hybridfree/eevblog-posts huggingface dataset:
What's the name of these plugs? - Page 1
Forum section: electronics / beginners

author: camurgo
author_rank: Newbie
timestamp: November 10, 2018, 04:33:23 pm
content: Hello,Does anyone know the name of the connectors shown at 1:40 of this video?They allow you to connect one plug atop the other (as done at 1:51). I know they're not that uncommon, I want to buy a few, but I have to know their names in order to search for them...Thanks.

author: PTR_1275
author_rank: Frequent Contributor
timestamp: November 10, 2018, 04:39:10 pm
content: Stackable banana plugs is what you should search.There are still heaps of different types, so I would suggest google image searching that and see what ones catch your eye

author: JackJones
author_rank: Regular Contributor
timestamp: November 10, 2018, 04:40:44 pm
content: Looks like just ordinary stackable 4mm banana connectors. They come in several different varieties, but keywords "stackable banana" should be correct. I did find some that look identical on aliexpress with just a quick search.E: I think the ones in the video might be called "gun type" banana plugs.

author: rstofer
author_rank: Super Contributor
timestamp: November 10, 2018, 04:42:19 pm
content: DigiKey stocks the Pomona brand 'stackable banana plug jumpers' and I use them a LOT

author: BrianHG
author_rank: Super Contributor
timestamp: November 10, 2018, 04:43:50 pm
content: Banana test leads:https://www.amazon.ca/s/?ie=UTF8&keywords=banana+test+leads&tag=googcana-20&index=aps&hvadid=208251271646&hvpos=1t2&hvnetw=g&hvrand=8207738299692015155&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9047894&hvtargid=kwd-295203067902&ref=pd_sl_wjs8nzoh5_eNot all of them have the pass thru on top, just search around.Also, Banana plug stack-able:https://www.mouser.ca/Test-Measurement/Test-Equipment-Accessories/Test-Leads/_/N-7uqeu?P=1y8vfai

author: camurgo
author_rank: Newbie
timestamp: November 10, 2018, 04:47:07 pm
content: Thanks everyone. "Stackable banana" worked.
What's the point of connecting a JFET like this ? - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: March 21, 2023, 11:25:25 pm
content: On a Keithley 177 DMM, at the input to a chopper amplifier circuit, they have an n-ch JFET with it's drain and source connected together, to the 5V rail, and the gate is between a couple of resistors, and caps to ground. So is it just there to act as a small cap to 5V? IIRC the gate capacitance changes with voltage as-well, so it it using that for some current offsetting reasons ?IDK much about chopper amps, but I've never see an JFET used that way. And it's not a schematic mistake, it's really soldered that way.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: March 21, 2023, 11:57:02 pm
content: This JFET acts as a very low leakage protection diode, a common application in multimeters.CheersAlex
Whats The Purpose of MAX3949 Laser Driver? Confusion... - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 18, 2019, 01:30:30 am
content: i know from the datasheet, it drives laser diode at 11Gbps. what i dont get is... TIN+ and TIN- (pin14,15) should be feed with equally fast 11Gbps input signal as well? from FPGA maybe with equally high speed RAM to store the data to be sent? i was expecting a chip that we can feed in a slow datarate data from i2c pin and be stored in ic RAM for a moment, hit a trigger (register or a pin toggle) and the chip bursts out 11Gbps, isnt that a MAX3949 capable of doing? i dont see built in memoryconfused...

author: KaneTW
author_rank: Frequent Contributor
timestamp: March 18, 2019, 01:48:00 am
content: No memory, you need 1 - 11GBps input.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 18, 2019, 02:00:13 am
content: thanks, so what will happen if i feed it with 1Kbps input? it wont output 1Kbps i think, but a pulse or what? how did leo bodnar drive it from nothing to create a pulse? or some data stream?

author: amyk
author_rank: Super Contributor
timestamp: March 18, 2019, 02:32:42 am
content: I believe iI's capactively coupled, so too low of a frequency won't result in much signal out.What application are you thinking of? This is a very specialised IC used for optical fiber communications.

author: ejeffrey
author_rank: Super Contributor
timestamp: March 18, 2019, 02:34:32 am
content: That chip is basically an "amplifier". It won't output anything different than what you put in. All the application circuits show AC coupling on the input and output. I don't know what happens if you try to DC couple it and operate at 1 khz. It may have some slow bias current loop for the laser diode that will cause problems if you drive it at low speed or maybe it will just work fine subject to the usual caveats about driving high speed logic. If your 1 khz singnal doesn't have very fast rise time you will likely get multiple triggers.An fpga is the way to do what you want.

author: KaneTW
author_rank: Frequent Contributor
timestamp: March 18, 2019, 02:47:42 am
content: Leo uses a comparator (https://www.analog.com/en/products/adcmp572.html) with ultrafast rise times.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 18, 2019, 03:26:22 am
content: Quote from: amyk on March 18, 2019, 02:32:42 ami just want to explore and understand. the possibility of say, as a square wave (or bits) generator, or simply fast rise time step/pulse generator as leo bodnar did.Quote from: KaneTW on March 18, 2019, 02:47:42 amyes thats earlier version. later version he uses this MAX3949 laser driver. thats why i have the datasheet
whats the purpose of these fork-like tracks (capacitance?)? - Page 1
Forum section: electronics / beginners

author: amon2_0
author_rank: Newbie
timestamp: September 02, 2019, 07:04:07 pm
content: I opened up a RJ45 gender changer (female to female) to find this pcb inside. Does anybody know the purpose of these interchanging, fork-like tracks? I have seen similar spark gaps but not with a soldermask. Is it some sort of very small capacitance?

author: mikerj
author_rank: Super Contributor
timestamp: September 02, 2019, 09:41:20 pm
content: Looks like capacitors. At a guess it would be to minimise any impedance discontinuity in the cable.

author: Jwillis
author_rank: Super Contributor
timestamp: September 02, 2019, 09:42:06 pm
content: Plate capacitor etched into PCB.Value will be very small.
what's the purpose of this microstrip track on a RF PA evaluation board? - Page 1
Forum section: electronics / beginners

author: liyuqihxc
author_rank: Newbie
timestamp: November 19, 2024, 01:13:43 pm
content: I'm building a RF amplifier for CC1101 using PA2460.There is an evaluation board layout in amplifier's datasheet.https://www.princeton.com.tw/Portals/0/activeforums_Attach/PA2460.pdfWhat I don't understand is the purpose of the following microstrip track (ML1), is it used as an inductor with C11 and C12 to form a pi filter? If so, can I replace it with an inductor?Here is the layout of the board

author: CaptDon
author_rank: Super Contributor
timestamp: November 19, 2024, 02:02:44 pm
content: Looks like a standard Pi impedance matching circuit. Not really a filter.

author: liyuqihxc
author_rank: Newbie
timestamp: November 20, 2024, 09:27:36 am
content: thanks for the reply.The reason I ask this question is that I want to know how to modify the design if I use a different board (like a 4-layer board). The evaluation board layout is on a 2-layer 1.2 mm FR4 board. Using components like inductors is clearly more flexible compared to a trace on the PCB.The datasheet doesn't specify the frequency range for the reference layout, but the amplifier IC operates in the 130 MHz to 500 MHz band. The amplifier module I want to build operates at 433 MHz.

author: Neganur
author_rank: Unknown
timestamp: November 20, 2024, 03:29:32 pm
content: impedance match to 50 ohm, the chip itself is not an mmic.
What's the purpose of using PNP transistors on I2S bus? - Page 1
Forum section: electronics / beginners

author: sidlauskas
author_rank: Contributor
timestamp: November 17, 2018, 11:17:06 pm
content: What could be the reason of using these 3 PNP transistors on I2S bus (LRCK, BCK and DATA pins)? On the one side of these transistors there is PCM5102 and on another is Qualcomm's CSR64215 bluetooth chip. I know for sure that this schematic would work even without these transistors, but I'm just curious what could be the real purpose of them in this particular schematic. Thank you!

author: Nerull
author_rank: Frequent Contributor
timestamp: November 18, 2018, 12:10:03 am
content: Probably to allow the use of a relatively low value pullup resistor without sinking all that current through the QSR64215. Low pullup resistor values allow for faster bus operation.
What's the reason for oscillation at output for a sharp step change in OPAMP? - Page 1
Forum section: electronics / beginners

author: kankanas
author_rank: Contributor
timestamp: July 23, 2020, 11:31:21 am
content: Can any one tell the reason for oscillation at opamp output for a abrupt change input provided at input(current or voltage)?I understand this to be related with slew rate and maximum operating frequency (BW) of the OPAMP, but how oscillation(overshoot and undershoot) i.e 2nd order effect is being produced?

author: mikerj
author_rank: Super Contributor
timestamp: July 23, 2020, 11:53:54 am
content: Insufficient phase margin. Is this just a basic op-amp circuit or are there additional components in the feedback loop e.g. is the op-amp driving something like a MOSFET?

author: capt bullshot
author_rank: Super Contributor
timestamp: July 23, 2020, 12:58:11 pm
content: Especially for high speed OpAmps (GBW > some 10MHz) this can happen due to stray capacitance at the negative input. Otherwise typical reason is too high a load capacitance.

author: kankanas
author_rank: Contributor
timestamp: July 23, 2020, 02:09:00 pm
content: Two example ckt configuration I have attached1. Trans impedance amplifier(TIA) ckt2. slew rate measurement ckt(Red output graph is showing some oscillation then becoming stable)Please have a look on this.Used OPAMP (TL074) SLEW RATE=13V/uS, Unity gain frequency= 3MHz--- As per data sheet

author: kankanas
author_rank: Contributor
timestamp: July 23, 2020, 02:10:38 pm
content: Attached image for slew rate

author: David Hess
author_rank: Super Contributor
timestamp: July 23, 2020, 11:56:12 pm
content: Oscillation can also be caused by poor power supply decoupling.Jim Williams wrote a classic application note which discusses oscillation with wideband operational amplifiers:https://www.analog.com/media/en/technical-documentation/application-notes/an47fa.pdf
What's the right answer for this impedance network ? - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: December 06, 2022, 08:33:11 pm
content: In a problem from some pdf textbook, on the bottom of page 6 (800p in doc) is prob18.2https://library.uoh.edu.iq/admin/ebooks/79828-ch18.pdf, the z-paramaters are given to a black box, and a Vs and Rs are in series w/ the input/ And the output side is shorted.I get the right answer for the ltspice model below, which doesn't have reactance, but in the pdf I'm using, Vs=2V(30deg) , z12=z21= -j4, and I getVs= ( R + z11 - ((z12)^2)/z22 ) *I1I1=0.2A(30deg), I2=0.1A(120deg) but the pdf says 2A(20deg) and 1A(-60deg)I could make up a capacitor and frequency and try an LTspice model that way, but maybe the pdf is wrong ?? Or what am I doing wrong ?Draft44.asc(1.21 kB - downloaded 28 times.)

author: Andy Watson
author_rank: Super Contributor
timestamp: December 07, 2022, 02:46:35 pm
content: Quote from: MathWizard on December 06, 2022, 08:33:11 pmThat is the answer that I'm getting.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 09, 2022, 03:12:16 pm
content: Convert all the impedances to admittances. Work it all through as admittances- less brain ache.

author: Andy Watson
author_rank: Super Contributor
timestamp: December 09, 2022, 11:57:30 pm
content: Quote from: Terry Bites on December 09, 2022, 03:12:16 pmNot really. The problem is set up to deliver nice round values of impedance. And then there's the slight problem of that 2\$\Omega\$ between the voltage source and the Z-network
What’s the value of this capacitor? - Page 1
Forum section: electronics / beginners

author: TPC
author_rank: Newbie
timestamp: June 20, 2023, 11:45:00 am
content: I pulled this cap from a laptop motherboard, can anybody identify the values from the markings?Markings:3376k814

author: srb1954
author_rank: Super Contributor
timestamp: June 20, 2023, 12:05:09 pm
content: Quote from: TPC on June 20, 2023, 11:45:00 am330uF 6.3V

author: Psi
author_rank: Super Contributor
timestamp: June 20, 2023, 12:21:34 pm
content: Cap values are often given in pF with a 3digit code.Last digit being number of zeros.So 337 would be 330000000 or 330,000,000 pF. So 330uF

author: TPC
author_rank: Newbie
timestamp: June 20, 2023, 01:43:26 pm
content: Fantastic, thanks.
(solved) What's these chips? - Page 1
Forum section: electronics / beginners

author: Logan
author_rank: Frequent Contributor
timestamp: October 23, 2021, 01:58:18 pm
content: Hello.Can anyone help me identify the 3 chips on this power PCB?The manufacture refused to tell the chip model...Thanks.

author: madires
author_rank: Super Contributor
timestamp: October 23, 2021, 02:47:32 pm
content: The two S36 are MOSFETs.

author: Jwillis
author_rank: Super Contributor
timestamp: October 23, 2021, 06:22:48 pm
content: POWERDI3333-8 PackageDMP2008UFG

author: amyk
author_rank: Super Contributor
timestamp: October 23, 2021, 09:33:14 pm
content: ...and the other one is a TPS61178.

author: Logan
author_rank: Frequent Contributor
timestamp: October 24, 2021, 11:24:43 am
content: You guys are AWESOME!I wonder why they just don't tell me the chip model, afraid of cloning? Then why don't they polish the chip marks...

author: madires
author_rank: Super Contributor
timestamp: October 24, 2021, 12:08:03 pm
content: To annoy you.The circuit is nothing special, most likely the reference design from the datasheet.
What’s this component? - Page 1
Forum section: electronics / beginners

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: June 28, 2020, 06:13:08 pm
content: So I got a huge lot of random components recently, and I found these. Tried to Google the number on them but only got a Kitchen Maid product. Could someone help me identify this?It says KSMPSA 20 and nothing else. I think it’s a FET, but I’m not exactly sure and don’t have a component tester.

author: jmelson
author_rank: Super Contributor
timestamp: June 28, 2020, 06:26:45 pm
content: Motorola MPSA20 ? NPN bipolar small-signal transistor, not a FET.Jon

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: June 28, 2020, 06:55:26 pm
content: Hm. Wonder why the baggie they came in was labelled FET. Must’ve been a mistake.Thanks mate!

author: cliffyk
author_rank: Frequent Contributor
timestamp: June 29, 2020, 12:02:56 am
content: images/f you are going to buy surplus lots of semi-conductors a good "identifier/tester" is essential: I have used anAtlas DCA55for nearly 10 years now and cannot say enough good about it--essential to ID unknown discrete components, and for selecting components with matching characteristics when necessary. It's $85 to $90 in the U.S. depending on where you shop but worth every penny...
What's this connector called? - Page 1
Forum section: electronics / beginners

author: SolderOcelot
author_rank: Contributor
timestamp: November 13, 2018, 12:52:05 pm
content: So what's this 3-pin connector called exactly? It's used often for laptop fans. The PC version often has 4 pins.I think it might be called acrowtailconnector, but there is a slight detail (inward bending hook) in aforementioned one that makes me doubt it.I'll be needing one in a DIY project (laptop fan tester).EDIT: yes, I've named the genders wrong in the photo..

author: Sudo_apt-get_install_yum
author_rank: Regular Contributor
timestamp: November 13, 2018, 12:56:23 pm
content: I think it’s a Molex connector since the stationary fan connectors are Molex 2510 if I’m not mistaken.Mind posting a picture?

author: SolderOcelot
author_rank: Contributor
timestamp: November 13, 2018, 12:57:39 pm
content: Quote from: Sudo_apt-get_install_yum on November 13, 2018, 12:56:23 pmLol I've been trying to post it for 5 minutes now. I gave up on the  tag and uploaded an attachment.

author: Monkeh
author_rank: Super Contributor
timestamp: November 13, 2018, 01:10:18 pm
content: Molex Picoblade, I believe.

author: SolderOcelot
author_rank: Contributor
timestamp: November 13, 2018, 01:14:02 pm
content: Quote from: Monkeh on November 13, 2018, 01:10:18 pmI think you're right. Looks exactly right on Google images.However I'm also getting similar results withJST connectors

author: SolderOcelot
author_rank: Contributor
timestamp: November 13, 2018, 01:33:02 pm
content: I've found this image which helps. I'm dealing with a Molex picoblade indeed.Edit: They also call it JST 1.25mm (pitch)

author: Efe_114
author_rank: Contributor
timestamp: November 13, 2018, 05:39:41 pm
content: Every connector is also called JST X mm i dont know why

author: SolderOcelot
author_rank: Contributor
timestamp: November 13, 2018, 07:04:44 pm
content: Quote from: Efe_114 on November 13, 2018, 05:39:41 pmI've noticed
What's this MOSFET relay board? - Page 1
Forum section: electronics / beginners

author: Adhith
author_rank: Frequent Contributor
timestamp: June 02, 2021, 10:55:50 am
content: Hello there,I came across this following MOSFET relay module.https://robu.in/product/d4184-mosfet-control-module-replacement-relay/?gclid=EAIaIQobChMI4q-jxd348AIVUFRgCh21ngEAEAQYBCABEgItRfD_BwEThe product page is titled as "D4184 Mosfet control Module Replacement Relay" and the output pins of the module have +ve, -ve & a load terminal. What's the load terminal used for?I got a bit confused looking at it and was wondering if its a general purpose MOSFET board or not. I'm hooking it up with my arduino UNO to operate a solenoid valve (5V, 500mA approx.)could someone help me out?

author: Manul
author_rank: Super Contributor
timestamp: June 02, 2021, 01:22:34 pm
content: As far as I can see, it is optocoupler isolated low side switch. "+" and "-" terminals are needed to power the the board itself (to control gate of mosfet). Load terminal is the drain of n-channel mosfet, it will be connected to "-" terminal when mosfet is switched on. So you connect load between "+" and "load". 5V supply might be a bit marginal for high currents, but for low currents (500mA) it should work fine.

author: DrG
author_rank: Super Contributor
timestamp: June 02, 2021, 01:35:22 pm
content: Take a look here for a full description, schematic and example connectionshttps://protosupplies.com/product/d4184-mosfet-control-module/These are becoming somewhat generic.

author: Adhith
author_rank: Frequent Contributor
timestamp: June 07, 2021, 05:13:43 am
content: Quote from: Manul on June 02, 2021, 01:22:34 pmThank you very much. I got it now.

author: Adhith
author_rank: Frequent Contributor
timestamp: June 07, 2021, 05:14:22 am
content: Quote from: DrG on June 02, 2021, 01:35:22 pmGreat! thank you. I'll go through it.
Whats this part? Help identify IC - Page 1
Forum section: electronics / beginners

author: Rizzrack89
author_rank: Newbie
timestamp: March 11, 2023, 02:44:17 am
content: Found this in a usb button type wall wart charger. It was for the rpi 3b+This is what i see.8-pin dip/soicBS183CFA79-5742I attached an image.Usually i find most parts on google with the code. This is one of those exceptions.Any idea? Thanks in advance.

author: Nusa
author_rank: Super Contributor
timestamp: March 11, 2023, 07:36:08 am
content: From context it's a switching regulator. But that's all I can tell you.

author: wraper
author_rank: Unknown
timestamp: March 11, 2023, 08:07:51 am
content: PWM switch with built in MOSFET if it drives transformer directly or PWM controller if there is a separate MOSFET on other side. Unless you need to replace it, it's a waste of time searching for such parts.
Whattype of data will be stored in this eMMC IC - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: August 15, 2024, 03:06:09 am
content: I am a hardware person and in an Electric vehicle infotainment display, we have an MPU along with this eMMC device (https://www.issi.com/WW/pdf/21-22TF16G-32G-64G-128G.pdf) along with an EEPROM.But I am not sure as a hardware person, what for is the eMMC and the EEPROM will be used for?Like, I understand both are memory devices, like one is non-volatile and the other is a volatile memory option.However, what data does get stored in either memory? Can someone let me know for what purpose from an application PoV (EV Infotainment display product is being developed), is a.)an MPU used instead of an MCU, b.)Use of eMMC memory and c.)Use of EEPROM memory?

author: JustMeHere
author_rank: Frequent Contributor
timestamp: August 15, 2024, 03:27:41 am
content: You home computer uses the same configuration. It boots off an EEPROM which loads BOIS (or UEFI). That loads the program that tells the computer how to read your flash drive (or boot of a USB, network, etc). It then loads data from the flash drive that tells the BIOS program where to find an operating system. It then "boots" the operating system.

author: Freshman
author_rank: Regular Contributor
timestamp: August 15, 2024, 06:43:34 am
content: Thank you.Since, there's also a display in the EV Infotainment display ECU, I thought that the image content for the display (the menu screens and display data), was usually stored in the eMMC. I was wrong then.In that case, which you say, where would the display data (or the image contents for the display) be stored in?

author: xvr
author_rank: Frequent Contributor
timestamp: August 15, 2024, 11:51:31 am
content: eMMC is an embedded version of SD/MMC card. In general it contains image of file system filled with some files. It could be anything - from a couple of files and up to complete OS image (Linux or Android for example)EEPROM also can be different. It could be just storage of some configuration (or run time) data. Or it can be fixed part of MCU firmware.In first case EEPROM could be some serial type, and second it could be FLASH type.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: August 16, 2024, 03:06:56 am
content: Quote from: Freshman on August 15, 2024, 06:43:34 amIt probably does store images. But it could also store an entire OS.
Wheatstone Bridge Alternative - Page 1
Forum section: electronics / beginners

author: graphtronics
author_rank: Contributor
timestamp: June 04, 2024, 04:24:31 am
content: HelloSETUPAn alternative to the Wheatstone bridge is the star bridge.Excitation voltage goes from Vdc Power to Earth groundSignal voltage goes from Vdc Signal to GNDBridge resistances R1, R2, R3 & R4 are the same.Arm resistances R5, R6, R7 & R8 are the same.(Bridge and arm resistances are different.)Signal adjustment potentiometer span across signal outputOPERATIONGiven a X Voltage the signal response is Z mV/V.That is a Z mV per excitation voltage.A 2 mV/V design produces 20 mV at full signal @ 10 VdcDESIGNGiven an B value of bridge resistance and S mV signal outputHow to determine the required arm and pot resistances?

author: m k
author_rank: Super Contributor
timestamp: June 08, 2024, 04:20:00 pm
content: You can start doing a D/Y variant to lower right part.
Wheatstone Bridge Balancing PRT100 University Question - Page 1
Forum section: electronics / beginners

author: Cmcada
author_rank: Newbie
timestamp: August 12, 2015, 06:28:28 pm
content: Good evening,Fresh blood here!I am busy revising for a 2nd year exam in Analogue electronics and I have hit a bit of a wall.The question is simple enough:Question 12An instrument is needed to monitor the temperature of a swimming pool and should give a zero reading at 28°C; the desired poll temperature. The pool temperature is allowed to swing by one degree above and below this, where the instrument should give +/-1V respectively, which triggers on and off the heating system.Assuming a 12V supply and a bridge ratio of one determine the values of R2. And the gain needed to achieve this.Correct Answer:R2 = 110.73OhmsGain=10.0Response Feedback:Yes you have correctly balance the bridge at 28°C and designed the gain to trigger the systemThe resistor R2 is found using the characteristic equation for the PRT in question:100*(1+((3.85e-003)*u)-((5.87e-007)*(u^2)))Which gives 110.7304 as required.Using the standard Wheatstone bridge equations, Vout is 0.0103v when the sensor reads 29c - To give the +-1v swing required the gain is therefore 100. Which is not the right answer!Any ideas where I am going wrong?I have even modelled this question in Simulink and came out with the same gain value of 100.Can anyone put me out of my misery?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 12, 2015, 07:50:42 pm
content: The voltage at the bridge depends on the voltage driving the bridge. So at enough power to the bridge a gain of 10 might be enough. But here way more than 12 V would be needed. So driven with 12 V a gian of 100 is about right.In reallity,however usually PT100 don't like to much driving voltage, but only a few 100 mV. So the bridge output voltage is much smaller, more like 0.2 mV / K. Thus much more gain (e.g. 5000) is needed to reach 1 V /K. One the other side - 1 V / K ist a pretty high amplification. Konparators can work with much lower levels and this would enable reading non regulated temperature as well.

author: Cmcada
author_rank: Newbie
timestamp: August 12, 2015, 07:59:50 pm
content: Its an exam question that was set that I have spent the better part of three hours on (its a 10 minute question), at least I have seeded my knowledge that bit further.It seems like the results I have produced are correct and the mark scheme is incorrect. It is a regular occurrence at my university mind so I would not be surprised!I am waiting for a response from my lecturer and I will be waiting with baited breathThankyou for the response.
when a capacitor is put in backwards? - Page 1
Forum section: electronics / beginners

author: algorithm
author_rank: Regular Contributor
timestamp: July 29, 2014, 06:39:48 pm
content: What happens when a capacitor is put in place backwards due to mislabeling?I know they break down and/or pop off.Im more curious about what happens to whats further down the line after that.Could this current flow damage nearby components?

author: Rigby
author_rank: Super Contributor
timestamp: July 29, 2014, 06:51:04 pm
content: Well polarized caps cease working pretty quickly.Any effect on other components will be determined by the circuit and the components in question.

author: Neilm
author_rank: Super Contributor
timestamp: July 29, 2014, 06:57:05 pm
content: Quote from: Rigby on July 29, 2014, 06:51:04 pmDepends on the capacitor - I have seen some that lasted for quite a while. Indeed, I ended up having a unit go into production at work with a cap (tant I think) fitted incorrectly due to an issue with the pick and place file. Only found it as some of the early units had the power rail sag.

author: mariush
author_rank: Super Contributor
timestamp: July 29, 2014, 07:35:47 pm
content: QuoteWhat current flow.The capacitor gets damaged and either behaves like a short or it will break down without short and act like it's never there.If it gets shorted, the power supply will see the capacitor as a load and something will eventually break down... ohm's law , v = i x r ... so whatever segment in that loop has a smaller resistance it will burn up.If it's open, then whatever's after the capacitor will receive the "unfiltered" power, as if there was never a capacitor in the first place.

author: nadona
author_rank: Regular Contributor
timestamp: July 29, 2014, 08:42:13 pm
content: Quote from: mariush on July 29, 2014, 07:35:47 pm+1

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 29, 2014, 08:45:56 pm
content: Aluminum electrolytics explode. After all, they're pretty much just a steel can with some aluminum foil and salty, acidic water in them. Put them in backwards and they overheat. They overheat and the water boils, expands, and explodes the metal can. How long it takes to blow up depends on the reverse (or over) voltage applied, as well as the thermal mass of the part itself; bigger caps take longer to blow just like bigger pots take longer to boil.

author: algorithm
author_rank: Regular Contributor
timestamp: July 30, 2014, 07:20:18 am
content: Luckily the one of my question did not blow. Just made a sizzle, might have been working up to blowing though.Thanks for the replies everyone. Great stuff.

author: JacobPilsen
author_rank: Regular Contributor
timestamp: July 30, 2014, 12:46:31 pm
content: Seeelectrolytic rectifier.
when a zener fails me. - Page 1
Forum section: electronics / beginners

author: ja421
author_rank: Contributor
timestamp: September 11, 2016, 07:17:11 pm
content: I have a small project that I need to have a digital trigger when the voltage is above 12v. so I bought a few 12v zener diodes.The problem is they trigger closer to 15v than to 12v.Here's the problem I am trying to find a solution for...I need a 12v+ "trigger" signal; but the source has the V+ always hot, the ground floats, or goes to ground. When it is floating it's possible that it's allowing 6 to 7v thru. So I can't use the source's V+ alone, I have to use it conjunction with the ground. My idea was to use the zener and an optoisolator so that the optoisolator triggers when there's 12 or more volts (and then pass 12v thru the other side). I wanted to use the zener in hopes that it would use less energy than a pull up resistor... but it seems a pull up resistor is going to be the better route to take. before I redo it; wanted to check if that's the best way to go, or if there's another simpler way I am overlooking.Thank you.

author: tatus1969
author_rank: Super Contributor
timestamp: September 11, 2016, 07:51:43 pm
content: you may use a TL431 instead of a zener, that will improve your setpoint accuracy and makes it also adjustable.

author: Zero999
author_rank: Super Contributor
timestamp: September 11, 2016, 07:55:30 pm
content: Please post a schematic.In fact the TL431 has an internal op-amp which can be used as a comparator +to trigger something when the voltage exceeds a predetermined threshold.See page 28 of the data sheet.http://www.ti.com/lit/ds/symlink/tl431.pdf

author: ja421
author_rank: Contributor
timestamp: September 11, 2016, 08:23:34 pm
content: Thank you... I ordered a tl431 ... thanks for the idea!
When Discharge Testing a Battery, how do you set your cut off voltage? - Page 1
Forum section: electronics / beginners

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: May 06, 2021, 01:49:37 pm
content: Hello,Let's say you are testing a 12v 100Ah SLA battery.So let's say at the moment it reaches that full SOC you connect it to a dummy load discharge capacity tester. In my case I use a DL24P, 180 watt device.What do you set the Cut-off voltage to? If you set it to 10.8 (or whatever the data sheet specifies), you will never reach that discharge voltage because voltage at the testing device is lower than at the battery terminals.At least not on this discharge tester. Does your discharge tester go by battery terminal voltage or internal to tester voltage drop voltage?You have your actual battery voltage at the battery terminals, and then you have your loaded voltage internally at the discharge device which will be significantly lower due to voltage drop and resistance Even if you use 0 gauge cables you will still have voltage drop.So for example, if you set your cut off voltage on the tester at 10.8v.....you will actually stop the test at a battery terminal voltage of 11.2vSo do you set the cut off voltage at the batteries specified cut off voltage and know that the battery will never actually reach that voltage because the discharge device will react to the loaded internal voltage and not the actual cell voltage....resulting in the appearance of reduced capacity.....Or do you set the cut off voltage so that the voltage at the battery terminals reaches the data sheet minimum discharge voltage?Thanks

author: SuzyC
author_rank: Frequent Contributor
timestamp: May 06, 2021, 02:09:35 pm
content: Set the cut off voltage so that the voltage at the battery terminals reaches the data sheet minimum discharge voltage.The data sheet is likely been written after careful testing to specify an end of discharge point, always the best authority.
When exactly should IC pins be grounded ? - Page 1
Forum section: electronics / beginners

author: coaxialgamer
author_rank: Contributor
timestamp: November 24, 2017, 11:20:13 pm
content: I'm working with 74F series TTL IC's for a logic project , and i've been told to always ground the input of an IC . However , say i have the output of an IC connected to the input of another. Should that be ground, or will that be taken care of by the IC itself?In fact , if the output of any IC feeds into another device ( LED , IC , transistor etc ) , should that be grounded as well?

author: rstofer
author_rank: Super Contributor
timestamp: November 24, 2017, 11:43:24 pm
content: What they should have said is "ground all unused inputs". However, that won't work when the unused pin needs to be held high. In this case, pull the pin high with a resistor (I usually use 4.7k).It would damage the device to ground an output pin and then try to drive it high.

author: David Hess
author_rank: Super Contributor
timestamp: November 25, 2017, 05:27:54 am
content: The original TTL uses multiple emitter input transistors so the inputs have to be tied to Vcc through resistors to limit the current but LS and FAST use diode input structures so their inputs may be directly connected to Vcc.Most TTL inputs can be left open producing a high input but of course it is better to tie them to ground, Vcc, or some other output.
When the Output is Also the Input.  USB Multimeter - 12volts INTO THE OUTPUT?    - Page 1
Forum section: electronics / beginners

author: Zero_Ego
author_rank: Regular Contributor
timestamp: May 15, 2025, 09:29:11 am
content: Hi,I saw this USB Tester on youtube (Link w/time stamp below)In the video - this person - plugs a live 12v directly into the OUPUT of this simple USB multimeter. Yes you read that correctly - he plugged a 12volts INTO THE OUTPUT of this USB mutimeter. This would generally be a very bad idea!But the USB Meter did not blow up nor smoke and did the opposite displaying the 12 Volts.He knows its wrong and lets out a warning with "Watch this" but it worked and as in INPUT displaying 12Volts.(Youtube with time stamp)https://youtu.be/CEPRTR4ToI8?si=uhdCrXaS3KhmXZvl&t=140Anyone know what is at the heart of the these units and how do they have bi-directional communication without blowing up?Why didn't this thing smoke?ThanksZE

author: golden_labels
author_rank: Super Contributor
timestamp: May 15, 2025, 10:05:26 am
content: My guess is that it simply went straight through the body diode of the transistor regulating output and became input voltage.

author: gabiz_ro
author_rank: Regular Contributor
timestamp: May 16, 2025, 07:05:45 am
content: Most likely all + inputs are straight to their outputs and via separation diode to 3.3V or 5V LDO for powering MCU and display etc. Also to one ADC input via some divider for measuring voltage.Shunt resistor for measuring current is on low side (interposed on GND path) compatible with most cheap MCU with ADC inputs.
When to use "PVB 16 Varnish" - Page 1
Forum section: electronics / beginners

author: nardev
author_rank: Unknown
timestamp: February 03, 2020, 04:19:49 pm
content: Should every PCB that is manufactured and installed in not very protected enclosures, be coated with "PVB 16 Varnish" spray?Is there a situation when you would not use that?Does those PCBa facilitates offer PCB ultrasonic cleaning and coating PCBs with "PVB 16 Varnish" after manufacturing? I never saw that as an option.What would be expected of a device which is installed mostly indoor but usually in a wall or some other plastic enclosure.Thnx

author: wraper
author_rank: Unknown
timestamp: February 03, 2020, 04:30:39 pm
content: Why you are so fixed on particularly "PVB 16 Varnish". It's just a conformal coating made by so-so Polish manufacturer. Is it a good idea to use conformal coating when PCB can be exposed to harsh conditions.QuoteMost likely it will be cleaning without ultrasonic.QuoteDepends on PCB. If there are a lot of switches or connectors or whatever what should not be exposed to it, then conformal coating becomes troublesome. Also generally you cannot wash switches.BTW don't forget that each additional manufacturing step results in increased price and manufacturing time.

author: nardev
author_rank: Unknown
timestamp: February 03, 2020, 04:34:53 pm
content: Quote from: wraper on February 03, 2020, 04:30:39 pmAh, i didn't now exactly how you say that in english. I knew only that brand.Ok, what could be a problem with relays or so?

author: wraper
author_rank: Unknown
timestamp: February 03, 2020, 04:39:34 pm
content: Quote from: nardev on February 03, 2020, 04:34:53 pmSome relays can be washed but generally no. Also even sealed relays often have breathing hole which is initially covered but then should be opened by breaking off plastic protrusion. Failing to do so will result in decreased endurance. Even if you don't wash PCB, clogging small breathing hole with varnish is not good.

author: nardev
author_rank: Unknown
timestamp: February 03, 2020, 06:11:49 pm
content: So, can we say in general, if it is possible, it would be good to cover all the boards with the coating and that's about it. And to be careful about some components.?

author: tooki
author_rank: Super Contributor
timestamp: February 05, 2020, 04:00:20 am
content: Um, no.There are good reasons why the vast majority of PCBs are not com formally coated. Like cost, lack of need, and how they make repairs much more expensive. Conformal coating is really only used in products used in harsh environments.
when will 230V AC motor gets damage..?? - Page 1
Forum section: electronics / beginners

author: manjunath
author_rank: Contributor
timestamp: August 21, 2014, 04:35:09 am
content: Hi all ,I have posted this question to know when will AC motor gets damaged and how can i protect AC motor section from this. Most of all farmers are facing this problem frequently. so please post your ideas.Thanks.

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 21, 2014, 04:52:46 am
content: There are many things that can damage a motor, no matter what voltage.Perhaps the major causes are overloading the motor, or operating on voltage too low or too high.Without knowing details of the motor and the application and the power, it is impossible to answer your question.

author: manjunath
author_rank: Contributor
timestamp: August 21, 2014, 05:03:53 am
content: topic is about Ac motor dumped to water to pump water .

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 21, 2014, 05:06:51 am
content: Still not enough detail to give any useful reply.WHY do you think the motor may be damaged?Did it fail before? How?

author: kizzap
author_rank: Unknown
timestamp: August 21, 2014, 05:12:00 am
content: Sounds like a University assignment question.There are many MANYMANYthings that can damage an electric motor.overloading the motor would be a common problem, if the motor is for water, some of them will actually seize from overheating if the water source runs dry.

author: mzzj
author_rank: Super Contributor
timestamp: August 21, 2014, 07:54:03 am
content: Quote from: kizzap on August 21, 2014, 05:12:00 amAnd was thinking that this is from some undeveloped country like India with wild variations in electrical supple and entire country is running without a single fuse.

author: SeanB
author_rank: Super Contributor
timestamp: August 21, 2014, 05:47:38 pm
content: Submersible motor will be damaged if the supply voltage is low, or it is run dry for extended periods or if the output head is too high. Solutions are undervoltage lockout relay, overcurrent relay to the motor for the voltage issue. For dry running the simplest is a float switch that only allows operation when the pump is under water. Cheap and simple. Output head you add a pressure relief valve that will open and dump back water into the pond to keep pressure in the allowable limit.

author: tsmith35
author_rank: Frequent Contributor
timestamp: August 21, 2014, 06:14:22 pm
content: Quote from: manjunath on August 21, 2014, 04:35:09 amHere is your answer:http://www.marcspages.co.uk/pq/2540.htm
When you see a "current source" symbol in a schematic, what is that exactly? - Page 1
Forum section: electronics / beginners

author: JoeN
author_rank: Frequent Contributor
timestamp: October 12, 2015, 04:20:04 am
content: I see these usually on schematics for ICs. In real life, I am not sure what component is used here for a discrete version of the design, other than you can obviously use a resistor if you know your voltage. What is used on an actual IC? What should be used for a discrete design if you want the circuit to work for multiple voltages? Thanks. Example:

author: Wim_L
author_rank: Regular Contributor
timestamp: October 12, 2015, 07:56:11 am
content: If you want to make these from discrete components, you need to keep in mind that it's essential to have nearly identical transistors. Not just the same model number, there can be too much variation between different batches of the same model. And worse, you need to keep them at the same die temperature too. For this reason, it's usually best to use a transistor array (IC package with multiple transistors) instead of discrete transistors for a circuit like this.

author: SeanB
author_rank: Super Contributor
timestamp: October 12, 2015, 06:59:39 pm
content: As Blueskull says, they are a current mirror, and all are identical. In the LM358 given as an example all the positive current sources are supplied from a single diode connected top transistor, with the various currents being provided by making the current mirror transistors with different areas, so that the current ratios are all going to be very close. Thus the 4uA has an area of 2, the 6uA an area of 3, and the 100uA an area of 50 times the area of the diode connected transistor.The current source is provided with startup current and bias with a jfet connected in pinch off, so that it gives a small well defined current. Smaller than a chip resistor of the same value by a large amount. The pull down is often implemented just by using a slightly larger jfet as a constant current sink, not too precise but will stay in the ballpark over operating range quite well.

author: Zero999
author_rank: Super Contributor
timestamp: October 12, 2015, 07:34:09 pm
content: Yes the LM358 uses a current mirror with multi-collector transistors. See the detailed schematic.
Where are the connectors? JLC PCB SMT - Page 1
Forum section: electronics / beginners

author: ssashton
author_rank: Frequent Contributor
timestamp: October 19, 2020, 02:29:31 pm
content: I like the SMT assembly service at JLC PCB.. but I can't find any wire to board connectors in the parts library.Am I going mad? They surely have IDC headers or JST sockets...https://jlcpcb.com/parts

author: tszaboo
author_rank: Super Contributor
timestamp: October 19, 2020, 02:35:18 pm
content: No, you are not.https://www.eevblog.com/forum/manufacture/jlcpcb-no-smt-usb-connector/

author: ssashton
author_rank: Frequent Contributor
timestamp: October 19, 2020, 05:42:40 pm
content: Well that's just nuts!

author: tszaboo
author_rank: Super Contributor
timestamp: October 19, 2020, 10:15:46 pm
content: Quote from: ssashton on October 19, 2020, 05:42:40 pmAgreed.
Where are the PWM controllers for the VRMs on this graphic card? - Page 1
Forum section: electronics / beginners

author: TheGenesis
author_rank: Contributor
timestamp: November 05, 2018, 09:42:01 pm
content: Please, someone help me to find the controller for the GPU and the RAMs.By just guessing i would say the controller for the GPU is the "ON NCP4205" on that little daughterboard on the left ... right?And is this thing controlling all the 6 phases (coils and drMOS's) in the middle?But where are the VRMs for the VRAM?Thanks in advance.Thom

author: aheid
author_rank: Regular Contributor
timestamp: November 05, 2018, 10:03:06 pm
content: I'm gonna go out on a limb and say there probably are no psychics or anyone with a crystal ball here...Did you forget to attach some pictures or some links?

author: TheGenesis
author_rank: Contributor
timestamp: November 05, 2018, 11:51:53 pm
content: Sorry ... and now with the pic

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 06, 2018, 04:34:13 am
content: Yes, NCP4206 is probably the controller, which is going to be VCORE I guess (1.1V or thereabouts)?IO supply is probably U14, whatever it is. I don't recognize the code, and there's no MFG mark... could be anyone...Tim

author: radioFlash
author_rank: Regular Contributor
timestamp: November 08, 2018, 01:59:09 am
content: There are six large inductors sitting next to chips marked SIC780: "The SiC780 is an integrated power stage solution optimized for synchronous buck applications..."https://www.vishay.com/docs/63788/sic780.pdf

author: Chris_S
author_rank: Newbie
timestamp: November 08, 2018, 03:31:00 am
content: The 2 small phases between the large inductors are your VRAM VRM.So the 2 R33 inductors, 4901NF Mosfets, and the surrounding components. The actual controller should be right below the r2r cap.You are correct about the other phases for the actual GPU.

author: TheGenesis
author_rank: Contributor
timestamp: November 08, 2018, 08:36:58 am
content: Ok ... thanks.I have already fearedif the little ic marked "OT=FF -H2B" would be the controller ... i couldn't find any information of that piece.Mhmm ... three of the GPU Mosfets are shorted.Can someone tell me, what should I expect, when measuring the resistance of the inductors?My Multimeter shows open-line on everyone. Is it possible that my Multimeter is not accurate enough?