hybridfree/eevblog-posts huggingface dataset:
What do you recommend for a brush on insulator? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: November 17, 2020, 03:22:50 pm
content: I've got a project that uses a CR2032 and the + is exposed. For the - I've run a short trace to a very low PTC (10mA), but there is also a small microcontroller, resnet, and a TVS. Is there a clear (and not ugly) type of liquid insulator I can brush on that won't be ugly? Something that is cheap, easy to get/use?

author: wraper
author_rank: Unknown
timestamp: November 17, 2020, 03:27:16 pm
content: There are Chinese RTV silicones for electronics which cost a few $ for a tube. There are several types with different properties with 701-708 model numbers. And they are actually pretty good.https://www.aliexpress.com/item/4000416228722.html?spm=a2g0s.9042311.0.0.51884c4dAa7hxC
What does (DC + Peak AC) actually mean? - Page 1
Forum section: electronics / beginners

author: sijmen
author_rank: Contributor
timestamp: August 17, 2021, 01:58:16 am
content: Hi,I've been looking at various test equipment specs and see specifications like the following:Max differential measuring voltage(DC + Peak AC): ±500VCommon mode voltage(DC + Peak AC): ±500VCan someone please explain what theDC + Peak ACmeans. Does the Peak rating meanpeak to peakon an AC signal, or the0V to PeakAC voltage?Also, am I right in assuming that if I had a 400V DC signal, and a standard AC sinusoidal signal sitting on it, then the AC signal can not be more than 100V (measured center to Peak)?Could the item with the above rating be used to measure mains 230V RMS AC, which is 325V centre to Peak, or 650V Peak to Peak?Regards,Sijmen.

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 17, 2021, 02:17:00 am
content: Quote from: sijmen on August 17, 2021, 01:58:16 amIf in your example you are implying a 200 volt peak to peak AC signal superimposed on a 400 volt DC, then your assumption is correct.

author: bdunham7
author_rank: Super Contributor
timestamp: August 17, 2021, 02:32:44 am
content: DC + ACPEAKis just an awkward and very slightly incorrect way of saying the peak voltage. They appear to simply mean the absolute value of the maximum instantaneous voltage.

author: David Hess
author_rank: Super Contributor
timestamp: August 17, 2021, 03:17:44 am
content: Quote from: sijmen on August 17, 2021, 01:58:16 amDC + Peak AC means the peak voltage including the DC component.For a floating input like a multimeter or isolated oscilloscope channel, the common mode voltage is what is applied between the low or common terminal and chassis ground. This depends on the built in galvanic isolation. Power supplies with floating outputs have this specification also whether they list it or not.The differential voltage is what is applied between the high terminal and the low terminal.
What Does * mean on PCB - Page 1
Forum section: electronics / beginners

author: Jbliss
author_rank: Regular Contributor
timestamp: May 31, 2015, 12:12:30 pm
content: Hi i have a Class D audio amplifier Kit and it of the PCB next to 3 capacitors which are 560pf it has a * (560pf*) there where none of these caps supplied in the kit does this mean to make a link or .....?thanks Jblissheres the kithttp://www.jaycar.com.au/Kits,-Science-%26-Learning/Electronic-Project-Kits/Audio/High-Power-Class-D-Audio-Amplifier-Kit/p/KC5514

author: Jbliss
author_rank: Regular Contributor
timestamp: May 31, 2015, 12:39:35 pm
content: Please Help

author: SeanB
author_rank: Super Contributor
timestamp: May 31, 2015, 12:40:03 pm
content: Probably means not supplied in kit, optional if needed. Those probably are only going to need installation if you are using it with either long leads to the speakers or have some RFI issues after installation.

author: janoc
author_rank: Super Contributor
timestamp: May 31, 2015, 02:00:30 pm
content: Quote from: Jbliss on May 31, 2015, 12:12:30 pmThat should be explained in the documentation to the kit, no? Usually that sort of mark indicates a footnote or remark, some catch that is explained in small script in the documentation. It doesn't have a particular meaning alone.SeanB could be right on the money that it is for optional caps, but check the documentation to be sure.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: May 31, 2015, 02:26:45 pm
content: The kit was originally described in Silicon Chip magazine, November 2012. You can buy the articles of Silicon Chip website, but I found an online reprint from EPEhttp://issuu.com/yurgenn/docs/everyday_practical_electronics_2013_25703931aba98bpages 12 onwards.It appears the 3 x 560pF are required for normal operation, not sure why they are marked *. I can't see any note in the article.

author: Zero999
author_rank: Super Contributor
timestamp: May 31, 2015, 05:23:40 pm
content: Ah, I hate adobe flash. Why not just use PDF?I've extracted the schematic.EDIT:The datasheet and application note for the IRS2092 will also help.http://www.irf.com/product-info/datasheets/data/irs2092.pdfhttp://www.irf.com/technical-info/appnotes/an-1138.pdf

author: SL4P
author_rank: Super Contributor
timestamp: May 31, 2015, 09:07:06 pm
content: Silicon Chip - definitely means the value or component selections is discussed in the text of the article, or as a side-bar to the schematic.
What does "200% Tested" mean? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: August 06, 2021, 12:31:17 am
content: Found it on some Opto22 modules:Also, I find it interesting that they makes a point to mention that the module is compatible with a Raspberry Pi:https://www.opto22.com/products/g4iac5

author: bob91343
author_rank: Super Contributor
timestamp: August 06, 2021, 01:02:51 am
content: It means that it has been shown to have double the leakage, half the gain, and double the price.

author: cortex_m0
author_rank: Regular Contributor
timestamp: August 06, 2021, 01:04:40 am
content: From the data sheet for that product, page 5:Quote

author: MarkF
author_rank: Super Contributor
timestamp: August 06, 2021, 01:17:22 am
content: I was just going to say that it was tested 4 times and passed 50% of those times...Two passes.Good to go!

author: Monkeh
author_rank: Super Contributor
timestamp: August 06, 2021, 02:30:51 am
content: Presumably that means they test before and after packaging processes? If that's the case, I tip my hat to them.

author: golden_labels
author_rank: Super Contributor
timestamp: August 06, 2021, 09:27:34 am
content: That means the manufacturer has given 200% to the marketing branch, on expense of -50% to quality control and R&D each.Not disapproving the idea of increasing testing, but “200%” in this context is used as “a number bigger than the competition uses”, not giving specific information. If they tested them twice using the same procedure, it is not 2x more reliable, but x² more reliable. If their product is half as reliable as competitors’, that would mean “75% of what others offer”. And that skips the whole question of which is better: repeated tests or applying two different methods.

author: tszaboo
author_rank: Super Contributor
timestamp: August 06, 2021, 09:39:10 am
content: Probably tested to 200% of the nominal hipot voltage rating.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: August 06, 2021, 09:41:51 am
content: Quote from: cortex_m0 on August 06, 2021, 01:04:40 amThen it should have two stickers.

author: RJSV
author_rank: Super Contributor
timestamp: August 06, 2021, 08:45:21 pm
content: I've LITERALLY smacked parts w hammer, I.E. QC Dept. Technician. For mechanical parts for airline installation, I think they advised "Don't hit too hard".Guessing , 200 % tested means:. "Strike part twice..."(THEY) started calling us 'QA', rather than QC;Guessing then, it was determined that testing, at1.41 times, was sufficient.(??)
what does 4000 counts per second mean for this dmm - Page 1
Forum section: electronics / beginners

author: m3vuv
author_rank: Super Contributor
timestamp: December 27, 2021, 04:33:08 am
content: just seen this listed on fleabay as beeing 4000 counts per second,can anyone tell me what the hell it means as ive never heard of that in relation to a dmm! tia m3vuv.https://www.ebay.co.uk/itm/154728555121?hash=item24068a6271:g:NiYAAOSwH45hiSc5

author: TimFox
author_rank: Super Contributor
timestamp: December 27, 2021, 04:35:52 am
content: Read itcarefully.It states "4000 counts", which means maximum display is 3999.Since it's not working, and cheap voltmeters are easily obtained that probably work out of the box, you probably don't want this one.

author: BeBuLamar
author_rank: Super Contributor
timestamp: December 27, 2021, 10:26:33 am
content: So now is your question changed to "What does 4000 counts mean for this dmm?"

author: Kleinstein
author_rank: Super Contributor
timestamp: December 27, 2021, 10:54:42 am
content: For a supposedly broken DMM the price is rediculous. A comparable (e.g. UT33A) new one starts about at thatr price point.
What does "limiting element voltage" mean for a 1206 resistor? - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: December 12, 2017, 08:27:35 pm
content: Hello,The RCV1206 series resistors are 1206 size resistors with 500V “Limiting element voltage”.What does “Limiting element voltage” mean?Resistors are usually rated for voltage in terms of “maximum working voltage” and “maximum overload voltage”. (eg as with the RMCP series resistors)Does “Limiting element voltage” equate to “maximum overload voltage”? or “maximum working voltage”?RMCP series resistors:-https://www.seielect.com/Catalog/SEI-RMCF_RMCP.pdfRCV1206 series resistors:-http://www.farnell.com/datasheets/2049090.pdf?_ga=2.79611860.1546388605.1512980491-191120965.1491231686&_gac=1.36319124.1512396957.EAIaIQobChMIuJKv2sXw1wIVRrcbCh19bQMeEAAYASAAEgKaW_D_BwE?

author: nicalitz
author_rank: Regular Contributor
timestamp: December 12, 2017, 08:31:39 pm
content: From the ROHM website:QuoteEDIT: Unnecessary convoluted explanation maybe. In short, maximum voltage that is safe for the part.
What does a Block Diagram Symbol "Pi" mean? - Page 1
Forum section: electronics / beginners

author: NY2KW
author_rank: Regular Contributor
timestamp: February 24, 2020, 10:28:22 pm
content: I thought I knew all of the block diagram symbols but I cannot find any reference that explains a box with the Greek symbol Pi with an arrow thru it. Please help!thanks

author: jmelson
author_rank: Super Contributor
timestamp: February 24, 2020, 10:30:58 pm
content: Quote from: NY2KW on February 24, 2020, 10:28:22 pmAn adjustable Pi section attenuator?Jon

author: NY2KW
author_rank: Regular Contributor
timestamp: February 25, 2020, 02:08:43 am
content: Duhh.. feel like an idiot missing the obvious. The block diagram showed the Pi-Arrow box and then 3 plain boxes labelled ATTN (all digitally controlled) before the RF output but on the PCB I found 4 identical HMC307 attenuators... and the datasheet said nothing about them being Pi pads. So I thought I was missing something on the PCB. Now I read the fine print and the 1st HMC307 is controlled in 2 dB steps from 0-30 while the others are wired as all or nothing 0/30 dB. Thanks for the quick reply.

author: Brumby
author_rank: Unknown
timestamp: February 25, 2020, 04:44:57 am
content: Quote from: NY2KW on February 25, 2020, 02:08:43 amYou'll fit right in here...!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 25, 2020, 05:53:34 am
content: While I think you have nailed the meaning in this context, you will sometimes find an upper case pi being used to indicate a multiplication just as an upper case sigma is used to indicate a sum. Comes from the math use of these characters and I've seen it most frequently in control system diagrams/drawings.
What does a "current sense" pin generally do? - Page 1
Forum section: electronics / beginners

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: June 14, 2021, 05:36:16 pm
content: Hi, on some schematics I've seen "current sense" as a label (usually on the pin of an op amp or IC) and I'm wondering what exactly it means. My googling suggests these pins are used for some sort of feedback, but I'm not sure if that's right, or if that's all they're used for. Thanks!

author: TimFox
author_rank: Super Contributor
timestamp: June 14, 2021, 05:41:07 pm
content: Often, it means a connection to an external, relatively low value, resistor in series with the output current to be sensed. A typical use is for the voltage from the desired current limit to equal a BE junction voltage (0.7 V), at which point the BJT steals drive from the output device.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 14, 2021, 05:48:04 pm
content: Exact technical meaning really depends on the circuit.Obviously it always has something to do with sensing current.Typical places where I could add such a label to a net would include:* Simple voltage as measured from one terminal from a current shunt resistor, another side being connected to GND or Vcc. This voltage is relative to the current going through that resistor* Voltage relative to current measured using some more sophisticated circuitry, for example a hall effect current sensor, or a shunt + amplifier circuitVery often such signal carries a voltage level thatrepresentsthe measured current, for example so that 1 volt corresponds to say 10 amps or whatever.The destination for such a signal could be a switch-mode supply controller IC so it can, using the current sense information, provide current limiting. Or it could go to an analog-to-digital converter inside a microcontroller so it can measure and log current in some circuit.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 15, 2021, 03:49:37 am
content: It means what the datasheet says it means.There isn't really much to generalize? It could be an input to a control circuit, or the output of a sense circuit. Or the input to a sense circuit. It could be poorly named or entirely irrelevant; sometimes datasheets themselves aren't all that much help.Tim
What does "channel bandwidth" actually means? - Page 1
Forum section: electronics / beginners

author: sangar
author_rank: Regular Contributor
timestamp: August 23, 2018, 06:30:49 am
content: Hello All,This might be a basic question but some RF transceiver manufaturer interpreted it in their own way. Ok, coming to the question, I am working on AD9361 which tells it supports 200KHz to 56MHz bandwidth and have operating band of 70MHz to 6GHz. Here 56MHz means that it support maximum of 56Mbps ?. If it is so, its frequency spectrum will come like belowfc-28MHz---->fc------------>fc+28MHzIf my above understaning is correct, with multiple channels located at every 100KHz, the above trasmission interfere with other channels?Please let me know...Thanks,Muthu

author: ataradov
author_rank: Super Contributor
timestamp: August 23, 2018, 06:50:13 am
content: This is basically correct. Except for the relation MHz == Mbps. This is not generally true and depends on the modulation scheme.And yes, you can't space 56 MHz channels 100 KHz apart, it will not work.

author: bson
author_rank: Unknown
timestamp: August 23, 2018, 11:32:03 pm
content: You don't have to use the full 200kHz bandwidth, just limit IF to 100kHz or less. This is why it specifies "<200kHz to 56MHz". In real usage you may want a second, even third LO and further narrow down the IF. (These can be fully digital conversions of course.) The 56MHz value is of more interest here since this is the max bandwidth you can monitor in real time.
What does floating operations mean in this context? - Page 1
Forum section: electronics / beginners

author: Mattjd
author_rank: Regular Contributor
timestamp: July 18, 2017, 08:28:39 pm
content: Reading about a memristor emulator. One of the features is "floating operations" I am not quite sure what this means.Quote

author: mikerj
author_rank: Super Contributor
timestamp: July 18, 2017, 08:35:52 pm
content: It simply means that the input voltage does not need to be referenced to ground in this case. Two input terminals are provided (V- and V?, is that a typo?), and only the difference in potential between the terminals is important.

author: Mattjd
author_rank: Regular Contributor
timestamp: July 18, 2017, 08:40:41 pm
content: Quote from: mikerj on July 18, 2017, 08:35:52 pmOkay. The next sections talks about the differences in the connection terminals for connectability. The requirement that the current going in must the same going out.Quote
What does "HAC" mean for a T2A, 250 V HAC, slow-blow Fuse? - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2020, 08:00:55 pm
content: All I find is stuff about Honda and hill-climb assist.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 10, 2020, 09:17:28 pm
content: "HACR stands for “Heating, Air-conditioning, refrigeration” For equipment or in a panel or enclosure feeding the HACR rated equipment."Apparently these fuses are rated for inductive loads like motors, etc., and can stand repetitive inrush current on equipment start-up. It would be wise to replace with the same type and rating of fuse. I found one size on Amazon.https://www.amazon.com/Edison-HAC-R-30-Buss-FUSE-HACR30/dp/B009EC7F1W

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2020, 09:20:29 pm
content: If you google "HAC fuse -honda", you quickly find reference to the Bussmann HAC-R fuse line. However, it seems to be larger, high-current fuses.It looks like HAC-R was a series of current-limiting fuses:http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/product-datasheets-a/Bus_Ele_DS_1038_HAC-R.pdf

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2020, 09:23:02 pm
content: And this is the recommended replacement, which does have a 2A model:http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/product-datasheets-b/Bus_Ele_DS_1019_FRN-R_1_10-60A.pdf

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2020, 10:13:42 pm
content: This is the actual part number for the fuse as it comes from the MFG. I don't HAC should be listed.https://www.newark.com/littelfuse/0213002-mxp/fuse-cartridge-2a-5-x-20mm-slow/dp/26K7595

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2020, 10:14:15 pm
content: It goes in a low power device like an O-scope.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2020, 12:22:50 am
content: So I guess they just needed any old slow-blow fuse and got a good deal on those HVAC ones.
What does it mean by 'Mains-Referenced' & what would trigger a NC Volt Detector? - Page 1
Forum section: electronics / beginners

author: thejoggingmat
author_rank: Regular Contributor
timestamp: January 19, 2016, 06:00:06 am
content: Recently, I've been coming across a lot of 'Mains-Referenced', 'Low-Voltage PSUs with live potential' etc. Does it mean that the low voltage is referenced to live (in my case, 240VAC RMS)? Apparently capacitor droppers are a very good example of the above.I've also just received a Fluke 2AC testpen to replace my current 'contact test screwdriver' (the one with the neon lamp within the screwdriver where one pokes its tip around). It is supposed to trigger from ~200VAC-1000VAC. Trying it out, some SMPS I have (such as for my WiFi router or my phone charger) trigger the testpen even though their specs show as 'DC out'. Some other SMPS don't trigger the testpen. My whole router and phone lights up the testpen when they are plugged in. Is this because they are mains-referenced and would theoretically liberate a nasty shock if I work with the 'low-voltage' side whilst it is live?

author: sparx
author_rank: Contributor
timestamp: January 19, 2016, 07:39:14 pm
content: The high frequency switching noise, and wireless signals from your router and phone will set off NC voltage detectors.

author: electr_peter
author_rank: Unknown
timestamp: January 19, 2016, 08:58:40 pm
content: Quote from: sparx on January 19, 2016, 07:39:14 pmNo, high frequency (MHz to GHz) will most likely will not set off NC detector. Frequency is too high for simple AC pen to work, it has filters inside it to mitigate high frequencies.To answer original question - most low power AC mains powered items (routers, WiFi, modems) are not grounded and will light up AC pen. It does not mean it is dangerous (it could be), it just how AC detector works (or fails to work, depending on your point of view).AC test pen work by capacitively detecting high rate of voltage change. AC test pen will light up when it feels that voltage field changed significantly - it could be AC mains coupling or some staticly charged object in close proximity. Rub AC pen in your sweater and it will light up. Also, whether AC pen can work better/worse/fail/misleaddepends significantlyon the grounding/earthing of location, humidity, other non-controllable aspects.In short - AC pen is not a good way to detect voltage, it is an indication at best (and you have to know what that indication suggests). However, at least AC pen is better than those neon screwdriver things (those are dangerous and should be banned in my opinion).Please, do not trust AC pens 100%, there are indicators only and they can mislead you in false positives (you think there is AC mains, when there is not) or true negatives (you think there is no AC mains when there is). Try to use DMM with low input impedance to be sure about AC mains presence.
What does it mean "to leak VAC" for a PSU? - Page 1
Forum section: electronics / beginners

author: analogo
author_rank: Regular Contributor
timestamp: May 13, 2018, 01:11:34 pm
content: In the thread "TS100 doesn't function properly when earthed" users Rooster Cogburn and Gyro discuss the implication of a non-earthed PSU connected with a 3-prong cable. They use expressions likeQuoteorQuoteorQuoteCould someone explain what is this AC leakage and how it can be detected?If I had an oscilloscope (I don't), could I measure the voltage between mains earth and the -V of the 12V PSU output and see an oscillating wave with amplitude 120V (240V/2)?What about probing earth and +V? Would I get an oscillating 108V wave (240V - 12V)?If so, isn't that extremely dangerous? How could it be that Rooster has hundreds of such PSUs in his house?

author: madires
author_rank: Super Contributor
timestamp: May 13, 2018, 01:24:45 pm
content: The last quote is the answerSMPSUs usually have an EMI suppression cap between primary and secondary side (typically 2.2nF class Y2). That cap passes a mains referenced low current from the primary side to the secondary side. It's not dangerous but can give you a tingle. To check for the cap simply take a DMM and measure the AC voltage between output (ground in most cases) and mains earth.
What does it mean when a component is drawn using dotted lines in a schematic? - Page 1
Forum section: electronics / beginners

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: June 24, 2022, 07:03:46 pm
content: See attached image for example. Does it mean the component is optional? Are those polarity protection diodes in the image?

author: retiredfeline
author_rank: Frequent Contributor
timestamp: June 24, 2022, 07:15:20 pm
content: I don't think they are diodes there are no cathode bars. I think they are just marked power I/Os..

author: golden_labels
author_rank: Super Contributor
timestamp: June 24, 2022, 07:48:11 pm
content: In theLM2662 datasheet, in figures 14, 15 and 19–21 those are marked as currents.

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: June 24, 2022, 08:21:41 pm
content: got it thanks
What does it means?? - Page 1
Forum section: electronics / beginners

author: Serge125
author_rank: Regular Contributor
timestamp: October 18, 2022, 01:17:42 pm
content: Hi all!! Ok I got this circuit board and I was wondering what does these numbers and letters mean. On other I see them like R V F etc..... So what all of those nombers and letters mean? Is there a web site that could explain what is written on a mother board?Thanks in advance!!!!Serge

author: ledtester
author_rank: Super Contributor
timestamp: October 18, 2022, 01:46:53 pm
content: They look like component designators -- names the designer has given to each component so you identify each one individually.The names also tell you what kind of component it is. Each name begins with "6" so you can just ignore that for now.6C2 -- "C" stands for capacitor, so this is capacitor number 2."6FB1" - "FB" usually stands for ferrite bead, so ferrite bead number 1."6RV6", "6RV7" - "RV" can stand for varistor, so varistors 6 and 7.Other component types on the board:"L" - inductor, e.g. "6L13""Q" - transistor -- "6Q3""R" - resistor -- "6R10""CON" - connectorOther commonly used component types:https://blog.mbedded.ninja/electronics/circuit-design/component-schematic-symbols-and-designatorsI'm not sure what kind of component "6CE2" refers to.

author: devinatkin
author_rank: Contributor
timestamp: October 18, 2022, 03:47:37 pm
content: Yup, it's a neat way they've done it there with the components help in the same outline. 5 components in the same overall outline. I haven't seen that done, but I think I may steal it next time I need to move my RESDEF away from the actual components.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 18, 2022, 06:31:45 pm
content: I've had to do this a few times when there is just no room next to a component to fit in the silk screen.
what does "J" mean in resistor values? - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: July 02, 2020, 05:31:19 am
content: I'm looking at the shematic for the Tesla Mono 130 amplifier, and most of the resistor values are understandable like "M82, 1M5, 1M, 4K7 etc." but there are a few resistors that have the values like "1J4, 3J3" are there 1.4Ohm and 3.3Ohm resistors?also there are a few caps values like "G2, G1" I have no idea about these...

author: garethw
author_rank: Regular Contributor
timestamp: July 02, 2020, 06:00:12 am
content: I’ve never seen J resistor values. Maybe post a capture of the schematic up?I think the capacitor values are in pF. So G1 would be 1 billion pF (1000uF).

author: floobydust
author_rank: Super Contributor
timestamp: July 02, 2020, 06:52:20 am
content: The special letter appears unique to the component on the schematic, like C302 "G2" and C311 "G5". So it must point to a particular part+rating. I've seen "J" meaning +/-5% tolerance on wirewound resistors. But 1.4 ohm cathode resistors seems quite low and a bit oddball value. They might even be jumpers, you open them to measure cathode current (at testpoint MB1, MB2) to set the balance potentiometers. That also makes sense to me. EL34 bias is around 30mA I guess 42mV is enough to measure.Odd using an SCR and aux winding for a protection latch.

author: evava
author_rank: Regular Contributor
timestamp: July 02, 2020, 08:04:54 am
content: Yes, 1J4, 3J3 are 1.4Ohm and 3.3Ohm resistors.Also caps values like "G2, G1", they mean 200microFarad resp. 100microFarad.Because 1G means 1000microFarad.As I was young we used that description commonly.KT502 is thyristor.

author: TimFox
author_rank: Super Contributor
timestamp: July 03, 2020, 09:26:38 pm
content: I have not seen the code "1J4" before, but I assume it means 1.4 ohms, 5% tolerance since "J" as a suffix in the more normal "1R4J" denotes 5% tolerance (K=10%, F=1% are other common suffices).Probably done to save one precious space in the label, since sometimes wiring diagrams get crowded with complicated part values. Incidentally, 1.2, 1.3, and 1.5 are the common values for 5% resistors, but not 1.4.
What does nB mean as a resistor value? - Page 1
Forum section: electronics / beginners

author: sajattack
author_rank: Contributor
timestamp: May 26, 2018, 05:27:27 am
content: I've modified this design a little and now I'm ready to assemble but I'm not sure what an nB resistor is.https://easyeda.com/wegi1/sd2iec-1-2-shadowolf

author: ataradov
author_rank: Super Contributor
timestamp: May 26, 2018, 05:42:45 am
content: Looks like do not populate. All the components with value nB are in clusters around optional features.Normally DNP would be just a note, but EasyEDA may not support this, so they had to put it into value, which is a horrible idea.

author: sajattack
author_rank: Contributor
timestamp: May 26, 2018, 05:47:15 am
content: Ok I was thinking it was either that or a 0 ohm resistor.

author: ataradov
author_rank: Super Contributor
timestamp: May 26, 2018, 05:49:20 am
content: One of the transistors in also nB, so it can't be 0 Ohm.

author: ElektroQuark
author_rank: Unknown
timestamp: May 26, 2018, 07:21:47 am
content: no BOM?

author: hydrolisk1792
author_rank: Contributor
timestamp: May 28, 2018, 09:55:07 am
content: Noting from where it is in the schematic on pin 42 it could be an optional component. Like try it with and without it and see what the best results are.

author: dsegel
author_rank: Contributor
timestamp: May 28, 2018, 03:51:02 pm
content: If it were nb or Nb I'd guess it meant Nota bene, which usually means there's an explanation somewhere else. Is there any more documentation you could look through?

author: BrianHG
author_rank: Super Contributor
timestamp: May 28, 2018, 05:03:00 pm
content: On my designs, I use DNP in my BOMs for do not place.

author: capt bullshot
author_rank: Super Contributor
timestamp: May 28, 2018, 06:32:58 pm
content: That's an German abbreviation: "nicht bestücken"As others pointed out, it means "do not populate"
What does NC mean in this table? - Page 1
Forum section: electronics / beginners

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 22, 2016, 02:06:49 am
content: Hi,I am just wondering what the NC means (see attached)?Its from Page 33 of the AX8052F143-D datasheet:http://www.onsemi.com/pub_link/Collateral/AX8052F143-D.PDFI am guessing it means Non-Critical, but I would like to know what it means.

author: zapta
author_rank: Super Contributor
timestamp: October 22, 2016, 02:08:04 am
content: No connection.

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 22, 2016, 09:41:46 am
content: Quote from: zapta on October 22, 2016, 02:08:04 amSo do I remove the cap entirely from the circuit? The reason I ask is because that part of the circuit is part of an LC filter.

author: SeanB
author_rank: Super Contributor
timestamp: October 22, 2016, 10:18:29 am
content: NC there means no component, as there is really no way you can get a 0.01pF capacitor in ceramic, so just leave it out and let the stray capacitance of the pads be it. In this application likely will only be populated if the frequency is below 100MHz.

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 22, 2016, 10:30:15 am
content: Quote from: SeanB on October 22, 2016, 10:18:29 amThat makes more sense. Thanks

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 23, 2016, 09:47:11 am
content: Quote from: SeanB on October 22, 2016, 10:18:29 amJust wondering if you can point me to a good source which explains the components of the circuit.
What does negative amperage mean in a datasheet? - Page 1
Forum section: electronics / beginners

author: MarkS
author_rank: Unknown
timestamp: August 13, 2023, 09:08:14 pm
content: I was looking throughthisdatasheet. On page 5, on the VOHline, it shows an IOHrange from -4.0 mA to -0.1 mA. What does this mean?

author: TimFox
author_rank: Super Contributor
timestamp: August 13, 2023, 09:15:58 pm
content: It means that the pin sources that current, rather than sinking it.Edit: fixed error on sources and sinks.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 13, 2023, 09:22:49 pm
content: It means the direction of the current flow relative to the pin. When with minus, it means the current flows out of the pin in the direction from pin to GND, with plus it means the direction of the current is from the V+ into the pin.

author: wasedadoc
author_rank: Super Contributor
timestamp: August 13, 2023, 09:32:26 pm
content: The above two answers state the opposite of each other. One must be incorrect.(For anyone who wants to consult the linked datasheet, look at the page with 4 in the footer, not 5.)

author: TimFox
author_rank: Super Contributor
timestamp: August 13, 2023, 09:38:11 pm
content: My bad: I exchanged source and sink.The clue is looking at the voltages for the two current levels.I have edited my response above.The spec for Vol at a positive Iol is sinking current.
what does "remote cutoff" mean? - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: December 11, 2019, 06:16:37 pm
content: I am constantly seeing these "remote cutoff" pentode's in rf stages. what does "remote cutoff" mean and what does it do?

author: TimFox
author_rank: Super Contributor
timestamp: December 11, 2019, 08:56:13 pm
content: A remote-cutoff tube is one where a relatively large negative grid voltage is required to reduce the cathode current to near zero (cutoff). In practice, this is done with a grid winding where the spacing is not constant along its length. It is roughly equivalent to two tubes in parallel, where the tube with a tight spacing cuts off at a lower grid bias, but the other continues to conduct up to a higher negative bias voltage. This grid structure is commonly used in pentodes, triodes, and mixer tubes in RF applications for better control of gain with small input signals.They are not used in ordinary audio circuits, since they are inherently more non-linear than the “sharp cutoff” variety. Typical examples: 6AU6 (sharp) / 6BA6 (remote), or the older 6SJ7 (sharp) / 6SK7 (remote). If you compare the plate characteristics graphed in the data sheets for these pairs, you will see the difference.In a guitar amplifier, you might exploit the distortion of the remote-cutoff tube, which would have large even-order harmonics at high levels.

author: TimFox
author_rank: Super Contributor
timestamp: December 12, 2019, 02:08:08 pm
content: If the audio signal applied to the grid is small, then varying the DC voltage on the grid will vary the gain from grid to plate. When building a theremin using a 6L7 pentagrid mixer tube, which has a remote-cutoff grid 1 for signal input, I found that the gain for the signal on grid 1 was a very accurate exponential function, with an almost constant slope in dB/volt,over a large range of DC bias. A sharp-cutoff tube will also vary the gain with DC bias, but over a narrower range of bias.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 12, 2019, 04:31:30 pm
content: Ah, for guitar amps where distortion is desirable to some extent -- you may need a fair bit of overdrive (10s of volts) but you can expect a remote-cutoff to generate more gradual distortion than a more linear type.Conversely, a more linear type tends to cut off or saturate more sharply, which means that, when overdriven, they tend towards a clipping distortion waveform rather than a saggy rounding/peaking shape.For small signals, the gain does not vary much during a cycle and the distortion is small; you only get significant distortion on larger signals.Quote from: TimFox on December 12, 2019, 02:08:08 pmHm, that's cool, and very handy. Which further implies a response similar to a transistor, although with much less gain (i.e., requiring many volts to cut off, rather than many 10s of mV). In other words, you could use a transistor to much the same end, given some consideration of transistor properties like temperature sensitivity.Tim
solved:What does S.O.T. mean on a schematic ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 04, 2019, 02:52:29 pm
content: I've seen is written over a resistor on a 1960's PSU, and today over a dc-blocking cap in an RF gen, completely different circuits. It might be a part that can be interchanged without soldering, in the schematics it's like they are on binding posts, possibly a value to be chosen or tweaked , IDK

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 04, 2019, 03:05:33 pm
content: Select (or Set) On Test.

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 04, 2019, 03:12:04 pm
content: ok solved
What does the "Hour", "Standby Use" and "Cycle Use" specs for a SLA battery mean - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: March 01, 2018, 06:38:18 am
content: Attached is a pic of a SLA battery.What does the "20 Hour" refer to?And what do the "Standby Use" and "Cycle Use" voltages and current specs mean?

author: tautech
author_rank: Super Contributor
timestamp: March 01, 2018, 06:49:18 am
content: 20hrs WRT the rated AH is the discharge time.Standby charge voltage lists the max voltage for continuous charge. eg alarm backup etc.Cyclic is for portable use where the battery is NOT on continuous charge and only topped up from time to time. eg hunting spotlight.

author: ledtester
author_rank: Super Contributor
timestamp: March 01, 2018, 05:05:36 pm
content: How do the 9AH and 20 hours relate to each other?Doesn't 9AH mean the battery will last 9 hours if I draw 1 amp continuously, or 18 hours if I draw 0.5 amps, etc.? How does the 20 HR figure in?

author: ovnr
author_rank: Frequent Contributor
timestamp: March 01, 2018, 05:25:29 pm
content: 9 Ah is capacity; yes, that would normally mean that an 1A load would deplete it in 9 hours, etc. However, due to lead acid batteries being somewhat terrible, the usable capacity gets worse with higher loads. If you put a 1A load on it, it might only have 8Ah capacity; if you put a 10A load on it, it might drop to 6 Ah.In this case, if you spend 20 hours discharging it, it will have a 9 Ah capacity. You could also write that as "With a 0.45A load, the battery will have a 9Ah capacity".
What does "WMP" mean in regard to a preset resistorr, and MR6 for a fixed? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 02, 2012, 10:37:43 am
content: What does the abbreviation "WMP" mean in relation to preset resistors? Is there a way of telling if these are linear or logarithmic? Or all presets linear? Also, looking at the 680 Ohm resistor designated R28, what does the "MR6" mean please? I have to recreate this circuit on stripboard to replace a missing auxiliary supplies circuit board in a nice Farnell 50 amp, 60 volt power supply I have rescued. Please see attached circuit diagram and a photo of the board someone sent me who has a similar PSU. Thanks.

author: David_AVD
author_rank: Super Contributor
timestamp: September 02, 2012, 11:01:13 am
content: Not sure about the WMP or MR6, but as far as I know preset pots are always linear.

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2012, 11:12:54 am
content: IIRC MR6 is a model number for a type of metal oxide resistors.Log trimmer pot exist but are not that common.Dave.

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 02, 2012, 11:26:21 am
content: Thanks, is there likely to be any good reason for the MR6 type of resistor or can I use any close tolerance metal film type? I would err on the side of caution and get a 1 watt if they are available in 680 ohm close tolerance. There looks to have been quite a bit of heat generated on the board that someone photographed for me.

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2012, 12:05:38 pm
content: Could WMP be Wirewound Multiturn Pot maybe
what does the apostrophe symbol mean in this exponential converter equation? - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: August 15, 2014, 01:16:19 am
content: I just started reading a document on "log and exponential (antilog) circuits" from this documenthttp://electronotes.netfirms.com/s019.pdfIt's make more sense to me now than I did the first time I stumbled onto it quite a while ago but I have a question about mathematical symbols.In the first equation Ic= I'eqVBE/kBTWhat does the apostrophe symbol "'" mean?I can plug in values as well as anyone else but when the equation contains symbols I don't understand it's not terribly useful.

author: c4757p
author_rank: Super Contributor
timestamp: August 15, 2014, 01:18:22 am
content: It tells you!Quote

author: dentaku
author_rank: Frequent Contributor
timestamp: August 15, 2014, 02:13:21 am
content: Quote from: c4757p on August 15, 2014, 01:18:22 amDoh!I read that but didn't notice it included the '.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 15, 2014, 02:32:27 am
content: Usually denoted as "Is"..

author: KJDS
author_rank: Super Contributor
timestamp: August 15, 2014, 09:35:55 am
content: I was going to suggest that you hadn't cleaned your screen properly

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 15, 2014, 12:24:30 pm
content: Quote from: KJDS on August 15, 2014, 09:35:55 amI'd post some suggestions, but on second thought I probably shouldn't go searching for "how to clean your screen" links...

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 15, 2014, 12:35:39 pm
content: using aposthrophe just to distiguish different variables of related or similar thing (just like OP to differentiate 2 type of current Ic and I') is not an elegant way. "Ic" symbol is ok but I' that stands for "Is" is not good, "Is" symbol is more elegant. as "'" usually means "inverse" or "image" of the variable. such as if Is is saturation current then Is' is its inverse or 1 / Is. next time pass the word to anybody who want to write something academic or to young kids in schools.

author: ctz
author_rank: Contributor
timestamp: August 15, 2014, 02:19:55 pm
content: This is a prime, not an apostrophe. It's really common in science, engineering and maths texts.http://en.wikipedia.org/wiki/Prime_(symbol)#Use_in_mathematics.2C_statistics.2C_and_science

author: dentaku
author_rank: Frequent Contributor
timestamp: August 16, 2014, 12:26:31 am
content: Quote from: ctz on August 15, 2014, 02:19:55 pmNice.That was rather educational.
what does the capacitor do - Page 1
Forum section: electronics / beginners

author: amateur_25
author_rank: Regular Contributor
timestamp: April 12, 2014, 10:24:34 pm
content: I'm trying to build a pre amplifier for my raspberry pi. I've been looking into amplifiers.In the designs I've studied they always have a capacitor in series with the input. Is this just what is called a blocking capacitor? So it's used to remove the dc component away from the audio signal right?http://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fwww.sentex.ca%2F~mec1995%2Ftutorial%2Fxtor%2Fxtor4%2F4xtor4.gif&imgrefurl=http%3A%2F%2Fwww.sentex.ca%2F~mec1995%2Ftutorial%2Fxtor%2Fxtor4%2Fxtor4.html&h=335&w=292&tbnid=frTBLO45_EWs5M%3A&zoom=1&docid=bw4w2YNQpXB49M&ei=cbxJU--PJKjb0QWn3YCoBA&tbm=isch&ved=0CGIQhBwwBA&iact=rc&dur=488&page=1&start=0&ndsp=33

author: mariush
author_rank: Super Contributor
timestamp: April 12, 2014, 10:58:38 pm
content: See the following video, from about 6:00 :Maybe it will help. Basically yes, it has to do with blocking dc signal.

author: amateur_25
author_rank: Regular Contributor
timestamp: April 13, 2014, 09:50:21 am
content: am right for once. I must be learning a thing or two. About time after spending so much time and money on electronics.

author: electronics man
author_rank: Frequent Contributor
timestamp: April 13, 2014, 10:10:08 am
content: It's called AC coupling
What does the capital letter "G" represent on these capacitors - Page 1
Forum section: electronics / beginners

author: Theodore
author_rank: Newbie
timestamp: October 20, 2020, 07:46:32 pm
content: I'm trying to find replacements for these capacitors that are part of a BMW suspension module built around 2010 or 2011. I believe I've found the correct replacement components, but I can't find any with same letter "G" printed on them and I have no idea if it is important or not to have it on the replacement units. In the manufacturer's documentation I see they use the letter "G" as a size code designation for some of their capacitor's lines, but those size designations don't seem to match the dimensions of the capacitors I'm replacing. Any information on what the printed letter "G" represents and how important it is in replacement capacitors would be greatly appreciated. Thanks!Sanyo Os-Con Technical Book Ver.12:http://pdf.datasheet.live/c901a0a6/semic.sanyo.co.jp/6SH15M.pdfDimensions are 10mm diameter and 10mm tall (it could be slightly taller, there is some protective coating or glue that on the board that makes getting an accurate height measurement difficult)

author: rdl
author_rank: Super Contributor
timestamp: October 20, 2020, 08:44:26 pm
content: Probably just means "Ground" since it's within the polarity marking stripe.
What does the flashing “-“ on a harbor freight DMM mean? - Page 1
Forum section: electronics / beginners

author: Dithyramb
author_rank: Newbie
timestamp: September 24, 2024, 05:44:54 am
content: It happens when I select the ohms setting. Not sure if I’m doing something wrong or my meter is damaged in some way.

author: ledtester
author_rank: Super Contributor
timestamp: September 24, 2024, 05:47:59 am
content: Which ohms setting is it set to? Does it show the blinking on all ohms ranges?Does it give correct results when measuring a resistor?And are we taking about one of these? (see attachment)A simple test: Touch both probes together. If it doesn't give you a measurement close to zero I'd say it's damaged.

author: Bryn
author_rank: Regular Contributor
timestamp: September 24, 2024, 06:34:41 am
content: Yes... the flashing dash you see on the device is related to the ohms setting, though it happens if can't measure resistance properly (whether the leads are not connected to anything or incorrectly connected).To ensure that it still works nonetheless, have the leads properly connected to the component or circuit you want to test with it but if you're testing a resistor, touch the leads to either end of it to get a valid reading.If not, it may be damaged, like what Ledtester had assumed earlier.

author: MrAl
author_rank: Super Contributor
timestamp: September 24, 2024, 08:50:42 am
content: Quote from: Dithyramb on September 24, 2024, 05:44:54 amHi,The flashing minus sign tells the user that they should not buy Harbor Freight multimeter anymoreOk, joking there, but it's kind of true. The worst meter I ever had came from HF. I tried to measure voltages on the car and when the engine was running the measurements were all over the place. That's the only meter that did that. It was a shame too because it had a backlight which made it easier to read in low light. I still buy stuff from them, but not meters and not soldering guns. The soldering gun I bought from HF the tip melted.Get another meter probably from just about any other place, spend at least $20 USD or equivalent.