hybridfree/eevblog-posts huggingface dataset:
Want to make an "oscilloscope basics" video, suggestions - Page 1
Forum section: electronics / beginners

author: taydin
author_rank: Frequent Contributor
timestamp: May 14, 2019, 11:14:07 am
content: I want to make a Turkish "oscilloscope basics" video for electronics beginners, to be published on YT and linked in my own forum. and trying to decide if a CRO would be better for this or a DSO.The advantage of a CRO is that, pretty much all CRO's out there have nearly the same user interface. If you have used one CRO, you will be able to fully use another brand/model CRO within 10 minutes. But the disadvantage is that, when somebody watches the video and decides to buy an oscilloscope, he/she will probably buy a new DSO. So this kinda reduces the usefulness of the video.The advantage of a DSO is that, first of all, I have one available right nowBut the disadvantage is that all DSO's have a different user interface. The screen looks different, the menus are different. And in terms of capabilities and features, DSO's from different vendors and models are VERY DIFFERENT. Also the DSO that I'm using is not something that a beginner would be buying. So how useful would it be to make a video with this DSO?I'm leaning towards making the video with my DSO, but only sticking to features and capabilities that are videly available and that are fundamentel to a scope's operation. But I'm willing to hear any suggestions you guys have about this.

author: rstofer
author_rank: Super Contributor
timestamp: May 14, 2019, 01:48:15 pm
content: I would think the fundamental operations on DSOs would be very similar: time/div, volts/div, trigger type and level, positioning, single shot and, to a lesser extent, measurements. The fancy stuff like FFT and decoding will probably be vendor specific but, still, why not demonstrate them with the advice to read the manual?There is a lengthy oscilloscope training video link at the top of this forum. You may get some ideas. I haven't watched it but w2aew produces some great videos.

author: bitseeker
author_rank: Super Contributor
timestamp: May 14, 2019, 05:39:30 pm
content: I'd recommend doing the video using a DSO. Although there are some front panel layout differences between different brands and models of DSO, the same is true of CRO.If you want to do one with a CRO, it could be a follow up to the DSO, but not a replacement.

author: pwlps
author_rank: Frequent Contributor
timestamp: May 15, 2019, 11:56:42 am
content: One thing you cannot show with a CRO is to analyse the signal before the trigger. I remember when first DSOs appeared in our lab we were fascinated by their ability to break causality rules imposed on CRO

author: taydin
author_rank: Frequent Contributor
timestamp: May 15, 2019, 12:03:53 pm
content: Thanks for the responses guys. I will use my existing scope and only stick to features that are more or less common to all DSO's.
Want to make/use a tACS/CES machine or equivalent. Ideas? - Page 1
Forum section: electronics / beginners

author: weirdnerd
author_rank: Newbie
timestamp: August 15, 2020, 01:35:55 am
content: I used a TENS machine for vagus nerve stimulation and it helped my depression, I don't want to buy a CES device for the prices they are offering it, so I am interested in using electronics tools to make them. This is a site with various ones on them.https://caputron.com/pages/ces-device-comparison.They are probably not much more different than the $5 waveform generators off eBay but with more marketing and a purpose. There are more here with specs too.http://www.medi-stim.com/stims.htmlthis is a link to the way the waveforms work.http://www.medi-stim.com/overview/waveforms.htmlI was not able to find a similar device in a small package, so I am going to use a feeltech fy6900 or something. I don't know what would be the most similar, but I know some of the specs I need:Symmetrical Biphasic Square Wave.5Hz generation, maybe up to 100Hz. To be safe I want at least 20Hz according to this chart.What device could be used for it? I asusme I would need adapters for the plugs, maybe some modding of the feeltech, I was going to run it off a 9v for safety reasons if possible and having a smaller device. I remember a mod on the site here talking about some weird russian wave generator that used crappy parts but worked, it was probably excellent R&D that went into it. Wondering if its similar to these devices I can try to dig out the post but its hard to find. Thanks!

author: weirdnerd
author_rank: Newbie
timestamp: August 18, 2020, 12:54:29 pm
content: Is no one willing to help because they fear its dangerous? I am going to do this with or without help, I would prefer help but if no one is willing to help me I am disappointed.
Wanted - Altium training material - Page 1
Forum section: electronics / beginners

author: NW27
author_rank: Regular Contributor
timestamp: April 08, 2017, 11:26:11 pm
content: Hi All,I have just started using Altium and CicuitStudio and I'm looking for any kind of 3rd party printed/ebook training material for these products.I tried Amazon without much success.Any ideas where I can locate training materia?There are various YouTube videos but the never seem to answer all questions ie sheets.Thanks for any direction or links.Neil.

author: tautech
author_rank: Super Contributor
timestamp: April 09, 2017, 12:53:05 am
content: James from Altium is a member, pester him by PM for some material or links.https://www.eevblog.com/forum/profile/?u=125777There's lots of info in these boards:https://www.eevblog.com/forum/index.php?board=15.0(Altium)https://www.eevblog.com/forum/index.php?board=35.0(CS)
Wanting to know about PSU current regulation. - Page 1
Forum section: electronics / beginners

author: David97
author_rank: Contributor
timestamp: December 04, 2015, 04:00:06 am
content: Hi, I'm wanting to build a dual channel PSU for lab use. Probably wanting something that will give me up to 30V at 6A. Wanting t do some more reading about how the current regulation works. I have a basic idea, but wouldn't have clue when It came to actually designing and building something. Could anyone point be in the right direction of where I could do some reading about this?I know I could buy a module pretty cheap, but I would rather design and build it myself.Thanks, David

author: Gyro
author_rank: Super Contributor
timestamp: December 04, 2015, 09:43:22 am
content: For something of that power you will be looking at a discrete, or semi-discrete implementation, ie. you're not going to get there with 3-terminal regulators.If you're looking at a lab PSU them you might well want to go for a linear solution rather than a switcher for minimum output noise.A couple of options are to look at the service manuals for good quality commercial PSUs, Eg. Some of the older Agilent/HP ones. The other is to start studying the datasheet for the LM723 power supply IC - this would form an excellent basis because it contains most of the internals of a PSU, opamps, current limit etc but no power elements. The datasheet and app circuits should at least give you a useful insight.If you're looking at a dual PSU, you would be best to look at two 0-30V 3A outputs that you can parallel to get 6A or connect in series to get 60V.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 04, 2015, 03:58:21 pm
content: A dual power supply if usually very much like two more or less separate supplys, that can be connected in series and sometimes also in parallel. Series connection is usually easy, parallel connection needs additional load sharing parts and is thus more complicated.With so much power, you likely want to use at least two transformer taps, to reduce the power dissipation.I would prefere the layout with a foating regulator, like many old HP supplies have used. This needs an additional auxialry supply for the regulator itself, but is very flexible (same board could be used for 10 V 5 A or 50 V 1 A - just change a few resistors and the transformer).Just for learning, a smaller supply (e.g. 2 A only) will not change much, but parts get cheaper, not as heavy and cooling gets much easies. For so much power one would usually consider a switched mode supply that is much harder to build and a little more noisy.
WAOKS Model 3.65V 10A battery charge - Page 1
Forum section: electronics / beginners

author: ascsunday
author_rank: Newbie
timestamp: January 24, 2019, 12:36:51 am
content: I have a WAOKS Model 3.65V 10A battery charger and a Powerizer 3.2V 100Ah (320Wh) LiFeMnPO4 Rechargeable battery pack. There does not seem to be a way to connect the battery to the charger. The plugs are not compantible. Do I just cut theend off of the output cord on the charger and hard wire it to the studs on the battery?

author: atmfjstc
author_rank: Regular Contributor
timestamp: January 24, 2019, 02:00:17 am
content: I wouldn't do that if I were you. The charger's 3.65V output suggests it's designed to work with a different type of Lithium cell. Most Lithium cells have a nominal voltage of 3.7V, but LiFeMnPO4 cells, like the one you are using, have a lower voltage of 3.2V.With Lithium cells, it is EXTREMELY important that the charger explicitly supports and is configured for the exact chemistry, voltage and structure (number of cells in series/parallel) of the battery attached. Mismatches will, at best, trip the charger/battery's protection circuitry (if they have any). At worst, they may cause the battery to be damaged, catch fire, even explode.

author: viperidae
author_rank: Frequent Contributor
timestamp: January 24, 2019, 05:52:37 am
content: 3.6v is the charge voltage for a lifepo4 cell, just like 4.2v is the charge voltage for a 3.7v cell and 4.35v for a 3.85v cell.
Warning Signs... (Caveat Emptor) - Page 1
Forum section: electronics / beginners

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 03, 2016, 09:13:56 pm
content: If you're ever feeling uncertain about the quality of a product, you can always act on that feeling:Product in question, a 30V/5A switching supply, of the poorest quality China can supply (as I understand it).Another warning sign (that came up in the IRC conversation that prompted the above message): if they don't state whatbandwidththe ripple measurement includes.This particular prize pony sports a lean 200mV of ripple. No bandwidth or operating condition stated.I can't imagine it'll last very long, either. The bargain-basement linear supplies are bad enough...(Not a burned customer -- I know much better than to bother!Just an FYI for "young players".)Tim

author: tautech
author_rank: Super Contributor
timestamp: June 03, 2016, 09:55:04 pm
content: Quote from: T3sl4co1l on June 03, 2016, 09:13:56 pmFound similar on a small 30V 5A SMPS bench supply.....the only way confirmation of the manufacturers stated ripple specs could be met was with 20 MHz BW limit and Averaging turned on, when tested in that manner it easily met spec.Yet these little units have given me a couple of years in the field to date with no failures.As you say: Caveat Emptor
Was there a standard trace width for old school 100mil PTH construction? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: June 19, 2020, 03:30:18 pm
content: Sort of like bypass with 0.1uF, back when IC packages were all DIP, was there a standard trace width that everyone used?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 19, 2020, 04:23:36 pm
content: When, and for what?Probably around 20 mils give or take your particular roll of Rubylith? Also regular thin traces (7 mil or so?) for getting a few between pins.Tim

author: alank2
author_rank: Super Contributor
timestamp: June 19, 2020, 04:28:20 pm
content: Basically all the pcb's you might see in early 80's computers. I'm making a microprocessor trainer emulator project with an AVR and I'd like the pcb to look like some of them from the time. It will allow the user to enter instructions for 8080/8085 and step through them, examine registers, etc.

author: alank2
author_rank: Super Contributor
timestamp: June 19, 2020, 04:31:10 pm
content: The beginnings of it:

author: alank2
author_rank: Super Contributor
timestamp: June 24, 2020, 08:07:45 pm
content: I ended up using 15mil traces for most signals and 50mil traces for VCC.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: June 25, 2020, 04:16:58 am
content: During the 80's we used 12 mil tracks and 13 mil spaces. The track tapes were layed out on 25 mil centers. Only power traces were fatter. This allowed us to get one track between DIP pins and to conform to 50/100 mil grid layout convention. Controlled impedance traces were still at least 12 mil wide but surrounding ground spacing and other-side-ground plane voids would be adjusted to get near the desired impedance.

author: alank2
author_rank: Super Contributor
timestamp: June 25, 2020, 12:09:09 pm
content: Thank you - that is what I was looking for!
Was this an inappropriate choice of power switch? - Page 1
Forum section: electronics / beginners

author: jameswilddev
author_rank: Contributor
timestamp: March 13, 2021, 08:10:54 am
content: Hello. Working on a project, just assembled a PCB and found that the power switch (a BS800L - might be a clone) doesn't seem to be working very well; the weight of the button cap is enough to make the switch open circuit if I turn the device upside down, and the power supply to the rest of the PCB can be disturbed just by nudging it with your finger. The flickering here isn't auto gain, it's visible to the naked eye.https://www.youtube.com/watch?v=BsSiMqcsq5s&feature=youtu.beI'm pretty sure it's well soldered to the board - joints look good and I can see that it's followed the PTHs through to the other side.The power draw at present is about 12mA, so within the 100mA spec of the switch.The possibilities I can see here are:- This might have been an inappropriate choice of switch. Are there any specific things I should be looking for on a datasheet to avoid this in future?- This might be a defective clone. I have some of the non-latching variety from another vendor and the plastics are noticeably different between the two. Could this be the problem?- It's possible I damaged the switch by overheating it. I'll note that I was careful to be quick when soldering its contacts and give cooling time between contacts. Its mechanical action doesn't appear to have changed. I've since replaced the switch with another from the same batch and it seems to act identically.

author: Gyro
author_rank: Super Contributor
timestamp: March 13, 2021, 10:53:54 am
content: It's probably just a cheap dodgy clone switch if you bought it off ebay. It's possible to damage any plastic switch if you overheat or distort it during soldering.Of the alternatives you listed, it's probably pretty much take your pick.

author: jameswilddev
author_rank: Contributor
timestamp: March 23, 2021, 06:07:14 pm
content: Just to follow up on this: I found another supplier for the switch and the switches I got from them are noticeably different - plastics and contacts quite different. Don't exhibit this problem at all and as a bonus the stabilization is considerably better.So all good!
washing machine motor - Page 1
Forum section: electronics / beginners

author: jhonny b
author_rank: Newbie
timestamp: May 08, 2020, 10:59:07 pm
content: My washing motor has a burnt wire. Please see in attachment.Iis there someone with some kind of advice on reconnecting DIY? lockdown and wife pressuring me to get it up and running or else :-)

author: Manul
author_rank: Super Contributor
timestamp: May 08, 2020, 11:18:23 pm
content: I'm not expert about washing machine motors. But I have idea. Are these points by any chance connected? Can you check with multimeter? Maybe it is thermal protection relay. If yes, then it can be just bypassed (at your own risk).

author: Cubdriver
author_rank: Unknown
timestamp: May 08, 2020, 11:38:52 pm
content: The failure more looks to me to be that the faston connector was a loose fit on the male tab, and it began arcing there, the arcing eroding away the terminals and the resulting heat melting the insulation of the wire. There may not be anything electrically wrong, but the issue was instead may well have been caused by a poor physical connection and the resultant arcing.I can't tell exactly what that switch is - is it mechanically activated by something on the rotor of the motor (start switch)? If not, perhaps as suggested above it is a thermal cutout. What brand/model of washer is it? Is there any schematic on the inside of the back cover, or available online?-Pat

author: JustMeHere
author_rank: Frequent Contributor
timestamp: May 09, 2020, 12:41:19 am
content: Just cut off the connector and tack the wire in place with solder. Clean things well with contact cleaner first.Be careful. It may have failed for a reason, but it could have also been vibrations from the spin cycle.

author: amyk
author_rank: Super Contributor
timestamp: May 09, 2020, 02:45:27 am
content: Looks like some bad corrosion. Check if anything around there got wet, and fix seals as necessary.
watch crystal microphonics absorption adheasive - Page 1
Forum section: electronics / beginners

author: peterthenovice
author_rank: Regular Contributor
timestamp: November 03, 2015, 04:46:07 am
content: hi I am looking for some kind of glue to bond a 32.768 watch crystal to a pcb. it needs to be hi stability and chemical resistant. maybe something urethane based.

author: coppice
author_rank: Super Contributor
timestamp: November 03, 2015, 04:50:38 am
content: Use an SMD crystal and avoid the issue.

author: peterthenovice
author_rank: Regular Contributor
timestamp: November 03, 2015, 04:53:07 am
content: i wanted something though-hole for ease of soldering. i want it for an ds1307 based rtc using a super capacitor for an arduino.

author: coppice
author_rank: Super Contributor
timestamp: November 03, 2015, 04:56:08 am
content: If its the typical metal can through hole crystal its best to solder the can down to the ground plane. Thermally that can sometimes be a pain to do, but it has real benefits.

author: peterthenovice
author_rank: Regular Contributor
timestamp: November 03, 2015, 04:57:41 am
content: Quote from: coppice on November 03, 2015, 04:56:08 amthank you for your answer you are a big help

author: coppice
author_rank: Super Contributor
timestamp: November 03, 2015, 05:03:10 am
content: Quote from: peterthenovice on November 03, 2015, 04:57:41 amA common solution is to solder down the cans for test samples, to get through the EMI/EMC/ESD/surge/microphony tests, and then not bother in production. That's cheating, though.

author: Zero999
author_rank: Super Contributor
timestamp: November 03, 2015, 09:23:04 am
content: Rather than attempting to solder the whole crystal to the ground plane, which can be difficult. Wrap some tinned copper wire round the crystal and solder that to the ground plane through some holes with thermal reliefs to make it easier.

author: coppice
author_rank: Super Contributor
timestamp: November 03, 2015, 09:44:10 am
content: Quote from: Hero999 on November 03, 2015, 09:23:04 amThat's fairly good for mechanically holding the crystal, and that's all the OP originally asked to do. However, to make a really robust design you really need to make a good electrical contact between the can and the ground plane. A lot of people do that with a wire hoop over the crystal, as you suggested, and then solder spot the hoop to the can. Its not quite a thorough as a broader soldered connection, but it gets most of the effect.Its really sad how few crystals are designed to make bonding easy.
Watch piezo drive method... - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: January 07, 2015, 02:20:23 pm
content: Hi Everyone,I've got this idea that I want to hollow out a casio watch and put an old style HP quad LED display in there instead so I am looking at the piezo mounted to the back metal cover of the watch. I wanted to see how the casio watch module drove it so I measured it and I expected to see a cyclic wave but instead saw a single pulse that was almost 100V for 3uS. Does that make sense? Was using a 10x scope probe on it with the spring ground lead.What would be the easiest drive circuit for a piezo from a 3V uC pin? Can different frequencies be done (even if the device is only optimal for one frequency?)Thanks,Alan

author: Zero999
author_rank: Super Contributor
timestamp: January 09, 2015, 09:32:52 pm
content: 100V sounds a bit high.Was this measured with the transducer connected?An inductor connected in parallel with the transducer is often used to increase the power output.Even more power can be delivered by using a small autotransformer.

author: alank2
author_rank: Super Contributor
timestamp: January 10, 2015, 03:08:18 am
content: I measured it with the piezo disconnected, maybe that was why it was so high... Is your driving circuit as simple as it gets? An inductor and a driving transistor? Could a mosfet be used too? How big an inductor?

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: January 10, 2015, 05:24:56 am
content: You pick L so that, at your required frequency you have a resonant circuit. So you need to know roughly what the capacitance of the piezo is at your chosen resonant frequency. If you want to know the maximum audio frequency of your piezo, connect it in series with a resistor and connect them across a signal generator, sweep up the frequency from low to high and you'll hear the peek sound. You'll also sweep through a few other maximum peeks as well. choose the one you like and use that frequency to work out your value of LAlso remember that you can increase the sound levels with a resonant chamber.The principle is, the short pulse sets the tuned LC(piezo) resonating; passing energy back and forth between the inductor and the capacitive piezo, that energy transfer is decaying but taking longer than the initial pulse. So for a very short pulse you have an extended audible sound. Keep pulsing it at the right time and it will continue to resonate.If you have a scope, a quick and dirty experiment is to put a coil ( any value for now ) in parallel with your piezo, connect the scope across the two and then just quickly momentarily tap a supply across the circuit, you'll see on the scope the resonance and decay. Single shot is good for this and measure the period of the sine wave you have on the screen to work out the resonant frequency for that LC combination
Watchdog circuit with permanent reset - Page 1
Forum section: electronics / beginners

author: Borstenhorst
author_rank: Newbie
timestamp: November 22, 2019, 10:15:35 am
content: Im not sure if this is a beginner question and if Im in the right forum.I fail to come up with a simple solution for the following application:An output signal (Watchdog OK) shall be high as long as a µC generates an alternating input signal. As this signal has to be generated by SW to make sense, the frequency is rather low (ideally configurable and somewhere between 10ms and 2s).If the input signal stops to oscillate, the output shall be low and STAY LOW.The input signal can be stuck at HIGH OR LOW, in both cases the output shall go low.The watchdogs ICs I saw satisfy all my needs, except that they generate a reset pulse, instead of a permanent reset.You know any off the shelf watchdog IC with permanent reset?Retriggerable monostable multivibrators keep the output high if the signal is stuck at high. At least the ones I saw so far.Some spooky 555 circuits might do the trick but I would prefer a low part count and ideally a single chip solution.A small µC will do the trick but I somehow consider this as a dirty hack because I failed to come up with a better solutionAll signals are (0-5V).Thanks a lot in advance!

author: Siwastaja
author_rank: Super Contributor
timestamp: November 23, 2019, 10:32:24 am
content: Maybe a stupid and simple series capacitor from the IO pin, then rectified by a diode, and stored by a capacitor, with added pulldown resistor which discharges the capacitor if the pulsing stops. A schmitt trigger buffer would make the signal edge clean.

author: Borstenhorst
author_rank: Newbie
timestamp: November 26, 2019, 11:18:49 am
content: Great idea!Many thanks for that!Adjustment of the timeout could happen via a Potentiometer which is discharging the second capacitor.However, I guess I will go with a small µC as watchdog. This simply gives the best results and the part count is low.

author: mikerj
author_rank: Super Contributor
timestamp: November 26, 2019, 01:58:26 pm
content: Quote from: Borstenhorst on November 22, 2019, 10:15:35 amYou could AC couple the trigger. However you can buy a single chip solution for exactly this purpose e.g. MAX6369–MAX6374 will allow you to configure a number of discrete timeout value via three pins.
Water Damage Laptop IC-Not_found - Page 1
Forum section: electronics / beginners

author: klazaridis1
author_rank: Newbie
timestamp: May 26, 2021, 08:30:36 am
content: Hello!My friend spilt coffee on his laptop and the laptop released the "magic" smoke... I disassembled it and found that the amplifier IC? was blown out. I removed it, cleaned the traces and... nothing no screen, so my investigation continued. When I was pressing the on/off button the fan was spinning and the power_on_led was glowing, my guess was that something went wrong with the ram. I was close, an IC close to the ram slots was hotter than other components, after a while I found out that three close components to that IC were also hot. Close to a specific IC, the capacitors were shorted, I removed the IC and the short circuit was gone. I can't find any info for the specific IC. It is the AYOA 743L. I found a similar-looking Ic on aliexpress but I don't know If it's the same.similar component:https://www.aliexpress.com/item/32856221367.htmldatasheet for the Aliexpress component:https://html.alldatasheet.com/html-pdf/1244924/AOSMD/AOZ1331DI/359/2/AOZ1331DI.html

author: Jwillis
author_rank: Super Contributor
timestamp: May 26, 2021, 09:42:34 am
content: Bottom number looks like a date/lot code . AYOA , AYO , and AY in a DFN-14L package seem to lead to a Ultra-Low On-Resistance 6A Dual Load Switch .AOZ1331DI Alpha Omega load resistor 220ΩAPE8990-HF-3 and APE8910-HF-3 Advanced Power Electronics Corp. The internal load resistor being the only difference between the two . 150Ω and 250Ω

author: klazaridis1
author_rank: Newbie
timestamp: May 26, 2021, 09:49:54 am
content: Nice, so I believe that the difference in resistance will not create any problem. Correct? Btw thank you for the informatios.
Watson Power Max 45 NF (Switch Mode PSU noise ) - Page 1
Forum section: electronics / beginners

author: g6ypk
author_rank: Newbie
timestamp: October 23, 2013, 07:45:28 pm
content: I'm curious: The Watson Power Max 45 NF PSU. I don't believe that this can handle 40 Amps continual. Is it me? Because mine, loaded with 0.345 ohm at? 13.8 V is 552 Watts... But the ripple is horrendous!!! What's going on here? Same with 30 A drawn too..0.46 ohm 414 Watts.Does anyone have a circuit diagram so I might find out why the ripple is so high? I suspect the use of none low ESR capacitors or a leaky shottky diode.Any help would be most gratefully received.. 73 de Tony> g6ypk1@yahoo.com
Watt and Decibel output of speakers and amplifiers. - Page 1
Forum section: electronics / beginners

author: usermatthew
author_rank: Newbie
timestamp: February 10, 2017, 05:56:06 am
content: I am trying to built a portable speaker box, but I am having trouble understanding the watt output of amplifiers. If it is a stereo amp do you divide the wattage between the two sepakers or is it a total? When it comes to decibel output I understand the equations from my physics classes, but how does this apply to speakers and power draw?

author: hayatepilot
author_rank: Frequent Contributor
timestamp: February 10, 2017, 06:33:14 am
content: Quote from: usermatthew on February 10, 2017, 05:56:06 amIn most amplifiers the power is normally given per channel for example 2x50W.If you want to know the decibel output of a speaker you must find the sensitivity spec of the speaker. This is given in xx dB/W/m .This is the sound pressure level of the box if it's using 1Watt in 1meter distance.Here you can find many acoustic formulas and calculators with good explanations:http://www.sengpielaudio.com/calculator-efficiency.htmDon't get hung up on amplifier power since doubling the power only increases volume by 3dB which is not a big step for our ears.Greetings

author: Zero999
author_rank: Super Contributor
timestamp: February 10, 2017, 09:25:15 am
content: Amplifier manufacturers often lie about the power output, quoting peak power when it's horribly distorted, rather than RMS power, with a clean, linear output.The RMS power output of an amplifier can be calculated using the following formula:PRMS= VP2/(2R)WhereVP= peak output voltage.R = the resistance of the speaker.

author: TimFox
author_rank: Super Contributor
timestamp: February 10, 2017, 04:14:59 pm
content: No. This is a very common error about AC power.Themeanpowerfor a sine waveis given by the common equationPmean=Vpk2/2R =VRMS2/RThe root-mean-square power can be calculated fromPRMS2= AVG((V I)2)but there is no use for that parameter in practice.

author: Audioguru
author_rank: Super Contributor
timestamp: February 12, 2017, 01:02:07 am
content: A speaker has its sensitivity listed when it is driven from maybe 1 Watt at a certain frequency and the dB level is listed. Some speakers are sensitive and produce loud sounds and other speakers are not sensitive and produce faint sounds when both speakers are driven with the same amount of power. Sometimes a cheap speaker is more sensitive than an expensive speaker but only at one frequency. I call it a squeaker, not a speaker.

author: Lightages
author_rank: Unknown
timestamp: February 12, 2017, 02:41:52 am
content: Just because a speaker has a certain sensitivity rating does not mean it will be able to produce the derived output level based on its maximum watt rating. A speaker will also compress as it reaches its maximum output level and distort too probably.
Watt Meter Schematic Questions - Page 1
Forum section: electronics / beginners

author: bitshift
author_rank: Regular Contributor
timestamp: September 10, 2015, 02:20:49 pm
content: Hey guys,I've been studyingthisschematic for a digital watt meter.Why is the diode D1 connected in series with the supply pin of the PIC?

author: AF6LJ
author_rank: Unknown
timestamp: September 10, 2015, 02:33:23 pm
content: That is a really good question.I'm not sure...

author: DmitryL
author_rank: Regular Contributor
timestamp: September 10, 2015, 02:35:31 pm
content: Quote from: bitshift on September 10, 2015, 02:20:49 pmTake a look at J3. It is used for in-circuit PIC programming. D1 prevents powering up whole circuit from the PIC programmer.

author: bitshift
author_rank: Regular Contributor
timestamp: September 10, 2015, 02:42:10 pm
content: Ah I see! Thanks DmitryL

author: AF6LJ
author_rank: Unknown
timestamp: September 10, 2015, 02:45:49 pm
content: Quote from: DmitryL on September 10, 2015, 02:35:31 pmThanks, makes all the sense in the world now.
Watt values of resistors with parallel connection - Page 1
Forum section: electronics / beginners

author: catalyst
author_rank: Contributor
timestamp: January 29, 2018, 07:23:49 pm
content: Hi. Does it increase? If it doesn't increase, how to increase watt values of resistors with connection style? Thank you all.

author: Zero999
author_rank: Super Contributor
timestamp: January 29, 2018, 07:29:19 pm
content: Quote from: catalyst on January 29, 2018, 07:23:49 pmThe power rating of each individual resistor remains the same. If the resistor values are all the same, then the power rating can simply be multiplied by the number of resistors.If the resistors are not the same value, then just apply Ohm's law: V2/R or I2R.
Wattage of current limiting Resistor running on AC  - Page 1
Forum section: electronics / beginners

author: dark_hawk
author_rank: Regular Contributor
timestamp: September 08, 2013, 09:05:02 pm
content: Hi,Got a 12.6-13.3 AC power source. Have put two LEDs anti-parallel to each other like this figure:Voltage drop for leds is 3.3V and Current is 20ma. Used a 270ohm 1/2W resistor.Question is, Does calculating wattage of the resistor differ from DC to AC or is it the same?Thank you.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 08, 2013, 09:15:28 pm
content: In principle if you use the RMS value of the AC, it will be equivalent to DC, but the peak current will be higher (probably won't be an issue).However the Vf of the LEDs will make the current slightly non-sinusoidal, so the RMS current will be slightly different to what you may expect, but not enough to worry about.
Wattage/voltage regulation in variable wattage vapes - Page 1
Forum section: electronics / beginners

author: IOcase
author_rank: Newbie
timestamp: June 10, 2020, 04:02:13 am
content: Hello all, electronics newbie here,I'm interested in creating my own variable wattage vape, 80W capable from two 18650s, but I'm having trouble figuring out how they manage to provide variable wattage (voltage really) to my design. I can't seem to find DC to DC boost converters that have enough amperage to meet the demands of a 80W mod. For example, my brothers mod outputs 13.3A when he's using 70W on a ~0.4 ohm coil. Most converters I've found max out around a couple amps and it doesn't seem cost effective or space efficient to do so many boost converters in parallel. I'm sure there's a better way to do this that I'm ignorant of.Since I don't know what I don't know, I figure I would ask the resident experts here on EEVblog for their input on how to proceed. What's the best way to convert battery voltage above and below the battery input voltage while allowing for such huge amounts of current?Thanks in advance
Watts from one ADC pin - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: March 29, 2018, 05:52:53 pm
content: Is it possible to figure out DC watts if you have just one ADC available? I'm currently using two to measure voltage and current.

author: Twoflower
author_rank: Frequent Contributor
timestamp: March 29, 2018, 06:16:36 pm
content: What about this analog multiplier:https://www.maximintegrated.com/en/app-notes/index.mvp/id/4134

author: MrAl
author_rank: Super Contributor
timestamp: March 29, 2018, 06:19:11 pm
content: Quote from: metrologist on March 29, 2018, 05:52:53 pmHi,Well you could use an analog switch, but you'd have to switch it from one channel to the other which would take a DIGITAL output pin. So you'd save an analog pin but use up a digital pin.There are other ways but require some external circuitry. For a simple example, use a second small low end uC to measure the power and send it to the 'master'.

author: metrologist
author_rank: Super Contributor
timestamp: March 29, 2018, 07:25:03 pm
content: I think I have a few SPDT ICs around, and plenty of extra digital pins.I might have a specific question once I figure out which chips I have.

author: MrAl
author_rank: Super Contributor
timestamp: March 30, 2018, 02:44:05 am
content: Quote from: metrologist on March 29, 2018, 07:25:03 pmHi,Oh that's great. If you have just one digital pin then you can multiplex one analog channel into two, and if you have two digital pins then you can multiplex into four analog channels using just one ADC input pin.There are cheap analog switches that can do 8 channels but for 8 you would need 3 digital pins unless you use only two of the channels.
Wave impedance for SATA traces? - Page 1
Forum section: electronics / beginners

author: fxr
author_rank: Contributor
timestamp: December 24, 2019, 01:46:37 am
content: Hello all,I'm trying to build PCB design with SATA interface.Board specification:- PCB material is R1755V High Tg 170.- Stackup of PCB is 4 layers;- SATA traces location on layer 1 (top layer);- Ground plane on layer 2.How to do calculate the wave impedance of traces for SATA interface?What I should consider when routing the differential traces?

author: Rerouter
author_rank: Super Contributor
timestamp: December 24, 2019, 03:38:59 am
content: grab the free tool "Saturn PCB toolkit" Its a set of PCB calculators including trace impedance for multi layer boardsDifferential traces, keep them close to one another, the tool will tell you your ground separation, match there length to keep in spec
wave player with PWM - Page 1
Forum section: electronics / beginners

author: alizare368
author_rank: Regular Contributor
timestamp: November 30, 2019, 03:24:50 pm
content: Hi guysI want to make a wave player whit stm32f4, read the wave files from sdcard and into PWM CH_1 and CH_2.and timer1_ch1 and timer1_ch2 pins are connected to RC filter(res: 1M,3.9k & c:4.7nf), ch_lo connected to 1M and ch_hi connected to 3.9k.but the filter output is consistently noisy.the MCU clock is 84MHZ and timer configuration is :prescaler:0Auto reload register :255pwm pulse:%50this program works as a ping pong.this is main code.Code:#include "main.h"#include "fatfs.h"SD_HandleTypeDef hsd;TIM_HandleTypeDef htim1;/* USER CODE BEGIN 0 */#define sample_no 256uint8_t sai_buf;uint32_t br;FATFS SDFatFs; /* File system object for SD disk logical drive */FIL MyFile; /* File object */extern char SDPath; /* SD disk logical drive path */uint8_t refill=0;uint32_t index_buf=0;static FRESULT res;uint32_t block_size;/* USER CODE END 0 */int main(void){/* USER CODE BEGIN 2 */uint8_t count=0;int t=1;res=f_mount(&SDFatFs, (TCHAR const*)SDPath, 0);if(res==FR_OK){res=f_open(&MyFile,"6.wav",FA_READ);block_size=f_size(&MyFile);if(res==FR_OK){res=f_read(&MyFile,&sai_buf,sample_no,&br);}}HAL_TIM_PWM_Start(&htim1,TIM_CHANNEL_1);HAL_TIM_PWM_Start(&htim1,TIM_CHANNEL_2);HAL_TIM_Base_Start_IT(&htim1);/* USER CODE END 2 */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */if(refill){index_buf++;res=f_read(&MyFile,&sai_buf[(index_buf)%2],sample_no,&br);refill=0;}}/* USER CODE END 3 */}this is a ISR code:Code:void TIM1_UP_TIM10_IRQHandler(void){/* USER CODE BEGIN TIM1_UP_TIM10_IRQn 0 *//* USER CODE END TIM1_UP_TIM10_IRQn 0 */HAL_TIM_IRQHandler(&htim1);/* USER CODE BEGIN TIM1_UP_TIM10_IRQn 1 */wcnt++;if(wcnt>7){wcnt=0;TIM1->CCR1=sai_buf[index_buf%2];TIM1->CCR2=sai_buf[index_buf%2][i+1];i+=3;if(i>=(sample_no-1)){i=0;refill =1;}}/* USER CODE END TIM1_UP_TIM10_IRQn 1 */}someone know what is the problem?
wave track FM modulation with another - Page 1
Forum section: electronics / beginners

author: Michael_P
author_rank: Contributor
timestamp: May 24, 2016, 04:46:57 am
content: Hi, I need helphow can I modulate one waveform/track with another to achieve FM(Freq. Modulation)?I look in Audacity(plug-in) for best quality of waveform but there are no posibility to make it becous as I know now .ny plugins work only with one track.
Waveform amplification and distribution - Page 1
Forum section: electronics / beginners

author: Jake1
author_rank: Newbie
timestamp: June 25, 2020, 08:56:34 am
content: Hi,I have a waveform generator that can produce a 5V output and I need to amplify it to 24V and 0.2amps along 6 different channels. I would ideally like some sort of dock that I could plug an external power source into with 6 independent amplifiers that could take the original waveform and distribute it to 6 different circuits. Im a little stuck on how to do this. Does anyone know how it could be done?Thanks,Jake.

author: Vovk_Z
author_rank: Super Contributor
timestamp: June 25, 2020, 01:13:19 pm
content: It depends on a signal frequency. Up to 100-200 kHz you can use usual audio IC (TDA2030/2050, LM1876, TDA7294, LM3886 etc)

author: David Hess
author_rank: Super Contributor
timestamp: June 25, 2020, 04:22:00 pm
content: We need to know the frequency or transition time requirements to know what kind of gain-bandwidth product and full power bandwidth or slew rate is required.

author: Jake1
author_rank: Newbie
timestamp: June 25, 2020, 11:43:14 pm
content: Hey David,The frequency will be low around 1-2Hz. The output amps from the waveform generator will be around 0.2amp and this shouldn't change. I need an identical signal but with an increased voltage.

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2020, 04:56:28 pm
content: That is well within the audio band so an integrated audio power amplifier will likely work well. Power operational amplifiers are also feasible but likely more expensive.I would use a circuit similar to the one shown below but I would add Vbe current limiting using the emitter resistors on the output transistors. See figure 2 of Linear Technology application note 18 for an example of this and another example of a similar circuit which would work and many more.A pair of quad operational amplifiers could also be used with the operational amplifiers all in parallel. This is probably the least expensive solution.
waveform cliping at around  800mv/1v - Page 1
Forum section: electronics / beginners

author: jawnuolis
author_rank: Newbie
timestamp: August 01, 2015, 12:59:28 pm
content: is there is any easy way to clip +/-13v waveforms at around +/-800mv or +/-1v? I was thinking about symmetrical zener or tvs diode clipping but there no so small nominal diodes... any suggestions?

author: c4757p
author_rank: Super Contributor
timestamp: August 01, 2015, 01:33:07 pm
content: Depending on the properties of the signal, a variant on theprecision rectifieris probably a good choice. What kind of signal is this?

author: jawnuolis
author_rank: Newbie
timestamp: August 01, 2015, 01:53:50 pm
content: its COP coil on plug secondary ignition waveform and when coil is turned of there is huge spikes from +/- 5v to +/- 13v and more when all useful information stays in up to 800mv region and automotive scopes not very happy about that.....

author: langwadt
author_rank: Super Contributor
timestamp: August 01, 2015, 02:33:54 pm
content: a series resistor to limit current and a set of regular diodes to clamp pos/neg, use set of two diodes to get slightly higher voltage

author: jawnuolis
author_rank: Newbie
timestamp: August 01, 2015, 04:35:23 pm
content: Quote from: langwadt on August 01, 2015, 02:33:54 pmdo you mean this?

author: langwadt
author_rank: Super Contributor
timestamp: August 01, 2015, 04:48:08 pm
content: Quote from: jawnuolis on August 01, 2015, 04:35:23 pmyes, that'll clamp at roughly 0.7V

author: jawnuolis
author_rank: Newbie
timestamp: August 01, 2015, 05:14:39 pm
content: thanks will try this

author: Marco
author_rank: Super Contributor
timestamp: August 02, 2015, 05:44:17 am
content: You need a low output impedance for this to work ... if you put this in between an attenuator probe and the oscilloscope input it will not work right.
waveform generator 250-300$?  30MHZ? - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: April 25, 2014, 01:00:38 am
content: any suggestion for a good waveform generator 250-300$? 30MHZ?thanks

author: Vgkid
author_rank: Super Contributor
timestamp: April 25, 2014, 02:55:53 am
content: What country are you located in, and do you mean arbitrary or sine/square/triangle.

author: electronics man
author_rank: Frequent Contributor
timestamp: April 25, 2014, 07:03:30 am
content: Does it have to be 30Mhz can it be 25Mhz if so then the siglent sdg830 is good, it's built we'll and the frequency output is very accurateCorrection: it is 30Mhz not 25Mhz
waveform on Rigor 1054z in Average acquire mode drifts to zero - Page 1
Forum section: electronics / beginners

author: SW_Perspective
author_rank: Newbie
timestamp: February 24, 2016, 03:51:19 am
content: I just got a Rigol 1054z and am learning to use it. I was using it with simple RC circuits driven with a sine wave from a function generator, using channels 1 and 2 and I adjusted the position of the signals to be superimposed on each other. Acquire mode was set to Average. So far, so good. I measured Vpp and the results were about expected. Then the waveforms began to to flatten out and drift to zero. Changing a vertical scale on either channel or the horizontal scale momentarily changed the waves back to normal and then slowly they would fade toward zero. Changing the Acquire mode to any other setting brought the waveforms back to expected size and there was no fade. And this problem is intermittent. When connected directly to the function generator signal fade did not occur. Until I tried again a bit later when signal fade occurred in this configuration. As I'm just learning I thought I must have set something wrong on the scope or maybe the the circuits had problems with their construction (altho one resistor and one capacitor on a breadboard that seemed unlikely). Is this a problem with the scope or am I just not smart enough to use an oscilloscope? Is there something I can try to test the scope? Is this a problem anyone has heard about before? I've searched on-line for answers without success. Please help.

author: ataradov
author_rank: Super Contributor
timestamp: February 24, 2016, 04:26:22 am
content: Is your signal properly triggered before you enable averaging? Average of sine waves with a random phase is 0.Also, what do you mean by "connected directly"? How else do you connect it?

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 24, 2016, 05:12:19 am
content: Make sure triggered signal swing is not too small on the screen and set trigger level to the center of the signal... you have intermitent trigger there, ie trigger level is near either the min edge o max of the signal.. activating auto (random) mode from behind the average screen. thats why average went to 0.. anyway, set to average by beginner is not a good idea.. real measurement only use peak,normal o high res. Average is only when you know what you are doing and what its for... not a daily life "i think its good" usage, it is not...