hybridfree/eevblog-posts huggingface dataset:
Scope Loading? - Page 1
Forum section: electronics / beginners

author: cswanson
author_rank: Newbie
timestamp: October 16, 2014, 01:57:55 am
content: I have a circuit (5V DC) that takes a 1 Hz sine wave at 800 mVpp and amplifies it to 4.46 Vpp with a DC bias that puts the lowest swing just above +80mV. This works great.I send this output to a MCP3008 ADC which is an SPI slave to an Arduino Uno. The master does nothing more than query the MCP3008 for the current value and sends it to the serial output. (Note: I am powering the arduino with the 5V DC supply and it is connected to the computer USB for serial output. ) The output is an increasing and decreasing list of integers mapping to the voltage swing.This works great as well...as long as the scope probe is connected to the circuit's ground rail and the analog input pin of the MCP3008.If I disconnect the probe, I get a constant output of 868 or 869 on the arduino's serial output.The scope doesn't have to be on, but the probe must be connected to the scope. ( Scope is a Rigol DS2072A )I measured the resistance (1.2MOhm) and capacitance (3.3 uF) of the probe and tried attaching passive components to the MCP3008 input channel and circuit ground but it had no noticeable effect.What am I not considering?

author: Unknown
author_rank: Unknown
timestamp: October 16, 2014, 02:16:42 am
content: Without seeing the actual circuit you've built, it's impossible to say.Quote from: cswanson on October 16, 2014, 01:57:55 amAgain, without seeing the actual circuit that would've been the first thing I would've tried, but you've done it. But 3.3uF probe capacitance seems awful (as in "a few orders of magnitude") high...

author: ludzinc
author_rank: Unknown
timestamp: October 16, 2014, 02:33:03 am
content: "The scope doesn't have to be on, but the probe must be connected to the scope."Do you mean as long as the probes ground wire is connected, or as long as the probe tip is connected to your circuit.I've seen the former a lot - broken ground path, never the latter.

author: cswanson
author_rank: Newbie
timestamp: October 16, 2014, 02:54:47 am
content: @Tac Eht Xilef I was surprised too, I'll double check.@ludzinc The probe must be connected to the circuit and plugged into the scope. If I disconnect the probe from the scope I get garbage. Thanks for keeping me honest.

author: w2aew
author_rank: Super Contributor
timestamp: October 16, 2014, 03:16:49 am
content: Also sounds to me that the scope's ground lead is establishing a common ground between the Arduino and your ADC. Without the scope probe, one of them is floating with respect to ground.

author: cswanson
author_rank: Newbie
timestamp: October 16, 2014, 04:33:05 am
content: Cool.I'm planning to integrate the atmega328 MCU onto the breadboard, and I am currently replacing the serial output with a 7 segment display.So when I rid myself of the computer the problem should clear.Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 16, 2014, 06:33:26 am
content: Sounds like bad layout... pictures? Schematic?Tim
Scope noise - did I damage it? - Page 1
Forum section: electronics / beginners

author: Red Squirrel
author_rank: Super Contributor
timestamp: June 06, 2016, 04:18:32 am
content: A while back I accidentally connected ground to the wrong (+5v at many amps) side of a circuit. The probe went boom, it's dead. But now I'm starting to wonder if I damaged my scope in that process. I was using it (with another probe) to measure and noticed quite a lot of noise and did some troubleshooting and then it turns out even with no probes connected I get noise, that, and the 1st channel is not even centered. I hit the factory reset button to ensure everything is factory.The scope is a Siglent SDS 1072CML 70Mhz. Is this normal noise to expect on a lower cost scope, or is there something wrong here?

author: Dave
author_rank: Super Contributor
timestamp: June 06, 2016, 04:58:09 am
content: It doesn't look damaged to me.Your vertical scale is set pretty low (2mV/div), so the input signal gets amplified quite a bit before it gets passed to the sampling circuit. You're looking at about 0.5mVpp here, which is a perfectly normal number for an average scope. The slight offset you see on CH1 is also normal and could probably be removed if went into the menu and performed an auto-cal.

author: tautech
author_rank: Super Contributor
timestamp: June 06, 2016, 05:25:19 am
content: You appear to have created a ground loop with your previous error, most of us have made that error however just as member Dave has said perform a Self Cal and report back.But another thing I want you check with the DSO unplugged and powered down is continuity between all BNC's and mains earth.The substantial currents involved can fuse the Gnd connections inside a scope if they're not robust enough so do that quick check. I've never seen a SDS1000 series Gnd connections damaged in this way but I know Tek had to do a factory recall of their TDS510 and 520 early models for fused Gnd connections.

author: Red Squirrel
author_rank: Super Contributor
timestamp: June 06, 2016, 05:55:03 am
content: Thanks did not even think of trying that, that fixed it!Much less noise too... so some noise is normal then right?

author: Dave
author_rank: Super Contributor
timestamp: June 06, 2016, 06:38:16 am
content: Quote from: Red Squirrel on June 06, 2016, 05:55:03 amYup.
Scope probe - BNC connector fixable? - Page 1
Forum section: electronics / beginners

author: aneevuser
author_rank: Frequent Contributor
timestamp: September 10, 2019, 03:03:38 pm
content: I have a scope probe which seems to have a problem at the BNC end whereby the channel amplitude occasionally drops by about 50%. This can be fixed by wobbling it around a bit. It is definitely a problem with the probe and not the scope connector.Is this fixable or should I simply buy a new one?

author: Gyro
author_rank: Super Contributor
timestamp: September 10, 2019, 05:45:21 pm
content: A photo would really help.If it's a probe with a compensation box attached to the BNC then it's quite likely that the solder joint between the BNC centre pin and the PCB has fractured. If you can get the box apart then it should be an easy fix.If the BNC is just on the end of the cable, it might be more difficult. You might get away with replacing the BNC (almost certainly a crimped one under the rubber boot) but the lead inner conductor might be made of a resistive alloy and difficult to solder.If it's a cheap probe then there's not a lot to loose in experimenting, worst case you have a spare clip for a new one.

author: aneevuser
author_rank: Frequent Contributor
timestamp: September 11, 2019, 10:10:18 am
content: I'll put up a picture later. However, the problem seems to be at the joint on the BNC that allows rotation - it seems somewhat loose, but I can't see how to take it apart to look more closely - it doesn't seem possible to remove the rubber shroud on either side, at least without significant force.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 11, 2019, 10:59:28 am
content: i've cut and replaced with china BNC of my earliest Rigol DS1000E probe, put small box enclosure around it to make neater appearance and all. my work is not super signal integrity in mind, made out of BNC that is meant for wall mounted but its working as it were, but lately it develop back its intermittent disconnection as you experienced, it must be something with my workmanship and durability. the center conductor is very thin you need great care protecting it during your diy repair. if you dont want to waste time and have the money, just buy new. look for china cheap $20 probe review around here, they are ok if you are really tight.
Scope PSU sag when my 6-GPU rig shuts off? - Page 1
Forum section: electronics / beginners

author: marked23
author_rank: Newbie
timestamp: September 20, 2025, 04:50:02 pm
content: I've got a computer with 2 PSUs and 6 GPUs. PSU1 runs 3 GPUs. PSU2 runs 3 GPUs, and motherboard, CPU, fans. When I do a big ML training run, sometimes the whole system just shuts off instantly. I'm guessing that PSU2 is giving up.I hooked up my Siglent 1104X-E with 3 probes:Probe 1 → 12V rail at a GPU powered by PSU1Probe 3 → 12V rail at a GPU powered by PSU2Probe 2 → 12V rail directly at PSU2What's the best way to set up the scope so I can actually catch the sag/shutdown? Falling edge trigger on 12 V? Something else? Any tricks for seeing a little before and after the drop?

author: bte
author_rank: Regular Contributor
timestamp: September 20, 2025, 08:23:33 pm
content: You could check the PSU "Power Supply Good" signal.https://en.wikipedia.org/wiki/Power_good_signalIf it goes low, the motherboard shuts the system down. Since PSU2 runs the mobo, you could check the Power Good signal on that. To see a little bit before and after, you could trigger on the Power Good signal with the other channels monitoring the 12V lines.You could also buy a (cheap) logic analyzer so that you can monitor 16 channels at once (using another PC). The SLA1016 Logic Probe for your scope is also an option but it's a bit expensive and it may not be the best experience to observe many channels on the small scope screen (compared to a PC monitor).
Scope trace assistance - Page 1
Forum section: electronics / beginners

author: Lee697
author_rank: Regular Contributor
timestamp: July 29, 2014, 03:40:04 am
content: Hi allI set up a current shunt in series with a fuse - the 3A fuse was a sacrificial one, testing in place of a rocket igniter (much cheaper!).The shunt is 2A/50mV, and the switching is accomplished by a BUZ71 MOSFET.The trace seems to show the fuse allowing about 14A to pass before blowing after 40ms. Actual igniters draw 7-11A, depending on the resistance of cabling hooked to them.I did this a number of times with other fuses (1A though) - this was the only time the large spikes appeared at the ends of the trace like this - does anyone know what these are from?This was hooked up to an Array 14.5A PSU - I wondered if it had something to do with current limiting by the PSU itself?Thanks for any advice...Lee

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 29, 2014, 03:47:45 am
content: Most likely wiring inductance generating a spike when the circuit opens. If you have a few more fuses to burn, you might set trigger level below 0V, trig mode NORM or SINGLE, and time/div around a few microseconds. It's probably even taller than you can see here, it just didn't happen to sample the very peak. The spike will be more exaggerated in the voltage across the fuse or ignitor, whichever one causes the circuit to open.Tim

author: Lee697
author_rank: Regular Contributor
timestamp: July 29, 2014, 04:00:54 am
content: Thanks - come to think of inductance - the shunt is coil like - I suppose that would contribute?
Scoping with diff probe and normal probe? - Page 1
Forum section: electronics / beginners

author: Faringdon
author_rank: Super Contributor
timestamp: November 09, 2023, 08:29:48 pm
content: Hi,Supposing you are probing on the AC side of an offline SMPS. (its supplied via isolation transformer)You are scoping two pulse type signals, one with the diff probe, one with a DIY coaxial probe which obviously connects the scopes earth to the PCB.The non diff probe is the trigger source.Have you ever heard of the diff probe signal jittering back and forth in time due to some Earth loop noise in the scope?Basically we have two such signals, and the diff probe one should be "in phase" with the other signal...and it kind of is...but its "dancing about" ("jittering")....moving back and forth each trigger over some 20-40us.Could this be due to scope noise?There is a way i can get a scope of both pulses (well, one pulse will be a "representation" of the pulse that i really want) using two of the non diff probes, so i will try that to see if that still "dances". So the probes will be grounded to the same place to see if we still get this "dancing", or "jittering.

author: tooki
author_rank: Super Contributor
timestamp: November 09, 2023, 09:03:06 pm
content: I dunno, get two identical galvanically isolated differential probes and see how it looks?Or ask your local test gear rep to loan you a galvanically isolated scope (like a ScopeMeter, ScopeRider, etc).(The Rohde & Schwarz rep just picked up the loaner ScopeRider I had. Nice little piece of gear.)

author: Gyro
author_rank: Super Contributor
timestamp: November 09, 2023, 09:23:25 pm
content: Another post in the Faringdon/Treez double post series!https://www.eevblog.com/forum/projects/probing-noisy-signals-to-the-scope/msg5145801/#msg5145801

author: Terry Bites
author_rank: Super Contributor
timestamp: November 10, 2023, 11:15:57 am
content: Yes, a blanking pulse is required......

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2023, 02:23:29 am
content: Quote from: Faringdon on November 09, 2023, 08:29:48 pmThe differential probe has limited common mode rejection, especially at higher frequencies, which will allow common mode noise from the ground connection to appear as a signal.QuoteAnother way is to connect the normal probe to a small coil of wire and use that as a pickup for the AC trigger signal.

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 10:08:02 am
content: Quote from: Terry Bites on November 10, 2023, 11:15:57 amGiven that faringdon "thanked" that post, I suspect he didn't understand it
SCR as fuse - Page 1
Forum section: electronics / beginners

author: Sigmoid
author_rank: Frequent Contributor
timestamp: July 29, 2013, 01:47:51 am
content: The fact that SCRs "stay on" as long as there's current through them got me thinking...Fuses are kinda slow, expensive, gotta change them after they've blown, etc... So I'm wondering if an SCR could be used as circuit protection instead! My idea: connect an SCR and a resistor in series, and connect this up to the positive and negative rails... When it gets gate voltage, it just shorts the power rail down to ground, poof!Gate could be driven from an op-amp hooked up somewhere buffering some voltage level or current flow converted to voltage, with the output through a Zener to define the blow voltage limit...What I'm wondering about is the reliability of this setup... Is it a good idea for low-voltage systems?

author: c4757p
author_rank: Super Contributor
timestamp: July 29, 2013, 01:52:30 am
content: You just described either the first or second most common use for an SCR. But what exactly do you think is going to go "poof"? The resistor? In that case you just made it into a fuse, why not use a proper one?

author: Jeff1946
author_rank: Regular Contributor
timestamp: July 29, 2013, 02:00:29 am
content: google crowbar

author: TerminalJack505
author_rank: Super Contributor
timestamp: July 29, 2013, 02:01:06 am
content: Such a circuitmightprotect the load and, if you're lucky, blow a mains breaker. If you're not so lucky then your house burns down.With the exception of the missing fuse, it sounds like you are talking about a crowbar circuit. They're used to protect a load from (typically) over-voltage conditions. They do this by shorting the power rail (with an SCR, typically) and blowing anon-boardfuse.

author: Sigmoid
author_rank: Frequent Contributor
timestamp: July 29, 2013, 02:05:33 am
content: Yea that sounds reasonable...I guess it'll help you get away with using a slower, bigger fuse that costs a lot less.

author: c4757p
author_rank: Super Contributor
timestamp: July 29, 2013, 02:06:57 am
content: Fuses aren't expensive for the level of protection and certainty they give you, and if you design the device and spec the fuse correctly, it will never blow. Just use a fuse.
SCR based dimmer on lamp with logic ciruit - Page 1
Forum section: electronics / beginners

author: CBP
author_rank: Contributor
timestamp: November 27, 2015, 08:02:32 pm
content: Hi AllI have a disco/stage lighting piece of equipment, it has a big toroidal transformer with a 24V tap for the 250W lamp and a 12V tap for the logic control board. This board has a 7805 with a PIC on it and a load of darlington drivers that move some motors for colours/patterns/mirrors. The lamp and motors are separate circuits.I would like to dim the lamp on the unit because it does not have the ability to dim it. I have one of these dimmer boards I had some time agohttp://www.dx.com/p/2000w-scr-voltage-regulator-module-dimming-motor-speed-controller-thermostat-142344#.VlizwfnhCM8(not for this purpose, was just another spurious DX purchase). That module only suggests that it works from 50V upwards, I was wondering what everyone's thoughts would be on dimming the main AC line?I have a little bit of knowledge but they say a little knowledge is dangerous! My thoughts are if the SCR dimmer 'chops' the AC wave then provided the dim level does not go to the level below that of the regulator drop out then will the power to the control board not be unaffected by the dim level of the lamp? The control board has a bridge rectifier on it then my thoughts would be that it would provide stable DC power whilst the AC power is not a 100% sine wave.Can I ask what peoples thoughts on this are? Am I wide off the mark?Thanks

author: Seekonk
author_rank: Super Contributor
timestamp: November 27, 2015, 08:40:31 pm
content: I doubt that it is a SCR from board layout, looks triac. Don't think it would be hard to mod but it is at the extreme of the current limit. Trace it out.
SCR max current ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 22, 2019, 11:25:03 pm
content: I don't own any SCR (that I know of) but I want some to try a crowbar circuit in an adjustable linear PSU. Checking ebay they start at 400V, 2A. I'm wondering if your max voltage is way way way lower, say 12V, can u go way over the 2A current max ? How is power calculated in these ?

author: dmills
author_rank: Super Contributor
timestamp: February 22, 2019, 11:41:07 pm
content: That's not the way any switching device works!An SCR is (simplifying outrageously) either non conducting in which condition it stands off lots of volts but passes essentially zero current, or conducting in which case the voltage is 1V or so and however much current is required to make that be a thing flows.Rule of thumb : Each maximum rating is independent, you need to satisfy all of them at all times.Now there are some parts that operate in the linear region, where things can get even more complex and there are some other limits that can be quite a bit lower then the ones on the front page of the datasheet that must also be complied with.... (And SCRs I would note have some dynamic limits as well, things like a maximum dI/dt value).Regards, Dan.

author: Totalsolutions
author_rank: Contributor
timestamp: February 22, 2019, 11:48:30 pm
content: 2Amps is 2 Amps. 400volts is the upper voltage limit the poor little device will hold back. So your 12 volts is ok in spec.
Scr power controler. Help - Page 1
Forum section: electronics / beginners

author: johnnyH
author_rank: Newbie
timestamp: October 11, 2018, 02:04:07 am
content: Hi. I am trying to resurrect a Pool chlorinator. I have the centre tapped transformer and and the power board which has 2 scr's and myriad unwanted circuitry. The SCR's are JIE JCT6055/8055 series. Vdrm 600V .It rms 55A and Igt = 10-50mA. I am trying to make a simple regulated supply for the chlorinator plates. I do not need all the control gear ie. timer , reversing , low salt etc. I have come up with what I think would work however I am unable to work out the values of the resistors, capacitors and diodes. also I'm not sure weather to use diodes D3 and D4 to bridge as shown in the drawing. can anyone help me with the values and indeed if they think it will work satisfactorily. any suggestions would be much appreciated. Diagram attached.
Scrap gol and silver - Page 1
Forum section: electronics / beginners

author: Dbeaver
author_rank: Newbie
timestamp: April 29, 2018, 04:23:48 pm
content: Wondering if anyone can offer suggestions, i have aprox 7200 gold plated silver contacts on copper from relays, trying to get silver and gold seperated, by hand is taking forever. Had them tested and are 25% gold and 65% silver each contact weight of each is approx .206 grams

author: dmills
author_rank: Super Contributor
timestamp: April 29, 2018, 04:31:53 pm
content: Amalgam the gold with Hg then heat the amalgam to boil off the mercury?Do it in a sealed system with a water cooled condenser to recover the Mercury for reuse.....IIRC there is also an approach using an CN salt, but that may actually be MORE dangerous then the mercury amalgam approach.There is an odd little corner of US Ebay fascinated by this stuff, fairly sure just selling the pins there will get you more then the gold is actually worth.Regards, Dan.
Screen capture from RIGOL DG1022 function generator - Page 1
Forum section: electronics / beginners

author: peterv6i
author_rank: Newbie
timestamp: February 13, 2017, 06:41:39 pm
content: Hi, this is my first post on this forumIs there a way to save screen shoot from a function generator RIGOL DG1022?On some web pages I have found this picture:It's exactly what I want but can't find any optio to store current screen from function generator to my usb key.Does DG1022 support screen capture?

author: tron9000
author_rank: Frequent Contributor
timestamp: February 14, 2017, 09:37:14 am
content: Good Morning;please introduce yourself here first -https://www.eevblog.com/forum/chat/new-member-please-introduce-yourself/?topicseenI think you need the rigol ultrawave application and connect it up to a PC to get screen grabs.
Screen sync problem in HX8357-C LCD - Page 1
Forum section: electronics / beginners

author: teslasystems
author_rank: Newbie
timestamp: September 10, 2023, 02:38:56 pm
content: Hello!I'm currently trying to learn a communication protocol of an HX8357-C based LCD (attached its photo) and connected it to PIC18 MCU. I understand, that it's not a good choice, because these MCU series don't have enough performance to achieve an adequate FPS rate, but it's all I can do for now and it should be enough for testing purposes and draw some simple stuff at 1 FPS, for example. So, I started from implementing a simple function - filling a whole screen with some color. I have used a "standard" initialization sequence, which can be found in many libraries for this screen and have written a code, which updates the screen with some color 1 time per second. It works, but I see, how the screen is filling from the top row to the bottom in real time. The filling itself takes about 63 milliseconds. It's obvious, that the controller performance should be much higher, but the problem is that the screen update is not synchronized with GRAM update and the higher performance MCU won't solve it. I also found a "tearing effect" function it the datasheet for HX8357 chip, which, if I understand correctly, may send a synchronization signal to MCU, but, as you can see from the photo, TE signal is not available in this module. Is there anyone, who worked with this one or some similar LCDs and knows how to solve the problem?[ Attachment Invalid Or Does Not Exist ]Upd: sorry, I can't add an attachment for unknown reason. The LCD module has power pins, data pins [DB15..DB0], reset signal (RESX), chip select signal (CSX), Data/Command signal (DCX) and write clock signal (WRX).
Screened power cable question - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: February 24, 2017, 11:51:24 am
content: I have Googled this, honest!!Naive question, say I want to screen a 12V supply to a PCB from a bench supply 5 feet away. Can I use simple co-axial cable, say RG-58 with -ve on the braid and +ve on the inner? Or do I need at least a two core cable with the braid grounded and +ve and -ve on the two cores? I am dubious which is better as the -ve 12V supply is ground anyway... Thanks. My goal is ensuring the 12V supply cannot pick up the large amount of RF floating about when I TX. Low frequency stuff, 136kHz. Yes, this damned amp I often post about still....

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 24, 2017, 12:36:57 pm
content: Is your "large amount of RF" being INDUCTIVELY coupled into the power wiring? If so, it is indeed very strong and using shielded cable won't help. But if it is CAPACITIVELY coupled, then shielding MAY help depending on other factors not in evidence here. Perhaps we should also ask why you don't simply consider using proper entrance filtering at the load end of the power wiring? That way you wouldn't be dependent on using a particular kind of wiring. Without knowing the full picture (and what "large amount" means), it can only be discussed in very general terms.

author: bharatcs
author_rank: Contributor
timestamp: February 24, 2017, 02:49:10 pm
content: HelloYou don't need need a co-axial cable here its not designed to carry power.Just use a twisted pair wire or get creative and make your own,simply twist two long wires one around the other
Screened versus co-axial cable for LF signals? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 06, 2016, 07:40:04 am
content: I ran out of single core screened cable the other day, when wanting to take 2 analogue wheel speed sensor signals from the input of a car's ABS unit to an aftermarket ECU as its traction control signals. I had a reel of RG-174 co-ax around, could I have used that instead? The extension to the aftermarket ECU fro the ABS ecu would have been about 3 feet for each of the 2 signals. From this article attenuation wouldn't be a problem, but could any other issues have arisen?http://www.dxing.info/equipment/rg_174_coax_bryant.dxThanks.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 06, 2016, 09:17:23 am
content: Coax is better than screened.

author: Zero999
author_rank: Super Contributor
timestamp: August 06, 2016, 12:18:44 pm
content: Single core cable and co-axial cable are really the same thing. The only different could be that cable sold under the name co-axial will have a more tightly controlled characteristic impedance and lower attenuation at high frequencies.

author: David Hess
author_rank: Super Contributor
timestamp: August 07, 2016, 03:50:17 am
content: Unless a difference in capacitance per foot was an issue or there was some special environmental requirement which the RG-174 did not meet, I could not see there being a problem. I usually use RG-174 in place of dedicated microphone and audio cable.

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 07, 2016, 07:46:17 am
content: OK, thanks a lot everyone, I may just use RG-174 in future as it seems to be a better braid coverage than most single core screened cables I find, and it's no longer expensive. Much appreciated and I am glad I asked.
Scrounging Parts......? - Page 1
Forum section: electronics / beginners

author: Simon_RL
author_rank: Regular Contributor
timestamp: January 19, 2020, 08:18:38 am
content: I have a bunch of old router and stuff like fetch TV boxes, all in good condition but out of date so not worth selling. I want to disassemble for them for parts part. There are lots of SMDs and other parts that I will no doubt use at some point.I have watch quite a few videos about IC removal, but they all assume that the IC being removed is faulty, so I am not sure if the method is correct for healthy ICs.What I want to know is if I use my heat gun (Atten 858D+) does it cook the ICs or will hey still be usable?If the heat gun is not the best method for lifting ICs I want to keep, what is the bet way to lift them?Thanks.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 19, 2020, 08:55:34 am
content: I prefer to let them stay on the PCB until they are needed, because by seeing their place on the PCB and the nearby components it's easy to identify which are for RF, which for filtering, which for audio, and so on.There is no problem desoldering ICs with hot air, but a preheater will help a lot.

author: kripton2035
author_rank: Super Contributor
timestamp: January 19, 2020, 09:30:25 am
content: +1 for the preheater.if you want to remove parts on a 4+ layers pcb with big ground planes, it's almost impossible to do it without killing the part.with a preheater, no problem, set it to some 200°C for 10 mins and then use the heatgun @ 360°C it will pop up within some seconds.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 19, 2020, 10:20:16 am
content: Forgot to write, if parts are left on the PCB, then a full block can be reused, either by cutting the traces and rewiring it, or simply by cutting out the PCB around the block to be reused. For example power regulator ICs with nearby resistors and filtering capacitors, audio (pre)amplifiers IC with nice ground plane PCB and proper layout, and so on.Sometimes it works cutting simply with a pair of snipers, or with metal sheet cutting scissors.When cutting the PCB with power tools, a respiratory mask or other method for avoiding inhaling fiberglass dust should be used.

author: Simon_RL
author_rank: Regular Contributor
timestamp: January 19, 2020, 10:52:41 am
content: Quote from: RoGeorge on January 19, 2020, 10:20:16 amSounds like a job for my trusty Dremel
Scullcom function generator - component functions ? - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: May 05, 2019, 08:29:56 am
content: HiWhat is the purpose of C21 and R33 ?Thanks

author: oPossum
author_rank: Super Contributor
timestamp: May 05, 2019, 09:35:48 am
content: Reduce noise from the power supply getting in to the output.

author: bd139
author_rank: Super Contributor
timestamp: May 05, 2019, 09:47:42 am
content: C21 is a decoupling capacitor. It reduces the impedance at AC on the junction of R33 and R15 therefore establishing a stable voltage there. The amplifier looks like a summing amplifier so this reduces the “wiggle” on the DC offset input at DC and allows AC to float on that DC level. At DC the capacitor is effectively open.You can model this by drawing the circuit twice. Once with the capacitor shorted (at DC) and once when it’s open (at AC) and think about each case independently.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: May 05, 2019, 09:14:16 pm
content: Thanks guys.
SD and interrupts - Page 1
Forum section: electronics / beginners

author: Yaro
author_rank: Contributor
timestamp: March 19, 2015, 10:33:35 am
content: Hi all,I'm looking for a method do storage data from sensors. I've tryed Flash RAM but I encountered an issue in the writing becouse if my interrupts starts when I'm erasing blocks or writing on RAM it cause wrong data recording.I want to ask if I can encounter the same problems on SD cards.Also, I want to ask writing speed on SD and if, without SD interface, If there is a library that use GPIOs to communicate with SDs.

author: 6thimage
author_rank: Regular Contributor
timestamp: March 19, 2015, 01:09:21 pm
content: That sounds like a problem with your code rather than an issue with using flash memory.However, SD cards offer many advantages over chips. You can interface with them in two ways - using either a SPI or SDIO bus. Which one you will want to use depends on which microcontroller you are using - some have a built in SDIO interface, which makes life easier. If your microcontroller doesn't have a built in interface, SPI is the way to go. To avoid any problems with your interrupts, it is best to perform the write and reading using DMA.The write speed depends on the operating frequency of the bus, but for the SPI interface it maxes out at around 120 kB/s. For the SDIO interface it is the write speed of the card - which maxes out at 10 MB/s.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: March 19, 2015, 03:27:41 pm
content: I don't know about your MCU, but on the MSP430 (where most of my experience is) you have to disable interrupts when you start erasing/writing to flash to prevent corruption. It's step one in all of the guides and examples.
SD card wear - Page 1
Forum section: electronics / beginners

author: DG41WV
author_rank: Regular Contributor
timestamp: September 28, 2019, 01:07:47 am
content: Hi guys,In a project I'm doing I am using an SD card to store log files. my question is is does writing to the SD card frequently(small strings of <100B) vs writing large blocks (a buffer of few KBs) at once infrequently make any difference to the durability of the SD card?

author: drussell
author_rank: Super Contributor
timestamp: September 28, 2019, 01:28:38 am
content: Flash writes in blocks of typically atleast4k at a time, so if you constantly write tiny writes of say, 100 bytes, it has to write at least that whole 4k+ block each time you write.... Yes.Constant writes like that will reduce usable write durability.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: September 28, 2019, 07:12:39 am
content: Make sure you are using wear leveling. Serial Peripheral Interface Flash File System supports this. I'm not sure how you are accessing your flash though.

author: iMo
author_rank: Super Contributor
timestamp: September 28, 2019, 07:35:46 am
content: All today's sdcards do the wear leveling automatically. Therefore the write latencies up to 200ms.The endurance of the flash memory inside a mainstream 8GB sdcard could be something like 5000 writes max.Thus your sdcard will wear out approximately in:Time = 8GB / 4kB * 5000 / F, where F is the frequency of your 100bytes writes.For example writing 100bytes 1000x per second will wear out the 8GB sdcard in aprox 10.000.000 seconds.PS: Mind the flash memory cell endurance (number of writes till it wears out) varies with the density (Gbytes on the chip) and flash technology used. It could be something between 1000 - 5000 writes. Typically the bigger the card the smaller the write endurance. Consult your sdcard's manufacturer.
SDG2042x a problem for me. - Page 1
Forum section: electronics / beginners

author: Bangu
author_rank: Newbie
timestamp: September 29, 2016, 09:00:50 am
content: Greetings to all,I am a true Newbie and I'm trying to do the editing software to get to 120MHz with Siglent SDG2042x.The whole procedure works ... but when it comes to ESC (after deleting the line <LICENSE>) the ability to add "WQ" does not appear to me .....You can kindly help me?Thank you all.BanguP.S.In this forum there is a place to introduce yourself?

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2016, 09:26:33 am
content: Welcome to the forum.I can't advise as I've never tried it but you can find the details early in this thread:https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/There will be some that have applied the improvementthat are sure to help you if you can't find what you need, just ask for advice in that thread and members will see your post.Good luck.

author: Bangu
author_rank: Newbie
timestamp: September 29, 2016, 10:41:05 am
content: Thanks Tautech.

author: Aeternam
author_rank: Unknown
timestamp: September 29, 2016, 11:17:41 am
content: Hello Bangu,The "wq" doesn't popup anywhere, it is a command you have to type. So you press , the cursor should jump to the bottom of the window, then you type "wq" and press . This writes the modified file to disk and exits the editor.Hope this helps.

author: Bangu
author_rank: Newbie
timestamp: September 29, 2016, 11:32:05 am
content: Aeternamthank you very much for your availability.I try again this evening.Unfortunately I am not a Linux user and are too old to start studying...Thanks
sdram autorefresh  ?? - Page 1
Forum section: electronics / beginners

author: 5282
author_rank: Regular Contributor
timestamp: November 30, 2016, 01:56:17 pm
content: self refresh the row address is increment by internal oscillator.so1- in auto refresh the row address is increment by internal oscillator or my external clock in ?2- in auto refresh row address increment internal automatically counter or i change row address by external command?3- auto refresh need minimum time or minimum clock cycle to endbecause i find in data sheet it need minimum time not minimum clock cycle ?4- precharge command can use it instead of auto refresh. if i will not use all sdram size capacity . to refresh some little row in bank

author: 5282
author_rank: Regular Contributor
timestamp: December 02, 2016, 08:38:04 am
content: are there problem in my question it is not clear ?
Sdram speed on fpga eval board - Page 1
Forum section: electronics / beginners

author: aussie_laser_dude
author_rank: Contributor
timestamp: April 12, 2020, 10:48:20 am
content: Hi allI'm pretty new to electronics / FPGAs and am trying to get my head around sdram transfer rates.1. I've got a de0 nano fpga evaluation board that comes with a sdram (32mb) chip. I want to know how quickly I could write 10,000 bits from the fpga to the sdram or vice versa. Just looking for ballpark numbers.(Edit: here's my guess: 16 data wires x 100 MHZ PLL clock Freq = 200Mbps transfer speed. I have no idea if this is what actually occurs?)2. What is the latency between asking the sdram for data and getting the data? 1 clock cycle? 10 clock cycles? Just looking for an estimate again.I'm trying to make an fpga controlled digital phosphor oscilloscope, waveform data needs to be converted to vga pixel data to view, the data streaming through the fpga is pretty high and data storage is also high which makes this a challenging project.Thanks guys 👍

author: aussie_laser_dude
author_rank: Contributor
timestamp: April 13, 2020, 01:32:02 am
content: Nevermind I found this forum post:https://www.eevblog.com/forum/microcontrollers/calculating-sram-write-speed/Appears it's something like 100Mbps with 10ns write cycle.
SDS1104X-E FFT: Help explain noise floor - Page 1
Forum section: electronics / beginners

author: catcream
author_rank: Newbie
timestamp: June 17, 2024, 11:16:55 pm
content: Hello, I tried using the FFT function on my SDS1104X-E to measure a 1kHz+5kHz sine signal from my Dayton Audio DATS v3 for any distortion. I see the noise floor decreasing as frequency increases, and also noise between the two spikes (1k-5k) often sit at -40dBV but sometimes drop to -50dBV at certain frames.My guess is that the DATS has a THD less than measureable by 8 bit and I'm only seeing the oscilloscope noise floor, however I'm still curious as to why it looks like this, especially the -40 to -50 dBV thing. Can anyone explain this?Also, can I use my Scarlett 2i2 gen 4 for audio measurements? (+0.1x or something-resistor voltage divider for amplified signals). I'd like to see THD and also make bode plots for op amp based filters/crossovers. Thanks!

author: aliarifat794
author_rank: Regular Contributor
timestamp: June 18, 2024, 07:16:49 am
content: The fluctuation between -40 dBV and -50 dBV could be due to various factors such as environmental noise, slight variations in signal input, or the oscilloscope’s internal noise characteristics.
Seagate Barracuda 2GB Hard Drive Controller - Page 1
Forum section: electronics / beginners

author: agarg_1
author_rank: Newbie
timestamp: January 15, 2024, 06:28:58 am
content: I took apart a non functioning 2GB harddrive. I wanted to tinker around and see if I can troubleshoot any faulty components. I came across this component that I don't recognize. Is it a diode? Feel free to identify other things as you see fit. I see the obvious resistors and a couple of diodes ..others I am not so sure

author: magic
author_rank: Super Contributor
timestamp: January 15, 2024, 08:55:13 am
content: Looks like one.It could bethistype. I simply searched for "33L 26 M diode datasheet".As for the rest, you have obvious SMD resistors and ceramic capacitors, diodes in similar packages to the above, inductors. The rest is ICs which need to be identified by their markings.
Deleted , of no use - Page 1
Forum section: electronics / beginners

author: GEuser
author_rank: Frequent Contributor
timestamp: September 19, 2014, 05:53:01 am
content: q

author: Unknown
author_rank: Unknown
timestamp: September 19, 2014, 06:24:15 am
content: Quote from: GEuser on September 19, 2014, 05:53:01 amThe short answer: In terms of usable capacity, almost none. Any voltage over and above that required to keep the battery floated is simply wasted in excess gassing / heat.(edit: Personally, I wouldn't float a SLA meant for stationary use at any more than 2.27V/cell @ 25 degrees C e.g. 13.6V for a nominally 12V battery. But that's an opinion based on many years of looking after the damned things in telco applications, and will differ slightly with the exact materials & construction used.)
Sealing/Potting goo recomendation  - Page 1
Forum section: electronics / beginners

author: daqq
author_rank: Super Contributor
timestamp: May 29, 2013, 08:12:54 am
content: Hi guys,For a project we need a sealant or potting goo. The one that was shown in the teardown of the insulation meter (http://www.eevblog.com/2013/05/08/eevblog-468-uni-t-ut513-insulation-resistance-meter-teardown/, time ~19:00). Does anyone know the specific product used there?We'd like to use the rubbery type, not epoxy - if needed servicing should be an option - so it should be clear also.Thank you,David

author: ddavidebor
author_rank: Super Contributor
timestamp: May 29, 2013, 09:55:48 am
content: Get a look at the 3M catalog

author: Paul Price
author_rank: Super Contributor
timestamp: May 29, 2013, 02:01:05 pm
content: Use GE 100% silicone rubber, available at your local hardware store in large cylindrical tubes. It generates some acetic acid when curing that could upset your apple cart, so be careful to allow the curing process to complete before device activation.

author: Psi
author_rank: Super Contributor
timestamp: May 29, 2013, 02:04:25 pm
content: Speaking of potting goo.Does anyone know of any that is transparent and thermally conductive?

author: JackOfVA
author_rank: Unknown
timestamp: May 29, 2013, 02:45:58 pm
content: Quote from: Paul Price on May 29, 2013, 02:01:05 pmIf you use RTV, a neutral cure version, such as Dow Corning 732, is safer around electronics.

author: Smokey
author_rank: Super Contributor
timestamp: May 30, 2013, 04:22:06 am
content: When choosing conformal coating, I usually pick the most toxic one. That has to be the bestI don't know about transparent, but there are some really great thermally conductive adhesives made by the loctite guys.

author: daqq
author_rank: Super Contributor
timestamp: June 20, 2013, 08:04:36 pm
content: Thanks for the replies, they were very useful!

author: peter.mitchell
author_rank: Super Contributor
timestamp: June 21, 2013, 09:14:12 am
content: Quote from: Smokey on May 30, 2013, 04:22:06 amThey are quite good, so good infact I used some in an enclosed space one weekend and had a terrible cough for months!

author: Smokey
author_rank: Super Contributor
timestamp: June 21, 2013, 05:18:07 pm
content: lungtite..

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 21, 2013, 08:13:40 pm
content: Quote from: Smokey on June 21, 2013, 05:18:07 pmYeah. For God's sake don't sit on it!
Searching for a Camera That Can Automatically Turn Toward Motion - Page 1
Forum section: electronics / beginners

author: JOSDHO
author_rank: Contributor
timestamp: April 22, 2025, 08:56:21 am
content: I’m helping a customer who is looking for a camera that can automatically rotate or tilt toward the area where motion is detected. She has a very specific reason for needing this kind of setup, and it would make a big difference for her use case.If full auto-tracking is not possible, a system where she can at least move the camera manually through a phone or tablet once motion is detected would still be helpful.I’m not very familiar with this type of gear, so any suggestions or advice would be greatly appreciated. Thanks for any help!

author: darkspr1te
author_rank: Frequent Contributor
timestamp: April 22, 2025, 09:36:01 am
content: Just google Auto-tracking PTZ camera, quite a few on the market.heres a examplehttps://cctvguru.com.au/collections/auto-tracking-cctv-cameras?srsltid=AfmBOor8fbydiV7zYx-q8GVbz51kzm1X0Cd_sg6SZj4E3rdqLakwSTVadarkspr1te

author: 5U4GB
author_rank: Super Contributor
timestamp: April 22, 2025, 12:33:56 pm
content: If you want a known brand then Hikvision do PTZ cameras with two lenses, a fixed wide-angle that captures the entire FOV and looks for motion and a standard PTZ lens that follows the object being tracked. They do a pretty good job of following things around.
Searching for a cheap power slide switch - Page 1
Forum section: electronics / beginners

author: Solenoid
author_rank: Newbie
timestamp: April 25, 2013, 06:17:54 pm
content: I'm building a power supply module for our robotics kit and it needs a small power switch, I'd like to use a slide switch, but I can't find a cheap one under $1.The rating should be above 12V and 3A, which is quite a lot. I've only found small switches capable of30V/0.3Aand such, but I need more current for my system as it has an included H-bridge and servo motors that consume quite a lot of power.This slide switchwas the best I was able to find on Mouser at 6A, I'm not limited to Mouser, but I'd like to source all from there, of course I won't limit myself if there are better alternatives elsewhere. The form factor is also important, is has to be quite small to fit on the PCB (such as the examples above).Can anybody advise? Or at least confirm that I won't find much better.
Searching for a good power supply, low volt, high amp - Page 1
Forum section: electronics / beginners

author: kenny_ken
author_rank: Newbie
timestamp: May 24, 2016, 06:51:36 pm
content: Hello there, fellow electronic afficionados!For a project I need a power supply, which fulfill these criterias:About 8 VoltUp to25 AmpsAs small as possibleI used those famous MeanWell PSUs for quite a long time and I'm happy with them, but I didnt find one which fits my needs. They're either too bulky or too weak.I don't really have a exact size for the PSU,I'm just searching for a psu which is small (Lets just say about 100x100mm).I actually don't know where to start my search, as I said - I only know those MeanWell (Or similar) PSUs in this package (please excuse the huge pic)Can you give me a hint where to buy a suitable psu or build one for myself? Thanks!Greetings from sunny GermanyKenny

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: May 25, 2016, 06:15:35 pm
content: Meanwell makes decent stuff. Lambda makes really nice stuff. Check on Mouser.com (or similar that delivers to DE). You could at least use Mouser to find the model number that fits your needs.You might also check ebay for used stuff, though it will likely be older, less efficient stuff.

author: rstofer
author_rank: Super Contributor
timestamp: May 26, 2016, 12:52:29 am
content: The only thing I found with a quick perusal was the Mean Well SP-200-7.5 - 7.5V at 26.7A and the voltage could be adjusted up to 8.25 but the current would come down a bit. It's also 99mmx199mm - much too largehttp://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_693530_-1There are other supplies around but this is what I found quickly. The thing is, you're looking for a 200W supply and they just aren't going to be tiny.

author: Marco
author_rank: Super Contributor
timestamp: May 26, 2016, 01:37:33 am
content: There are300W 12V DIN rail power supplieswhich get close, but 110mm high, and you'd have to hack the feedback for lower voltage (assuming that's possible, they might have a secondary voltage dependent on the output voltage for the converter which could become too low if you turn it down to 8V ... hopefully not).Also I'm not sure about the reliability,Mean Well's open frame 12V 300W power supplyof similar dimensions says it needs forced air cooling.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: May 26, 2016, 03:26:47 am
content: That is a lot of power, which I am guessing is why they are so big.Have you considered multiple lower current units? Any way to divide it up? They could also be spaced far apart for cooling perhaps.