hybridfree/eevblog-posts huggingface dataset:
Mystery Resistor  - Page 1
Forum section: electronics / beginners

author: cscott242
author_rank: Newbie
timestamp: April 15, 2023, 01:09:16 am
content: Can someone tell me the watts of this resistor?Thank you in advance if you help me.I don’t know the voltage.Brown, Black, Red, Black?

author: Jwillis
author_rank: Super Contributor
timestamp: April 15, 2023, 01:44:30 am
content: Difficult to say without a point of reference to size. Measure the diameter and length of the body. But going by the wire size it looks like 1/4 watt.

author: barshatriplee
author_rank: Regular Contributor
timestamp: April 15, 2023, 11:23:49 am
content: The size looks like 1W to me.

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2023, 11:31:26 am
content: Without knowing the size, it's impossible to tell. It appears to be made of a ceramic material. so will be able to tolerate a higher temperature, thus more power, than a carbon or metal film resistor of the same size.

author: cscott242
author_rank: Newbie
timestamp: April 15, 2023, 01:07:24 pm
content: Thank you very much! Here is a more logical pic.

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2023, 02:10:20 pm
content: Quote from: cscott242 on April 15, 2023, 01:07:24 pmVisit an electronic component distributor's website.Go to the section of the site for through hole resistors.Select axial and the dimensions of the component, about 12mm in this case.Look at the results.Here's an example showing Farnell's website.https://uk.farnell.com/w/c/passive-components/resistors-fixed-value/through-hole-resistors?resistor-case-package=axial-leaded&product-length=12mmIt's probably either 1W, or 2W, depending on whether it's carbon film, or metal oxide/wire wound. Going by your picture, it's probably not carbon film, so the power rating will be 2W. Note that, if you intend to use it anywhere near 2W, then it will get very hot and should be mounted on stand-offs, so as to avoid burning the PCB.

author: cscott242
author_rank: Newbie
timestamp: April 15, 2023, 04:05:26 pm
content: Wow. Thank you very much. This is amazing that this site exists and you helped me. Thank you

author: Gyro
author_rank: Super Contributor
timestamp: April 15, 2023, 06:41:33 pm
content: What was the reason for you removing the resistor? Has it gone open circuit? If so, it might be a fusible resistor, designed to open safely to protect against fire under circuit fault conditions. A little background might be helpful.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: April 15, 2023, 08:50:59 pm
content: Usually fusible resistors have the last band in the color WHITEWire wound resistors have the last color BLACKThe exterior construction also suggests a wire wound.

author: Gyro
author_rank: Super Contributor
timestamp: April 15, 2023, 09:13:31 pm
content: Sure. It's worth checking though, this is the beginners section and we don't have any context to go on.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: April 15, 2023, 09:59:24 pm
content: Yea, if the resistor is "open" then perhaps chipping away some of the surface would reveal some wire.
Mystery transistor - Page 1
Forum section: electronics / beginners

author: MrWizerd
author_rank: Contributor
timestamp: October 01, 2015, 03:02:42 am
content: Ok I have a Transistor based on measurements is in a SOT23 case the main making is 1B but there are two markings on the sides, a p and after a p8 I think but it is 90 degrees turned from the main 1B. If those markings are insignificant it is a BC856B NPN transistor. I attached a picture from my phone through a loop with a flashlight shining on it.Sent from my SPH-L710 using Tapatalk

author: Mr.B
author_rank: Unknown
timestamp: October 01, 2015, 03:14:56 am
content: Firstly a BC856B is a PNP transistor, not an NPN.Taiwan Semiconductor, Diodes Incorporated, Infineon Technologies, Fairchild Semiconductor and NXP Semiconductors all have 3 character markings for their BC856B, none of which are "1B"It appears to be a Vishay BC846B.What is your mystery?Edit: Spelling.

author: MrWizerd
author_rank: Contributor
timestamp: October 01, 2015, 05:33:31 am
content: Sorry, was paying from my phone and the first one on this listhttp://www.s-manuals.com/smd/1bis the bc846b like you said. My mystery comes in the form of the extra characters. If it had just the 1B I would call it good but the two on the right are P8 by my eyes and want sure if these were significant or not.Sent from my SPH-L710 using Tapatalk

author: MrWizerd
author_rank: Contributor
timestamp: October 01, 2015, 05:36:02 am
content: That site shows the 1BP as the bc846b NPN by nxp. This is the confusion I'm having sorry couldn't edit previous post from tap talkSent from my SPH-L710 using Tapatalk

author: Mr.B
author_rank: Unknown
timestamp: October 01, 2015, 06:27:32 am
content: The important thing is the "1B".The other markings may be batch/date codes...I would suggest it is a Vishay BC846B.
Mystery Voltage Monitor Board - Page 1
Forum section: electronics / beginners

author: danlb_2000
author_rank: Newbie
timestamp: June 26, 2021, 12:28:43 am
content: I found a bunch of these boards in my surplus bin, no idea where I got them but based on the date codes they date back to the late 70's. I finally decided to play with them a bit so I traced out the circuit and did some experiments. They have 4 LED's, +V and GND inputs but no other inputs. I hooked it up to a variable power supply and found that LED's 8 and 20 come on around 6V, at 9V LED 8 goes out and 20 stays on, at 12V all the LED's go out, and at around 13V, LED 14 comes on. The part that perplexes me is, what condition would cause LED 28 to come on? The element of the comparator it's tied to has it's minus input tied to ground, so based on my understanding of comparators, there should be no way for that element to turn on. Anyone have and ideas on this?

author: Renate
author_rank: Super Contributor
timestamp: June 26, 2021, 12:24:16 pm
content: On the schematic, if you move the 2nd from the top op amp to the bottom and put R23, R21, R18, R17 in a vertical line it will be easier on our brains.LEDs 8 & 20 should come on at different voltages, but it's a small difference.Maybe you have the top opamp circuit wrong? Maybe it's a blinker. Are you sure the - input doesn't go to the same bias as the other ones?

author: danlb_2000
author_rank: Newbie
timestamp: June 26, 2021, 04:01:17 pm
content: Good suggestion on the schematics, I have made that change and attached the new version, it does make it clearer. I double checked and Pin 6 definitly goes to ground. In my experimentation I have also not found any scenario that causes LED 28 to come on.

author: Renate
author_rank: Super Contributor
timestamp: June 26, 2021, 04:50:57 pm
content: Do you have the wiring for pin 8 & 9 backwards?You say that that LED only goes on with higher voltage.What is this +5? Is there a regulator not shown?Is C11 electrolytic in the microfards or tiny?

author: danlb_2000
author_rank: Newbie
timestamp: June 26, 2021, 06:59:37 pm
content: I double checked 8 & 9 and they are correct. +5 was a mistake, there is a single voltage input so that should have been labeled +V like everything else. C11 is a 10uf, 35 V electrolytic.

author: Renate
author_rank: Super Contributor
timestamp: June 26, 2021, 08:37:58 pm
content: Oh, so I was confused which was the reference.D27 is a Zener for the reference.Run the voltage up and see what it peaks at.D28 will only go on if there is lots of spikes on the power.I don't know why they are doing that.D14 is on for voltage OK.D8 is for low voltage.D20 is for really low voltage.If you can't get D8 & D20 to behave somewhat independently try playing with the pot.It may be that the voltages they are trying to sense is lower than the Zener voltage.
N.C. Switching 5V using 12V. FET? - Page 1
Forum section: electronics / beginners

author: vv_eev
author_rank: Contributor
timestamp: July 31, 2024, 03:59:48 am
content: The target is a 5V line (4.3 to 5.5 VDC) which already gets grounded by a physical switch to trigger an action. It sinks 4.5-5 mA @ 5V to ground when active. Current is limited by the source.I need a normally-closed switch in series, which will open with application of anywhere from 12 to 15 VDC (it varies uncontrollably). This will prevent the 5V switch from having any effect. I can't draw more than ~25-50 mA from the 12V line.Can someone help with the schematic and specs? And the math? I'm so rusty since I ended up in firmware!

author: inse
author_rank: Super Contributor
timestamp: July 31, 2024, 04:56:39 am
content: PMOS transistor + 10k pull down resistor, two componentsSwitch over or NC reed relay, one component

author: vv_eev
author_rank: Contributor
timestamp: July 31, 2024, 09:59:13 pm
content: Danke. Schematic bitte?

author: Benta
author_rank: Super Contributor
timestamp: July 31, 2024, 11:00:07 pm
content: How about a simple relay?Example (draws 9 mA @ 12 V):https://omronfs.omron.com/en_US/ecb/products/pdf/en-g6k.pdfRugged, noise-resistant, cheap (~1.5 $ in single qty.)...
n-Channel JFET characteristics  - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: August 15, 2020, 06:55:44 am
content: In the above picture why it is written "negative voltage of -1 V has been applied between the gate and source terminals for a low level of VDS".My question is wht happend if we use high level of VDS??This line is not clear to me?

author: magic
author_rank: Super Contributor
timestamp: August 15, 2020, 07:30:28 am
content: At low Vds the FET is in its ohmic region and Ids increases proportionally to Vds.At high Vds the FET is in its saturation region and Ids is roughly constant regardless of Vds.What they mean is that the transition from ohmic region to saturation happens at lower Vds when Vgs gets more negative.
N-Channel MOSFET for switching 400mA @ 3.3V - Page 1
Forum section: electronics / beginners

author: Tantal
author_rank: Contributor
timestamp: June 11, 2015, 07:22:17 am
content: I am looking for a logic level N-Channel MOSFET for switching 400mA @ 3.3V (I'd like to turn on/off LEDs with a 3.3V Arduino).RDS,onand VGS(th)seem to be the key parameters here, no?Which one would you recommend?

author: con-f-use
author_rank: Unknown
timestamp: June 11, 2015, 08:02:15 am
content: 1. Go tomouseror the distributor of your choice2. Look for N-MOS, filter for >500 mA, a threshold voltage <2V and maybe the package (smd, through-hole)3. Order 100 of the cheapestThe majority of N-MOS on the planet should suit your needs. A typical jelly-bean is theNTR4170.(Bonus Points: Calculate on-state power and compare it to the datasheet's thermal characterisitcs, most should take your 400mA without hesitation, unless you plan to switch really rapidly)
N Channel MOSFET turn on voltage question - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: July 27, 2015, 10:26:08 am
content: Do only "logic level" N trype MOSFETS always turn on with 5V on the gate? I am wondering why this circuit attached needs the gate voltage to be about 15V higher than the voltage being switched (100V or so)? Could this switching by Q5 not have been achieved without the added component count just to achieve the higher voltage just used for the switching level for this one device? MOSFET is an IRF260 N Channel. Thanks.

author: ovnr
author_rank: Frequent Contributor
timestamp: July 27, 2015, 10:41:44 am
content: Remember, the gate of a NMOS must be pulledabove the voltage on the source pin- this means, for Q5 (I presume you meant Q5 anyhow), you need to pull it to 110+ volts relative to ground to get full turn-on, because the voltage on the source pin is 100v.It doesn't matter if it's logic-level or not.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 27, 2015, 01:36:49 pm
content: So, wait, you opened a Word document with an embedded picture...Took a screenshot of that (full screen, no cropping)...Opened that (in IrfanView), and screenshotted THAT...And posted that (no cropping)?You have a very peculiar way of doing things..Anyway, voltage is always a difference. Gate voltage is Vgs, i.e. always relative to the source pin. After all, how would the transistor ever "know" anything else?For related reading: source follower.Tim
N stage parameterised flip flop synchroniser for 8 bit input. - Page 1
Forum section: electronics / beginners

author: AnuI
author_rank: Newbie
timestamp: May 04, 2018, 05:45:02 am
content: Hi all,I want to design an N stage flip flop synchronizer.For one bit input, I can use shift register of N bits and have my parameterized synchronizer as shown in code.//////////////////////////////////////////////////////////////module N_stage_synchronizer #(parameter NUM_STAGES = 2) (output sync_out,input async_in,input clk);reg [NUM_STAGES:1] shift_reg;always @ (posedge clk) beginshift_reg <= {shift_reg[NUM_STAGES-1:1], async_in};endassign sync_out = shift_reg;endmodule/////////////////////////////////////////////////////////But what to do if the input is a vector.For eg: Async is 8 bit.Then how to do it?Do i need to use an array?Any help would be appreciated.Thanks.
N-Type Connector Grade/Connector saver - Page 1
Forum section: electronics / beginners

author: ezalys
author_rank: Frequent Contributor
timestamp: November 29, 2017, 05:20:02 am
content: I just acquired an HP 8595E spectrum analyzer (good to 6.5 GHz), and would like to keep the connectors in as good as shape as possible. I'm aware that mating precision connectors with lower grade connectors will degrade them due to the lower tolerances. Is this true of N connectors as well? What would be a reasonably priced SMA to N connector to keep permanently on the front of the unit to use as a connector saver? Is it necessary to spend 50-150 bucks on a connector to get something that won't degrade the connector on the front panel?

author: vk6zgo
author_rank: Super Contributor
timestamp: November 29, 2017, 11:59:40 am
content: Quote from: ezalys on November 29, 2017, 05:20:02 amIt might be a problem with SMAs & the like, but "Ns" are pretty rugged.Just don't use a 75 Ohm "N" plug in a 50 Ohm socket.

author: dmills
author_rank: Super Contributor
timestamp: November 29, 2017, 12:12:41 pm
content: Yep, a nice trap that.N are robust, and for a SA (Where connector impedance is not the nightmare issue that it is in a VNA) I would not worry too much.One thing about N type however, when mating them turn the screw collar but keep the connector body from turning, less wear that way.If you go on fleabay you can sometimes find Huber-Schurner N to SMA for not a lot of money, especially if you don't mind a short cable to adapt the sexes.You will fairly quickly find that you have hundreds of bucks in inter series adaptors, and it gets MUCH worse as soon as you acquire a VNA, them things are BAD news from a really expensive gear acquisition syndrome perspective.Regards, Dan.

author: CJay
author_rank: Super Contributor
timestamp: November 29, 2017, 12:43:22 pm
content: Quote from: vk6zgo on November 29, 2017, 11:59:40 amYeah, I got caught that way, I bought a bag of RF connector including a number of N chassis sockets from a local eBay seller, they're a good quality brand but on each and every one of them they have stamped 75, checking out the rest of the markings confirms it and trying (gently) to connect a 50R cable, it's immediately obvious that something will get damaged if I used enough force to make it mate.Not all lose though, there were three really nice quality SMA to N connectors which now live on one of my SAs as well as a bunch of silver plated SO239 chassis sockets and a pile of silver plated BNC plugs.There are bargains out there
N00b power supply question - Page 1
Forum section: electronics / beginners

author: lazarusr
author_rank: Regular Contributor
timestamp: November 08, 2015, 09:32:49 am
content: I am working on a project based on a rather flaky book I have found from the 1980s. I have already established that there are quite a few errors in the book, so I am having to try to work round these. My latest problem relates to the power supply requirements.The project requires both a +5v rail and a +12v rail. The +5v supply is taken from a port on a retro 80s 8-bit computerThe +12v supply is taken from a wall wart.In the schematic in the book, the +5v from the computer port is connected to the +5v supply, the GND from the computer port is connected to GND and the +12v from the wall wart is connected to +12v (all, obviously, as expected).However, GND from the wall wart is connected to +5v. I do not understand this at all. So my questions are this:Am I correct in thinking that tying the GND from the 12v wall wart to +5v on the schematic is likely to be an error?Is it OK to for the two separate power sources to share a common GND or should the +12v rail have it's own dedicated ground that?I attach a copy of the schematic. A few points should be noted. The text confirms, rather surprisingly, that the +12v wall wart is centre -ve. Also, the +12v supply isn't meant to be doing anything in this schematic, it just goes off to a header for supplying other projects. Hence the outer connection from the wall wart isn't connected to anything else in the schematic and, rather confusingly, isn't labelled. Also, it's the centre connection (which is GND on the wall wart) which is shown connected to the +5v rail.Any help working this out would be greatly appreciated.

author: lazarusr
author_rank: Regular Contributor
timestamp: November 08, 2015, 09:39:36 am
content: I should point out that all the projects that interface to this require that power (whether it is +12v or +5v) and data share a common GND.

author: jeroen79
author_rank: Frequent Contributor
timestamp: November 08, 2015, 01:04:47 pm
content: QuoteIf you attach the - of the 12V supply to the +5V rail then the + of the 12V supply would be raised to +17V.QuoteYes, you can connect rails from different supplies together as long as they are floating. If the suplies are already referenced to different potentials then you could create a short.

author: lazarusr
author_rank: Regular Contributor
timestamp: November 08, 2015, 07:12:27 pm
content: Thanks.I am pretty sure there was no intention for there to be a +17v supply.Both power supplies have floating grounds. So I will proceed with a common ground. Indeed, it is apparent from the other projects in the book that it is intended that +12v and +5v share a common ground. The other projects simply wouldn't work if they didn't.
n00b Scope question - Page 1
Forum section: electronics / beginners

author: ScottyAU
author_rank: Contributor
timestamp: June 26, 2014, 07:05:11 am
content: Hi all,I've just got a new bench power supply - and I've been playing around with it with my scope - looking at the noise on/off etc.I have a Rigol DS2072 with the 300Mhz "option" - but still on v2 - haven't touched v3.My question is - I have my bench supply set to 5v. (the setting doesn't matter but let's go with 5v). If I meter across the outputs with my multimeter I see bang on 5v. If I connect my scope though - I only see 1v. If I chance the setting on the bench supply to say 10v - the multimeter sees it just fine - but the scope sees 2v.What am I doing wrong on the scope to get the scale/output on the scope wrong like this? (I've tried a restore to defaults with no luck).Cheers.Scotty

author: tautech
author_rank: Super Contributor
timestamp: June 26, 2014, 07:15:31 am
content: You say you see 1 or 2 V.How do you see this?Are you reading this from the graticules?Or from some on-screen measurement?What is your vertical attenuator setting?Is the Ch input set to match the probe?

author: ScottyAU
author_rank: Contributor
timestamp: June 26, 2014, 07:16:58 am
content: I figured it out - I have 10x probes but only had them set to 1x in the channel settings.Setting it to 10x I now see the correct voltage...Cheers!

author: ScottyAU
author_rank: Contributor
timestamp: June 26, 2014, 07:17:31 am
content: PS - thanks tautech for the reply.

author: tautech
author_rank: Super Contributor
timestamp: June 26, 2014, 07:23:14 am
content: Scotty, have you worked out that to measure ripple, you need to set your channel input to AC coupling and lower V/div.

author: ScottyAU
author_rank: Contributor
timestamp: June 26, 2014, 07:24:52 am
content: I've been playing with different scales on the v/div etc - but i'll set it to AC coupling now - ta for the tip!

author: w2aew
author_rank: Super Contributor
timestamp: June 27, 2014, 04:17:18 pm
content: Quote from: ScottyAU on June 26, 2014, 07:24:52 amHere's a video of mine that describes scenarios where AC or DC coupling are useful:

author: ScottyAU
author_rank: Contributor
timestamp: June 27, 2014, 07:54:08 pm
content: I'm still working my way through a lot of your videos w2aew - thanks very much!
N+1 Power with protections - Page 1
Forum section: electronics / beginners

author: Darlington
author_rank: Contributor
timestamp: April 29, 2025, 05:11:45 pm
content: Hi guys,I was designing an low cost circuit to have redundancy on the 12V rail with RPP and ICL protection.I don't know how to polarize DZDH0401DW correctly.There will be some mistake. Can you help me or give me some suggestions?I'm attaching a simulation with LTspice and circuit diagram.

author: jwet
author_rank: Frequent Contributor
timestamp: April 30, 2025, 05:20:27 pm
content: I couldn't run your spice sim. Post your plots if you have spice data.I think the probe the first fet's are backwards. These are reverse polarity protection, this will put their body diodes in conduction and for proper polarity will get shorted out. I'm not sure these FET's are even required, the pass fet and your controller serve this fuction. It includes a diode for reverse polarity.This circuit is just an OR'ing controller- kind of a smart diode OR'ing circut.LTC and others make more sophisticated Or'ing controller (that also use Hi Side N Channels) and can "auctioneer" and prioritize supplies when available.
N21FR Multimeter: how to change the battery? - Page 1
Forum section: electronics / beginners

author: midgk0
author_rank: Newbie
timestamp: August 08, 2018, 12:20:24 pm
content: Hi there,I'm new to a job which requires measuring the temperature and humidity of the environment. I've been given a spot meter (Precision Gold N21FR) to take readings, but just wondering for future reference how I change the battery? The instruction manual says to remove the screws in the cover, but I see no screws! The yellow part I'm assuming is the cover and it is loose around the sides of the monitor (see attached photos) but it doesn't seem to want to come off. Any thoughts much appreciated!Katherine

author: Adam60
author_rank: Regular Contributor
timestamp: August 08, 2018, 12:41:23 pm
content: Peel off the yellow cover. Start from the top and just work your way around to remove it from the meter. Once you have the cover off, look at the back of the meter. At the bottom of it, thereshould be a rectangilar or square cover with 1-3 screws holding it in place. Remove the screws and the cover and you should find the battery and fuses for the meter. Cheers.

author: drussell
author_rank: Super Contributor
timestamp: August 08, 2018, 01:28:48 pm
content: Yeah, the holster thingies can be tricky to get off until you get the knack for it.Usually the top or the bottom lip will be smaller than the other one. On yours, it looks like the top is the smaller one. Pry back on that top lip of the holster until it stretches enough to pop over the top of the meter.Installation is the reverse of removal.

author: midgk0
author_rank: Newbie
timestamp: August 08, 2018, 01:33:44 pm
content: Thank you, I've managed it now! it was very stiff and I was worried about breaking it..
N76E003 pin high/low takes larger time - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: May 27, 2019, 01:52:21 pm
content: 1. I am using N76E003, keil v9.51 . Controller is running at 16Mhz, I can measure this on Clockout pin by DSO.2. Internal clock diagram shows, Clockout frequency & peripheral frequency is same.3. Timers works correctly accroding to 16Mhz clock.4. Issue I faced is when I write:P04 = 0; or P04 = 1;it takes around 250ns as measured on DSo with 10x probe for single instruction.5. Disassembly on keil shows:C:0x07FE C284 CLR P04(0x80.4)C:0x0800 D284 SETB P04(0x80.4)6. These are single cycle instruction. What I dont understand is when cpu is running at 16Mhz, single cycle time should be 1/16Mhz i.e 62.5ns, but on DSO it takes 250ns around7. Then why pin high low takes large time

author: garethw
author_rank: Regular Contributor
timestamp: May 27, 2019, 02:27:19 pm
content: Clock cycles and machine cycles are not the same.For example: Your clock is 16MHz. If your mcu is running 4 clock cycles per machine cycle then each instruction takes 1 / 4MHz = 250ns.The data sheet will explain how long each instruction will take in machine cycles as well as how long a machine cycle is.Sent from my iPhone using Tapatalk

author: garethw
author_rank: Regular Contributor
timestamp: May 27, 2019, 02:47:05 pm
content: Checking the N76E003 datasheet reveals:1 clock cycle per Machine cycle.SETB (set bit) = 4 Machine cyclesCLR (clear bit) = 4 Machine cyclesHope that helpsGareth

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: May 28, 2019, 05:42:20 am
content: thanks
NAD 5325 CD repair attempt - Page 1
Forum section: electronics / beginners

author: RichardM
author_rank: Frequent Contributor
timestamp: October 29, 2022, 10:22:04 pm
content: Hi All,I thought I would try to repair an old NAD 5325 CD my brother left me. Just a hobbyist. At the moment you insert the disc and it seems to focus, starts to spin and then stops with "Disc" shown on the led display. I have scoped a number of points around the circuit as per the service manual but before asking questions about that I thought I would start checking some power supply voltages. BTW I think its a defective "pickup" but wanted to see what others thought of the volatages first. Could be many things based on my readings. I have attached an image of some of my measurements.Basically I see "high" +12V and -12V rails ie. -12V is more like -14.3V ? I also see a lot of ripple even though I have recapped the unit. The frequency of the ripple either side of the bridge recifier is 100Hz which seems correct? but the positive side of the recitier(D604-604 junction) has 700mv ripple and looks like a relatively clean sawtooth wave. The Negative side is a not a clear wave and has 350mv peak to peak.Any comments much appreciated. Are these voltages too high to be correct ? I am really not sure how this circuit regulates to get the 12V rails. Leaky diodes of transistors ?RegardsRichard

author: RichardM
author_rank: Frequent Contributor
timestamp: October 31, 2022, 10:07:50 pm
content: In hindsight this should be in the repair forum.
Name brand VS other sodlering flux paste - Page 1
Forum section: electronics / beginners

author: bsahdy
author_rank: Contributor
timestamp: April 07, 2014, 09:09:00 pm
content: helloi am kinda new to soldering world and i want to know if buying those ebay soldering flux pastes are any good or should i buy name brand ones?the only bad thing that i could think of is that the Ebay ones have less flux or no flux and are just fakes. but i dont know much about it.btw the same qu would apple to soldering wick.thank you your responses are greatly appreciated.

author: Johnny5
author_rank: Newbie
timestamp: April 07, 2014, 09:40:23 pm
content: Stick to the name brands, you know what you're gettingYou can still find them on ebay.As a newbie into electronics, i've tried the cheapy no brand stuff and it is crapyou get what you pay for

author: bsahdy
author_rank: Contributor
timestamp: April 08, 2014, 01:05:39 am
content: what other brand names are there that are good besides for kester and muiticore?

author: Holograph
author_rank: Regular Contributor
timestamp: April 08, 2014, 04:13:09 pm
content: Another good one is MG ChemicalsFor flux, Chemtronics is good tooKeep in mind places like Ebay and Amazon Marketplace may try to sell no-name stuff as one of the name brands, or they may try to sell you old product that may not work as well. I'd only order from an actual electronic supply company (Mouser, Digikey, Newark, Allied, etc.) or possibly Amazon (NOT the marketplace / third party sellers unless it's a known-good seller).Edit: Oh, and I'd like to add to the question a bit. Anyone know if there are any good Made in USA brands of solder/flux? This wouldn't matter to the non-US people here, but I'm from the US and would like to support the US economy when possible... Is Interflux a good brand for flux? Any good ones for solder? I buy from the brands already listed by OP and myself, currently...

author: nanofrog
author_rank: Super Contributor
timestamp: April 08, 2014, 05:47:00 pm
content: Another vote to stick with name brands for flux, wick, and solder.Too many issues with the no-name brands from eBay IMHO.For flux, Kester, Multicore, MG Chemicals, and Chemtronics are excellent, and offer pens or small containers suitable for hobbyists (smallest container from other brands would be 1 gal/4 liters, and run ~$60 per). MG Chemicals sell small bottles of rosin flux, which is more economical than disposable pens.If you live in the US, you could also opt for refillable pens from SRA-solder (here).

author: mcinque
author_rank: Unknown
timestamp: April 08, 2014, 06:53:19 pm
content: Name brands, Stannol for me.
Name for CD/DVD drive spindle? - Page 1
Forum section: electronics / beginners

author: ryanmills
author_rank: Unknown
timestamp: September 01, 2020, 09:28:45 pm
content: I'm trying to source what I call a CD/DVD drive spindle. The part that the CD/DVD/BLURAY would attach too that in turn attaches to the motor. I know they are being phased out but I can't find them anywhere. I assume they are known under a different name?

author: thm_w
author_rank: Super Contributor
timestamp: September 01, 2020, 10:08:01 pm
content: Spindle hub:https://www.aliexpress.com/item/33046562113.htmlWith motor attached to hub:https://www.aliexpress.com/item/32817259257.htmlhttps://www.aliexpress.com/item/32823148616.html
Name for part of a via between plated through hole and the annular ring? - Page 1
Forum section: electronics / beginners

author: AndrejaKo
author_rank: Frequent Contributor
timestamp: December 20, 2021, 11:48:30 am
content: Hi guys,I've been trying to find out the name for the part of a via resting on the top/bottom layer of the PCB, between the through-hole itself and the annular ring. That's the part which is flat on the PCB surface, but also makes connection to the through-hole. Unfortunately, search engines are failing me, and I don't really know how to explain the part better. In the attached picture, the part is circled in red." alt="" class="bbc_img" />

author: gamalot
author_rank: Super Contributor
timestamp: December 20, 2021, 12:16:11 pm
content: pad?

author: wraper
author_rank: Unknown
timestamp: December 20, 2021, 12:19:27 pm
content: Annular ring, LOL.

author: NorthernWing
author_rank: Contributor
timestamp: December 20, 2021, 12:21:19 pm
content: That would be the annular ring (or sometimes pad), connected to the annular ring on the other side by the barrel.

author: gamalot
author_rank: Super Contributor
timestamp: December 20, 2021, 12:27:15 pm
content: I also found a picture that says it is a annular ring, but the wiki says it is a pad.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 20, 2021, 12:30:41 pm
content: Pad and annulus / annular ring are synonymous.Pad might not have a hole (SMT pad) so isn't an annulus in that case.The inner metal is the "barrel".The whole structure is a via if no component lead is intended to solder into it (or is prevented for various reasons e.g. plugged/capped, blind/buried vias), or a thru pad/pin/hole if so.Tim
Name of a Connector - Page 1
Forum section: electronics / beginners

author: ElektronikLabor
author_rank: Regular Contributor
timestamp: August 16, 2014, 08:14:04 am
content: Hello,I'm looking for some connectors but I don't know the name of them. They look very simmilar; I think, when I find out one name, I will find all.The connectors are used in the Alcatel SCM 650 Sputtering System:http://www.wotol.com/1-alcatel-scm-650-sputtering-system/second-hand-machinery/prod_id/1040885Here I found an similar connector with metall housing but without any hint about the name:http://www.ajvs.com/alcatel-cff-450-turbo-pump-to-controller-connecting-cable-3m-063037-7266Does anybody recognize it?Thanks!
Name of hardware to directly program AVR - Page 1
Forum section: electronics / beginners

author: branjb
author_rank: Contributor
timestamp: June 16, 2016, 09:39:40 pm
content: I've seen programmers that you can place directly over avr's that have tiny contacts that touch the corresponding SPI pins on an avr for programming chips directly without need for an ISP header. I can't find any at all from googling around, anyone know the name/model of one?

author: Mr.B
author_rank: Unknown
timestamp: June 16, 2016, 09:48:12 pm
content: I have never seen such a device commercially available.I have built one using laser cut acrylic and pogo pins specifically sized for an ATMEGA328P-AU.

author: Buriedcode
author_rank: Super Contributor
timestamp: June 16, 2016, 10:07:03 pm
content: Do you mean something like this?Found here:https://www.hobbyking.com/mobile/viewproduct.asp?idproduct=27195

author: Mr.B
author_rank: Unknown
timestamp: June 16, 2016, 10:29:28 pm
content: Very cool.That would have been a lot easier than my home built pogo pin solution.I have gone to Tag Connect for all of my designs now rather than the usual 0.1" header.

author: branjb
author_rank: Contributor
timestamp: June 16, 2016, 10:41:00 pm
content: Yup exactly what I was trying to find. Thanks!
Name of this chip? Google-help please :) - Page 1
Forum section: electronics / beginners

author: ViktorVS
author_rank: Newbie
timestamp: January 04, 2017, 01:09:23 pm
content: Hellosee pictureI found this chip inside a phone usb charger(NOKIA) and i wonder what it is for.. I've tried my best to find the datasheet on google, but i struggle, nothings matching!Do you have better eyes than me? Can you read the chip name?Do you have better googleing-skills than me? Can you find the datasheetor is the datasheet top secret?Or is this just a non-datasheet-needed-chip?-Viktor(beginner on this forum and in destroying electronics)

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 04, 2017, 01:11:33 pm
content: I see a + and a - on the top part, makes me think it is a bridge rectifier. Does it have 4 pins?

author: ViktorVS
author_rank: Newbie
timestamp: January 04, 2017, 01:13:37 pm
content: Yes, 4 pin indeed

author: TopLoser
author_rank: Unknown
timestamp: January 04, 2017, 01:16:48 pm
content: http://media.digikey.com/pdf/Data%20Sheets/Micro%20Commercial%20PDFs/MB05M~MB10M.pdfBridge rectifier

author: ViktorVS
author_rank: Newbie
timestamp: January 04, 2017, 01:22:13 pm
content: Thank you very much!
Name that chip - Page 1
Forum section: electronics / beginners

author: junkjer
author_rank: Newbie
timestamp: April 17, 2025, 08:48:30 pm
content: Hi-I'm new here, and not much more than an electronics newbie. Would anyone be able to help me identify and find a datasheet or other details for this chip?An image is attached (I hope).The markings are:NECC551E6S1DIt has ten pins, and in this application pins 1, 4, 7, 8, are not used. It's from a film camera circa 1975.I've tried a web search but have had no luck getting anything but garbage results.Thanks in advance.

author: amyk
author_rank: Super Contributor
timestamp: April 17, 2025, 09:27:26 pm
content: uPC551E is its likely part number, following the rest of NEC's convention.Unfortunately no hits in the databooks I could find either, but it may be an opamp - trace the circuitry around it and see how it's connected.

author: 5U4GB
author_rank: Super Contributor
timestamp: April 18, 2025, 06:16:04 am
content: I'd be more curious to know about the MDF-based circuit board technology they're using :-).

author: junkjer
author_rank: Newbie
timestamp: April 19, 2025, 02:13:16 am
content: amyk- Thanks, when I have some time over the next few days I'll try to examine the circuit around the chip. This came out of a camera circa 1975, the last in a line of aperture-priority automatic exposure cameras that were cutting edge in '66. This camera had an upgraded metering system using a silicon photo diode. My reading tells me SPDs need amplification, so it seems likely this chip is an op amp.5U4GB -- as this was the last in its line, I imagine not much money went into the design, so the circuit board was... cheap. In fact, the unit I pulled it from had nasty water damage throughout, and part of the board (not seen in the pic) had soaked up some water. Also around '75 the same company was making SLRs with surface mount chips and components on ribbon-like circuit boards. That's where the energy and money went, I guess.

author: junkjer
author_rank: Newbie
timestamp: April 21, 2025, 06:21:59 pm
content: And here's a look at the parts connected to the chip.
Name the connector - Page 1
Forum section: electronics / beginners

author: LostElectron
author_rank: Newbie
timestamp: August 14, 2019, 02:06:46 pm
content: Hi guys.I am having trouble finding the wire harness for a UART port.I have bought two connectors so far. So time for askingThe connector you cans see in the pics near the receptacle is 1MM pitch so at least I know I need a 0.8MM one.Do you guys think that a JST SUR will work?If so anyone have an idea where to find them (crimped and not by the 1000s)

author: Jwillis
author_rank: Super Contributor
timestamp: August 15, 2019, 05:37:03 am
content: Micro Mini JST I believe .

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: August 16, 2019, 04:16:14 am
content: JST-SH maybe? Aliexpress has a lot of them

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 16, 2019, 04:37:22 am
content: Agree that it is something like a JST connector. Relatively generic and widely available.However, a CRITICAL detail is the PITCH of the pins.EXACTLY what is the space between the pins?1mm? 1.27mm? 2mm?, 2.54mm? etc.Also, that keyway may indicate a custom connector.You may have to take the standard JST mating connector and file a groove for that key.

author: ledtester
author_rank: Super Contributor
timestamp: August 16, 2019, 05:40:11 am
content: Here's a chart of JST connector data:
Name this connector please - Page 1
Forum section: electronics / beginners

author: Zillolo
author_rank: Contributor
timestamp: November 29, 2013, 09:01:07 pm
content: Hello guys,I have seen this type of connector used everywhere, yet I've never heard it's name.Could anybody aware me of it please?Thanks in advance!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 29, 2013, 09:05:07 pm
content: Looks like a JST XH series

author: Zillolo
author_rank: Contributor
timestamp: November 29, 2013, 09:06:49 pm
content: Yep Google seems to confirm that.Thank you very much kind sir!

author: jamesb
author_rank: Regular Contributor
timestamp: December 03, 2013, 01:30:54 pm
content: I name it: "Bob"PS: Good call, Mike

author: Kremmen
author_rank: Super Contributor
timestamp: December 03, 2013, 03:33:22 pm
content: Dammit, too late. I was going to name it "Eric".
Mystery Module /Board For Radio Broadcast Device From '07...... - Page 1
Forum section: electronics / beginners

author: sos_radiogear
author_rank: Newbie
timestamp: October 14, 2024, 02:41:44 am
content: This module /board goes in some sort of commercial radio broadcast device. It has 160 resitors, thats all i know.... Any ideas? Thanks!

author: coppercone2
author_rank: Super Contributor
timestamp: October 14, 2024, 03:27:11 am
content: it looks like some kind of circuit board

author: radiolistener
author_rank: Super Contributor
timestamp: October 14, 2024, 04:09:30 am
content: maybe some IO board from old notebook

author: Jeroen3
author_rank: Super Contributor
timestamp: October 14, 2024, 06:08:57 am
content: Looks like a DAQ board, the LTC1605 for some analog channels and a bunch of digital inputs.

author: CaptDon
author_rank: Super Contributor
timestamp: October 14, 2024, 11:54:34 pm
content: Don't think it has anything to do with R.F. broadcast.
NAND gates open collector testing issue - Page 1
Forum section: electronics / beginners

author: gkmaia
author_rank: Frequent Contributor
timestamp: April 27, 2019, 07:36:39 pm
content: I am trying to test this NAND gate with an open collector.http://pdf.datasheetcatalog.com/datasheet_pdf/national-semiconductor/DM5438J_to_DM7438N.pdfIf you look at my images you will see when one of the gate inputs are LOW the output goes LOW.When both inputs are HIGH I should be getting a LOW input, but that is not happening.Obviously doing something wrong here. Can anyone give me a light?

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 27, 2019, 07:44:35 pm
content: I see nothing wrong here, your LED is connected to +5V so it will light when the output is low.

author: gkmaia
author_rank: Frequent Contributor
timestamp: April 27, 2019, 08:53:18 pm
content: Thanks for the answer. I appreciate.Can you please help me understand and confirm a few things?1 - Because it is an open collector gate my LED anode should be connected to +5v and the cathode to the gate output.2 - If it was NOT an open collector I would have to connect my led cathode to GND and the anode to the gate output.3 - On open collector gates when the output is LOW it allows the current to flow from +5v through the LED then out to GND.4 - On open collector gates when the output is HIGH it works is stops the current from flowing +5v through the LED then out to GND.Then one question:Why when the gate inputs are X (disconnected from either Vcc or Vss) my output is LOW?

author: rstofer
author_rank: Super Contributor
timestamp: April 27, 2019, 09:25:28 pm
content: Because you can't allow inputs to float. More often than not, they float high. On CMOS logic circuits they float to the mid-voltage level and the magic smoke pours out of the package.With TTL, you never want to pull upward. Even if you have a totem pole output, you would still organize the gate to pull the LED cathode down.Look at IOHand IOLon page 2: The low output (sink) current is 16 mA but the high output (source) is only 0.8 mA.https://www.jameco.com/jameco/products/prodds/49146.pdf

author: Nusa
author_rank: Super Contributor
timestamp: April 27, 2019, 09:28:49 pm
content: When an input is left unconnected, it's called "floating". Unless there's an internal pull-up or pull-down or has specific behavior defined in the datasheet, its state is indeterminate. It might be high, it might be low, it might switch unexpectedly. The ambient temperature or humidity might even be a factor.For your IC, the datasheet defines a LOW input as a max of 0.8V and a high input as a min of 2V. What voltage is an unconnected input?
deleted  - Page 1
Forum section: electronics / beginners

author: hem213
author_rank: Contributor
timestamp: July 14, 2024, 12:10:07 pm
content: deleted

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 14, 2024, 02:46:46 pm
content: Have you used it and do you have real problems with those VNA or do you want just to talk about a theory of VNA design?(I have LiteVNA64 just about three months and found it extra-usefull, especially for it's price. I have done a lot of work with it, a lot of R&D where you need VNA, and I have to say that for 100% I don't care which wavefom it uses if it does its work).
NanoVNA software language? - Page 1
Forum section: electronics / beginners

author: AnneRanch
author_rank: Contributor
timestamp: October 31, 2019, 04:56:04 pm
content: Whatsoftware languageis used in original NanoVNA analyzer ?The github clone has "Python" folder , but the code looks as plain C .

author: mikerj
author_rank: Super Contributor
timestamp: October 31, 2019, 06:35:08 pm
content: The firmware is written in C. The Python code is for controlling the device from a PC over USB/Serial connection.

author: AnneRanch
author_rank: Contributor
timestamp: October 31, 2019, 08:38:53 pm
content: Thanksbut the cloned folder containing C code is named Python.I have notchecked / verify the Python PC control code.I need to do more homework.

author: mikerj
author_rank: Super Contributor
timestamp: October 31, 2019, 09:50:48 pm
content: Where did you clone if from? Theofficial repositorydoesn't have any C files in the python folder.

author: AnneRanch
author_rank: Contributor
timestamp: November 01, 2019, 01:19:47 am
content: Cloned from the repository linked in last reply.The folder "Python" is in root directory.Screenshot from Eclipse attached.PSis there a way to copy clipboard to here ? Or is there a way to "attach" clipboard?

author: oPossum
author_rank: Super Contributor
timestamp: November 01, 2019, 03:08:41 am
content: Those C files are in root, not the Python directory.

author: AnneRanch
author_rank: Contributor
timestamp: November 02, 2019, 01:55:21 am
content: OK. mu mistake.How do I close this thread?

author: radiolistener
author_rank: Super Contributor
timestamp: November 02, 2019, 03:08:32 am
content: Quote from: AnneRanch on October 31, 2019, 08:38:53 pmfirmware is written in C."python" folder is not used for firmware, it just contains some python tools used for debugging"doc" folder also is not used for firmware, it just contains some files about NanoVNA, such as schematic, etc.You can delete "python" and "doc" folders, it won't affect firmware.
NBN fiber optic modulation scheme - Page 1
Forum section: electronics / beginners

author: merseyless
author_rank: Contributor
timestamp: October 13, 2016, 06:45:45 am
content: Hi All,Does anyone know what kind of modulation scheme is currently used in PON networks such as EPON or GPON?I'm doing an assignment for university on the different types of modulation schemes used in fiber optics and am having one hell of a time trying to find out what is being commonly used in these systems. It's easy enough to write about the advantages and disadvantages of the various different modulation types, but one hell of a mission to find out what is actually in use as I'm trying to link it all back to current systems and the hardware limitations.
Nchan Mosfet with AC on the Drain? - Page 1
Forum section: electronics / beginners

author: TheBaconWizard
author_rank: Regular Contributor
timestamp: September 05, 2018, 03:24:11 pm
content: Hi there,I am working with an AC waveform that has DC offset and never goes negative. It is a 500khz waveform going from 0v-1kv and I would like to attenuate it (from anywhere between peak and o) using a PWM signal to determine by how much and when. It is being generated in the first-place by a mosfet and gate-driver and then goes to an output (where a load will be placed) and finally, ground.Is there any way I could use a mosfet operated in its saturation region to sink that signal to ground before the load, to greater/lesser extent as desired, or is the AC nature of the current going into the drain always going to be a problem? Or could I maybe use the a fet as a variable resistor instead? Either way, we have AC at the drain (and therefore the source) and I don't know if there's a way to have that work.

author: thm_w
author_rank: Super Contributor
timestamp: September 05, 2018, 11:19:11 pm
content: Should be OK.I assume the capacitance of the FET won't be a significant load on the output waveform.If I'm understanding correctly a typical constant current load design will work, with some consideration for the bandwidth required.