hybridfree/eevblog-posts huggingface dataset:
Peripheral LCD display for the uCurrent - Page 1
Forum section: electronics / projects

author: Aleksolder
author_rank: Contributor
timestamp: September 03, 2014, 09:46:34 am
content: Here's a peripheral display for the uCurrent, my own creation, excepting that I copied it from the datasheet.I'd be very pleased to hear feedback about how to improve this, particularly with respect to the mating of the MAX1494 to the uCurrent. I'm just a microcontroller guy, not an EE.I'll put a 9V battery into the cargo hold of the uCurrent, and will not attempt to share power supplies.This display bolts directly onto the two output binding posts of the uCurrent. It uses a standard triplexed 4.5 digit LCD (Varitronix VIM-503, DIP) and the MAX1495 integrated delta-sigma super duper 4.5 digit ADC.I just copied the datasheet schematic, laid it out around the binding posts, trying to keep it as small as possible.I had to add a LED for the peak option (which I want), since the LCD does not have this feature.The LCD is a bit big, but it's the only one at Mouser now, and that's where my next parts order happens to be going.Since my uCurrent arrived a couple weeks ago, it's been in use continuosly, a very valuable addition to the bench. I don't bother using my DMM for current anymore, since the uCurrent is easier to work with (no need to swap sockets on the DMM). But I have only one DMM (Fluke 87V, yeah!), and sometimes I want to see the uCurrent output concurrently with other values on my DMM. Even if I had another DMM, I don't really want another set of leads snaking around my tiny bench.

author: Isaac_alaska
author_rank: Newbie
timestamp: November 11, 2014, 10:57:24 pm
content: Hey this is awesome! Did you end up building any of them, got any pictures? Really cool addition to uCurrent!

author: Aleksolder
author_rank: Contributor
timestamp: November 12, 2014, 01:58:47 am
content: Funny you should now: the boards just arrived. I'll populate soon and get some better pictures then (if it works!).

author: Aleksolder
author_rank: Contributor
timestamp: November 26, 2014, 11:01:19 am
content: Here's photos of the completed and working display. It works beautifully, as far as my Fluke 87V can say, and the MAX chip has more counts than my Fluke, which is a big bonus.I made many mistakes, but figured them out, drilled new vias, laid new cables across the landscape, mounted a squashed bug onto the back (forgot to order the regulator, used one from stock), and got it working.
PerkinElmer Thermopile Module... - Page 1
Forum section: electronics / projects

author: unmanaged
author_rank: Newbie
timestamp: May 11, 2020, 07:16:32 pm
content: I have a Perkin Elmer Thermopile module I can't figure out how to convert it's output to a temperature reading... All that is listed is the voltage swing of 0.25 volts and I am not sure how that equates to a reading at all. I have attached a few data sheets and photos of this device.... its a pull from a device. Trying to make a thermometer.... I looks like PE is now Excelitas I called and was asked to send photos but not holding my breath to hear back from them as I am not a OEM...73KE4TVVGavin GUnmanaged

author: unmanaged
author_rank: Newbie
timestamp: May 11, 2020, 08:01:45 pm
content: OK so I am guessing the voltage swing is 0.25 from lowest possible reading to 4.75 volts for highest but without the specs on this module i cant figure it out without guessing ...

author: Kleinstein
author_rank: Super Contributor
timestamp: May 11, 2020, 08:05:39 pm
content: It is a little odd that there is no more info on how to convert the voltage to temperature. Chances are the the 0.25 - Vdd-0.25 V range corresponds to the specified temperature range. So 250 mV for -20 C and 4.75 V for the maximum.If in doubt just compare to a normal thermometer.
Permanent / Long Life rated Electrolytics - Page 1
Forum section: electronics / projects

author: Docara
author_rank: Regular Contributor
timestamp: October 05, 2018, 11:36:48 am
content: Hello everyone,I am working on a diesel based 12V automotive power supply which I need to install a transient / filtering / reverse polarity for a permanent supply stage.The most convenient location is downstream of the main voltage regulators etc and before the ignition switch. This would also be very heplful for a 'clean' 12V to some servo's. The trouble is this would mean, pretty much, permanently charged capacitors (5-15yr assumed) other than when the main start battery is changed out or the control electronics swich off the battery isolator for low voltage protection.The absolute maximum working temp is approx 30deg C. Using 105-125degC rated Electrolytics (I was lookng at the Vishay 136RVI range) can caps be used reliable in this application? Would permentaly charged be bettter than power cycling?Thoughts would be most welcome.ThanksMatt
Permanent Power Supply to Car Battery - Page 1
Forum section: electronics / projects

author: munnaz
author_rank: Newbie
timestamp: January 20, 2016, 07:54:43 am
content: Hi,I'm just seeing if anyone knows of any possible problems I might have with attaching the 12v output of a computer power supply (see attached picture) permanently to a normal car battery (being used in a car normally). I want to use the power supply to charge the car battery anywhere but have it permanently in the car so I just have to plug in 240v to the power supply. I have 3 main questions:will it drain the car battery when car is not running?could it damage the power supply when the car is running and power supply not powered?and of course, will it actually charge a car battery?Thanks! Munnaz

author: tautech
author_rank: Super Contributor
timestamp: January 20, 2016, 08:07:04 am
content: Welcome to the forum.Typical charged voltage for a 12V LA battery is 13.2VTypical charging voltage for a 12V LA battery is 13.8-14.2V.PC PSU is not suitable.

author: Landrew2390
author_rank: Regular Contributor
timestamp: January 20, 2016, 08:10:15 am
content: 1. Depends on the charger topology2. Probably because you're effectively feeding up to 14.4V backwards through the power supply. They're normally not designed to handle that.3. 12V isn't enough to charge a car battery. You need a higher voltage to charge lead acid batteries. The charger also needs to be a Constant Current/Constant Voltage charger.If you want to learn about battery charging in depth, I recommend this website. It's a little more complicated than just hooking up a power supply and letting it go.http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

author: munnaz
author_rank: Newbie
timestamp: January 20, 2016, 08:12:42 am
content: Thanks guys.

author: Rerouter
author_rank: Super Contributor
timestamp: January 20, 2016, 08:14:44 am
content: Way to hack a solution, Get a 1W load for the 3.3V rail, grab the feedback 3.3V wire from the ATX24 plug, and divide it down with a pot (start at a ratio very close to 1, then slowly edge away with a voltmeter on the 12V rail, this will raise the output voltage as the regulation % follows from the 3.3V rail,also get yourself a big stud diode, if the atx looses power and there is still power on its outputs, weird things can happen,

author: Jeroen3
author_rank: Super Contributor
timestamp: January 20, 2016, 08:34:18 am
content: 1. No. There will be reverse power diodes.2. Yes. It will not survive automotive transients. ATX supplies are build for a low price, transients are nonexistent in their intended application scenario. Maybe with additional rectifiers it will. But you'll worsen point 3.3. Only the first few Ah's, then the voltage required to charge is above 12.5V.Instead, get a charger. A normal power supply will not enjoy the current hungry nature of batteries and will not run at all on CC mode when the battery is low.Also consider that you do not want your car to go up in flames due to a faulty DIY charger circuit.
Permanent Split Capacitor motor speed control, and PV event on production - Page 1
Forum section: electronics / projects

author: sata
author_rank: Newbie
timestamp: July 22, 2021, 02:03:21 am
content: Hello guys,I am here asking for your expertise on two questions.I have several PSC motors (desk fans and inline fans) that i would like to speed control.I tested with a simple AC phase dimmer, it does get the motor spinning slower but it gets hot really fast.Upon several reads, the correct way to vary the speed of this motors is trough frequency changing, so VFDs.I was wondering if there's a cheap way to do this, like a Chinese module or something? The fans are like 25$, i either find a cheap method or i'll just purchase a new fan with built in speed controlling.The other question is, i have a small heat pump that i want to turn on when a PV instalation produces more than 1000W, and shuts down below that.Assuming the Inverter has no communication / GPIO to the exterior with this function, how would you do it?I was considering a current sensor at the DC part of the Panels, above x amps it turns the power to the heat pump (trough an enable input, with an relay for interfacing).Any help or tip is appreciated!

author: bdunham7
author_rank: Super Contributor
timestamp: July 22, 2021, 02:38:18 am
content: Fan motors are often speed controlled with series dropping capacitors. If you have a PSC motor, just start by adding a capacitor twice the size of the run capacitor. These need to be motor run capacitors, not anything else.
Personal project: LED lighting retrofit. - Page 1
Forum section: electronics / projects

author: Brage
author_rank: Contributor
timestamp: November 16, 2021, 08:52:07 pm
content: I finished a project some time ago that I spent some time on. I'd love to get some feedback on it if anyone feels like it.The application is a retrofit for interior lighting in a vehicle.Runs on anything the LED-driver can handle: 7V to 42V. 2 strings of 3 constant current driven LEDs. One driver for each string. Current draw for both strings is maximum 3A, but tuned down to 1.5A for sustained use.Analog input to dim down, PWM input to dim down, digital signal to disable the light, NTC readout. None of these has to be used in order for the light to function.Reverse polarity protection. Under voltage cut-off. Temperature compensation.1 layer alu board, 1oz, black soldermask, white silkscreen.The terminals are for through-boards fed wire, 0.75mm2- 1.5mm2.Hand placed and soldered using under-heat and a heat gun.
Peugeot CAN bus investigation - Page 1
Forum section: electronics / projects

author: bifferos
author_rank: Regular Contributor
timestamp: May 06, 2023, 06:39:28 pm
content: I've hacked together some software for investigating my car CAN bus.Arduino sketch for the CAN shield is:https://github.com/bifferos/peugeot-can-bus/blob/main/CAN_bin_rx/CAN_bin_rx.inoCurses-based script for displaying the codes on PC is:https://github.com/bifferos/peugeot-can-bus/blob/main/CAN_bin_rx/monitor.pyI'm sure someone already wrote something like this before (although I couldn't find it), but I needed something that would read the codes, display the values sorted by ID, and highlight the specific byte when a value changes. This way I can poke and prod things in the car and see what the response is.I've found the bits for indicators and side-lights. But as far as I can see there is nothing for the brake pedal (stop light). Is that to be expected?

author: mikerj
author_rank: Super Contributor
timestamp: May 06, 2023, 09:38:22 pm
content: Is this the project you were looking for?https://www.eevblog.com/forum/projects/van-bus-interfacing-(to-read-car-speed-and-engine-rpm-peugeot-206-1-4-hdi-2002)/
PFC inductor as several offtheshelf series inductors - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: November 17, 2017, 02:00:42 pm
content: Hello,Do you now why people don’t just use a series chain of offtheshelf inductors as a power inductor when they design low power (<150W) critical mode boost PFC stage?Why do people always do a single custom-wound inductor? (its more expensive)

author: dmills
author_rank: Super Contributor
timestamp: November 17, 2017, 02:21:07 pm
content: In reasonable volumes, it really is not usually any more expensive by the time you pay for assembly.PFC inductors are usually a gapped core operating at very high flux, not that common to find an off the shelf part that has low core losses when operated in this mode. Also compare copper losses for your series chain with the copper losses for a single inductor of equivalent volume, I think you will find the single part to have a useful efficiency advantage.I have had custom magnetic components done in the hundred units range for not outrageous money, by the time you are ordering 10k units at a time it is very, very affordable, any you get exactly what you design.Regards, Dan.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 17, 2017, 04:21:07 pm
content: With magnetic parts like transformers and inductors the quality usually get better when they are larger. If you look at transformers, the usual 1 VA type is well below 50% efficiency, while a 100 kVA unit is more like 98 %.As a crude approximation the weight of a transformer and likely also Inductor goes up like the power rating to a power of about 0.6 to 0.8. So it is also more economic to use one large part than 2 smaller ones.

author: ocset
author_rank: Super Contributor
timestamp: November 18, 2017, 01:01:31 am
content: Thanks, we have a 10mm height restriction, and the PCB is 150mm * 66.5mm only. As such, since the off the shelf formers are too high, we have to use offtheshelf indductors instead...and they must only be SMD.We are thinkin gof the wurth 7447709221http://www.farnell.com/datasheets/1920198.pdf?_ga=2.213410839.2064163281.1510966879-287702491.1506211291Do you think we need to have RC dampers across each inductor in order to damp ringing, since the middle of the three inductors is "seeing" high Z in either direction?
PFC modeling in DC-DC converter  - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: February 25, 2024, 01:24:52 pm
content: Hello everyone, may I ask what is the reason for obtaining the transfer function Gd(s) based on the video link:https://www.youtube.com/watch?v=wEZG5Ykbt_o&t=20s.Is it used to reduce the ripple of the rectified AC signal and why the equation of the Gd(s) is constructed in this format as shown in the Figure below. Thank you very much for the help and sorry for my ignorance.

author: jonpaul
author_rank: Super Contributor
timestamp: February 25, 2024, 01:48:00 pm
content: Reason is to learn .read comments on that video.Send message to the video author.No one here can do morej

author: Patrick66
author_rank: Regular Contributor
timestamp: February 25, 2024, 03:07:29 pm
content: Ok I will do that thank you for the advice.

author: moffy
author_rank: Super Contributor
timestamp: February 25, 2024, 09:44:24 pm
content: Just for a little context the video relates to modelling a flyback driven constant current LED driver and Io(s) is the output current and d(s) is the PWM signal. So Gd(s) is the transfer of the desired output over the controlled input. First appearances, the man, Marcos Alonso, seems brilliant, a true engineer reducing by reasonable assumptions complex problems to manageable solutions. But to confirm or understand his analysis would take many hours of derivation as quite reasonably for the video he only provides the results with basic steps. But thanks for the question, I learned a little, un piquito.
PFET Pulse Generator - Page 1
Forum section: electronics / projects

author: Evan.Cornell
author_rank: Regular Contributor
timestamp: November 07, 2020, 07:54:07 pm
content: So I recently got some prototype hardware back that behaves exactly as I intended. I have a Switch as input to the circuit (see attached photo).Truth table as below:SW StateVOUTClosedGNDOpen+3.3VHowever, it turns out that my design really needs to have the following truth table:SW StateVOUTClosedGNDOpen+3.3V for ~40ms, then GNDDoes anyone have any clever/elegant ideas on how to accomplish this without adding a 555-type one-shot / monostable multivibrator IC into the equation? The design is rather space constrained. The pulse width accuracy isn't critical, so some simple RC-based solution would be acceptable.

author: drvtech
author_rank: Regular Contributor
timestamp: November 07, 2020, 09:04:34 pm
content: Can't you just put a cap in series with Vout and then a pull down on the output of that.

author: Marco
author_rank: Super Contributor
timestamp: November 07, 2020, 09:54:26 pm
content: How good a pulse does it have to be? Simply by capacitive coupling and relying on the thresholding of the FET you can create a pulse, it won't be supersquare but ehh.I don't know the significance for those two 1 Meg resistors around the switch, so I left them in place (I assume the m stands for Meg, bad habit by the way, m is generally used for milli). Replace the diode by a capacitor and add two resistors, here the second resistor is a potentiometer because it will need to be tuned depending on the threshold voltage of the FET. That's the disadvantage of using the threshold voltage of an ordinary FET, it has huge variance.

author: Evan.Cornell
author_rank: Regular Contributor
timestamp: November 07, 2020, 10:50:11 pm
content: Thanks for the great suggestions everyone! The solution I am going to go with is sticking 1kOhm in series with PFET drain, and then use MCU GPIO pin connected to VOUT node as high-Z input. When high level detected, wait 40ms and change to output low GPIO.
PGCPSU / Small lithium battery charger with dual output rails - Page 1
Forum section: electronics / projects

author: pysco68
author_rank: Contributor
timestamp: February 19, 2019, 04:35:52 pm
content: PGCPSU => Pretty Good Cheap Power Supply UnitOh wow, I think I found a really crappy name for that side-project.So what's this about? Last year we bought a pick and place machine to start our in-house production line and figured out that we should learn to use that machine on something that doesn't hurt financially. Especially as we were expecting to throw away a bunch of ruined board in the beginning. So we designed a small PCB using many of the footprints we were to use later on.In an attempt to make something useful we ended up with a small-to-tiny, surprisingly good, relatively cheap to make switching mode 1S lithium battery charger with attached boost and buck stage DC/DC converters that provide 5V and 3.3V rails.The full "features" list is:- switching mode 1S lithium battery charger set to ~1.3A- battery protection (over current / shortcut / over discharger / reverse polarity)- 5V rail (at up to ~600mA)- 3.3V rail (at up to ~800mA) with enable pin and solder-blob switch to select default EN mode- Short circuit recovery / hickup mode on both output rails- Can work as uninterruptible power source (can be bad for the lithium cell however as charge is maintained at > 90%)- Small: 25x20mm- micro USB connector or 2-pin header for power source- 4.7V to 5.8V input- pin headers for output rails- JST PH 2-pin connector or solder pads for the lithium battery- low stand-by battery drain (less than 155uA @ 2.6V battery voltage / ~400 uW)- good efficiency (between 70% and 93% depending on load, input voltage etc, I have some plots I may upload later if anyone's into that)Ok, cool, so what's the deal?Well, we got the pick and place machine up and running with much less friction than we expected and have a whole bunch of these boards sitting around as well as some more panels and parts. So we're thinking about finishing the batch and selling them. So that's basically what I'm asking you guys: is anyone interested in this?I didn't run the exact numbers but we should be able to keep the price below 10-12€ which is not crazy cheap, but not bad comparing it to a protected TP4056 plus two DC/DC converters, especially considering the space saving and the wiring mess relief.So, what do you think?

author: Cliff Matthews
author_rank: Unknown
timestamp: February 19, 2019, 05:29:52 pm
content: This should not be posted here.. One of moderators should likely have it moved tobuysellwanted?

author: pysco68
author_rank: Contributor
timestamp: February 19, 2019, 08:17:03 pm
content: Hi again,just to clarify things, this is not yet a product and may well never be. We just stumbled upon that box of PCBs (like 20-25) we built about six months ago while setting up pour P&P machine during inventory. And we figured that we should ask the world if it needs such a small battery-charger-PSU thingy, as it actually turned out to be not bad at all.I just really would like to get some feedback on if it is useful to someone.
Phantom current - where's it going? - Page 1
Forum section: electronics / projects

author: angust_uk
author_rank: Regular Contributor
timestamp: September 27, 2019, 07:18:05 am
content: Hi allI'm struggling to figure out where I'm losing ~11mA in the very simple design below - it's an STM32F103 and a TLC5947 LED driver (driving 24 white LEDs). The design will be battery powered, so in standby I am putting the STM32 into sleep mode (which I've checked works ok with current consumption reducing as it should), and switching the driver's VCC off with a P-channel MOSFET. However even in this state I'm seeing 11mA into VCC and I can't figure out where it's going!I have noticed that when off, the MOSFET's drain is at 1.5V (around half of VCC), so I guess I'm seeing leakage from somewhere else, but I can't figure out where!Any ideas appreciated!(post edited as apparently I managed to forget the schematic!)

author: Siwastaja
author_rank: Super Contributor
timestamp: September 27, 2019, 07:22:39 am
content: Assuming Vcc=3V, 33mW dissipated in a small spot on a PCB should cause small but well noticeable heating, which you should be able to see using, for example, a cheap IR no-contact thermometer. In similar cases, I remember seeing heating of around 1-2 degC over the surroundings.Put it on a table, let it run for 15-20 minutes without touching it anywhere and measure.

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: September 27, 2019, 07:51:15 am
content: Wild guess, but are you disabling output drive on the STM's SPI pins when going to sleep?

author: angust_uk
author_rank: Regular Contributor
timestamp: September 27, 2019, 08:00:14 am
content: Ok, it looks like the issue may well be my lack of understanding of the STM's various sleep modes! After more poking around at the registers I've put it into a deeper sleep mode which reduces consumption to around 1mA. I'm not using an external 32kHz crystal which I guess may limit my ability to go much lower, but for the moment this is significantly better at least!Many thanks jhpadjustable and Siwastaja for the pointers!
Phantom Power pass through ? - Page 1
Forum section: electronics / projects

author: XavierM
author_rank: Newbie
timestamp: April 27, 2020, 11:10:09 am
content: Hi all !I've been wondering for a bit : generally you'd have a Mic preamp feeding 48V to the mic, followed by all sort of equipment.But what if I want to introduce a little compressor of my design between an audio interface and and the mic ? Could it be possible to remove the DC coupling at at the signal output of my compressor and have the 48V be sent to the microphone using several order of low pass filters ?Doing so I could have a little portable battery powered compressor and not have to worry about generating 48V phantom power.I mean, in term of frequency separation it doesn't seem impossible, but I can't find exemple out there so am I missing something ?Thanks !Cheers !

author: Bassman59
author_rank: Super Contributor
timestamp: April 28, 2020, 03:50:06 am
content: Quote from: XavierM on April 27, 2020, 11:10:09 amAudio line-out transformers from Jensen (now owned by Radial) and others work well for this. Also adding DC blocking capacitors after the output driver chip is standard. 100 uF ought to work, just make sure they're rated for at least 63 WVDC.

author: XavierM
author_rank: Newbie
timestamp: April 28, 2020, 09:20:08 am
content: Great !thank you I'm gonna check this out !
Phase Correct PWM Generator Chip - Page 1
Forum section: electronics / projects

author: CM800
author_rank: Frequent Contributor
timestamp: September 13, 2015, 07:05:44 pm
content: I am currently working on a full bridge controller to drive high power high frequency transformers, I have a bit of trouble trying to pick out the heart of it.Ideally I want to have:15-35kHz (possibly up to 60kHz) Variable frequency controlI want to vary the pulse width for power control between 0 and 50% and a form of variable current limiting.Looking to have some form of controllable deadtime to help deal with the use of large IGBTs and opto-isolated gate drive.Originally I was just going to use an Arduino, however I found that I cannot vary the frequency to any useful degree.Does anyone have any recommendation of a chip I could use?While I am aware I could make a triangle wave generator and use op-amps and other circuit components to make a complete analog circuit the time required to do so and the exponential raise of mess and things that could go wrong, I don't think it is worth it.

author: ajb
author_rank: Super Contributor
timestamp: September 13, 2015, 08:18:12 pm
content: A lot of the more powerful mcus have much more advanced PWM capabilities than the rudimentary counters in the Arduino's ATMega provide. If you prefer to stick with 8-bit, Atmel's XMega parts have much more powerful timer/counter modules, and most of the major mcu makers also do several chips specifically designed for controlling power stages, such as Atmel's AT90PWM series. There are more options in the ARM realm as well, for instance I know Atmel's SAMD21 (Cortex M0+) series have what they call "Timer Counter for Control" modules with programmable fault inputs and things. I haven't used them for anything but basic PWM to date, but they seem reasonably powerful from the datasheet. I'm sure other ARM integrators have parts with similar if not superior features. Probably best to browse a few catalogs and skim the datasheets of the most likely parts to see which best suit your application.

author: CM800
author_rank: Frequent Contributor
timestamp: September 13, 2015, 09:17:14 pm
content: That certainly has merit, I would rather like to stay within the Atmel Range as I already brought the ATMEL-ICE programmer. Seems I may have to be spinning my own board.Does anyone else have any suggestions?
Phase detector? - Page 1
Forum section: electronics / projects

author: Hercog
author_rank: Newbie
timestamp: June 09, 2021, 02:28:17 pm
content: I have a digital clock for example 10MHz, dutty cycle 25/75, +3.3 or + 5V logic and the same clocks that are delayed. The delay ranges from less than 1ns to a maximum of 20ns.I need to measure this delay with an MCU .My idea is to compare the clock on a phase detector that converts the difference to a voltage and measure this voltage by the ADC in the MCU.I have it even implemented, but due to the Phase detector dead zone I can't compare the above signals, but I have to first select a clock rotated 180 degrees from the original reference clock and this complicates the design.It is not my field and therefore I want to ask, is there an available / cheap phase detector that would allow to measure a delay of 0-20ns with a resolution of at least 1000?

author: Terry Bites
author_rank: Super Contributor
timestamp: June 09, 2021, 03:48:35 pm
content: For some great ideas and discussion, seehttps://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwivz42_8orxAhWVnFwKHVL-By0QFjAAegQIBxAD&url=https%3A%2F%2Fcds.cern.ch%2Frecord%2F2235847%2Ffiles%2FCERN-BE-2016-003.pdf&usg=AOvVaw2ZoF8lsKlB9NtBlzaAgN9N.Also seehttps://www.ti.com/lit/gpn/cd74act297

author: MasterT
author_rank: Frequent Contributor
timestamp: June 09, 2021, 05:59:09 pm
content: If there is uCPU with ADC, I'd not use any external hardware. Run sampling by adc - two channels or two adc, sampling rate doesn't matter much since there is single tone, and undersampling is o'k.Than Goertzel and averaging/post-processing in software

author: Marco
author_rank: Super Contributor
timestamp: June 09, 2021, 06:32:02 pm
content: If you did it in software, you'd first have to divide by two to get 50% duty cycle, then low pass so the software actually has something to work with (won't get subsample phase accuracy from a squarewave) and the ADC needs sufficient bandwidth to subsample.The circuit from the CERN paper isn't complex enough to bother.

author: David Hess
author_rank: Super Contributor
timestamp: June 09, 2021, 11:01:43 pm
content: I would stick with an XOR phase detector but with a trick. If I understand correctly, you are comparing the original signal to multiple delayed copies, so run the copies *and the original* into a multiplexor and then do the XOR comparison. Now only one delay needs to be added after the multiplexor to remove the null zone for all signals, and when the multiplexor is set to the original, then the phase comparator measures just the delay introduced by the mutiplexor and delay which can be used to calibrate the zero. An extra fixed width delay signal can be added to another copy of the original to the multiplexor to calibrate gain as well.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 11, 2021, 04:04:05 pm
content: A gift from TI: TDC7200
PHASE LOCKED LOOP: TRF 3750 - Page 1
Forum section: electronics / projects

author: Jasmeet Kaur
author_rank: Newbie
timestamp: July 09, 2011, 09:08:28 am
content: Hello allWe are working on a PLL circuit, using TRF3750, FREQUENCY SYNTHESIZER.We have tried with the Supply voltage: 3.3 V (and VCP=4.3v).We are sending serial data through docklight to the data pin (pin 12) of the IC, and then enable the LE pin for an instant, and remove it. According to the datasheet, the data should be loaded onto the selected latch from the shift register. We are first programming the function latch with r divider and then the r-counter. But we are unable to get the desired output at the MUXOUT pin (pin 14).Can anybody guide us about the programming of the TRF3750?

author: Frangible
author_rank: Regular Contributor
timestamp: July 11, 2011, 09:51:57 pm
content: Here's a list of stuff you'll have to know before mucking about with the PLL:How fast is the shift clock into the PLL?Are you making sure to meet tsu1 and th times?Is the LE strobe long enough?What is the frequency of REFIN?What is your VCO range?What is your desired frequency?What is your prescaler setting?What are you writing into the AB counter latch?What are you writing into the R counter latch?What are you writing into the Function latch?What are you writing into the Initialization latch?If you using Fastlock mode, is it appropriate to your VCO?Is your loop filter design appropriate to the output of the PLL?This is not a trivial task. It takes quite a bit a research to get it right the first time you work with them.
Phase margin plot of LDO - Page 1
Forum section: electronics / projects

author: promach
author_rank: Frequent Contributor
timestamp: June 10, 2020, 12:01:08 pm
content: For this LDO circuit design athttps://github.com/promach/LDO/tree/development,1) which exact circuit node(s) contributes to the zeroes near 1MHz after removing CL ?2) If I remove "AC 1" from Vref, why the whole bode plot becomes erratic ?
Phase noise measurements and effective noise bandwidth - Page 1
Forum section: electronics / projects

author: dnessett
author_rank: Regular Contributor
timestamp: April 20, 2019, 11:58:48 pm
content: Hello,This is an advanced question. I am attempting to measure and characterize the phase noise of oscillators. After a rather long preparatory period, I am now able to carry out measurements using a setup involving a mixer generating a signal for which variations in voltage represent variations in oscillator frequency. I won't go into detail how this setup works because it is not germane to the question. However, those interested can read the discussion startinghere.The measurements sample this signal using a PicoScope 4262. Since the version of the PicoScope software I am using (on Linux) does not support output in dBm @ 50 ohms, I have to make measurements in dBV units, then convert to dBm. The measurement setup includes selecting a Blackman-Harris window. This is the foundation of the question.From what I have read in the literature, using a window to shape the input to a DFT (hereafter, FFT) calculation requires correction when stochastic signals like noise are involved. In particular the window, which is applied in the time domain, creates a transfer function in the frequency domain that "bleeds" power into adjacent bins of the FFT. This requires correction in computing the power spectral density (PSD) of the noise.This is discussedin this paper, from which I now quote:"Due to the width of the window in the frequency domain, each frequency bin collects not only the noise in that frequency bin, but also from adjacent bins. Dividing the result by the effective noise bandwidth corrects for this phenomenon." (page 15, paragraph at top of page).This applies specifically to white noise. So, if an FFT calculation involves computing the spectrum of white noise, to get the correct value, it is necessary to divide the result by the effective noise bandwidth associated with the window. For Blackman-Harris, the divisor is 1.7.However, phase noise isnotcomprised only of white noise. Various noise sources combine to generate phase noise. For example, variations in very small frequency offsets may occur due to FM flicker noise, at higher offsets the source of these variations occur due to random walk phase noise, then there may be a region of offsets where the noise is generated by flicker phase noise. Finally, further out in frequency offset, white noise may be the source of frequency fluctuations.It is not my intention to open a discussion of these noise processes. Rather, they are mentioned only to establish that the PSD of phase noise is not simply that of white noise.This brings us to the question. How should FFT calculations of phase noise be adjusted to correct for "bleeding" associated with a windowing function? Since, the portion of the spectrum generally of interest (i.e., that close to the fundamental frequency of the oscillator) is generated by noise, butnotby white noise, is it correct to divide the spectrum values by the constant associated with that window? Or, should some other strategy by used?
Phase noise to jitter conversion : Strange equation - Page 1
Forum section: electronics / projects

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: March 25, 2023, 01:48:07 pm
content: Hi,A question for the math wizards of EEVBlog..I was reading some papers on converting phase noise of an oscillator to the jitter in time domain. One of the best papers in this has been written by Drakhlis.https://dokumen.tips/documents/drakhlis-boris-calculate-oscillator-jitter-by-using-phase-noise-analysis.html?page=2However, I could never find an explanation to the Eqn. 11 which equates the Autocorrelation of the phase to the cosine transform of the phase spectrum...Can someone explain this or point to any source for this equation?Regards
Phase Synchronization for Demodulation - Page 1
Forum section: electronics / projects

author: jemazter
author_rank: Newbie
timestamp: March 21, 2017, 12:54:33 pm
content: Hello. Currently i'm designing a respiration rate measurement device based on Impedance Pneumography for a university project (http://www.ti.com/lit/an/sbaa181/sbaa181.pdf> similar to that)I have already defined the first part of the circuit (modulation signal will be generate by a DDS IC, applied to a Howland current pump then applied to patients body), now i working on the second part of the circuit (measuring the sinal from patient, demodulation, filtering and sampling).My questions is, how can i phase align the modulated signal coming from a human body to the demodulation clock, and then demodulate that to extract the information needed? I was reading about PLL, but couldn't figure out exactly how it works and how i can (if i can) use it in this case.Thanks in advance.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 21, 2017, 01:13:43 pm
content: It depends how demodulation is supposed to be done:If in hardware one needs a square wave of the same frequency with suitable phase, possible two with a 90 deg phase shift. For a phase shift one might use an PLL, but with fixed frequency an other method might be easier.The DDS chip might have an extra sync / square wave output, but not all DDS chips have one.I doubt one would really need a pure sine for excitation - it might be easier to crate the drive signal from a filtered square wave. This would make is easier to derive the demodulation signal(s). The filter circuit could also be used for phase adjustment (if needed).The alternative would be demodulation in software: using a faster ADC and doing it in math. This would also need a start signal, but one could use something like an µC do generate a square signal for the driving signal and read the ADC and do demodulation - so no external demodulation signal needed, it is just virtual in software.

author: jbb
author_rank: Super Contributor
timestamp: March 21, 2017, 06:41:20 pm
content: Quote from: Kleinstein on March 21, 2017, 01:13:43 pmThis is a very powerful technique. You would need an ADC to run at several times the excitation frequency; maybe a divided copy of the DDS clock would do it. Then you can do the sampling function in software and have easily adjustable delay. Or you can set the delay to zero and extract in-phase (0 degrees) and out-of-phase (90 degrees) components, and do some trigonometry to get info about both magitude and phase which could be useful.Depending on your excitation frequency, the AD5933 might be suitablehttp://www.analog.com/en/products/rf-microwave/direct-digital-synthesis/ad5933.html#product-overview.They also do the ADUCM350 with a Cortex M3 inside but it's lower bandwidth and BGA package.http://www.analog.com/en/products/processors-dsp/microcontrollers/precision-microcontrollers/aducm350.html#product-overview
Phased Array Audio Speakers - Page 1
Forum section: electronics / projects

author: Charles Creations
author_rank: Contributor
timestamp: April 08, 2015, 04:49:10 pm
content: I am interested in finding some analog delay lines with delays in the range of 10us. The difficulty with a phase array for sound in air is that the speed of sound is fairly slow (compared to sound in solid things like in biomedical ultrasound). To get adequate beam steering, I need on the order of 10us delay.The delay also needs to be bidirectional because during transmission it would be possible to produce the waveforms with the delay already built in, but the tricky part is adding the echos back together again on the return journey while incorporating the same delay they were transmitted with.I see delay lines in the ps, ns, and ms range and many are digital. Do such delay lines exist? Where can I find them?

author: Howardlong
author_rank: Super Contributor
timestamp: April 08, 2015, 04:59:56 pm
content: If the delay in time is fairly small in comparison to the periods of the band limited signals you're delaying, which at 10us in audio terms it is, you can use an all pass filter. In its simplest guise, this could be an op amp with a capacitor and a few resistors.I'm not sure what you mean by "bidirectional" though.

author: Pjotr
author_rank: Frequent Contributor
timestamp: April 08, 2015, 05:18:32 pm
content: It is not clear at what frequencies OP is talking about, what medium, what kind of transducers, what purpose etc.Bit nowadays al this kind of processing, whether it is medical ultrasound or stadium PA, is done in the digital domain.

author: Howardlong
author_rank: Super Contributor
timestamp: April 08, 2015, 06:53:35 pm
content: Quote from: Pjotr on April 08, 2015, 05:18:32 pmThe title talks about "audio speakers" so to me that means a few Hz to 20kHz.Normally I would agree, but typically in the digital domain, the processing will insert its own latency well in excess of 10us. If the delay has to be 10us, everything will need to have a constant latency delay and then add on 10us to the channel(s) of interest.There's not enough info on what the OP is trying to achieve to be able to make a judgement.

author: mazurov
author_rank: Frequent Contributor
timestamp: April 08, 2015, 07:37:54 pm
content: Back in the days I was using SAD1024 bucket-brigade chips (http://en.wikipedia.org/wiki/Bucket-brigade_device) to do delays in audio. The primary use of those was medical devices to correct stuttering in humans. You may want to see if anything linked in wikipedia article is still available.

author: wiss
author_rank: Frequent Contributor
timestamp: April 08, 2015, 09:34:01 pm
content: Just a regular first order passive LP-filter will give enough delay to stear higher audio frequencies noteciably.
Phasenoiseplots from low cost GPSDO*s on ebay ? - Page 1
Forum section: electronics / projects

author: Pifke
author_rank: Newbie
timestamp: November 20, 2018, 04:17:21 pm
content: Hello, i am locking for phasenoise infos about gpsdo's from ebay - allan deviation and 10.xxx mhz is often / always shown in net - but phase noise, i missed.NEC Star4+ and and - find nothing.Can someone show phase noiseplots ?greetings

author: Pifke
author_rank: Newbie
timestamp: November 23, 2018, 11:07:05 pm
content: nobody have one ?? want to verify with my homebrew VE2ZAZ Gpsdo - looking for low phasenoise für GHZ PLL's

author: KE5FX
author_rank: Super Contributor
timestamp: November 23, 2018, 11:21:38 pm
content: Quote from: Pifke on November 20, 2018, 04:17:21 pmThere's a shot of the BG7TBL GPSDOhere, and a couple of different versions of the Trimble Thunderbolthere. Also, leapsecond.com has some plots from theJackson Labs Fury.One useful trick for finding data like this is to do an image search on Google. Graphs of varying quality and believability can be found on almost any subject,if you use the right search terms.

author: Pifke
author_rank: Newbie
timestamp: November 23, 2018, 11:24:21 pm
content: Thanks
Philips LivingColors hack to drive external LED strip - Page 1
Forum section: electronics / projects

author: martinLink
author_rank: Newbie
timestamp: June 10, 2015, 01:58:17 pm
content: Hi guys,recently I got an Philips LivingColors lamp. I wasn’t too happy with its brightness so I decided to do small hardware modification. I added few N-channel transistors to the LED drivers and connected an RGB LED strip. The effect was soo good that I decided to write a post about the moddification. The single lamp with a strip was able to light up the complete room. The control of the lamp is done via a Philips remote control.Here is the full article how to modify Philips LivingColors lamp with schematic:Phlips LivingColors lamp brightness increase with a LED stripHere is the YouTube movie:Please let me know what you think about it. Maybe some other stuff can be driven by this 'magic' lamp?Best regards,Martin
Philips MSL Connector Pin-out? - Page 1
Forum section: electronics / projects

author: hap2001
author_rank: Regular Contributor
timestamp: January 05, 2024, 02:24:52 pm
content: Hi, Does anyone knows the pin out for Philips MSL Connector on their medical devices?I only need the power pins, because I don't want to buy their power supply which is too expensive. Thanks.
Philips / NXP Chip  13B0141 and 13B0140  - Page 1
Forum section: electronics / projects

author: Robert_Ploucha
author_rank: Newbie
timestamp: November 03, 2024, 10:10:40 pm
content: I'm looking for datasheet or any other documentation 13B0141 or 13B0140 - Philips or NXPdo you have any documentation od this chip?
Philips PM5139 error 6 - Page 1
Forum section: electronics / projects

author: Jere
author_rank: Newbie
timestamp: August 16, 2012, 05:22:47 am
content: I have a Philips/Fluke PM5139 function generator with error 6. User manual tells only that frequency generation does not work. Does anyone have service manual or some schematics for PM5139?

author: grumpydoc
author_rank: Super Contributor
timestamp: August 16, 2012, 06:58:51 am
content: User manual kicking around in various places - jetecnet lists the service manual & they won't mind an email to as if it includes schematics.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 16, 2012, 02:23:02 pm
content: Found something in German telling you to check the voltage regulators for the VCO PCB: (how is your German?)Sollte jemand mit einem ähnlichen Problem (ERR 6) hier drüberlesen: Eswäre eine gute Idee, die Versorgungsspannungen des VCO (unter dicker,runder Alu-Abschirmung auf der CPU Platine) nachzumessen. An Pin3 desLM78GCP sollten es +10V sein. Gleicher Pin uA79G -10V. Beide ICs sindgleich unterhalb des VCO-Gehäuses zu finden wenn man von Vorne in dasGerät schaut. Ist einer davon hinüber, durch einen LM317 bzw. LM337 mitentsprechender Beschaltung ersetzen. Datenblätter der Spannungsreglerfindet man, wenn man nach "uA78G" oder "uA79G" sucht.

author: Jere
author_rank: Newbie
timestamp: August 18, 2012, 09:43:59 am
content: It was that +10 volt regulator. Replaced that and now working, thanks!

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 18, 2012, 12:47:46 pm
content: Great, good to see you fixed it!
Phone alert - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: October 13, 2025, 05:00:30 pm
content: My neighbour is very hard of hearing and needed a visual alert for her telephone.She uses a hearing loop.The phone is on a wi-fi VOIP adapter. It has a puny REN value.So I thought about it and came up with this circuit built from parts in my junk box.A supercap charges at a low current stolen from the -48V line voltage.I was very conservative with the stolen current. Stolen from me not EE.Not so conservative with the blinding LEDs.About 3 hours to full charge which is fine as she doesn't field a lot of calls on her landline.When the phone rings it powers an LED array which flashes with the ringing cadence.Its very bright over the first 20s. You could subsitute a small Lipo for thee supercap I guess.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: October 14, 2025, 07:38:21 pm
content: Nice design and build Terry Bites, but you have reinvented the wheelhttps://www.amazon.com/Krown-Manufacturing-Inc-KRN-PF200-Flasher/dp/B00DOAHD80