hybridfree/eevblog-posts huggingface dataset:
ADC reading falling overtime when measured - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 04, 2020, 07:38:06 am
content: 1. I am interfacing sensor thermopile and thermistor , whose data-sheet is attached.2. Here is schematic of 24 bit adc which is used to measure thermopile mV and thermistor mV.3. Issue is thermistor tempreature either keep on falling or increasing even if room tempreature is stable. It increase/decrease gradually in steps of 0.01 in either way sometimes up, sometimes down. I have pasted external fluke meter sensor to measure ambient its stable.4. Measured by CRO the REFPN remians stable also5. Is the filter capacitors? C1,C2,C3 and C8,C9 & C10? and resistors of 47ohm in series?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 04, 2020, 08:09:00 am
content: Driving the current through the thermistor should be from the ADCs reference. Depending on the ADC used the thermistor may be a little high in impedance.For the thermcouple one would also make sure the cold junction temperature is stable an known. Some ADCs may also have significant noise at the sub µV level.Even if the room temperature is considered stable local fluctuations at the 0.01 K level are not uncommon, but more like expected, if the sensor is not well shielded.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: July 12, 2020, 03:03:43 pm
content: I have removed C8 in #1. But still varation is there. But when i connect fixed 100K resistor there, I measure 25C without any fluctuation.1. One reason could be this, I was reading this. Currently minimum current which will pass thorugh my thermistor at 25C is = 3.3V/(100K + 100K + 100K) = 11uABut i was reading this pdf , here it says to have max 1 to 5uA .2. Can this be reason?Thermopile, has some sort of lens in front and whatever infrared falls onto it, it concentrates on inside. There we have thermopile and thermistor? Could it be reason, when heat gets into inside, it also heats up the thermistor? This is very random thought though. Dont know if this could be issue?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 12, 2020, 04:48:16 pm
content: Heating due to the current could be a problem, though I would consider it low. 11 µA at some 1 V ist only some 10 µW. At some 200 K/W this would be only 2 mK of temperature rise. The self heating effect would be always the same direction.Which ADC is used ?
ADC Reference power consumption issues - Page 1
Forum section: electronics / beginners

author: ConnorGames
author_rank: Regular Contributor
timestamp: February 24, 2013, 02:35:35 am
content: I am making an acceleration logger ( accelerometer running at 1ksps+some flash) that will be powered off of an ultracapacitor. To make the best use of my $11 adl337(provides ~12 significant bits of output), and keep power consumption low, I have selected the TI ADS8332 (Admittedly overkill, but too much is better than too little), partially because i can reduce power consumption by setting it to deep power-down when not in use(it has a 1uS wakeup time). The only issue is the reference input resistance is spec'd at 20k ohms, and I am using a 2.048 volt zener on a 3v3 supply. This means I would need to use quite a bit of power to keep the zener input above 2.048v, and using 200~300 uA of my 1-2mA power budget for that hard to swallow.How do I work around this using minimal board space and price? Do I just select another ADC? If deep power-down makes the ref inputs have higher resistance, I could always use an op-amp, but a) I don't know if deep power-down actually does that b)Opamps use a lot of board space and cost moneyThanks a ton for any suggestions

author: AndyC_772
author_rank: Super Contributor
timestamp: February 24, 2013, 08:32:25 am
content: Power your reference from a GPIO pin on your host microcontroller, and set it low when the ADC isn't being used. That way the reference is only drawing current when it's needed.

author: ConnorGames
author_rank: Regular Contributor
timestamp: February 25, 2013, 03:26:44 am
content: Do ADCs like this tolerate references being powered up/down well? I'll be taking it in and out of deep power down at 1 kHz, and it will never be disabled. Also, the datasheet says to use a 10uF cap across the reference inputs, so if putting the chip in deep-sleep doesn't increase reference resistance, I'll be unable to have the reference at the right voltage during the conversion unless I power it up long beforehand, so this approach doesn't work. I do like that way of doing it, so if anyone can verify the aforementioned things are not problems, I will use it!Mostly I want to know if putting the chip in deep power-down increases reference resistance.Thanks!

author: ConnorGames
author_rank: Regular Contributor
timestamp: February 25, 2013, 04:18:43 am
content: Probably going to go with another ADC for other reasons, so it's not an urgent question anymore
ADC selection for IR image sensor... - Page 1
Forum section: electronics / beginners

author: sangar
author_rank: Regular Contributor
timestamp: February 17, 2019, 04:21:29 pm
content: HiFor one of my projects, I am going to use ML8540. The problem I am having is in the selection of ADC to convert analog output from ML8540. I know it gives 6fps. So, below is my calculation for the minimum ADC sample rate from ADC to be selected,1 fps = 48 x 47 pixels = 2256 pixels6 fps = 6 x 2256 pixels = 13,536 pixelsthe above means that I should select an ADC which supports minimum 13.536K samples. Am I right? ...The second concern is ADC resolution...The spec says the measurement range is -30 to +300C and 0.5C resolution, here, what is the voltage step per 0.5 degree change ?please suggest...Edited: Attached the spec of ML8540Thanks,Sangar

author: Raj
author_rank: Frequent Contributor
timestamp: February 18, 2019, 04:40:44 pm
content: volts/step = (max volts out-min volts out) /330 i guess (for 0-5v out, its 0.0152v for each degree)any decent fast flash adc ,preferably parallel out, should doyou should attach, not link PDFsTrying to go for Indian military contract? (they'll need more resolution )

author: sangar
author_rank: Regular Contributor
timestamp: February 19, 2019, 04:13:36 am
content: Hi,Thanks...I have attached the spec of ML8540...The problem is that I am not sure how much voltage it will give per degree change. It is not clearly explained in the document...The things I made in the first post is my knowledge from reading the spec. Could you confirm for the same?.Thanks,Sangar
ADC Signal To Noise Ratio (SNR) Confusion - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 26, 2011, 04:32:00 pm
content: while searching for 1MSps ADC Chip datasheet. i look at SNR spec and most of them (at least 2 datasheet) showing similar figure. Below is the figure i got from 1MSps MAX153EWP (datasheethere). from what i know, that figure means its only usefull at 195.8KHz (KSps?) then what about and why it is speced at 1MSps? if the SNR at freq other than 195.8K are useless. or maybe i understand it wrongly, does it means the adc is feed with 195.8KHz signal, and the adc conversion is speced at around -80dB noise floor? what i expect is the SNR graph if the chip is to be feed by a range of input frequencies, say 0-1MHz sine input signal, and the graph will show the noise floor for each input frequency? is it too costly for that?since i'm at this, actually i'm looking for 10bit 1MSps ADC 1Channel input with parallel interface output, SOIC or smaller pitch. still dont have luck finding the right one. if you know some chip to recommend, or have worked with it before, i will appreciate your suggestion. thanks.edit: why 10bits? because i want to use 8bit only and since i expect there will be noise creeping in the low 2 bit, so i think i will skip the 2 LSB bit and get cleaner 8 bit in MSB, am i delusional here?

author: ejeffrey
author_rank: Super Contributor
timestamp: November 27, 2011, 11:30:12 am
content: That is showing the ADC sampling at 1 MS/s with a full-scale input signal of 195.8 kHz sine wave. You always must measure SNR of an ADC with some signal. Many ADCs have less than 1 LSB of random noise so if you connect constant DC voltage to the input you may measure zero noise due to the quantization error.There are two main things you can tell from this type of plot. The first is the baseline. That is the broadband noise that is independent of signal (as long as your input is properly dithered). The second is harmonic distortion. The peak at 390 kHz is the second harmonic of the test tone. In principle you could also see spurious tones: narrow peaks that are not harmonically related to the test signal, but there don't appear to be any that rise above the noise floor here.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 27, 2011, 12:48:02 pm
content: thanx jeff. so what about test signal for other frequency? say at 500KHz? can i safely assume the same plot? -80dB other frequency SNR, and one harmonic at 1MHz at a bit lower than -60dB?
ADC with non-linear sensor - Page 1
Forum section: electronics / beginners

author: Hayat Qurt
author_rank: Newbie
timestamp: April 30, 2013, 09:18:03 am
content: I have a question regarding ADC . What is the best way ( fastest) to match the reading from the ADC output with non-linear sensor output ?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 30, 2013, 09:28:45 am
content: Depends on the mcu and how much memory you have.If you had lots of ram you use the ADC input which is an integer, as an index into a lookup table.If you are shorter on ram then you could do the same but make the lookup table (array) smaller and interpolate the point.

author: Neilm
author_rank: Super Contributor
timestamp: April 30, 2013, 06:55:04 pm
content: Look at the analogue signal and see if it could be linearised before it reached the ADCNeil

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 30, 2013, 07:22:40 pm
content: Depends on the way it is non-linear of course, maybe you can just calculate the result, just to name another solution.

author: ejeffrey
author_rank: Super Contributor
timestamp: April 30, 2013, 09:40:43 pm
content: Lookup table with interpolation if necessary.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 30, 2013, 09:45:42 pm
content: Quote from: Neilm on April 30, 2013, 06:55:04 pmIf you can do it by software, save on hardware.David.

author: jmole
author_rank: Regular Contributor
timestamp: April 30, 2013, 09:49:07 pm
content: The problem with linearization in software is that you're wasting a ton of bits on data that might not even matter, especially if your signal is logarithmic or exponential in nature.Check out this app note for details on building a log amp:http://www.analog.com/static/imported-files/tutorials/MT-077.pdf

author: nerdyHippy
author_rank: Contributor
timestamp: April 30, 2013, 10:23:39 pm
content: Quote from: HackedFridgeMagnet on April 30, 2013, 09:28:45 amIf speed isn't an issue it's always possible to store the LUT in program memory to save RAM.
ADC0804 test - zero offset and scope corrector. - Page 1
Forum section: electronics / beginners

author: toboswarley
author_rank: Newbie
timestamp: May 27, 2014, 07:29:11 pm
content: It's my first post on this forum so I say hallo! My name is Tobo and I came from Poland.I hope You know how to help me.I have problem with adding to ADC0804 tester zero offset corrector and scope corrector. I based on circuit from datasheets ADC0804 (http://www.ti.com/lit/ds/symlink/adc0804-n.pdfpage 27). Do You know how to do that?My english is not very good, so I please to use simple language as far as is possible.My circuit:
ADCMT 6241 LabVIEW Example - Error When Running VI - Page 1
Forum section: electronics / beginners

author: Evan11223344
author_rank: Newbie
timestamp: February 12, 2025, 04:21:55 am
content: Hello everyone,I am trying to control an ADCMT 6241 precision source meter using LabVIEW, and I encountered an issue when running the example VI provided by ADCMT.System Setup:ADCMT 6241 connected via USBLabVIEW (2017 32-bit)ADCMT 6241 official LabVIEW driver and example VIProblem:When I run the example VI, I receive the following error:(Poly VI 'Read.vi':SubVI is missing)Has anyone encountered a similar issue with ADCMT 6241 and LabVIEW?Any suggestions on debugging or modifying the VI to fix this error would be greatly appreciated!Thanks in advance!
Add a fixed negative offset to the output of a opamp buffer  - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: January 02, 2024, 02:11:07 pm
content: Hi all,I'm trying to add a -100mV offset to the output of an opamp which is a just a non-inverting buffer with no gain.I thought that passively mixing a fixed offset with a high valued would do the trick and it seems to work in simulation but I'm not sure I'm doing correctly.I attached the schematic of my simulation.

author: CaptDon
author_rank: Super Contributor
timestamp: January 02, 2024, 02:30:46 pm
content: Take all of that stuff away from the output that you have proposed. Insert something like a 1K resistor in the negative feedback loop then connect a 100K resistor to the negative input pin of the opamp. the free end of the 100K resistor can attach to the wiper of a pot of perhaps 100K. There are two ways of connecting the free ends of the pot. One end to your +12 and one end to your -12 gives you the ability to have both a positive and a negative offset up to about 1/100th of your supply voltage. Decrease the 100K series resistor if you need more offset. Your buffer will however show a small amount of gain due to resistance in the feedback loop. The other way of connecting the pot is one end at ground and one end to either supply depending on if you want minus only offset or positive only offset. Take your output directly from the opamp output. The offset adjustment ends up being on the input side of the negative feedback loop.
Add a PSpice command to a schematic - Page 1
Forum section: electronics / beginners

author: AJollet
author_rank: Newbie
timestamp: March 27, 2017, 09:31:14 am
content: I'd like to know how to add raw PSpice commands to a design in OrCad Capture. So far I've done everything using the menus but that's quite limiting.Editing the output file seems complicated and it will be overwritten each time I lauch a simulation anyway.So how can I add let's say ".IC V(1) = 0" to my design ?
add backlight to LCD  - Page 1
Forum section: electronics / beginners

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 10, 2013, 11:41:35 am
content: is it possible to add backlight to an exist LCD display like this one for example?

author: garak
author_rank: Contributor
timestamp: November 10, 2013, 11:56:58 am
content: Sort of. It's generally more of a pain than just getting an LCD with a backlight though. You'll probably have problems getting even illumination and a whole host of other things, assuming you can even get the backlight behind the LCD as there's not usually any space. Most people resort to frontlighting for this reason.Bottom line: Yes, but it's probably more trouble than it's worth. You're better off finding a backlit display to start with.

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 10, 2013, 12:02:48 pm
content: this screen HAS backlight version but i can't find it anywhere...

author: SeanB
author_rank: Super Contributor
timestamp: November 10, 2013, 12:52:36 pm
content: You can add a small set of white SMT LED's at the sides but it will give poor illumination without the proper back diffuser screen.
Add Hysteresis to Window Comparator Circuit - Page 1
Forum section: electronics / beginners

author: ghassan
author_rank: Contributor
timestamp: September 25, 2017, 10:01:28 pm
content: Hello,I am unable to build a stable window comparator that accepts input voltage from 21 Volts DC till 30 Volts DC.SO i think if the HYS was at 1V then it would fix the situation better.When i add a capacitor 1uF or greater at the drain pin of "M2" , things get crazier .Label "main_vin" without "R9":I would like to build a window comparator similar to this IChttp://cds.linear.com/docs/en/datasheet/4418f.pdfDo you think it is safe to use a zener diode 6.2v as a regaulator from 24v supply or 30 vdc or greater!!! ?I am looking for a fast start regualtor that is why i thought of using a zener diode . Your recommendation is appreciated.By the way , resistor "R_MON1" or "R_MON2" shows that each comparator is dissipating continuous 16 mA which is bad for a battery .Is there a fast comparator with low power dissipation ?I appreciate your help.

author: ghassan
author_rank: Contributor
timestamp: September 26, 2017, 11:20:50 am
content: How to add hysteresis 1V ?

author: danadak
author_rank: Super Contributor
timestamp: September 26, 2017, 12:06:40 pm
content: These might help -https://www.maximintegrated.com/en/app-notes/index.mvp/id/3616http://www.ti.com/lit/ug/tidu020a/tidu020a.pdfhttps://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-071j-introduction-to-electronics-signals-and-measurement-spring-2006/lecture-notes/24_op_amps3.pdfCalc tool -http://sim.okawa-denshi.jp/en/compkeisan.htmRegards, Dana.

author: macboy
author_rank: Super Contributor
timestamp: September 26, 2017, 05:18:52 pm
content: Comparator U2 already have hysteresis, via R9 and R12, which provide feedback to the positive inputs. You can adjust those resistors to change the hysteresis (smaller R = more delta V).Why label node main_Vin at two points in the circuit, instead of drawing the short connection between them? This makes it hard to read the schematic, because it is unusual and unexpected on such a small schematic.

author: ghassan
author_rank: Contributor
timestamp: September 27, 2017, 02:02:56 am
content: I have a problem and I would like it to get fixed . Zener Diodes D1 and D4 are acting as regulators and their output voltages raises when the input voltage at main power supply changes which is causing voltage references to change.Is there any better solution with fast and stable regulation ?.Do you prefer to use High Voltage Comparator instead of using 5v comparator since my power supply would be changing from 20VDC till 30VDC .Your help is highly appreciated

author: macboy
author_rank: Super Contributor
timestamp: September 28, 2017, 07:28:59 pm
content: Zener voltage always varies a little bit with changing current. You can try to pre-regulate with another zener stage before the 6.2 V one. Make the first stage, say, 12 V. This will vary a little bit too, but much less than the 20 to 30 V input voltage. This should provide a more stable input to the 6.2 V stage, which will then have a more stable output.
Add symetry control voltage to a low freq oscillator - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: April 07, 2023, 05:34:05 pm
content: Hey all,I was wondering how I could add a control voltage signal (say a +/-5V AC signal (triangle sine or whatever ) to a symmetry offset of a low frequency oscillator.I attached the schematic of the LFO and highlighted the node of interest.This node needs -6V DC for the output to be a triangle at the range I'm interested in (I don't use the other one so let's say that the summing 100k is tied to a single pot)With about -5V I get a rev saw and -7V I get a saw so my whole range is +-1V and at mid level it needs to sit a -6V.Now the tricky part:I can scale a -+5V control signal to be +-1V with an inverting amplifier of 1/5 gain.Directly feeding that +1 signal with a decoupling cap to the 100k I get a tiny amount of change at the output.The result is almost neglible so I thought that maybe those voltages were in parallel and the bigger always wins so I tried adding that offset with another 100k going to the inverting input to properly sum them at that node but I get almost the same results!What can I do to make it work?Do I need to rectify the control signal and feed it as a proper offset? I don't understand why it doesn't work.EDIT : It seems that the decoupling capacitor between my control voltage and my 2nd 100k summing resistor was loading the opamp down probably because of the vgnd there. I removed and attached the output of the scaling opamp directly to the 100k and it seems to work!
“Adding” 4 audio signals? - Page 1
Forum section: electronics / beginners

author: 240RS
author_rank: Regular Contributor
timestamp: December 20, 2021, 11:00:55 am
content: I have 4 microphones with 4 audio signals that I expect to sum op to zero. Ultimately I want to detect whether the sum of the signals is below a threshold.I ran a test with two signals of which I inverted one. I fed those into an opamp and was very pleased to get the difference (which is the sum in reality). Believing I had found the way. But then got stuck extending that idea to 4 signals.Which made me wonder: is there a standard way to add two and more signals? My signals are between -1 and 1V, 40 to around 1kHz.Thanks!!

author: Berni
author_rank: Super Contributor
timestamp: December 20, 2021, 11:16:28 am
content: https://www.google.com/search?q=op+amp+sumWorks for any number of inputs, just add resistors.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: December 20, 2021, 03:42:14 pm
content: You wanto hear the audio ?,then you need to use half the volume when mixing more harmonics.You only detect the volume ?, then distortion dont matters, go to the limits.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 20, 2021, 04:46:41 pm
content: https://www.electronics-tutorials.ws/opamp/opamp_4.htmlFor least phase error use DC coupling where possible. The majority of modern opamps won't work as comparators. A TL07x?Between the summer and the comparator you are going to need to turn the signal to DC. The Simplified Peak Reading Detector is the thinghttps://sound-au.com/appnotes/an012.htm

author: 240RS
author_rank: Regular Contributor
timestamp: December 20, 2021, 07:09:36 pm
content: Wow! Why had I missed that basic circuit. Thanks! And issue more than solved. No more inverting.
Adding a LV winding to a mains toroidal transformer - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 25, 2014, 10:08:10 pm
content: If I add a few turns of 14 swg enamelled wire to get 14v AC from a new toroidal mains transformer that gives 2 x 35 volt AC outputs as standard, should I spread the windings around the core equally, or keep them close wound on just a section of the core? Thanks.

author: amyk
author_rank: Super Contributor
timestamp: November 25, 2014, 10:11:46 pm
content: It shouldn't matter for voltage since the flux circulates in the whole core.

author: Fank1
author_rank: Regular Contributor
timestamp: November 25, 2014, 10:24:43 pm
content: Spread them out,

author: Zero999
author_rank: Super Contributor
timestamp: November 25, 2014, 10:59:54 pm
content: I agree. Spread them out as the heat will dissipate more evenly.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 25, 2014, 11:39:06 pm
content: Spreading them out also gives lower leakage too. If you're not drawing much current, neither this nor power dissipation will be a problem though.Total VA is still limited by the primary wire gauge, of course.Tim

author: SeanB
author_rank: Super Contributor
timestamp: November 26, 2014, 05:50:17 pm
content: Wind evenly around the core, and then insulate with mylar tape (not PVC insulating tape, but silicone self amalgamating tape will do here) to keep them from shorting to the chassis. The mounting kit should have a big dished washer and 2 silicone rubber disks to isolate the transformer. Sleeve the leadouts with glass fibre sleeving to keep them from shorting.

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 27, 2014, 11:08:51 am
content: Thanks Sean, will be doing this tonight, with luck, the transformer did come with dished washers and rubber insulators. I have had Kaptan tape arrived in the post this AM, to protect the new winding. Cheers.

author: SeanB
author_rank: Super Contributor
timestamp: November 27, 2014, 06:10:02 pm
content: I rewound a toroid ( it had been cooked rather well by a shorted secondary) and converted it into a current transformer, using only the core and the plastic end caps, then making a new secondary of 12 turns of 2.5mm wire and then simply had a primary pass through it. Connected to a 5A AC ammeter and it did sterling duty to measure incoming mains current. It originally was used for a 50W downlighter, so no problem here of core saturation, it probably would have worked up to 1kA primary current, though I would have had a hard time getting the 200 turns of wire through the centre along with the 35mm primary wire.
Adding a super-capacitor in the output stage of a switch mode power supply? - Page 1
Forum section: electronics / beginners

author: abhishekkumar1902
author_rank: Regular Contributor
timestamp: May 03, 2017, 08:05:25 am
content: I just wanted to ask like what happens when you add a very large capacitor (supercapacitor ~ 4F) in the output stage of a switch mode power supply like the ones that are found in mobile chargers and all. Does it affect the efficiency of the power circuit? Does it improves anything?

author: ebclr
author_rank: Super Contributor
timestamp: May 03, 2017, 08:11:23 am
content: Put a wire instead will be the same effect of a 4 F capacitor, will burn the power supply

author: abhishekkumar1902
author_rank: Regular Contributor
timestamp: May 03, 2017, 08:22:54 am
content: Oh is it, But how?

author: ebclr
author_rank: Super Contributor
timestamp: May 03, 2017, 08:32:09 am
content: Was a joke, a 4F capacitor will be a short circuit on the output of your power supply for a good time, if and only if your power supply does not burn on the time 4F need to be charged, then will be a nice reserve of energyIn other word forget this idea

author: tszaboo
author_rank: Super Contributor
timestamp: May 03, 2017, 08:40:34 am
content: A 4F capacitor could have 10mOhm ESR, so on 5V it could take 500A for a few milisec. This is not how you make fast response power supplies, and not how you make UPS. I was working with a 100F capacitor. Charged, it contains the same amount of energy as a 9mm bullet, and it can release it just as fast. Not a toy.

author: abraxa
author_rank: Frequent Contributor
timestamp: May 03, 2017, 08:52:17 am
content: Aside from the charging inrush current issue that was already mentioned, there's also the issue of short-circuiting the output of the power supply. Imagine your power supply features such a supercap directly (!) at the output and something shorts it. The connected circuit will now see all the energy from the supercap pumped into it, even if you set a current limit on the power supply. Most likely not what you would want to happen.To avoid this, you'd have to put the supercap before the current regulation stage in the PSU - however, that stage usually also has the filter capacitors for smoothening out the DC voltage, so there's plenty of capacitance there already. Sure, the capacitance would be much higher in that case, but there's not much benefit unless you have a load with a wildly (and abruptly) changing load profile.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 03, 2017, 08:58:20 am
content: My highest current power supply support 100A.And when charging a 3500F 2.7V supercap, this capacitor really takes 100A for a many seconds.It is like a short.Super capacitors can be very dangerous.Be careful what you are doing, even with 4F

author: Brumby
author_rank: Unknown
timestamp: May 03, 2017, 08:59:39 am
content: If you really want THAT much smoothing - use a battery.

author: rob77
author_rank: Super Contributor
timestamp: May 03, 2017, 09:04:34 am
content: Quote from: Brumby on May 03, 2017, 08:59:39 am+1and the battery is cheaper and have a better energy density.
Adding adjustable over current protection to large server SMPS units? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 22, 2017, 10:12:06 am
content: I use a few 52V at 50 odd Amp computer server power supplies made by HP for my LF amplifiers for amateur radio. it would be very useful to have at least one with some form of external, adjustable, fast acting over current protection. If it could work from say 5 Amps to 40 Amps that would be ideal. Is it viable and what would be the best way of achieving this without internally modding the SMPS? Thanks.

author: Kalin
author_rank: Regular Contributor
timestamp: April 22, 2017, 11:49:34 am
content: Would an online fuse on the output be fast enough action for what you need?Sent from my SM-G930W8 using Tapatalk

author: max_torque
author_rank: Super Contributor
timestamp: April 22, 2017, 12:32:43 pm
content: 52V at 50A is getting tricky to break, and you'd need to use semi-conductor switches to get any kind of sensible reaction time (<1ms) A parallel array of charge pumped N-FETs will probably be required, with suitable current sensing and either analogue comparator based triggering or a small micro etc.That's assuming you want a simple "when the current exceeds this value, turn off" type arrangement. If you want a constant current control, then the task gets really hard, because the potential power dissipation in the 'switches' becomes large.

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 25, 2017, 06:27:44 pm
content: This is what I feared, it needs to be fast otherwise I might as well use a simple fuse. Any idea how many devices I would need to parallel to safely switch that sort of current and voltage? Thanks for all the replies.

author: bingo600
author_rank: Super Contributor
timestamp: April 25, 2017, 06:40:01 pm
content: Maybe have a look @some of the large HP LABSUPPLY's schematics , ie. the 60xx series.I think they use a "Crowbar or SCR" to pull output down , if a condition is exceeded/Bingo
adding am/fm tuner to hifi amplifier - Page 1
Forum section: electronics / beginners

author: daneprostamo
author_rank: Newbie
timestamp: April 15, 2018, 12:02:07 pm
content: hey guys i have purchased myself one of these 2 channel TAS5613 chip based mini hifi amps as it meets my requirement for higher rms output that some cheaper models lack.https://www.aliexpress.com/item/The-wind-TPA5613-BA10C-2-1-channel-bass-gun-with-Bluetooth-4-optional-power-amplifier/32719281168.htmlone thing i found virtually all of these higher power output style amps lack is an am/fm tuner build in so i planned to retrofit one into the input. where i was having trouble was finding the appropriate physical board/module that i should use for this task. i planned on simply wiring it into the rca input of the board which shouldn't be an issue. any recommendations on what to use is greatly appreciated! cheers

author: daneprostamo
author_rank: Newbie
timestamp: April 16, 2018, 03:53:17 am
content: to add to the initial post i was initially looking at a unit like this to use--https://www.aliexpress.com/item/New-Arrival-for-87-108MHz-DSP-PLL-LCD-Stereo-Digital-FM-Radio-Receiver-Module-Serial-Control/32762686047.html?spm=2114.10010108.1000023.10.48a248fdo4GFyZI couldnt find hardly any info on the chip used or decent specifications so i was hoping there may have been a superior product but worse case scenario any input on whether or not this type of board is suitable to use in place of the original amplifiers rca input is greatly appreciated
Adding Current Regulation to a Variable Lab Power Supply  - Page 1
Forum section: electronics / beginners

author: Cattmy
author_rank: Newbie
timestamp: September 01, 2013, 07:12:31 pm
content: Hello all,I am more a chemist than an electronics guy, so I am wondering how I could add variable current tothis Instructable. It is in essence a power supply made from a Micro ATX power supply that already has variable voltage. I am mainly using this for charging supercapacitors and electrolysis. Any guidance would be much appreciated!Thanks in advance.

author: Paul Price
author_rank: Super Contributor
timestamp: September 02, 2013, 01:25:24 am
content: The idea is to sense the current to control using a tiny-ohm valued sense resistor, amplify the voltage produced by the current through the sense resistor and then use this voltage to control a pass element/regulator/transistor/MOSFET.See the attached, the current sense resistor's amplified output controls the current out of the LM317.

author: echen1024
author_rank: Super Contributor
timestamp: September 02, 2013, 01:31:19 am
content: This is exactly what I was looking for. Do you have an Eagle schematic, or a finer drawing, so I can read the component values? Any help would be appreciated. Thanks.

author: TerminalJack505
author_rank: Super Contributor
timestamp: September 02, 2013, 07:56:40 am
content: Here's a few simulations that use an INA169 high side current shunt monitor. They work exactly like Paul explains. The control voltage Vsetdetermines the maximum output current. 1A output per 1V input. Vsetcan be set using a 10-turn pot, for example.I haven't built either of these so they may not work as-is, if at all.

author: dr_p
author_rank: Frequent Contributor
timestamp: September 02, 2013, 09:11:25 am
content: if you're not too sure about you're doing, a cheap and easy way to add constant current (current limit) is to power your linear regulator fromone of theseinstead of straight from the ATX board. In a linear regulator (LM317) the current going in isequalthe current going out, so you get away with limiting the input current.

author: Paul Price
author_rank: Super Contributor
timestamp: September 02, 2013, 12:04:41 pm
content: All the component values are clearly marked.Just download and open these pictures in a picture viewer that has zoom.I can easily read the values just from clicking on the picture schematics shown here on this page.

author: Zero999
author_rank: Super Contributor
timestamp: September 02, 2013, 02:04:22 pm
content: If you open the pictures in a new browser window, the whole picture will be automatically scaled to fit.

author: echen1024
author_rank: Super Contributor
timestamp: September 02, 2013, 02:12:37 pm
content: Ok. Tried that. Thanks.

author: TerminalJack505
author_rank: Super Contributor
timestamp: September 02, 2013, 07:35:30 pm
content: Another method is to use something like an LM317 or TL431. See their datasheets.The good news is the circuit is much simpler. The bad news is the transfer function is crap. See attached.
adding esr to mlcc capacitors.. - Page 1
Forum section: electronics / beginners

author: bobbydazzler
author_rank: Regular Contributor
timestamp: August 19, 2021, 04:38:48 pm
content: Just wondering if it matters which side of the capacitor you add a resistor to to add esr to a capacitor? ie is adding a resistor to the -ve side wrong in some way? I've been adding it to the vcc side because that's what circuit diagrams I see do.

author: TimFox
author_rank: Super Contributor
timestamp: August 19, 2021, 04:42:56 pm
content: The only way I could see that the side of the capacitor matters would be an Al electrolytic cap, with the metal can connected to the negative terminal. The stray capacitance from the can to “ground” would be in parallel with a resistance in the negative lead for a grounded negative connection. MLCCs have far less (but non-zero) capacitance from the body to the environment.

author: David Hess
author_rank: Super Contributor
timestamp: August 20, 2021, 11:34:34 pm
content: In a low impedance application like decoupling it does not matter.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 21, 2021, 07:30:23 pm
content: It generally does not matter.Therefore, you could swap it if it makes routing on the PCB easier.
Adding Ethernet to my project - Page 1
Forum section: electronics / beginners

author: michaelym
author_rank: Regular Contributor
timestamp: August 08, 2012, 07:13:16 am
content: I currently send data via USB - virtual com port.I want to add Ethernet capability, so my project would have an IP address and I can get the data through a network.The data being sent is a simple string of about 100 characters.Where do I start?

author: notsob
author_rank: Frequent Contributor
timestamp: August 08, 2012, 07:32:47 am
content: - It would be a GOOD idea to actually provide some details of your "project" - so others can provide better guidance or help.Anyway, have a look at wiznet  or if your were doing some sort of microcontroller development, you may wish to look at a micro with ethernet ( ie PIC18F97J60 for example)

author: michaelym
author_rank: Regular Contributor
timestamp: August 09, 2012, 06:00:12 am
content: Once a minute I need to send to a computer a string of about 100 characters. It must be done through the network.I'm new to Ethernet, so I don't understand a few concepts.With "regular" serial communication SPI of UART , you simply "send" the byte.I understand that with Ethernet it's not so simple. If I add the WIZ820io or have a micro with Ethernet what extra things do I need to do in my code? How do I communicate with and send my string to a specific IP?Thanks

author: SeanB
author_rank: Super Contributor
timestamp: August 09, 2012, 06:25:24 am
content: There are serial to ethernet designs, that are a serial interface on one side, and have the ethernet stack, the phy and such all in a simple bolt on board. There are open source designs around, so you just add them to your existing device. They either have a tiny webserver on them or you communicate via udp packets that they send, but your device only has to send a serial data stream in to it, or get one back.

author: yyrkoon
author_rank: Newbie
timestamp: August 09, 2012, 06:42:36 am
content: You can also do IP over USB. Or some years ago you used to be able to. As for the details. I have never looked into it.I get the feeling you're already entrenched in a project, but might I add that some micro kits out there come with Ethernet / wireless Ethernet included. Usually, they have some sort of web server implementations. Which can be used with, or without an OS. You'd at minimum have to learn basic HTML, javascript, but once figured out it can be really simple and easy to create good looking / functional web interfaces.Much easier than mucking around with bits on the Ethernet layer level, but not sure if that is what you're looking for.

author: T4P
author_rank: Super Contributor
timestamp: August 09, 2012, 11:42:54 am
content: Those are just cables ... cables will be cables, just only how many pieces you need for an "interface"
Adding external audio to existing car sterio. Toyota Avensis B9010 - Page 1
Forum section: electronics / beginners

author: Sprutbærsj
author_rank: Contributor
timestamp: July 07, 2015, 10:03:54 pm
content: Hello.TL;DR:Want to connect phone to the car. Schematic from automotive shop. Can't understand shit. Need help.Background:I was hoping there was an easy way to connect external audio (aux, phone, usb...) to my car. This is the unit without the option for Bluetooth and have no existing line-in connection that I have found.My local shop could support me with what they have in terms of schematics of the car (see below).I can't find anyone online that have worked around or found an easy solution to this problem. I was hoping not to change the enitre unit as it costs 7000,- nok (~$850 US) for a retail one (from dealer). Ebay ones go for 4000,- nok (~490$ US). The cheapos online goes for anything from 2000,- to 4000,- nok (240$ - 500$ US). And then there is the problem with connections and what not.I have found some third-party devices that could(!) support the unit, but some specify the B9010 as not compatible.It is possible to remove/reuse/reconstruct/destroy a compartment above the existing unit and place a separate device there. It is a useless compartment anyway.Situation:Add external audio to existing car stereo, video is bonus. Less modification to existing setup is ideal.Additional screens are possible and might be preferred in terms of backing-sensors/camera and what not.External FM transmitter is possible, but strongly preferred to avoid.Preferred parameters:Automatic power on/offHandsfreeAuxOnboard storage; usb, sd, hddSpotify on unitConnected to buttons on steering wheelRearview camera / parking sensorsSolutions:Substitute entire unitThird-party unitThird-party deviceConstruct new unit; mini-pc..?Seperate/additional amplifier to speakersFM transmitter to existing unitMaterial:Budget: ~400$ USOriginal unit from ebay:http://tinyurl.com/nh2vnu3,http://tinyurl.com/nmhtfupThird-party device (might not be compatible!):http://tinyurl.com/oxd75fy,http://tinyurl.com/nz29z6lLink to schematic 1/2:http://tinyurl.com/pxqsds9Link to schematic 2/2:http://tinyurl.com/qgpnhh5All help, feedback, tips is much appreciated

author: Sprutbærsj
author_rank: Contributor
timestamp: July 07, 2015, 10:18:27 pm
content: Interior:http://tinyurl.com/o6dnu5s,http://tinyurl.com/purhocqBackside of B9010:http://tinyurl.com/naefnpjUnit removed:http://tinyurl.com/nej2ompGood thing I know how to edit
Adding external DC power to 2xAA device - Page 1
Forum section: electronics / beginners

author: Theronlas
author_rank: Newbie
timestamp: November 01, 2015, 04:34:56 am
content: I have a wireless rain gauge, it works pretty well but the external sensor's batteries last only a month or so. Replacing the batteries requires resetting the receiver (and losing the stored data).There is an irrigation controller nearby (<3m) so I have access to its 24V AC transformer output (screw terminals). I was thinking to tap and rectify that, pass it through a cheapo DC-DC convertor and run the sensor from that. If possible however I would like to keep some sort of battery backup to stop a power outage from disconnecting the sensor from the inside unit (they do not automatically connect only when the RX power's up), looking for a simple way to do this?Can I just feed a pair of AA NiMH cells with less than their full voltage (say 2.5V, unit works fine there) indefinitely, or is that asking to kill them?Also where is a good place to get the few parts I am likely to need, (diode + cap + DC converter i guess)?Thanks

author: nowlan
author_rank: Frequent Contributor
timestamp: November 01, 2015, 05:09:42 am
content: You can use the battery & dc converter in parallel with diodes.

author: Theronlas
author_rank: Newbie
timestamp: November 01, 2015, 07:17:40 am
content: Quote from: nowlan on November 01, 2015, 05:09:42 amTHat would require modifying the device, as far as I can tell the plastic is sealed, would need to cut into it. I suppose I could mount batteries elsewhere, instead of in the holder.

author: SeanB
author_rank: Super Contributor
timestamp: November 01, 2015, 08:27:26 am
content: Put a pair of NimH cells in the unit, and see if it works with them. Then simply use a bridge rectifier and a series resistor to trickle charge the cells with around 30-50mA of current. Resistor would be a 680R 2W resistor in series with the input to the bridge rectifier.Will kill the cells in around 3 years, but will work well, and is both cheap and simple. If you get some low capacity NimH cells ( 500mAh), use a 1k 2W series resistor, the cells will still provide back up for a few days to the sensor. Preferably get tagged cells and use the tags to connect the charger side, and connect the bottom tags which are normally shorted by the contacts in the case. That way a loose connection will not blow up the rain sensor with 30V DC applied to it.

author: Gyro
author_rank: Super Contributor
timestamp: November 01, 2015, 09:30:49 am
content: I remember seeing the results of manufacturer's study ages ago (might have been in EDN) that found that NimH batteries didn't suffer any significant degradation from long term charging as long as the rate is below C/20. For something low consumption like this you could probably get away with dropping the charge current at 5 - 10mA.To drain 1800mAh'ish alkaline AA batteries in a month (730hrs) the rain gauge must be pulling roughly 2.5mA (maybe less depending what voltage it drops out at) so I would guess that charging at 2-3 times that would be ok.
Adding External Power / Lighting / Functional Brake Light to Electric GoKart - Page 1
Forum section: electronics / beginners

author: bonifacio
author_rank: Contributor
timestamp: September 09, 2023, 09:19:38 pm
content: I have some experience tinkering but would say I'm a novice. I've done some modding and have made some simple things. I know this is something really simple for you guys.I wanted to add lightning to a GoKart I have on the way. Picked up a Ninebot GoKart Pro. I haven't found much about modifying them. When I did come across something, I hated how it was done.Want to keep things clean.Would you recommend making my own lights or modifying existing bicycle lights?Most existing lights I was interested in have internal batteries. So even after I kill power, the internal batteries would still keep the light running.Just don't want to run around hitting 4-5 switches everytime just to turn lights on and off.Existing lights on the GoKart.The front light seems to be a LED cob strip. I'd assume putting something functional there would overdraw or be underpowered. I'll be checking this when it arrives.The taillight might be non-functional. No lightning at all.I did come across this light. Since it could power, could a hub be added for that third output?Appreciate any ideas and guidance you can give. Maybe I overlooked something that's already out there.Requirements:Avoid touching factory wiring. Figured I'll get something working. Once I figure out how I want things set up, I'll start digging into the GoKart. Going in stages.Figured I'd hunt down connectors later to be as plug-n-play as I can later on.Have 3 switches control everything. (1) Main - Power for all, (1) Front Light and (1) Aux.Taillight power would just be controlled by the Main.Power to have 3 outputs.Functioning Taillight. Dim when on. Brighter when braking.Trying to find or think of a way to do this. There is an existing taillight housing. Make something or retrofit something to fit in there.Was thinking it could have rows of LEDs. Half on when power. Then other half turn on when braking.Then figuring out how to trigger this. Add a momentary switch and trigger it by the brake? Movement/Magnet sensor?I found these switches that seemed like they would be good.https://magnasphere.com/switch-series/