this you need more efficiency or more parts. And this is only the component level. There is testing, sourcing, hard to repair (because coating), for assembly you have extra steps, and it is harder to find someone that has the brains to put it together.
What good is the cores from CRT TV yokes ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 16, 2018, 07:51:08 pm
content: I have a few TV yokes for the wire (and a working 1 to play with some day). What about the core material? Do people try cutting them, or breaking them and sanding the little pieces into some little rod shape ? As a scientist I wonder but as an engineer I just smash 1 and try.I'm guessing they are made mixed like a cake with a binder and 'cooked'/pressed solid or maybe fired like ceramics.Do people crush them back up and try to reform them into something ?Just wondering since it's a waste to throw it out, and its very hard to make stuff without factories, or after WW4 wandering the wastelands.

author: Gyro
author_rank: Super Contributor
timestamp: February 16, 2018, 08:01:12 pm
content: Believe it or not, this exact question has come up before...https://www.eevblog.com/forum/chat/recyling-scrap-ferrites/

author: james_s
author_rank: Super Contributor
timestamp: February 16, 2018, 08:30:44 pm
content: IMO the yokes are more useful intact, if you rewind the vertical you can make a vector monitor of the sort used in some classic arcade games. I've never found any use for the parts, it's easier to just buy a roll of magnet wire if you need that, and ferrite cores in useful shapes with known properties are inexpensive and readily available.

author: Jwillis
author_rank: Super Contributor
timestamp: February 17, 2018, 01:02:01 am
content: Make a home made particle accelerator! But if you create a small black hole in your living room ,I'll deny knowing you.
What GSM/GPRS class is my modem? - Page 1
Forum section: electronics / beginners

author: Mad ID
author_rank: Regular Contributor
timestamp: December 24, 2014, 05:35:13 pm
content: Hi all,SIM900 GPRS modem from SIMCOM is both GPRS class 10 and class 8 compatible.How can I know what class is used during communication? What interests me the most is the peak pulse current of 2A. In class 8 its 577us, and 1.15ms for class 10. I designing a capacitor bank to deliver the peak power.Does it depend on my network operator?Thank you.

author: Quark-elec
author_rank: Contributor
timestamp: April 17, 2015, 02:35:15 pm
content: Check this product which is designed based on SIM900, it can be used to control door/garage. Very helpful.http://www.quark-elec.com/product/class/2.html