hybridfree/eevblog-posts huggingface dataset:
How can current flow from positive rail to negative rail? - Page 1
Forum section: electronics / projects

author: Efe_114
author_rank: Contributor
timestamp: March 27, 2022, 06:15:30 pm
content: How can current flow from the positive output to the negative output in this adjustable dual tracking power supply? I see 2 different regulators isolated from each other. The schematic is from HP E3631a service manual.

author: TimFox
author_rank: Super Contributor
timestamp: March 27, 2022, 06:25:11 pm
content: The two otherwise isolated supplies are connected together at the right at the node marked "A".
How can I apply custom fonts in u8g2 library - Page 1
Forum section: electronics / projects

author: rizlesz2000
author_rank: Contributor
timestamp: October 23, 2023, 12:40:28 pm
content: I read that I need to do set font command but in this case I only need one custom font. So I converted my ttf file to bdf which is supported by u8g2. The thing is that I wanted to add the setfont command on the beginning and rest of the place should be the scalling of the font and don't want to use separate font files for different sizes. I meant that, the smaller font is 8px which is default and othe size should be multiples of 8 which double the size (double the pixel size) . Any ideas? Thanks

author: coromonadalix
author_rank: Super Contributor
timestamp: October 23, 2023, 02:03:04 pm
content: https://forum.arduino.cc/t/u8g2-custom-font-tutorial-with-fony/686061

author: rizlesz2000
author_rank: Contributor
timestamp: October 23, 2023, 02:39:06 pm
content: OK, but how do I scale the font in the program

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 23, 2023, 02:53:55 pm
content: You can't, you must make the font for a specific size.Read the u8g2 wiki!
How can I create phase shift of filters in Pspice? (like red curve) - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: February 05, 2024, 09:12:58 am
content: How can I create phase shift of filters in Pspice? (like red curve)also measure the delay at the output for a band pass filter created cascaded amplifiers.

author: Terry Bites
author_rank: Super Contributor
timestamp: February 05, 2024, 03:08:29 pm
content: https://www.ti.com/video/6162727926001

author: electronx
author_rank: Regular Contributor
timestamp: February 05, 2024, 05:51:14 pm
content: You are the hero of my day, thank you!!
How can I designed non-Isolate DC to DC Boost-Buck use uc3843? - Page 1
Forum section: electronics / projects

author: jlian168
author_rank: Newbie
timestamp: April 26, 2017, 01:09:23 am
content: Dear all:DC in : 12 or 24DC out:14.2Does anyone has schematic?Or buck I need it too.Thank you.

author: ebclr
author_rank: Super Contributor
timestamp: April 26, 2017, 11:23:44 am
content: https://electronics.stackexchange.com/questions/291915/uc3843-buck-converter

author: jlian168
author_rank: Newbie
timestamp: April 27, 2017, 04:04:30 am
content: Sir:But R4 is after C2 that Isense couldn't be detected!Thank you.
How can I duplicate the behaviour of this component? - Page 1
Forum section: electronics / projects

author: guscrown
author_rank: Regular Contributor
timestamp: October 20, 2012, 09:26:23 pm
content: I'm having problems hot swapping a powersource to my board due to the input capacitance, I have a big inrush current and hence I see arching (sparking) on the connector when I connect it to my board. I believe this could lead to damage down the line so I want to avoid it.I tried NTC Thermistors to limit the inrush, they worked, but you suffer from the 120seconds reset time of the Thermistor.This is the device in question:This device limits the inrush current in a unique way, by creating a slow transition on the output voltage. But alas this is a very specialized device for military use, and hence must be very expensive, and also looks quite bulky.Can you recommend a similar device but for commercial products? Or any other way to duplicate the behavior of this device?Input source:External Power Supply Brick. 24V DCSteady State Current: 3AMax Peak Current : 8A

author: IanB
author_rank: Super Contributor
timestamp: October 20, 2012, 10:48:19 pm
content: Quote from: guscrown on October 20, 2012, 09:26:23 pmYou're funny. Quoting from the video: "The DVCL is very small, about one inch square." It's pictured in the video as a tiny package. Why do you think it looks quite bulky?QuoteThis device is nothing special at all. Hint: The military uses very expensive, very ordinary components. That is why supplying to the military is so attractive--massive profits from overpriced itemsThe simplest device that will do what you want is an inductor. However, passive inductors truly may be very big and bulky when they need to handle large currents. What the video shows is something like an active inductor, a module that electronically limits the rate of change of current dI/dt by applying a varying resistance in series with the supply.I don't see anything that suggests such an item would be expensive or difficult to obtain commercially, although I couldn't give you any ideas about vendors. What search terms have you used so far?

author: guscrown
author_rank: Regular Contributor
timestamp: October 20, 2012, 10:59:01 pm
content: So far I've searched for MOSFETS as Soft-start controllers. And I've found many examples but nothing concrete.
How can I electronically enhance my feather duster? - Page 1
Forum section: electronics / projects

author: GabrielMoss
author_rank: Newbie
timestamp: June 05, 2020, 05:58:37 pm
content: Hey folks,Thank you for your help in advance! After searching this forum I couldn't find an answer to my question. so here go's my first post.Objective: Make a feather duster which is changed with ions to attract dust and then switch the charge so dust is repelled from it when it's time to clean.I saw this great video on turning a USB air purifier into a static generator.https://www.youtube.com/watch?v=P5za9sa4-qkMy question is can this project be modified so it can both generate a charge as well as reverse the static charge and repel the dust?If so, how?My hope is that if I can do this in a small form factor I can add it to the dusters my cleaning company uses to make us more efficient as we work.Thank you again!

author: larrybl
author_rank: Regular Contributor
timestamp: June 05, 2020, 06:08:49 pm
content: I'll bite. Strap your duster to a electronic bug zapper. Done!

author: Labrat101
author_rank: Unknown
timestamp: June 05, 2020, 09:46:57 pm
content: If you have a Cat rub the cat with the feather duster.You will get a great static charge on the duster ..... Plus a very angry Cat .That is also supper charged... With teeth & claws .....

author: coppercone2
author_rank: Super Contributor
timestamp: June 05, 2020, 10:05:17 pm
content: make a belt of synthetic sheep fur like a vandergaff charger and hold it against it
How can I make a mobile power switch like latching switch for my esp32? - Page 1
Forum section: electronics / projects

author: Rishles69@
author_rank: Regular Contributor
timestamp: July 14, 2024, 11:54:40 am
content: So I wanted to make my esp32 project a latching switch using all smd components. What I want to do is to have a single power switch. (note: the same switch should work as a cancel button which is decided by the esp32 and my project has 4 buttons including this cancel button. The first two work as navigation or up and down, the third button is enter/OK and finally the cancel/back switch) so before when I press this cancel button I mentioned before, the esp32 should be in full turned off state and there is no power consumption from the battery. If I pressed the cancel button, it should turn on. And if I pressed the cancel switch when in on state the esp32 should not turn off simply and it should only work as a back/cancel button. After navigating the custom menu on my esp32 with a display and the navigation buttons and when I select the "power off" option on my esp32, it should turn off. If it is on sleep mode or deep sleep mode, the circuit should NOT turn off the esp32.If my esp32 is turned off, when I plug my charger through tp4056, the esp32 should automatically turn on to show in the display, it's charging just like on phones. Any ideas? Thanks
How can I program a CPLD Lattice chip (M4A3) from the "Mach 4" family with a HW- - Page 1
Forum section: electronics / projects

author: leonardovenpin
author_rank: Contributor
timestamp: April 26, 2019, 09:02:22 pm
content: How can I program a CPLD Lattice chip (M4A3) from the "Mach 4" family with a HW-USB-2A?

author: DaJMasta
author_rank: Super Contributor
timestamp: April 26, 2019, 09:39:43 pm
content: Don't know your specific situation, but I've run into a similar issue with a different chip and the answer may actually be "you can't".Basically, the programmer used has to support the software package you're programming from, and the package you're programming with does not generally support older chips for very long, so you may need to download an older development package to program the older chip, which in turn would need an older programmer (or a programmer compatible otherwise compatible with the older application) to make it work.Ran into an issue with the Xilinx tools this way, where to program a PROM from the early 2000s I had to download a software package that didn't support my current generation programmer, so I had to buy a second programmer to use it.....

author: leonardovenpin
author_rank: Contributor
timestamp: April 27, 2019, 06:21:28 am
content: what happens is that the programming software I use if it has the cpld but I buy a hw-usb-2a to be able to program from usb to FTDI or Parallel, the ports that the chip has are TCK, TDI, TDO and TMS. and the cable that brings the hw-usb-2a is those mentioned but VCC two of GND and other 3 more I think, then I connected the 4 GNDs that had the chip to GND of the cable, and the 2 VCC to VCC of the same, and then the other 4 four with their respective cables ... and in the Diamond software I get it that detected the hw-usb-2a but then tells me that "the card of the cpld is not on" then I do not know what to do ..

author: iMo
author_rank: Super Contributor
timestamp: April 27, 2019, 08:16:21 am
content: It could be your hw-usb-2a programmer is just checking whether the target Vcc is "on", and it does not source it (the programmer's "Vcc" pin is an "input").Try with an external Vcc for your chip..Doublecheck with the documentation of your programmer.

author: leonardovenpin
author_rank: Contributor
timestamp: April 27, 2019, 09:18:32 pm
content: thanks friend, it detects it but now I can not load the JED file. I do not know if I have to see what it says "Device Operation: Bypass"
How can I record the Line Out from my tape deck using the Mic input on my phone - Page 1
Forum section: electronics / projects

author: FBMinis
author_rank: Regular Contributor
timestamp: August 29, 2023, 10:25:59 am
content: I would like to record a video of a k7 tape playing and capture the sound with my Android phone using the mic input (the headphone jack).Is it possible?

author: RoGeorge
author_rank: Super Contributor
timestamp: August 29, 2023, 10:52:33 am
content: Yes, though the connector pinout depends of the phone model.

author: wasedadoc
author_rank: Super Contributor
timestamp: August 29, 2023, 11:42:47 am
content: 1. You will need to massively attenuate the LINE OUT signal to bring it down to a suitable level for the MIC input.2. The MIC input is mono. If the source is stereo and you want both left and right channels you need to combine them.

author: Psi
author_rank: Super Contributor
timestamp: August 29, 2023, 11:50:14 am
content: Yeah, mic ports turning out to be mono is really annoying.They can also sound terrible as they often have correction filters applied to them to make them sound better, and you can't always turn them off.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 29, 2023, 12:18:01 pm
content: K7, not seen that written for years!Mono mix or stereo. See attached.Yes, look up TRS connections

author: wasedadoc
author_rank: Super Contributor
timestamp: August 29, 2023, 01:48:01 pm
content: Fromhttps://source.android.com/docs/core/interaction/accessories/headset/plug-headset-spec"CTIA pinout order (LRGM)"L = Left Audio out (at tip)R = Right Audio outG = GroundM = Microphone in (furthest ring from tip).

author: Wolfram
author_rank: Frequent Contributor
timestamp: August 29, 2023, 02:32:05 pm
content: It might be possible to use a USB sound card with stereo input, together with a USB OTG cable using stock Android. Whether or not this works depends on the phone, Android version and sound card in question. I also came across this which looks like a potential solution to the problem:http://www.extreamsd.com/index.php/products/usb-audio-recorder-pro

author: floobydust
author_rank: Super Contributor
timestamp: August 29, 2023, 03:04:13 pm
content: Also discussed in thisthread,fooling the phone's external mic detect is sometimes an issue but that OP didn't write back for a followup.I think the youtube video circuit was junk IMHO

author: coromonadalix
author_rank: Super Contributor
timestamp: August 29, 2023, 04:42:24 pm
content: i would not use the mic input for sure ... even with the right attenuator, unless you are sure there is no filter in the circuit .... the sound get distorted, or no bass no mid etc ...

author: wasedadoc
author_rank: Super Contributor
timestamp: August 29, 2023, 06:57:46 pm
content: Quote from: Wolfram on August 29, 2023, 02:32:05 pmYes, it depends. Some Android phones do not have USB host capability. Admittedly they are not top end phones but none of the three I have here do.
How can I reduce the sensitivity of a capacitive touch external trigger wire? - Page 1
Forum section: electronics / projects

author: Hootis Tigglebits
author_rank: Contributor
timestamp: November 09, 2023, 01:30:55 am
content: I have a 1.5" long 30awg insulated wire soldered to pin 3 of a TTP223 and the other end attached to an external trigger. The external trigger has the proper sensitivity, but the wire connecting the two is triggering even when my finger is within 1/2", is there anything I can do to insulate the wire better so that it doesn't trigger the TTP223?

author: Ian.M
author_rank: Super Contributor
timestamp: November 09, 2023, 03:49:30 am
content: Adding insulation will not work. Any insulation will have a greater permittivity than air so will increase the capacitance between the wire and your finger. You could try a grounded screen, but the extra capacitance from the wire to ground may reduce sensitivity, so the greater the spacing of the screen relative to the wire diameter, the better. TheTTP223 datasheetrecommends Cs (the stray capacitance from input to ground) of under 50pF.A short length of Coax with low density dialectric might be suitable, but if you can, put it on a capmeter with a <200pF range to check how many pF it adds!

author: floobydust
author_rank: Super Contributor
timestamp: November 09, 2023, 03:56:46 am
content: What I do add capacitance to the TTP223 input, sometimes a resistor as well. You want the ratio of no touch to touch capacitance to be in range for the IC.I can dig for the schematic. But the trigger wire can't be too long or it picks up hum and noise. The board needs to be close to the sensor.Careful this IC can be a dog - upon power up it calibrates itself, and also when it toggles due to touch.BUT I was using it running for long periods of time and it would drift out of cal -ve and get stuck, not sensing anything. So I had to do a cold boot for a re-cal.edit: from my notes, the mods I did, adding 27pF cap. The DC block capacitor is so the touch sense works even in the rain.

author: Hootis Tigglebits
author_rank: Contributor
timestamp: November 09, 2023, 07:37:49 am
content: Thanks for the suggestions. 47pF achieved the result I was looking for!

author: floobydust
author_rank: Super Contributor
timestamp: November 09, 2023, 08:29:05 pm
content: One last quirk about the TTP223 - it's supersensitive to changes in power.If it powered up and self-calibrated say at 5.05V and VDD later moves around to say 4.90V, the internal oscillator frequency shifts (same as with temperature changes) and the part either false-triggers or just sits there failing to detect touch. It was unreliable.For this reason I gave up on the part and changed over toAT42QT1011note Sparkfun board is terrible to mod, ick.This is in a burglar alarm with door handle touch detection, outdoors.
How can I scale a 3v3 DAC output to a higher, unknown, rail (e.g. 10 to 14v) - Page 1
Forum section: electronics / projects

author: RossK
author_rank: Contributor
timestamp: August 24, 2013, 04:50:22 pm
content: I cant seem to find a rail to rail 10+ bit DAC that can take TTL SPI/I2C and operate rail-to-rail up to 16v (tolerating transients up to 18-20v) - i'm sure they exist but mouser and digikey don't let me query via voltageAnyway, links to DAC's meeting these specs would be welcomed but i'm also academically interested in the practical application of using an Op Amp to radiometricly level change between rails. The easy solution, which will not work here, is to use an op amp with a fixed gain - this solution is not acceptable as the the target voltage scale is not known a priori. The system must dynamically scale its output to the environment in which it finds itself.Expressed mathematically:V1 := 3v3 regulated supplyVr := some value between 0 and 3v3 (DAC output)V2 := an unknown voltage rail, likely in the range of 10 to 14vVo := ratiometric outputVo = (Vr / V1) * V2

author: free_electron
author_rank: Super Contributor
timestamp: August 24, 2013, 05:58:25 pm
content: what you need is a programmable resistor. not a programmable dac.or , you could tackle this a different way:take unknown voltage , divide by known amount , apply to vref input if the dac.take output of dac , multiply by same amount of divider.so : take your unknown voltage ( lets say max 30 volts. divide that by 10. feed that to the vref.you now have a dac that can go from 0 to vref.by applying a gain of 10 at the output of the dac you are back where you need to be.1+1 >=2

author: RossK
author_rank: Contributor
timestamp: August 24, 2013, 07:20:59 pm
content: cleaver DAC solution i'll give this one a shot
How can I see sound on an oscilloscope with a microphone? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: March 30, 2014, 11:40:26 pm
content: Hi Everyone,I'd like to see sound waves on my DS2072 from a tiny microphone I have. Do I need to build a circuit to do this? If so, how?Thanks,Alan

author: dc101
author_rank: Regular Contributor
timestamp: March 30, 2014, 11:46:29 pm
content: Try running the mic to the input of your computer and then the speaker output to the input of your scope. Otherwise you could get by with a simple audio amplifier circuit.

author: nctnico
author_rank: Super Contributor
timestamp: March 30, 2014, 11:59:09 pm
content: Chances are it is an electret microphone. All that needs is a bias of around 3k Ohm to 5V. The sensitivity will depend on the value of the resistor but 3k is a good start.

author: alank2
author_rank: Super Contributor
timestamp: March 31, 2014, 12:03:36 am
content: Something like this or simpler?http://electronics.stackexchange.com/questions/36795/using-a-microphone-with-an-arduinoThanks guys!

author: EEVblog
author_rank: Unknown
timestamp: March 31, 2014, 12:08:31 am
content: You don't need anything more than your scope probe:

author: GreyWoolfe
author_rank: Unknown
timestamp: March 31, 2014, 01:15:18 am
content: I tested a Kenwood MC-50 desk microphone just using my Hantek DSO.

author: mcinque
author_rank: Unknown
timestamp: March 31, 2014, 11:15:11 am
content: I guess an electret should work but since AFAIK its sensitivity is not linear you may get wrong readings: I suggest you to use a good dynamic microphone without any other use of circuitry. You should be able to read the AC variations caused by the sound that makes vibrate the microphone's membrane

author: alank2
author_rank: Super Contributor
timestamp: March 31, 2014, 02:35:16 pm
content: I did get the electret to work with the circuit I posted, but I'm not so sure how well.There are a lot of dynamic microphones at amazon for around $10 or so. They look like they have a 1/4" jack on them. Will this need an amplifier circuit to work?

author: ju1ce
author_rank: Regular Contributor
timestamp: March 31, 2014, 03:05:34 pm
content: If seeing sound is all you want to do, you can also connect a speaker to your oscilloscope and shout at it.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 01, 2014, 03:05:15 am
content: Quote from: alank2 on March 30, 2014, 11:40:26 pmset the DS2072 to mV range and set the sound volume into the mic to the maxed you can, done!

author: zapta
author_rank: Super Contributor
timestamp: April 04, 2014, 02:48:41 pm
content: If your probes are x10 don't use them, connects wires directly to the scope.

author: MikeGyver
author_rank: Newbie
timestamp: April 05, 2014, 04:34:25 am
content: Ground the pin of the electret mic with the little ground path to the case, pull up other pin to 5-12volts or whatever with a 4.7-47k resistor, and put a cap to that node, other side of cap is audio out. 3 components to use an electret condenser mic, doesn't get much easier than that.
How can i start developing windows software to talk with BLE? (HM-11) - Page 1
Forum section: electronics / projects

author: JPortici
author_rank: Super Contributor
timestamp: August 29, 2017, 03:12:07 pm
content: Thought i would be able to google at least some pointers but no such luck yet.I have a bunch of HM-11 BLE <-> UART modules and i'd like to use them to talk between a computer and a microcontroller board.. and while it is reatively easy to find out informations, tutorials and projects to write android/ios apps i wasn't able to find anything useful about writing a WINDOWS application.If anything, the devices are programmed and i can see them in both win 7 and 10. Can pair but can't connect to them.Does anybody have some pointers?

author: Avacee
author_rank: Unknown
timestamp: August 29, 2017, 03:51:39 pm
content: There are many sorts of Windows applications and many different languages.Can you be more specific?Edit: Or is your problem that the virtual COM port isn't created?http://www.collideabq.com/2016/04/28/bluetooth-serial-connection-with-windows-10/

author: colorado.rob
author_rank: Frequent Contributor
timestamp: August 29, 2017, 06:10:15 pm
content: I have just started working with BLE on Linux. I will need to tackle Windows next. My understanding is that Windows 7 does not support BLE. You need at least Windows 8 to get BLE support.Here's what I did for Linux:https://github.com/mobilinkd/bleptyIt is a little crude. It is a Python application that creates a bridge between an HM-10 (an HM-11 will also work) using the Linux BLE stack and a Linux PTY emulating a serial TTY, so that applications that expect to talk to a serial port can talk to the BLE device.I know next to nothing about Windows BLE APIs, but they will need to have similar features. You need to be able to find the BLE devices, discover their characteristics, and read and write to them. You should be able to take the code above and adapt it to Microsoft's APIs:https://msdn.microsoft.com/en-us/library/windows/hardware/hh450825%28v=vs.85%29.aspxI will be giving it a try with IronPython soon.

author: pigrew
author_rank: Frequent Contributor
timestamp: August 30, 2017, 01:46:03 pm
content: I've had to develop BLE applications for my company (which uses Windows 7).There are two USB->BLE dongles that I know of which will run on Windows 7 that I'd suggest looking into (though both have downsides).TheCypress CY5677has a nicely documented API, and supports BLE 4.2 (faster data transfer, longer packets). However, it requires driver installation, is physically much larger, and doesn't come with a case.TheBlueGiga BLED112is a generic serial port device which doesn't require any driver installation, and is very small (more convenient packaging). However, it doesn't come with a nice Windows driver (Here is my fork of a library I've been using). It's antenna is also a bit weaker than other devices I have. It also is only BLE 4.0 (using TI CC2540).Otherwise, you might be able to use TI's "HCI" mode to talk to their ICs with a serial port, but that'd require you to fabricate your own dongle.
How can I undo embeded Forth? - Page 1
Forum section: electronics / projects

author: Andy Watson
author_rank: Super Contributor
timestamp: August 30, 2017, 10:12:21 pm
content: I am trying to reverse engineer the GPIB interface of a Wayne Kerr (a.k.a Farnell, Hi Volt and more recently HiTek) AP7030 and I would like to understand the operation of its "brains". The 1990's brain is composed of a Z80 processor, 32k EPROM and 8k of battery backed RAM. Having sucked the bits out of the EPROM, a scan for ASCII strings is strongly suggesting that the code was based on Forth.This is where I come unstuck. My last encounter with Forth was 30+ years ago. It was brief but sufficient to cause an aversion that has lasted three decades. My encounter was so brief that I did not progress to the stage of understanding how to translate code into an embedded system. So where do I start? Any ideas?

author: helius
author_rank: Super Contributor
timestamp: August 30, 2017, 10:44:20 pm
content: Forth code is normally compiled to a dense representation called"threaded code", which is basically a list of jump addresses. The compiler is usually built in to the Forth runtime system as it is very small.Reverse engineering compiled Forth programs is aided by being able to interact with the Forth prompt, if the interactive words likeseeandwordsare present. There are Forth books available online, but I don't know of any centered around reverse engineering; Sun'sOpenBoot documentationdoes provide enough detail to understand how it works.To be able to enter new code at runtime, the Forth system needs a data structure called a "dictionary", made up of "words" which are source code operators. They correspond to the functions and control statements of a conventional language. If runtime patching will not be required, the dictionary can be deleted, and without it the code is harder to decompile.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 13, 2017, 11:49:25 pm
content: @Helius, thanks for the pointers. With a bit of guess work I was able to suss-out the commands that I needed to exercise the GPIB board and bring it back to life - only five chips and faulty DIP switch needed replacing!Unfortunately, whilst replacing the DIP switch I think I clobbered the battery-backed RAM. The GPIB still controls the power supply but it will not read-back voltage or current. In fact it will not read-back any decimal value - it just replies with a semicolon. It will read-back integer values from the DAC/ADC - so I know the hardware is good. I have tried removing the power from the RAM but the problem remains. Any ideas? It may respond to Forth commands up its GPIB - there's no other obvious method of talking to the controller.A bit of a long shot but can anybody point me towards the Wayne Kerr, GPIB programming manual (9HAPHIBUS ?) for these power supplies. I believe the GPIB option is common to the whole AP range, 500/1k/3kW units.
How can we make an intel account? what am I messing up? - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 18, 2018, 07:08:48 am
content: Hi,I want to create an Intel account, so I can check their HDL tutorials. the problem is that I do not see any link or something to make an accountWhat am I missing?

author: marshallh
author_rank: Unknown
timestamp: August 18, 2018, 06:20:38 pm
content: It's a bit hidden - here is the direct link.https://www.intel.com/content/www/us/en/forms/fpga/fpga-individual-registration.htmlIf you previously had a myAltera account, you still have it, but the username is now your email and your password has been reset.Hoping intel doesn't ruin Altera..

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 19, 2018, 10:27:44 am
content: Really thanks for the Tip, I hope too. but why they hide it anyway?
How can you modifie a current mirror to work for negative voltages? - Page 1
Forum section: electronics / projects

author: ZeTeX
author_rank: Frequent Contributor
timestamp: February 20, 2017, 05:14:48 pm
content: A usual NPN current mirror looks like this:https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Simple_bipolar_mirror.svg/200px-Simple_bipolar_mirror.svg.pngBut I want to use Vout for negative voltages, e.g negative voltage regulator output to meet minimum load requirements. (the resistor dividers are over 50k in total), so how can you change it to work with negative voltages?

author: ZeTeX
author_rank: Frequent Contributor
timestamp: February 20, 2017, 06:10:01 pm
content: Got it, Thanks!
How close can a 240 VAC trace to its neutral line - Page 1
Forum section: electronics / projects

author: drakejest
author_rank: Regular Contributor
timestamp: October 27, 2020, 05:30:01 pm
content: I am designing for a 240VAC 3phase ADC Front end. I have decided to design saftey clearance for surges of up to 2000 volts spacing wise. But as i am planning the layout i am running to trouble with the neutral trace having to come close to each phase. Kind of tricky since the adc takes in a differential so each phase must have a accompanying neutral.So how close can i trace a neutral line to the each phases of the 240VAC line?I also of thought of placing some components of the bottom side of the board, if i trace all neutral on the bottom would the 1.6mm board thickness alright?ImageThe pads labeled with R,F are the connector, the three connector on the left side are for the 3 phases while the one spaced on the right is for the neutral. The component on the bottom layer (blue) are local tvs

author: m k
author_rank: Super Contributor
timestamp: October 27, 2020, 06:56:42 pm
content: I think the rule goes something like max peaks and then small multiplier.I wouldn't accept 2mm.

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 28, 2020, 01:19:59 am
content: Can you use isolation slots?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 28, 2020, 01:14:44 pm
content: Voltage differential between GND and a phase is about 70% or so of the voltages between the phases themselves, so you will need to keep very similar clearances.1.6mm fiberglass and epoxy would be plenty isolation between GND and the phases. But be careful with capacitive coupling and vias. You can define ONE potential as the gnd level for your circuit, It can even be one of the phase signals, but it would be much more logical to use the Neutral as your GND.In total the high voltage area should be pretty small. Just from the connector to some resistor divider, and maybe some capacitors for frequency compensation.It is perfectly all right to use the Neutral of the 240Vac as "GND" potential of your ADC, as long as the power supply is isolated and has sufficient isolation. This way you have no issues with linearity of complex analog circuit in the frontend of your ADC. You can also connect a microntroller or whatever other circuitry needed directly to mains. But then you do need an isolation barrier in the digital domain on the other side of the ADC. It's also a complication for reprogramming the uC during development.

author: drakejest
author_rank: Regular Contributor
timestamp: October 28, 2020, 02:28:32 pm
content: Quote from: Doctorandus_P on October 28, 2020, 01:14:44 pmThe adc is comepletly isolated power and signals by digital isolators, and have been designing that the citical compenents are capable of tolerating upto 2kV surges. And yes trying too keep even spacing and reduce the High voltage. Im worried that a phase (or multiple phase) will just just arc to the netural line, from the connector going straight through the pcb directly to the bottom neutral traces
How common are "nonstandard" PT100 sensors? - Page 1
Forum section: electronics / projects

author: peter-h
author_rank: Super Contributor
timestamp: May 06, 2021, 07:39:28 pm
content: Depending on the alloy and purity of the platinum, the nominal temperature coefficient, α, may range from 0.00375 Ω/Ω/°C on the low end to 0.003927 Ω/Ω/°C for pure platinum. The current international standard for process control RTDs is 0.00385 Ω/Ω/°C, meaning the resistance of a "PT100" RTD is 100Ω at 0°C and 138.5Ω at 100°C:Are sensors other than 0.00385 common?
How diode, zeners and LED tester works? - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: December 05, 2018, 12:50:06 pm
content: Hi!Is diode and LED testers a sort of current source or voltage source?I`m looking for simple project to test my LEDs and zeners

author: Zero999
author_rank: Super Contributor
timestamp: December 05, 2018, 05:12:00 pm
content: They'll be constant current sources or perhaps the cheap ones will just use a resistor.What voltage range zeners do you want to test? Most diode testers have an open circuit off under a fer volts, so aren't much good for testing the reverse breakdown voltage of zener diodes.

author: AngraMelo
author_rank: Regular Contributor
timestamp: December 06, 2018, 04:12:07 pm
content: Usually constant currenthere goes a project that I build and works like a charm!

author: queennikki1972
author_rank: Regular Contributor
timestamp: September 22, 2019, 03:35:48 pm
content: I built this version with a transformer, its overkill (one of my first projects, didn't know any better) but does the job for all zener diodes up to 27v....
How do design power up/down sequence for an FPGA? - Page 1
Forum section: electronics / projects

author: zapta
author_rank: Super Contributor
timestamp: August 22, 2024, 04:54:15 pm
content: My immediate need is power for a ICE40UP5K-SG48I FPGA but this is a general question. The FPGA requires power up in two stages, first the 3.3V and 1.2V and then 2.5V. The power down sequence is in reverse, first dropping the 2.5V and then the 3.3V and 1.2V. Maybe some cascading of LDO's EN and Power-Good pins? Is a sequencer such as LM3880 an overkill?Any suggestions for a simple, inexpensive and clean design? One solution I saw is in the diagram below but 1) it doesn't use an LDO for the .25V (I presume I can just replace the diode with an LDO), 2) Doesn't guaranty that the 1.2V is up when the 2.5V is up and 3) Doesn't guarantee the power down sequence.

author: bson
author_rank: Unknown
timestamp: August 22, 2024, 07:00:45 pm
content: Why not just another AP2127K-2.5 regulator and a small RC delay on its EN pin?

author: jbb
author_rank: Super Contributor
timestamp: August 22, 2024, 08:52:22 pm
content: Don’t have any particular chips in mind but:- if there is a dev board for this FPGA, can you copy its power supply design?- maybe you can find a Power Management IC (PMIC) that includes multiple buck converters and built-in sequencing?- you can get dedicated power supply sequencing ICs which are designed for this job (ie monitoring supply rails and sequentially enabling / disabling converters as appropriate)- you could maybe use a little microcontroller to do itEdit: you might need to control an FPGA reset pin in addition to the supply rails

author: tggzzz
author_rank: Super Contributor
timestamp: August 22, 2024, 09:27:37 pm
content: https://duckduckgo.com/?q=power+supply+sequencing+icis a starting point, or use one supply as the input to the enable pin of another PSU regulator.TI seems to have a range of dedicated controllers; no doubt there are alternatives.

author: tom66
author_rank: Super Contributor
timestamp: August 22, 2024, 10:21:39 pm
content: If the board needs a microcontroller for other functions, then controlling the power sequencing from that is an option. This is my preference.Either way, in terms of cost effectiveness, it's going to be hard to beat something like an 8-bit micro PIC12F kind of thing - and you can then tweak the power-up sequence as needed if you discover issues with your sequencing. RC values can be changed as well, but software is easier.
How do extract parasitic inductance in a power mosfet (PWM/SMPS design) - Page 1
Forum section: electronics / projects

author: Fusion916
author_rank: Regular Contributor
timestamp: January 19, 2018, 09:28:11 pm
content: Hi all,I kind of got caught with my pants down not modeling the parasitic inductance on the PWM drive line (both layout/routing inductance and parasitic from power mosfet). I can figure out how to model the layout parasitic, but is there any way to extract and model the parasitic inductance inside a power mosfet package from the datasheet? Or is there anyway to make an educated guess given the device package or given parasitic capacitance?

author: jbb
author_rank: Super Contributor
timestamp: January 20, 2018, 03:00:17 am
content: There is a way to extract it, but I suspect it's pretty difficult. First up, does your data sheet have anything to say about it?Second, does the manufacturer offer a SPICE or SABRE model for it?Typically the source leakage inductance is the most critical.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 20, 2018, 03:31:26 pm
content: Are you okay with typical values for various package types?For example, TO-220 inserted to full depth (i.e. up to the shoulders on the pins) is about 5nH per pin.Tim
How do hall effect switches not oscillate at the crossover point? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: April 26, 2024, 07:42:01 am
content: I had run out of Allegro A3144 hall effect switches so I tried to make a similar thing using two 3503 linear hall sensors feeding into the differential AB inputs of a Max485 chip in receive mode.I waved a magnet in front of one sensor and assumed that the 200mV hysteresis would give a clean signal, but instead I see a series of spurious pulses before it finally flips state.Do real hall effect switches have the same problem internally, but just capture the first pulse and stretch it out to meet the fully flipped state?The datasheet for the A3144 doesn't really explain what it does internally, other than showing a Schmitt trigger block.
How do I calculate the Temperature rise in the Ferrite core? - Page 1
Forum section: electronics / projects

author: Gowda1
author_rank: Contributor
timestamp: February 03, 2021, 05:44:06 pm
content: Hello,This question might seem basic but I would like to state it. I would like to calculate the operating/Rise temperature of the ferrite core of an inductor. I am modelling my own bobbins for the core so I need to decide on the material/filament to use for 3D printing which can take the temperature of the core without causing any damage or melting of the bobbins. I looked into it but could not get the answer I am looking for. Inductor specifications which might be useful for better understanding: E70 core N87 material, v= 450VRMS, I=40A, f=85khz, Litz wire for the windings, distributed air gap on each leg. I attach the datasheet as well. Please help me with this, any links or any articles would be great too. Thank youhttps://www.tdk-electronics.tdk.com/inf/80/db/fer/e_70_33_32.pdf

author: Mazo
author_rank: Regular Contributor
timestamp: February 03, 2021, 07:35:32 pm
content: Estimate all the losses in the transformer,one way or another.Click here:http://encyclopedia-magnetica.com/doku.php/thermal_resistance_of_ferrite_cores

author: TimNJ
author_rank: Super Contributor
timestamp: February 03, 2021, 08:01:01 pm
content: It's a nice exercise to try to calculate total inductor loss (core/hysteresis loss and copper loss) and to use core volume to estimate temperature rise...Depending on how accurate your calculations are, it might just be betterto just print it out of the best material you have access to and check the temperature rise with thermocouple, IR, etc.Quote from: Gowda1 on February 03, 2021, 05:44:06 pmAlso, I think you had another thread talking about gapping all three legs, right? Just another reminder that this does not make it a distributed air-gap (it's not powder/alloy core), and please be mindful of gapping the outer legs for fringing fields/EMI control.

author: Gowda1
author_rank: Contributor
timestamp: February 04, 2021, 08:42:16 am
content: Hey, This does not take any power ratings. it just gives out the losses. I dont know if this is right

author: temperance
author_rank: Super Contributor
timestamp: February 07, 2021, 10:01:06 pm
content: Maybe an old unitrode app note can help you:SLUP126:https://www.ti.com/lit/ml/slup126/slup126.pdf
How do I calculate this resonant point? - Page 1
Forum section: electronics / projects

author: Glenn0010
author_rank: Regular Contributor
timestamp: April 26, 2025, 04:03:46 pm
content: 1

author: moffy
author_rank: Super Contributor
timestamp: April 26, 2025, 11:15:38 pm
content: The nearest simple resonance is L34 in parallel with L35 and C31, but it is a complex little circuit with other components interacting, looks a little like a crystal but the resonance highs and lows are too spread.

author: Someone
author_rank: Super Contributor
timestamp: April 27, 2025, 10:38:15 am
content: Quote from: Glenn0010 on April 27, 2025, 09:58:37 amThere is no direct way to mathematically isolate resonant modes from such a complex circuit, as with that many reactive components the number of possible resonances becomes impractical to test.The general solution is to bash it into a frequency domain simulation and make a sensitivity analysis of the component values (at which point you may as well have gone straight for a brute force solution to your problem).

author: moffy
author_rank: Super Contributor
timestamp: April 27, 2025, 10:41:01 am
content: I just noticed that it is a GAIN plot vs frequency, not impedance as I assumed.So for the 68.1kHz peak C28 is being nulled out by the composite reactances so that node is going high impedance. All I could suggest is to use SPICE and look at the behaviour of the nodes at the points of interest, you might through much pain derive the Laplace equation for it all, but it looks like it would be messy and unlikely to provide any easy insight.

author: moffy
author_rank: Super Contributor
timestamp: April 27, 2025, 02:38:29 pm
content: Did a quick sim, you have two nulls, one at the junction of R27/C28 and one at the junction of C31/C29 and since you are measuring the output/input, the input null at C31/C29 looks like a peak.The blue trace is: R27/C28The green trace is: C31/C29

author: IconicPCB
author_rank: Super Contributor
timestamp: April 28, 2025, 12:36:40 pm
content: A simulator (SPICE) will give you a numerical solution when you really need an analytic solution in the form of a ratio of two polynomial such that you can then find the roots of the equation to determine poles and zeros of the transfer function in symbolic form.This will then give you an insight into the contribution of each component to the overall circuit behavior.Google nodal analysis and mesh analysis.

author: mikerj
author_rank: Super Contributor
timestamp: April 28, 2025, 01:34:47 pm
content: Quote from: Glenn0010 on April 26, 2025, 04:03:46 pmWhy would you delete your opening post? It removes any context from the rest of the thread.

author: Someone
author_rank: Super Contributor
timestamp: April 28, 2025, 10:59:58 pm
content: Quote from: mikerj on April 28, 2025, 01:34:47 pmSmells like a homework problem.
How do I connect this piezo transducer with no pins ? - Page 1
Forum section: electronics / projects

author: TrotsKeeper
author_rank: Newbie
timestamp: February 10, 2023, 04:20:39 pm
content: Hello,I have this piezo buzzer (Mallory Sonalert AST100Q) and I have no clue how to connect it to arduino or how to operate it - the tutorials I came across have wires on the device.Product Link:https://www.mouser.ca/ProductDetail/Mallory-Sonalert/AST100Q?qs=yTNxYlKScpxTY7LEiSaOPg%3D%3DDatasheet:https://www.mouser.ca/datasheet/2/252/AST100Q-1519790.pdf

author: MarkS
author_rank: Unknown
timestamp: February 10, 2023, 04:35:43 pm
content: It's a surface mount component. The "pins" are the 3x3.6mm pads. You'd have to solder wires to the pads to connect it to an Arduino board, or find one that's a through hole component.You might want to consider this, and they have Arduino examples.https://www.adafruit.com/product/1739
How do I control a 120vac light using low voltage 12vdc  - Page 1
Forum section: electronics / projects

author: Sigma957
author_rank: Contributor
timestamp: July 04, 2022, 05:38:46 pm
content: Hello,I am trying to find out how to make a light work the way I want.What I would like to do is as follows.I have a light in a garage controlled by light switch and I want to make it so if a door opens it turns on said light.It's not the main door or I would simply add a motion light switch.I want the light to turn on if one of the overhead doors open and stay on until door closes.But I also want the light switch to stay working in the garage except not shut off the light if overhead doors are open.Where I live have 120vac.I thought of using relays and low voltage magnetic door switchs but am unsure of how to wire them and keep it safe.Just in case someone tries using light switch if light is on from Overhead door being open.If there some premade relay for such a project or how would I go about it.Thanks in advanceSigma

author: David Hess
author_rank: Super Contributor
timestamp: July 04, 2022, 06:19:09 pm
content: A relay, or solid-state relay, wired in parallel with the wall switch will allow the door to turn the light on without affecting the operation of the switch.

author: Sigma957
author_rank: Contributor
timestamp: July 04, 2022, 06:31:03 pm
content: Hello,Thanks for the fast reply to my post, I really appreciate it.I will give the solid state relay a shot.Will pick one up later this week.ThanksSigma

author: SL4P
author_rank: Super Contributor
timestamp: July 05, 2022, 06:41:08 am
content: It sounds like you’re not so confident working with mains power.If you make a simple mistake or oversight that results in a disaster or tragedy, not only are you likely to be held accountable, but there’s every chance any insurance policies will be looking the other direction.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 05, 2022, 06:56:29 am
content: Quote from: Sigma957 on July 04, 2022, 06:31:03 pmNo, use a normal relay.And let an electrician install it. It's not safe for you to do it.