hybridfree/eevblog-posts huggingface dataset:
Math channel got me confused... - Page 1
Forum section: electronics / beginners

author: eTobey
author_rank: Super Contributor
timestamp: December 20, 2024, 09:07:17 am
content: Info:I post this here, so that others could benefit from. It got me confused, because i expected the math channel to display the exact same data, not beeing influenced by the vertical scale. I have the SDS800X HD, but i guess this would apply to other scopes too.When saving data from a math channel, from a certain scale onwards, signal values are cut off:Since pure data has nothing to do with an opamp, that could only go to a certain value, i would have NEVER expected this. It makes no sense at the memory level, since saving the value 0, or the value 6537478245 would not make a difference. See picture "same data...": The same waveform (at a different scale), but the signal is cut off at ~0.5V.Same cause, but different result:When the math channel is scaled, it looses precision (see picture "precision loss").Seems to be a 16 bit datatype. So the precision of the saved data would be roughly:Precision = vertical_scale* 8.53 / 65520vertical_scale= needed_precision * 65520 / 8.53(8.53 = max vertical extend in divisions / 65520 values for datatype)(Yes, the labels of the traces are bad, but thats due to the stupid keyboard in this scope, where i dont want to do 3 clicks to have a spacebar or a "-" added. I copy filenames over, to not introduce errors.)
Math function to signal  form Converter app - Page 1
Forum section: electronics / beginners

author: electronx
author_rank: Regular Contributor
timestamp: December 25, 2023, 11:10:43 am
content: There is a very nice application that gives mathematical output of opamp circuits: Maplesim, Create the existing opamp circuit and see the mathematical expression at the output. (Please let me know if there are similar applications)Are there any applications where we can create a certain function equation for the output and transform it into a circuit topology with opamps?

author: rstofer
author_rank: Super Contributor
timestamp: December 25, 2023, 02:37:27 pm
content: [quote author=electronx link=topic=407442.msg5240259#msg5240259 date=1703502643Are there any applications where we can create a certain function equation for the output and transform it into a circuit topology with opamps?The entire field of analog computing...https://en.wikipedia.org/wiki/Analog_computerFor example, the differential equation for the Mass-Spring-Damper system (similar to R-L-C circuit)https://www.math.arizona.edu/~jwatkins/h-ode.pdf

author: electronx
author_rank: Regular Contributor
timestamp: December 25, 2023, 02:46:33 pm
content: Yes u are right so we can call all analog things as a function .But ım looking for apps
Math help: calibrating adxl375 - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 31, 2014, 01:42:19 am
content: I have read the two calibration app note as I have attached. I am using adxl375.1. I have been able to do 6 point calibration correctly as in AN4399.2. Now I want to do 12 point calibration as in DM00119044 or AN4399.Page 8 of DM00119044 shows the matrix for calculation.This matrix will yield to 18 equations right? As below. Now I have 18 equations & 12 variables.Is there any software which can solve these for me:Code:/* 18 equations *//* +z axis */a11*30 + a12*50 + a13*2548 + o1 = 0a21*30 + a22*50 + a23*2548 + o2 = 0a31*30 + a32*50 + a33*2548 + o3 = 1/* -z axis */a11*20 + a12*10 + a13*980+ o1 = 0a21*20 + a22*10 + a23*980 + o2 = 0a31*20 + a32*10 + a33*980 + o3 = -1/* +y axis */a11*30 + a12*1911 + a13*50 + o1 = 0a21*30 + a22*1911 + a23*50 + o2 = 1a31*30 + a32*1911 + a33*50 + o3 = 0/* -y axis */a11*20 + a12*49 + a13*10+ o1 = 0a21*20 + a22*49 + a23*10 + o2 = -1a31*20 + a32*49 + a33*10 + o3 = 0/* +x axis */a11*2303 + a12*30 + a13*50 + o1 = 1a21*2303 + a22*30 + a23*50 + o2 = 0a3/* +z axis */1*2303 + a32*30 + a33*50 + o3 = 0/* -x axis */a11*392 + a12*20 + a13*10+ o1 = -1a21*392 + a22*20 + a23*10 + o2 = 0a31*392 + a32*20 + a33*10 + o3 = 03. Now for 15 point calibration as in AN4399. page 33. They had added a cubic nonlinearity.What is its purpose?Why to add cubic factor here?

author: electr_peter
author_rank: Unknown
timestamp: December 31, 2014, 10:42:53 am
content: Quote from: Vindhyachal.takniki on December 31, 2014, 01:42:19 amAll is explained in the app note.QuoteHave you read a note?Nonlinear elements in calibration model allows to compensate for sensor nonlinearity.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: January 01, 2015, 04:10:39 pm
content: 1. From Page 8 of DM00119044 matrix, I have made 12 equations. now how to solve that. i didn't understand the way it is done in DM00119044?2. Sorry I didn't frame my qyery right. The 15 point calibration in AN4399 is for freescale accelerator or I can apply in adxl375 also?

author: electr_peter
author_rank: Unknown
timestamp: January 01, 2015, 06:07:22 pm
content: Quote from: Vindhyachal.takniki on January 01, 2015, 04:10:39 pmDM00119044 suggests to use LS method, it is pretty straightforward. See appendix.QuoteYou can use same calibration method for both devices, it is independent of accelerometer used. Note that 15 point method will be valid only if you can assure that your calibration points are exact.
Math help in datasheet - Page 1
Forum section: electronics / beginners

author: rx8pilot
author_rank: Super Contributor
timestamp: April 26, 2015, 05:36:21 am
content: I am going through a data sheet for a boost controller - TI TPS43060. In the section about calculating the output caps, I am not getting the same answer as the datasheet example.Equation (24) when I solved in excel gives me 53.3uF where the datasheet answer is 21.3uF. Am I wrong or mis-interpreting what seems to be rather simple. Equation (23) evaluates as expected.excel:Code:=(0.6*5)/(750000*0.075)Thank you for any comments. I am more than willing to put on a dunce hat if needed.

author: android
author_rank: Regular Contributor
timestamp: April 26, 2015, 05:54:43 am
content: Looks like a typo. They've usedIIN(5A) instead ofIOUT(2A) in the formula. Using 2A gives 21.3 ?F.

author: rx8pilot
author_rank: Super Contributor
timestamp: April 26, 2015, 05:55:59 am
content: Quote from: android on April 26, 2015, 05:54:43 amyou are correct.I think the culprit is here......Going a few pages up to look at the feeder data, it shows Iout should be 2A not the 5A shown in the equation example. Had me running in circles thinking I was nuts.Not sure who to send a message to.
Mathematics knowledge - Page 1
Forum section: electronics / beginners

author: sdli
author_rank: Newbie
timestamp: June 10, 2011, 04:12:44 pm
content: How important is mathematics knowledge (calculus, differentials equations, etc) to be a very good electronics designer?Thanks.

author: Simon
author_rank: Unknown
timestamp: June 10, 2011, 04:20:46 pm
content: you do need maths to be real good but many of us cope with being maths dunces

author: dengorius
author_rank: Regular Contributor
timestamp: June 10, 2011, 05:13:39 pm
content: That's why after inventing calculus, Leibniz, invented Wolfram alpha

author: ivan747
author_rank: Super Contributor
timestamp: June 10, 2011, 06:06:05 pm
content: I think you will probably end using the online calculators...Or maybe only I do

author: EEVblog
author_rank: Unknown
timestamp: June 11, 2011, 01:31:19 am
content: Quote from: sdli on June 10, 2011, 04:12:44 pmI haven't had to solve an integral or diff equation outside of school, in 20+ years of professional electronics.YMMVDave.
Finding peak values in Matlab - Page 1
Forum section: electronics / beginners

author: Karamel
author_rank: Regular Contributor
timestamp: October 23, 2016, 08:35:19 am
content: Hi everyone,Nowadays, I am working on sound recognation project via matlab. I am currently able to realize some notes. All of them are good but, I, now, have a problem with matlab.I should recognize frequencies of peak values in my array. (fourier output) So, I can find peaks in my array like that,Code:pks = findpeaks(abs(F));[m,n] = size(pks);for i=1:mfprintf('peak%i: %i\n',i, pks(i,1));endbut it gives to me values of at max point. Not frequencies. (in frequency domain x axis describes frequencies and y axis describes magnetude of signal)So, how can I get frequencies for all peak(local max values) values?Best Regards,Karamel

author: ataradov
author_rank: Super Contributor
timestamp: October 23, 2016, 05:22:31 pm
content: Code:[pks, locs] = findpeaks(data)locs will contain locations of the peaks.

author: Karamel
author_rank: Regular Contributor
timestamp: October 24, 2016, 02:29:07 pm
content: Thanks for replying my question dear Atarov,Actually, I had solved this problem when after asking but, I asked it and then, I went library, so I did not write solution.Code:[pks, locs] = findpeaks(abs(F))[m,n] = size(pks);In there, locs are local values, m and n are size of pks. If there is no signal. n = 1(n is always 1 because of pks is mx1 vector) and m = 0. If there is signal and is has some peak values, then, m has a different value that depends on peaks.Matlab has a different coding and different approaching to solve problems. Okay, it looks like c programing but, certainly, it is different. I could, therefore, be asking stupid questions or etc. because of difference.Thanks for all,Karamel
MATLAB problem - Page 1
Forum section: electronics / beginners

author: miketan3904
author_rank: Contributor
timestamp: October 10, 2020, 04:50:56 pm
content: Hi. Does anyone know how to measure the two break frequencies for the bode plot below in MATLAB?

author: Thedon
author_rank: Contributor
timestamp: October 11, 2020, 09:01:34 am
content: If you asking about the -3dB frequency you should be able to click on the plot your mouse will be a white cross and it will show the magnitude and frequency. I use live editor to plot wave forms much easier to plot and manipulate. What script did you use to plot the bode? I'm always on the look out for good scripts the one I'm using at the moment is causing issues. Converting radians to frequency would be a lot easier f = 2pi/w.

author: Phoenix
author_rank: Frequent Contributor
timestamp: October 11, 2020, 09:47:26 am
content: Are you trying to automate it? Or just manually?You can use the phase plot to find the exact frequency easily as the break point occurs at the 45deg shift points (ie -135deg and -225deg). Then you can get the magnitude at that frequency.

author: Phoenix
author_rank: Frequent Contributor
timestamp: October 11, 2020, 09:51:52 am
content: Quote from: Thedon on October 11, 2020, 09:01:34 amLooks like he used the built in bode() function. You can change to Hz using bodeoptions.http://ctms.engin.umich.edu/CTMS/index.php?aux=Extras_Tips

author: Thedon
author_rank: Contributor
timestamp: October 11, 2020, 11:42:39 pm
content: Yeah I thought he used the built in bode (sys) function but it was the appearance of his plot that made me think he used another function or script. He probably just changed the plot properties to semi-log or something like that and i forgot about all the options. What I'm interested in is scripts that plot the bode from oscilloscope csv. data the one I'm currently using works fine for a 2-pole LPF but not so good for a 7-pole LPF anyway if interested I'll start a new thread don't want to hijack this thread.
Matlab Question(s) - Page 1
Forum section: electronics / beginners

author: Karamel
author_rank: Regular Contributor
timestamp: March 05, 2017, 02:41:51 pm
content: Hi,I am, now, learning matlab coding. I want to identify this function which at below. Before asking question, I looked up matlab's help but I really did not understand anything. How can I define this state function?P.s: ss command heps to us but actuallty, I did not understand using ss command.

author: Caio Negri
author_rank: Contributor
timestamp: March 05, 2017, 03:20:55 pm
content: You have a linear state space model defined in the standard format:dx/dt=Ax+Buy=Cx+Duxis the state vector of your system anddx/dtis the derivative of that, in your case you have 3 states.uis your input (or control) vector,yis your system ouput.A,B,CandDare matrices.You can create this dynamic system model in matlab using the ss fucntion:Code:sys = ss(A,B,C,D);After that, use sys with any of the Matlab linear system analysis tools, for example:Code:bode(sys); %Plot the bode diagramsor plotting the step response for each input:Code:step(sys);

author: rstofer
author_rank: Super Contributor
timestamp: March 05, 2017, 05:05:40 pm
content: I posted the matrices below. 'A' for example is entered asA=[-10,16.5,-7;-8,12.5,-5;-4,6.5,-3]'B' is a column vector so:B=[4;3;2]Code:A =-10.0000 16.5000 -7.0000-8.0000 12.5000 -5.0000-4.0000 6.5000 -3.0000B =432C =1 -1 00 -1 2D =01Interesting project! I had to buy the Control System Toolbox to run the simulation but it was worth it for the education.

author: Karamel
author_rank: Regular Contributor
timestamp: March 05, 2017, 05:51:09 pm
content: I have done it before read your comments, now, I couldnt find transfer function with using tf2ss function.

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: March 05, 2017, 07:02:43 pm
content: free options can be goodScilab is free, has some serious support, has simailar toolboxeshttps://www.scilab.org/scilab/features/scilab/controlbut often the toolboxes aren't as complete as Matlab'sOcatve is supposedly more nearly Matlab compatible, .m files run with fewer modfications

author: Caio Negri
author_rank: Contributor
timestamp: March 05, 2017, 08:07:29 pm
content: Quote from: Karamel on March 05, 2017, 05:51:09 pm1st of all, you want to use the ss2tf function since you're converting from state space to transfer function. Also bare in mind your system has 2 outputs so you need 2 tranfer funcions to describe it. Here's an example:Code:A=[-10,16.5,-7;-8,12.5,-5;-4,6.5,-3];B=[4;3;2];C=[1,-1,0;0,1,-2];D=[0;1];[b,a] = ss2tf(A,B,C,D); % Tranfer function coeficients (b will have 2 rows)sys1=tf(b(1,:),a); % Tranfer function of output 1sys2=tf(b(2,:),a); % Tranfer function of output 2sys1sys2figure(1)step(sys1);figure(2)step(sys2);If you need help with any specific function, just type "help function_name" in the command window and matlab will display all the documentation for it.
Matrix pad board with copper ground plane on reverse. Useful stuff? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 21, 2016, 02:00:19 pm
content: Whilst trying to get the hang of Eagle I continue with matrix pad boards. I see some suppliers offer a matrix pad baord with a plain copper ground plain on the reverse side, making an easily accessible ground from any point on the board. If you don't want a leaded or pinned component to be grounded you remove the area around that pin, on the ground side, with a drill bit. It seems great for many projects. Does anyone have experience of this? I could envisage high capacitance if you were not careful with high frequency circuits, but I rarely build such stuff save on commercially designed boards. Thanks for any insights.

author: Gyro
author_rank: Super Contributor
timestamp: November 21, 2016, 07:22:05 pm
content: QuoteOn the contrary, the main problem with using matrix board for high frequency/high speed stuff is the lack of a decent ground plane. The only drawback I can see (apart from the hassle of isolating non-grounded leads) is getting in to solder top-side ground connections if you go too dense (or don't plan ahead). I would say that the benefit outweighs this.

author: CJay
author_rank: Super Contributor
timestamp: November 21, 2016, 07:39:32 pm
content: Dartec RF proto boards are really excellent for HF work (and possibly beyond)http://stores.ebay.co.uk/DAR-Tec-Matrix-BoardsI've used a few now but still use cut out islands or even squares of scrap PCB stuck down to an unetched piece of laminate for quick lash ups that aren't intended to be around for long.

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 22, 2016, 05:44:57 pm
content: Some DarTec board arrived this morning and hey, it *IS* useful stuff, I wish i had come across this before, having a ground plane accessible from anywhere with the matrix pads on the other side is very handy. One has to concentrate though as soldering in say a IC socket and then finding you forgot to remove the ground plane around the correct pins is a PITA. But I would imagine that once you get used to working with it it is a very neat way to construct stuff, short of making a proper PCB.Thanks for the replies.

author: CJay
author_rank: Super Contributor
timestamp: November 22, 2016, 07:43:18 pm
content: Welcome, and don't forget the slug tape.
Max current output(s) of XL6009 DC boost converter circuits on eBay? - Page 1
Forum section: electronics / beginners

author: salil
author_rank: Regular Contributor
timestamp: March 26, 2015, 03:38:36 am
content: I can't seem to find what the maximum output current is of this DC boost converter and at what voltages...the seller doesn't know. Anyone know?http://pages.ebay.com/link/?nav=item.view&alt=web&id=281624716041I didnt see anything about output max current on the XL6009 data sheet. Any ideas?

author: codeboy2k
author_rank: Super Contributor
timestamp: March 26, 2015, 10:16:12 pm
content: The datasheet says 4A, the seller's text says 4A. However, I doubt it will push 4A without exploding.I would not run that at more than 1A maybe 2A without additional heatsinking. Then, when you do have adequate heatsinking, I still would not run it at more than 3A max.The LM2577 version has been around the net for a while, lots of people have posted in their blogs and here on the forum about their troubles with it not surviving.It's $1.51 and free shipping. Just buy one and characterize it yourself. I just bought one. I'm curious too.If I wanted to use it in anything I really cared about, I'd put it on a test bed and run it for up to 6 months on dynamic loads to give it something to be afraid of.

author: Seekonk
author_rank: Super Contributor
timestamp: March 27, 2015, 09:30:44 am
content: I use lots of those and really like them. They use the data sheet spec for the IC under ideal conditions. I would be cautious at even an amp with a heatsink. Biggest limitation is the inductor and diode. A circuit board just doesn't thermally conduct that well. Remember that an inductor can loose half its inductance when it heats up. You wouldn't put 4A through that inductor if you just used it as a resistor!Be sure to use extra input and output electrolytics with those.
max input CH1 question BG7TBL FA-3 - Page 1
Forum section: electronics / beginners

author: JeromeS
author_rank: Newbie
timestamp: March 11, 2024, 09:09:46 pm
content: Hi,I am definitely a newbie. As for this direction of electronics.And have a question about the BG7TBL FA-3.I can't figure it out myself, but what is the maximum V what the input of CH1 can be at 50Ω.I did read that 3V is the ideal V for measurements but can't find the max input value anywhere.I would love to hear it.Kind regards!Jerome

author: m k
author_rank: Super Contributor
timestamp: March 22, 2024, 06:06:46 pm
content: FA2 sensitivity is said to be up to 2V RMS, possibly same with 3V and FA3.Above that you start losing stuff.

author: kevin.gibbs
author_rank: Regular Contributor
timestamp: March 26, 2024, 03:40:47 pm
content: CH1 at 50 ohms sensitivity from 25mV to 2V RMS
Max input voltage for voltage reference? Is it unlimited? - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: July 17, 2022, 05:14:56 pm
content: What is the max input voltage for the MAX6006 or the LT1389? It's not listed in the datasheet? Could I theoretically have 100v on the "output" pin, as long as the current doesn't exceed 20ma?LT1389:https://www.analog.com/media/en/technical-documentation/data-sheets/1389fa.pdfMAX6006:https://datasheets.maximintegrated.com/en/ds/MAX6006A-MAX6009B.pdf

author: Andreas
author_rank: Super Contributor
timestamp: July 17, 2022, 05:43:22 pm
content: Quote from: LooseJunkHater on July 17, 2022, 05:14:56 pmHello,both parts are shunt references which work like a zener diode: so yes the "input = high side of resistor" can be any voltage.both parts are specified for a 2mA maximum operating current.You should stay away from the destructive limit of 20 mA. (= maximum rating)On the resistor you can apply the 100V provided there are no parasitic capacitances which may lead to excessive currents on powering up.with best regardsAndreas

author: Siwastaja
author_rank: Super Contributor
timestamp: July 17, 2022, 05:44:39 pm
content: Think about it - why is it unlisted?See the "typical application" on LT1389 datasheet front page. LT1389 has one pin on ground, and another outputs 1.25V. How does it know what is connected to the top of the resistor?In other words, the resistor sees Vin - 1.25V, so make sure the resistor can handle whatever input voltage, and also the power dissipation. But the reference only sees 1.25V.
Max./Recommended Load Capacitance for NTCs - Page 1
Forum section: electronics / beginners

author: Traceless
author_rank: Frequent Contributor
timestamp: September 06, 2025, 03:37:57 pm
content: Hi everyone,looking through some NTC Datasheets I stumbled upon the load capacitance property which isn't even provided by all manufacturers. Bourns specifies a "max. Load capacitance" in column six on page one intheir datasheet. TKS merely calls the spec "Recommended Load Capacitance", see page 4 inthis datasheet. Since the NTCs are used as inrush limiters more capacitance means more inrush current, but soemthing doesn't add up here. Take the Bourns BN-LG15Y3R0Mx (3.7W, 7A) vs TKS SCK15037 (3.6W, 7A). Both have a dissipation factor of 21 δ (mW/°C). Despite its slightly higher power rating the Bourns one specifies a much lower max. load capacitance (470µFmax.) in comparison to the TKS (680µFrecommended).Here a 3rd similarly specced NTC (NTC3D-15)which has an even higher permissible max capacitance (820µF, @ 240V) How does this make sense? Why is Bourns NTC so much worse than the lesser known brands? Also how important is the load capacitance and what happens if it exceeds the specs?

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: September 06, 2025, 05:35:18 pm
content: Bourns looks “worse” only because they publish a conservative maximum limit at high mains voltage. Smaller brands may quote larger numbers based on less conservative assumptions.
Max Vgs on J211 Datasheet - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: May 16, 2018, 06:50:01 pm
content: Hi,I was wondering what the Max VGs(off) = -4.5V value in the J211 datasheet is. I'm getting 0uA when I go to the Min VGs(off) cutoff of -2.5V and didn't see any change when I moved VGs lower (more negative). I have a 220 ohm resistor at the drain of a test VCR circuit.Datasheet:https://www.mouser.com/datasheet/2/308/J211-1120841.pdfThanks,Carl

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 16, 2018, 07:30:25 pm
content: Its the range of cutoff voltage across a selection of devices, you will never need more than -4.5V to get cutoff but some will cutoff as low as -2.5V

author: eev_carl
author_rank: Regular Contributor
timestamp: May 16, 2018, 08:54:57 pm
content: Does that mean that there are some J211's out there that won't cutoff at -2.5V (all 3 that I tried cut off at -2.5V)? Is the difference in packaging? The datasheet has an MMBF packaging for a surface mounted device that I didn't try.

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 17, 2018, 07:27:50 am
content: I think it just to allow them latitude for process variations so you should design your circuit to be abe to operate across the full range unless you want to follow a select on test procedure (can be expensive).As you can see they do not state a typical!

author: Kleinstein
author_rank: Super Contributor
timestamp: May 17, 2018, 01:51:40 pm
content: The cut off voltage with JFETs shows quite a lot of scattering between units. When you buy a few from the same batch, chances are they are a little closer together, but next batch can be quite different.The difference is not from the package, but from making the silicon chip.
MAX vs typical propagation delay on IC - Page 1
Forum section: electronics / beginners

author: coaxialgamer
author_rank: Contributor
timestamp: November 17, 2017, 08:56:42 pm
content: I'm currently working on a project involving logic IC's ( the 74F series specifically ) , and i'm slightly confused about the propagation delay ratings shown in the datasheets . Here's the specs found in the 74F374 for example ( below ).There's a huge difference when comparing the typical delay vs the maximum delay ( >50% or more! ). How is this rated?Does it mean the same IC , in the same operating conditions might suddenly take 2X longer one operation ? Or are those rating there to account for variability in the different chips themselves ? If that is the case , how often do they reach those max rating , and do the vast majority of the chips you buy run at typical speeds?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 17, 2017, 09:37:02 pm
content: A given chip will give consistent operation (low jitter). The measurement is taken over manufacturing variation.I don't know what statistics are used. I might guess about a 3 sigma cutoff, so you're very likely to get a typical part. (Note that the statistics of this particular parameter aren't going to be Gaussian, because the time certainly can't be negative. Likely it's a Gaussian warped by a physical process, so it has a minimum cutoff of so-and-so, a typical somewhat higher, and a long tail that is truncated by the max during testing.)Ideally, you should design your system so that, even if a single chip were malfunctioning, in such a way that it had extreme jitter from cycle to cycle, but still met its timing spec, the system still works. Clocked state machine logic has this property, which is part of the reason why it's so popular. (The other being it's easy to synthesize!) Such designs aren't always possible (many systems require controlled jitter, high frequency purity, that sort of thing -- especially cutting edge signal processing systems), but this helps whenever possible.Tim

author: danadak
author_rank: Super Contributor
timestamp: November 17, 2017, 10:29:15 pm
content: My experience as test engineer quite old, but we used 5 runs typically,and characterized most of those parts. Then added a fixed percentageguard band to that, 20% typically. Depended on process. This was beforebig data procedures were used.Customer specific parts test programs would be more extensive. Stufflike standard logic, were not extensively AC tested. Characterizationdata derived limits used. Then periodic samples taken and a characterizationtest tape was run on the parts still meet data sheet specs.You could contact an FAE at the vendor, and submit to him a list of questions.In some cases the FAE may put you in direct contact with production engineer.Regards, Dana.
max038 chip - Page 1
Forum section: electronics / beginners

author: Cali-Sam
author_rank: Contributor
timestamp: December 28, 2013, 07:50:07 am
content: Where can I get my hand on a Max038 or a similar chip?The only place I could find it was china through eBay...quite frankly, I'm not sure I want to buy such a chip from china..

author: Bored@Work
author_rank: Super Contributor
timestamp: December 28, 2013, 08:08:02 am
content: There are no reliable sources for them any more. Maxim stopped producing them some time ago. The story was somewhat along the line that the fab burned down and it wasn't economically viable to rebuild.

author: EEVblog
author_rank: Unknown
timestamp: December 28, 2013, 08:40:48 am
content: It is long since obsolete. Maxim don't have the required fab capability to produce it any more.

author: notsob
author_rank: Frequent Contributor
timestamp: December 28, 2013, 09:31:58 am
content: A quick search shows futurelec have them in stock for $US22.90 MAX038CPPhttp://futurlec.comnot sure of the authenticity of them tho

author: Cali-Sam
author_rank: Contributor
timestamp: December 28, 2013, 06:16:57 pm
content: Is there a chip that does a similar function??

author: fcb
author_rank: Super Contributor
timestamp: December 28, 2013, 06:21:08 pm
content: The daddy of the MAX038 was the ICL8038, it's possible there are more of these 'laying' around than the MAX038.

author: Unknown
author_rank: Unknown
timestamp: December 28, 2013, 06:26:47 pm
content: The modern way to do it would be a direct digital synthesis (DDS) chip from the likes of Analog Devices. There are some cheap DDS boards on eBay that some people on this forum seem reasonably happy with.

author: matkar
author_rank: Regular Contributor
timestamp: December 28, 2013, 06:33:10 pm
content: I've ordered it twice from different chinese sellers over Ebay. First was fake, the second didn't arrive. Recently a colleague ordered it from UK and it works fine. I'm going to order one from the same seller when he reopens the store after holidays.http://www.ebay.co.uk/itm/MAX038CPP-High-Frequency-Waveform-Generator-MAX038-/180860239105As I recall Maxim stopped producing this chip in 2006. Judging by the date code the one from UK is probably original. Some chinese chips are marked 09XX, 11XX and 12XX which is highly suspicious.
Max232 Rx pin TLL side 2 volt ripple - Page 1
Forum section: electronics / beginners

author: lk
author_rank: Regular Contributor
timestamp: October 24, 2012, 02:31:41 pm
content: GreetingsI decided to battle with my long time Nemesis, the rs232 port, so i made myself a TTL to RS232 converter using the max232. And what i discovered is that there is almost 2 volts of ripple on the TTL side (pin 12 on the MAX232) and that fact surprised me somewhat, i can see that it does send my signals trough from the PC serial, I'm just curious if this is normal. I did not notice any ripple on the RS232 side.I have anotherone of those converters i bought and that one exhibits the same ripple.I guess what I'm asking is if this ripple is normal or i should just ignore it?-lk

author: deephaven
author_rank: Frequent Contributor
timestamp: October 24, 2012, 02:34:50 pm
content: Sounds a bit strange. What frequency is the ripple? Have you got decoupling on the chips' power?

author: SeanB
author_rank: Super Contributor
timestamp: October 24, 2012, 03:50:46 pm
content: Max232, did you use the correct supply decoupling caps in the suggested layout, with them connected correctly. Cheap ones often do not use the right value caps.

author: lk
author_rank: Regular Contributor
timestamp: October 24, 2012, 05:20:11 pm
content: Thanks,was the newbie decoubling cap againpicure 1 is before he cap and picture 2 is after.I used a 10uf and that solved it, i guess i was baffled by the fact that the datasheet, atleast the part where i looked said that 4 caps are all that is needed, i used 4 ceramic caps, and did not think any more of it-lk
MAX232N converter circuit idels at 5v - Page 1
Forum section: electronics / beginners

author: sean87
author_rank: Regular Contributor
timestamp: December 03, 2012, 11:22:58 pm
content: Hi all,For a project I needed to make a RS232 to CMOS level converter. So I went ahead with MAX232 and 4 1uF caps. Just followed the schemtic here:This is the result from my PC's old school RS232 port (Yes I have a RS232 port on my PC!):After I fed the same signal into my MAX232N chip, I noticed that when I do not send something, it is idle at +5V....is this what it should it be? is this cmos level (Considering 5v PP) if not, what can be wrong?!for the 5v Vcc for the chip I used a LM7805 to convert 12v from a wall adapter to 5v and it works ok (I checked with multimeter).

author: kxenos
author_rank: Frequent Contributor
timestamp: December 03, 2012, 11:45:51 pm
content: MAX232 has inverted buffers in it so I think it is correct. Doesn't it work?

author: baljemmett
author_rank: Unknown
timestamp: December 03, 2012, 11:48:29 pm
content: Yes, that looks right -- RS232 idles in the logic high ('mark') state, so will be at 5V on the logic-level side of the MAX232. The RS232 data signals themselves should be negative (between -3V and -15V, with -12V being a common standard) for a high, and positive (again, between 3V and 15V) for the logic low ('space') state, so it looks inverted compared to the logic-level signals your uC will be working with. The MAX232 handles this inversion for you, in addition to the level shifting.Just to make life interesting the RS232 control signals (DSR, DTR etc.) arenotinverted, so a logic high is positive and a logic low is negative. Since you aren't handling those at all you don't need to care about this, but it's worth bearing in mind if you do need to probe them at some point.

author: sean87
author_rank: Regular Contributor
timestamp: December 04, 2012, 12:10:50 am
content: Thanks guys, I think its working fine since I managed send and receive correctly.

author: Psi
author_rank: Super Contributor
timestamp: December 04, 2012, 12:53:28 am
content: Most MAX232's seem to output around +/- 8V on the RS232 side.So not quite +/-12V but still within spec.

author: sean87
author_rank: Regular Contributor
timestamp: December 04, 2012, 02:55:25 pm
content: Quote from: Psi on December 04, 2012, 12:53:28 amThe first scope shot is from PC's serial port directly.
MAX30100 NDA datasheet - Page 1
Forum section: electronics / beginners

author: Yuri1737
author_rank: Newbie
timestamp: December 30, 2014, 11:30:44 am
content: Hi,I just bought MAX30100 ic but its manufacturer Maxim requires NDA for the datasheet and doesnt response for individual requests. Does anyone has any idea how to get the full datasheet for this ic?

author: free_electron
author_rank: Super Contributor
timestamp: December 30, 2014, 02:15:05 pm
content: Too bad. Find a different chip.The pdf files of such datasheets have watermarks embedded that tell you which nda they are under and for what company. So if they leak they can be traced back ...

author: amyk
author_rank: Super Contributor
timestamp: December 30, 2014, 03:06:20 pm
content: ...Then why did you buy it?If you bought it from some vendor in China, ask them for the datasheet...

author: FreddyVictor
author_rank: Regular Contributor
timestamp: December 30, 2014, 10:53:28 pm
content: can only suggest you look at similar sensors such as MAX21000 and hope they didn't change too much....

author: Marco
author_rank: Super Contributor
timestamp: December 31, 2014, 12:23:54 am
content: If you are at a University try to get your professor to broker a deal?
MAX4460 inst. amplifier - maximum differential input voltage difference? - Page 1
Forum section: electronics / beginners

author: Ptzf
author_rank: Newbie
timestamp: December 04, 2018, 01:53:35 pm
content: Hello!I have a hall effect current sensor that outputs 185 mA per Ampere. The quiescent voltage is 2.5 V at 0 A, the current sense signal is summed op top of that. My ADC unfortunately demands a maximum of 2 volts at the input (0-2V that is). Now, my solution would be to use a differential amplifier to subtract 2.5 volts at the inverting input and set the gain to around 3.5 (3 A max input, thus (0.185×3)×3.5=1.94 V).I went for a simple solution (I can be corrected here) and tried out a MAX4460 instrumentation amplifier to achieve the desired goal. I set the gain with R2=68k and R1=33k, as specified in the datasheet. I fed the inverting input a steady 2.5 VDC from a power supply. The non-inverting input signal was also fed from a power supply. The following behavior was present with or without a load resistor at the output. Inst. amp supply voltage was 5 V.What I discovered was that the output of the inst. amp. was very nicely around 0.00V at non-iverting inputs below 2.5 V. As soon as the input went above 2.5V, I saw a nonzero output. What puzzled me, however, was that as soon as I reached an non-inverting input of 2.94 V, the output latched to 5V (the difference between the input ports at this point was 400 mV). A few millivolts below and the output went back to around the expected ~1,3 V.The datasheet says that this inst. amp is meant to amplify small diferential signals, and even specifies some ranges for other models than the MAX4460.My question: Is this latching behavior at "large input" voltage differences a "real life" property of opamps (inst. amps in specific)? I'm a opamp newb, so I have the feeling that I'm missing something. Or in general - whats up with this latching?

author: Wimberleytech
author_rank: Super Contributor
timestamp: December 04, 2018, 06:44:52 pm
content: Quote from: Ptzf on December 04, 2018, 01:53:35 pmNo. Generally it is not a "real life" property of opamps.Not sure what's up with the latching.Their input structure may be this: US6559720https://patentimages.storage.googleapis.com/92/22/18/3f127117f41ba2/US6559720.pdf
MAX5389 resetting by noise - Page 1
Forum section: electronics / beginners

author: aless2056
author_rank: Contributor
timestamp: May 19, 2022, 01:09:06 am
content: Guys, I made a simple project with a PIC16F877 and a MAX5389, which is a digital potentiometer. I'm just connecting the UP/Down and Inc terminals directly to the PIC.Both the PIC and the MAX5389 have a 100nF capacitor next to the VDD and GND pin.The PIC also drives a transistor, which drives a relay to activate a contactor.It doesn't happen every time, but sometimes it happens that when activating the contactor, the MAX5389 resets and returns to the average resistance value it has when it is initialized (on power-up).How can I resolve this?Swap the 100nF capacitor for another one?Also include capacitors in the two connections between the PIC and the MAX5389 (On the connections with Up/Down and Inc).

author: free_electron
author_rank: Super Contributor
timestamp: May 19, 2022, 02:30:20 pm
content: the peak current in the relay coil creates enough of a power dip to reset the processor / max5389. you need to isolate the relay coil and provide a buffer.
MAX7219 + IRF520N + PI4 - Page 1
Forum section: electronics / beginners

author: Flekka
author_rank: Newbie
timestamp: November 13, 2024, 02:37:41 pm
content: Hi guys, this is my first "big" project. The idea is with a Rasp Pi4 controlling 6x 4digit 7 segment LEDs with 6 MAX7219CNG+ in series (each connected to 28x IRF520N). The LED panels have 13x 1.5V 20mA(3x4 with 150R 1x 470R). I only tried it with the first digit(7segment), because thats all i have atm. The LEDs lighted up fine running one of the demo program with the Luma library. My question is, do i have to modify something that i missed or add something before ordering a lot of components to make the whole thing with 6x4 digits.

author: xvr
author_rank: Frequent Contributor
timestamp: November 13, 2024, 06:23:46 pm
content: MAX7219 intended to be used in dynamic display configuration, not to directly control each separate LED.Quote'Big' project means 'use a LOT of MOSFETs' ?Correction - your circuit is something in the middle of 'direct' connection and classic dynamic display. And it will not work at all
MAX7219 LED segment driver insight - Page 1
Forum section: electronics / beginners

author: mayor
author_rank: Regular Contributor
timestamp: July 09, 2014, 12:40:22 am
content: Hi there,I am breadboarding a prototype for a power supply, components of which are 2 4-digit 7-segment LED displays. I am controlling a MAX7219 (http://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf) through SPI for the display.I am using a 100K resistor for now to control current (being conservative, per datasheet). For my tests, I have only one segment connected.My question: I measured 250mA across the chip's VCC which seems high. The chip gets pretty hot after a few seconds. Is it meant to dissipate this much energy (datasheet says ~.9W for SOIC)? If you can provide insight into the datasheet, or share experience with this IC, it would be appreciated.

author: mayor
author_rank: Regular Contributor
timestamp: July 16, 2014, 02:22:34 am
content: For anyone who cares, the MAX7219 doesn't normally run hot. Problem turned out to be a defective IC.
MAX7219 Reverse Voltage - Page 1
Forum section: electronics / beginners

author: MuhKuh
author_rank: Newbie
timestamp: December 01, 2012, 07:18:12 pm
content: Hi,I am confused about the way the MAX7219 works.According to the datasheet:- The MAX7219 pulls the digit outputs to V+ when turned off.- On the MAX7219, when a segment driver is turned off it is pulled to GND.So when the LED segment and digit is turned off it will have a reverse voltage of 5V. Of course the segment will be off this way but looking at different 7 segment datasheets I see that they all say:Absolute Maximum Ratings: Reverse Voltage: 5VIs there something I misunderstand or is the MAX7219 really driving the LEDs at their limits?

author: MuhKuh
author_rank: Newbie
timestamp: December 03, 2012, 11:21:09 pm
content: It looks like most LEDs survive higher reverse voltages than specified. Still strange the MAX7219 design runs the LEDs at the specified absolute maximum.
MAX9611 Current Sense Amplifier maximum continues current  - Page 1
Forum section: electronics / beginners

author: sean87
author_rank: Regular Contributor
timestamp: May 29, 2017, 11:43:54 am
content: Hi all,I want to monitor the current out of a power supply. The current I am going to measure is normally supposed to be between1.5A to 2.0A. I have some MAX9611 chips laying around that seem to be a good choice for this application. The typical application (per datasheet) is something like this:I have a big concern:The datasheet states that the maximum continues current into any pin is only20mAwhich is much smaller than my applications intended current measurement. My question is, can I still use this chip for measuring around 2A of current continuously without destroying it? If so, I guess it will be about choosing the right sense (shunt resistor) then what is the recommended value?

author: danadak
author_rank: Super Contributor
timestamp: May 29, 2017, 12:13:48 pm
content: I think this rating is to limit current into / out of pins that are taken outsidetheir common mode range to prevent CMOS latchup. Not a load current issue.https://en.wikipedia.org/wiki/Latch-upYou might contact the local FAE to confirm.Regards, Dana.

author: The Soulman
author_rank: Super Contributor
timestamp: May 29, 2017, 12:20:45 pm
content: The current shunt resistor will carry the current from your supply,From the datasheet:QuoteI'd recommend using 55mV full scale to minimize the power lost in Rsense.Assuming you'd want a full scale current of 3A, Rsense can be easily calculated with ohms law: R=U/I = 0,055/3 = 0,18 Ohms.Power dissipated by Rsense then would be P=U*I= 0,055*3 = 0,165 W So a 0,6 watt resistor would be sufficient.

author: sean87
author_rank: Regular Contributor
timestamp: May 29, 2017, 12:25:29 pm
content: Thanks! So you mean If I use a e.g. 18mresistor, the 2.5A current would not damage the chip right? So my understanding is that the current being measured is irreverent in regards to the RS+ and RS- pins of the chip as long as the shunt resistor is rated with a high enough watt ratings?

author: The Soulman
author_rank: Super Contributor
timestamp: May 29, 2017, 12:53:38 pm
content: Correct, with a appropriate shunt you can measure thousands of Amps with this chip.Another thing to keep in mind when designing your device is this one:QuoteNeither of the RS pins may go 0,3V below or 65V above the ground, not a problem in most cases but something to keep in mind.If you use the schematic from the datasheet you should be ok. (assuming your power supply is below 60V dc).

author: mikerj
author_rank: Super Contributor
timestamp: May 30, 2017, 10:45:51 am
content: Quote from: sean87 on May 29, 2017, 12:25:29 pmNote that 0.18 Ohms = 180 milliohms. If you want precision measurements you might want to consider a four terminal resistor.
Maximize laser beam hitting cadmium photocell - Page 1
Forum section: electronics / beginners

author: fixit7
author_rank: Regular Contributor
timestamp: June 07, 2019, 02:17:21 am
content: I am trying to maximize the amount of light that a red laser produces when it hits a cadmium photo cell.I went from a photocell with a small area to one with about double the area.I salvaged this from a laser printer and was wondering if that clear thing is a fresnel lens?Am also trying to figure what that clear led is.?There is a drawing on the circuit board that looks like this.LD1A |-->|CThanks.
maximum achievable speed by Kv - Page 1
Forum section: electronics / beginners

author: swatHuman
author_rank: Newbie
timestamp: August 13, 2024, 04:06:01 am
content: Hello Everyone!I was wondering if it is possible to find the maximum achievable speed of a brushless motor by looking at the Velocity constant Kv?Looking at a few definition of Kv here:https://en.wikipedia.org/wiki/Motor_constantsKv = W(no-load) / VpCould you please explain what is Vp here? is it the peak voltage measured across one phase to another phase of the motor? OR is this phase to neutral(midpoint of the star connected motor load)?Also I found this thread that has a different formula:https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1271711/mcf8315a-speed-control-issueElectrical Speed = (DC/sqrt(3)/(Back Emf in mV/Hz))*1000Could you please explain if they are the same?
maximum burden resistor across CT - Page 1
Forum section: electronics / beginners

author: embedded.world@aol.com
author_rank: Contributor
timestamp: July 04, 2014, 09:53:08 am
content: How to calcluate maximum burden resistance across CT.I have CT with 60Hz frequency.I want to generate 2.5V across it to measure it across adc.How to calculate what could be maximum & minmum values of burden resistor for proper operation i.e without saturating the core.

author: rob77
author_rank: Super Contributor
timestamp: July 04, 2014, 10:10:28 am
content: sorry i don't have my crystal ball with me , therefore i can't guess the missing details accurately to provide you a meaningful answer

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 04, 2014, 11:12:18 am
content: Too large a resistance and the winding inductance reduces gain and causes phase shift. The cutoff is: Rb <= 2*pi*F*Ls*/err, for err ~= 0. Example: err = 0.01 (a 1% gain error).This requires knowing the winding inductance, which is usually provided. Sometimes, manufacturers will give a recommended maximum resistance, directly.Tim
Maximum dissipation question  - Page 1
Forum section: electronics / beginners

author: crazyjim30
author_rank: Contributor
timestamp: March 26, 2016, 10:17:02 pm
content: Determine the maximum dissipation that should be allowed for a 75W silicon transistor rated at 22°C. Derating is required above 22°C by a derating factor of .35 W/°C at a case temp of 142°C. I'm stumped. Not sure where to even start. I'm going to take a smoke break before I throw my computer out of the window. I've been taking a test for 3 hrs.Sent from my SM-G900V using Tapatalk

author: uncle_bob
author_rank: Unknown
timestamp: March 26, 2016, 10:20:37 pm
content: Quote from: crazyjim30 on March 26, 2016, 10:17:02 pmHiLook more carefully at the terms. I believe you will find that one of them is not phrased the way you have typed it above.... hint (spoiler alert ...) ...It's on the same line as the number 0.35Bob

author: crazyjim30
author_rank: Contributor
timestamp: March 26, 2016, 10:33:25 pm
content: Quote from: uncle_bob on March 26, 2016, 10:20:37 pmNot getting the hint. Sorry. That's the question, word for word. I checked for typos.Sent from my SM-G900V using Tapatalk

author: uncle_bob
author_rank: Unknown
timestamp: March 26, 2016, 10:36:38 pm
content: HiOk:what is the delta temperature between 22 and 143 c?what is 0.35 times that delta?what is 75W minus that result?Bob

author: crazyjim30
author_rank: Contributor
timestamp: March 26, 2016, 10:51:11 pm
content: *sigh* That was so simple it hurt. Thank you.Sent from my SM-G900V using Tapatalk

author: uncle_bob
author_rank: Unknown
timestamp: March 27, 2016, 01:37:17 am
content: Quote from: crazyjim30 on March 26, 2016, 10:51:11 pmHiThus the initial hint about the lousy (or deliberately obscure) wording ....Bob