hybridfree/eevblog-posts huggingface dataset:
Python tkinter error - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: October 21, 2015, 03:23:23 pm
content: 1. I have written below code. It shows error.Code & error are below.2. What does this statement mean:self.master=masterCode:from Tkinter import *import Tkinterclass menu1():def __init__(self,master):self.master = master#clear valueself.val1 = 1#default selectionself.v = IntVar()self.v.set(1)#create a labelself.x1 = Label(self,text="Title",justify = CENTER,padx = 100)self.x1.pack()#first radiobuttonself.x2 = Radiobutton(self,text="Title1",padx = 100,variable=self.v,value=1)self.x2.pack(anchor=W)#create buttonself.x6 = Button(self,text="OK",command=self.submit)self.x6.pack()def submit(self):self.val1 = self.v.get()self.destroy()def suicide(self):self.val1 = 0self.destroy()def screen():#create a root objectroot = Tk()app = menu1(root)app.title("Option")app.geometry("480x320")app.mainloop()return app.val1screen();Code:Traceback (most recent call last):File "C:/Users/abc/Desktop/c.py", line 47, in <module>screen();File "C:/Users/abc/Desktop/c.py", line 41, in screenapp = menu1(root)File "C:/Users/abc/Desktop/c.py", line 19, in __init__self.x1 = Label(self,text="Title",justify = CENTER,padx = 100)File "C:\Python27\lib\lib-tk\Tkinter.py", line 2591, in __init__Widget.__init__(self, master, 'label', cnf, kw)File "C:\Python27\lib\lib-tk\Tkinter.py", line 2081, in __init__BaseWidget._setup(self, master, cnf)File "C:\Python27\lib\lib-tk\Tkinter.py", line 2059, in _setupself.tk = master.tkAttributeError: menu1 instance has no attribute 'tk'>>>

author: Maxlor
author_rank: Frequent Contributor
timestamp: October 21, 2015, 03:57:21 pm
content: - Your Menu1 class should probably inherit from a default tkinter class.- mainloop() should be called on the root object.-self.master = mastercauses the method parameter calledmasterto be stored in the member variable (self.master) so that it can be accessed later, in another method.

author: krish2487
author_rank: Frequent Contributor
timestamp: October 21, 2015, 06:52:30 pm
content: It means you are trying to bite more than you can chew.Not to discourage you, but maybe you should gain some experience in working more on python before you can get started with tkinterTkinter, if memory serves correctly, is python's answer to Qt.And yes, you should also read up and understand OOPs concepts and general programming methodologies.Wiki is a good place to start and you can always buy books based on what you would like to pursue.(Mike McGrath - pythons book comes to mind) It is a good read for a beginner.

author: amyk
author_rank: Super Contributor
timestamp: October 22, 2015, 03:48:22 am
content: ...and what does this have to do with electronics? I was hoping you'd at least mention "Arduino".
PZT2222 says both pins 2,4 are connected, do you have to connect both? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: June 25, 2015, 12:09:32 pm
content: The datasheet for PZT2222 says both pins 2,4 are connected. When routing tracks, do you have to connect both?

author: ConKbot
author_rank: Super Contributor
timestamp: June 25, 2015, 01:42:05 pm
content: For an sot-223, or other 3 pin + thermal tab transistors, no you don't have to connect both, as the middle pin and tab are connected in the leadframe. But verify that there isnt exposed metal between the center pin and thermal tab. SOT-89 can have this, so running a trace, there would only be soldermask providing insulation.

author: flynwill
author_rank: Regular Contributor
timestamp: June 25, 2015, 01:42:58 pm
content: No you don't need an additional connection. They are literally the same chunk of metal inside the plastic. The "tab" is there for heat-sinking, so depending on how much power the part will be dissipating in your design the PCB may need a significant copper area connected to the tab, an added heat sink or both.

author: alank2
author_rank: Super Contributor
timestamp: June 25, 2015, 02:26:40 pm
content: Thanks guys. I'm using a part that has no connection between the pins on the underside, I did look at one like that, but it seemed like you could get a bridge between that and pins 1 and 3 pretty easily so I moved to the SOT223 instead. I'll route the track if it is easy to, but if I need to route another track through it I'll just connect one or the other. I'll make sure there is enough copper on the larger tab for heat sinking.
Q: Batteries & Charging requirements ? - Page 1
Forum section: electronics / beginners

author: LeWidget
author_rank: Regular Contributor
timestamp: April 15, 2016, 11:04:47 am
content: Hi guys,Quick question.. how do charging batteries work? Whether it be single batteries like AA, AAA, C, D etc.. or a phone / electronic device or even a car battery, what's the requirements in order to charge them? Do the input voltage from the charger have to match the voltage of the battery your charging.. ie.. 12v car battery, do I have to use a 12v charger.. or can I use a lower voltage, say 6v .. or even a slightly higher voltage..say 14v?What about charger source?.. can the source be from anything that outputs voltage.. like a power supply from another device ? If so, what the the Pros / cons of it?Does the current output from the charger matter? or does that just determine how quickly it will charge?Do the batteries determine how much Amps are drawn from the source.. like an electrical device?Sorry for the odd random Question, though just thought I'd askRegards,

author: Kilrah
author_rank: Unknown
timestamp: April 15, 2016, 11:09:16 am
content: Depends on the battery type, each has its own requirements.Lots of reading available for that.

author: tszaboo
author_rank: Super Contributor
timestamp: April 15, 2016, 11:14:27 am
content: There is a bucket in the battery, electrons get trapped in the bucket when you charge it. You have to be sure not to spill it, otherwise the entire floor will be fill with electrons.But maybe it is more complicated. Have you tried reading online about batteries?

author: LeWidget
author_rank: Regular Contributor
timestamp: April 15, 2016, 11:25:16 am
content: Thanks guysI haven't read much about them yet, just thought about it and jumped here to ask. Ill see what I can find about the different battery requirements

author: pitaaasa
author_rank: Newbie
timestamp: April 15, 2016, 11:36:27 am
content: Have a look athttp://www.batteryuniversity.com/learn/

author: LeWidget
author_rank: Regular Contributor
timestamp: April 15, 2016, 12:57:30 pm
content: Quote from: pitaaasa on April 15, 2016, 11:36:27 amAwesome!, thanks for the link, Ill have a read and see what I find

author: Audioguru
author_rank: Super Contributor
timestamp: April 15, 2016, 01:33:02 pm
content: You must never try to charge a battery that is not rechargeable. If you do, it will not get charged but instead it might leak or explode.
Q: Ebay fluorescent ballast  - Page 1
Forum section: electronics / beginners

author: wilfred
author_rank: Super Contributor
timestamp: September 17, 2013, 08:40:03 am
content: /.

author: Zero999
author_rank: Super Contributor
timestamp: September 17, 2013, 11:16:51 am
content: If it's not as bright, it's possible the ballast isn't really outputting 32W into the tube - the power output of cheap ballasts is often overstated. An electronic ballast should theoretically give a brighter light, for the same power output.In nay case, I wouldn't recommend a florescent for intermittent operation, since it takes awhile to warm up and achieve full brightness.EDIT;If you keep the heaters permanently powered with a small twin 6V secondary transformer and the tube will start instantly but you need to consider the standby power consumption will be high.

author: Unknown
author_rank: Unknown
timestamp: September 18, 2013, 03:34:17 am
content: Hi,I'm not quite sure why you wanna buy what must be a common-type ballast from China but providing the tube is happy, a 32W ballast for a 20W tube should certainly give you more reliability (and light) than your 21W.Personally wouldn't recommend going to a much higher wattage than 32W though (30% more), as you may damage the tube when starting up with the larger coil if you went to say 40W.For example if I am changing a 4ft 40W choke (ballast), I won't go buying a 75W - 80W choke (50% more).That said, for 7 bucks, the worst that can happen is you need to find a more powerful tube (or a slightly lower wattage choke), and you'll have learned where the limit lies with choke to tube-wattage ratio.
Q: Fixing Attinys with AVR ISP mkII - Page 1
Forum section: electronics / beginners

author: JamesHowlett
author_rank: Contributor
timestamp: April 01, 2015, 05:33:31 am
content: Hello everybody,I posted the question in the microcontrollers section, but i did not get a response until now.https://www.eevblog.com/forum/microcontrollers/q-fixing-attinys-with-avr-isp-mkii/I believe the question is also proper for the beginners section. Should i move it here completely?RegardsOz
Q: re 555 timer monostable circuit that doesn't want to timeout. (solved) - Page 1
Forum section: electronics / beginners

author: wilfred
author_rank: Super Contributor
timestamp: November 08, 2013, 01:48:16 pm
content: /.

author: Zero999
author_rank: Super Contributor
timestamp: November 08, 2013, 01:56:32 pm
content: Does the relay have a protection diode in reverse parallel with it and another diode in series with it?

author: dcel
author_rank: Regular Contributor
timestamp: November 08, 2013, 02:01:40 pm
content: You are going to need a transistor or a MOSFET to run the relay. Don't forget the anti-kickback diode. You should have no problem finding the schematics online. A scan of your penciled schematic is very acceptable in order to help you.Good luckChris

author: dr_p
author_rank: Frequent Contributor
timestamp: November 08, 2013, 02:03:57 pm
content: 22-680pF across the relay?edit: but firstly, what happens to your power rail when the relay switches? Put a scope on it.

author: dcel
author_rank: Regular Contributor
timestamp: November 09, 2013, 07:00:18 am
content: Looks to me that the additional circuit on pg2 is there for debounce. It also may have the effect of lowering the impedance of the input, thus lowering the sensitivity. Someone smarter than me will have to confirm that regarding the 555, I haven't played or built a project with a 555 since around 1990, when I built a dome light minder for my car.Chris

author: oldway
author_rank: Super Contributor
timestamp: November 09, 2013, 07:24:32 am
content: 1N4004 is far too slow, you should use a fast free wheeling diode in parallel with the relay.1N4148 of UF4004 for example.

author: Zero999
author_rank: Super Contributor
timestamp: November 09, 2013, 09:17:29 am
content: You may find adding another diode in series with the relay might help.

author: Andy Watson
author_rank: Super Contributor
timestamp: November 09, 2013, 12:54:22 pm
content: Pin 2 is a relatively high-impedance input. When you open the trigger switch the pin will float, probably to a voltage slightly above its trigger level, and due to its high impedance it will be susceptible to noise. By putting the 100k resistor to Vcc you've stopped it floating and pulled the voltage away from its trigger point to its inactive state. When you've worked out why that has the effect that it does you might want to look at pin 4 - that also appears to float when the switch is open. As to why it works with an LED and not with a relay, it's probably due to the extra noise introduced by the relay - and luck (or un-luck!)
QBlackBox - Page 1
Forum section: electronics / beginners

author: muffenme
author_rank: Contributor
timestamp: May 21, 2016, 11:39:02 pm
content: Dave Jones, have you seen this BS on Youtube,https://www.youtube.com/watch?v=_uItJj8PeU0.I not that smart with electronic but this QBlackBox clamming in this video just seem too good to be true. Putting energy into a battery without charging it. Either I not getting what he saying or it BS? Love your Youtube channel.
QC 3.0 (Quick Charge) Trigger Decoy Circuit - Page 1
Forum section: electronics / beginners

author: EdHayes3
author_rank: Newbie
timestamp: January 19, 2021, 05:13:05 am
content: I just designed a multi port power supply that has 12v/24v input, and multiple USB outputs, all with their own buck voltage converter. I found a chip (FP6601QS6 or IPT2601) that will negotiate and control the regulator voltage feed back network for 5/9/12v using QC 3.0 (quick charge) protocol. I also have another regulator (IP6510) that handles a USB-C port PD (Power Delivery). I'd prefer the QC over the PD since the PD requires the additional pins on the USB-C cable, and seems it's more complex and not as ubiquitous.I've been trying to find a circuit to trigger this from the consuming device, but have only found pre-made boards, cords, or testers. Seems like this can be done with just a handful of parts. Has anyone designed something that would do this? I attached two modules I found on Ebay. I cant see the chip marking to know what they are though. There is probably other ways to do this. I'm guessing the SOT-23 is a 5v or 3.3v LDO, and the other is an ATTiny10 which triggers out pins to configure the voltages. The traces seem to support this idea.One example design, but requires intervention by the user.http://www.hackvlog.com/2016/12/bitbanging-quick-charge-2.htmlPage 6-7 has some more details on the handshakehttps://www.ti.com/lit/ug/tidu917/tidu917.pdfAnyone have any thoughts on this?
QFN Chip stuck won't come off Help! - Page 1
Forum section: electronics / beginners

author: kifu88
author_rank: Newbie
timestamp: January 20, 2022, 08:04:54 pm
content: Hello!SO decided to fix my broken GPU (sapphire rx 480 nitro) , changing the IR qfn Chip (rectifier power stages.)i bought a hot air station (KD 858). My problem is that the solder will not melt. The chipset is stuck. i tried with hot air station 300c-400c medium air with flux for 20sec-2 min multiple times and nothing. chip is not budging! I tried adding new Solder (Sn60Pb40 2.5flux) still nothing.Is the chip welded itself to the ground PCB?What should i do?

author: Siwastaja
author_rank: Super Contributor
timestamp: January 20, 2022, 08:13:35 pm
content: The multilayer board is just not heating up.You can try to heat the whole board at slightly lower temperature setting (like 200 degC) for a LONG time (like 15 minutes!) and then increase the temperature and start working around the chip. Don't go beyond about 370-380.But better yet, use preheating. Even a simple frying pan on a stove does. You don't need high temperatures. A cheap IR thermometer helps here. If you can keep the frying pan at, say, 200 degC, so that the board finally heats up somewhere around 150 degC, this will already make a huge difference; now let the hot air do the rest of the job: keep the board on the pan, and start working with hot air around the chip.

author: kifu88
author_rank: Newbie
timestamp: January 20, 2022, 08:39:52 pm
content: IT WORKED! i DID exactly as you said! your the best!Btw the back of the card (PCB) was sweating a bit, is that normal?

author: Siwastaja
author_rank: Super Contributor
timestamp: January 21, 2022, 10:40:29 am
content: What do you mean by sweating? If it creates blister-like structure or emits smoke, you have applied too much heat to it, the FR4 board material itself can't take much beyond 200 degC for a long time, or much beyond 300 degC even for a shorter time. (Because of limited thermal transfer capabilities of air, the air itself can and must be hotter than this.)The key with preheating is to get whole board to as equal temperature as possible, using modest heat and long enough time. If you have any dummy boards, practice.

author: kifu88
author_rank: Newbie
timestamp: January 21, 2022, 02:43:17 pm
content: No somke no blister-like structure. Just like spots of water/liquid and then they evaporated.I replaced the QFN chip, there was a extremely small SMD ceramic capacitor missing next to it desoldered when i was trying to remove the chip.the card worked, but as soon as i installed the driver bum! the second QFN blew and burning circuit smell.

author: HumbleDeer
author_rank: Contributor
timestamp: January 21, 2022, 05:59:09 pm
content: Sounds like something's wrong with the GPU itself then. It's possible that the drivers installing initiates activation of specific graphics cores for acceleration, and if those are bad or a circuit connected to it, then this could be the result.
. - Page 1
Forum section: electronics / beginners

author: fullmoon6661
author_rank: Newbie
timestamp: May 07, 2023, 11:48:23 pm
content: .

author: jpanhalt
author_rank: Super Contributor
timestamp: May 08, 2023, 07:56:32 am
content: It could be clearer. See Capture1, which gives as Option 1 a pad the same width as the max. Unfortunately, Renesas doesn't give guidelines for how to pick each option. Capture2 clearly shows the pads wider. Since two of the three recommend a wider pad, and the outlier (Renesas) gives wider as an option, that seems to be the way to go. Maybe with the narrower pad one is expected to have a larger aperture in the solder mask (or no mask).References:Options (Capture1):https://www.renesas.com/us/en/document/psc/20-qfn-package-outline-drawing-40-x-40-x-075-mm-body-050mm-pitch-ncg20Pad wider (Capture2):https://www.renesas.com/us/en/document/oth/qfn-mounting-manualEDIT: It is frustrating dealing with the messy way images are handled here. I intended to have Capture1 before Capture2. Unfortunately, the first image uploaded created a huge blank space. So, I uploaded Capture1 a second time. It posted OK as the third image. Then deleted the first, so now it's the second. That's a real pain and requires multiple edits.

author: thm_w
author_rank: Super Contributor
timestamp: May 08, 2023, 10:20:04 pm
content: For the outside pads, extending significantly from the QFN IC makes it easier to hand solder, hand rework and inspect the solder fillet, but reduces the board density. Its a trade off depending on what is more important to you.The one thing thats considered superior though are the rounded pads from NXP, no reason not to use those.
QFN soldering by hand  - Page 1
Forum section: electronics / beginners

author: signalhardware
author_rank: Newbie
timestamp: January 10, 2023, 11:35:14 am
content: Hello.One of my suppliers delivered a PCBA prototype partially assembled, one of the missing parts are two QFN devices (16 and 48 pins).Does anyone have experience soldering this by hand?I have microscope, soldering station with pico iron, and reworking station, which would you will use for this task, and with which kind of products (flux, solder past or solder wire..)?.Also temperature specs for the job will be appreciated.I find this procedure:https://www.digikey.be/de/maker/projects/how-to-solder-a-qfn-component-using-a-hot-air-rework-station/77b9331e7183452f97041c75d946c7c7Thanks a lot in advance!Francisco.

author: RogerThat
author_rank: Regular Contributor
timestamp: January 10, 2023, 10:58:11 pm
content: My way:1. pre-tin both board and QFN (there shall be small bumps on both)2. Put a good "blob" of flux on the board. This prevents the chip from flying away when you put hot air to it and it also helps conduct the heat.3. place chip and put some flux on top of it.4. Pre-heat from 10cm away for 1min, always straight vertically from the chip. To get the temps correct you can first do a test where you put a thermometer on a blank board and put your hot air 10cm away...the temp should be around 180c after 1min.5. Move your hot air really close, 1cm, and keep it there until you see the part pop into place. With the hot air still in place tap down on every side of the chip to make sure the solder attaches.6. Move hot air to the 10cm point for 15sec and then off completely.7. Clean with IPA and done.

author: Faranight
author_rank: Unknown
timestamp: January 11, 2023, 06:07:41 am
content: Alex (from NorthridgeFix) also pushes down on the QFN chip after solder solidifies and then re-applies hot air so that any excess solder is pushed out from underneath the chip. Finally, he cleans the solder blobs around the IC with a soldering iron.

author: coppercone2
author_rank: Super Contributor
timestamp: January 11, 2023, 06:20:55 am
content: if you fail take a day off and try it another day, do not keep trying because you will blow a gasket

author: Psi
author_rank: Super Contributor
timestamp: January 11, 2023, 08:08:14 am
content: You can also drag solder them with a fine tip to tidy up after if some pins don't look good under microscope.Just add flux and use a clean tip to drag along the pins carefully.If only 1 or 2 pads are under-soldered the solder already there on all other pads will evenly distribute itself.If many pads are under-soldered then you will have to add a tiny bit of solder to the iron tip.Fluxing the pins is the key.Drag soldering will only work on QFN chips where the pads go up the side of the package, sometimes the pads are only on the underside and you cant drag it
Qi charging problem - Page 1
Forum section: electronics / beginners

author: FrankBuss
author_rank: Unknown
timestamp: December 05, 2018, 09:55:55 am
content: I'm using aBQ51050Band loading works when the coil is in free air over the charging station. But when it is mounted below a battery, it is very unreliable and difficult to start charging, and often it stops charging.Here is a scope image measured at the coil wires, when it is in free air and charging without problems:And this is how it looks like mounted below the battery, just captured before it stops charging:I'm using this coil:https://katalog.we-online.de/pbs/datasheet/760308101214.pdfThe battery is a Varta EZPack S-3.7V:https://products.varta-microbattery.com//applications/mb_data/documents/product_information/VARTA_EasyPack_Design_In_Handbook_en.pdfThe ferrite shield is in the opposite direction of the charger. It looks like this, each line a "layer":PCBbatterycoil ferrite shieldcoilplastic caseQi chargerThe coil is glued on the bottom side of the battery, half of the coil is overlapping at one side. If in air without the battery, PCB and plastic case, I can charge with the coil in up to 8 mm distance from the Qi charger.I can't post much more details of the product, because it is a client project and he doesn't want to make it public before release, but maybe someone has already an idea what I can do, measure, modify etc.

author: perieanuo
author_rank: Frequent Contributor
timestamp: December 05, 2018, 10:49:28 am
content: hi,you have 2 coils involved, you specified just one.second, magnetics calculation is a pain in the ass, make shure you respected what datasheet IC says regarding capacitor values.if you aren't at ease with those calculations, just test C values with caution and current limiting ob BQ board and you'll find the right onesregards, pierre

author: FrankBuss
author_rank: Unknown
timestamp: December 05, 2018, 11:10:18 am
content: It is basically the same circuit as in the application note on page 15:http://www.ti.com/lit/ug/tidub31/tidub31.pdfA colleague designed the values for the capacitors, as described in the datasheet with measuring the coil etc. The coil in the Qi charger shouldn't matter, it works without problems with my iPhone and the device should work with any Qi charger.But I guess the battery and PCB changes the field? I could try to increase or decrease the capacitors in the input resonant circuit.

author: NickZA
author_rank: Newbie
timestamp: December 05, 2018, 12:53:36 pm
content: Try changing C5 and C21 (on the COMM1 and COMM2 pins) from 22n to 47n.

author: FrankBuss
author_rank: Unknown
timestamp: December 05, 2018, 01:39:10 pm
content: Quote from: NickZA on December 05, 2018, 12:53:36 pmI tried it and it doesn't help.

author: FrankBuss
author_rank: Unknown
timestamp: December 05, 2018, 04:07:35 pm
content: I think the battery is the problem. If I place the coil in free air above the charger, it works, but as soon as I place the battery on top, it stops charging. Can I shield this somehow with ferrite foil, or maybe a bigger coil would be good? The current coil has only 2 cm diameter, the case would allow maybe a little bit over 3 cm.
QI wireless receiver PCB modification. Have I broken anything? - Page 1
Forum section: electronics / beginners

author: angelus2141
author_rank: Newbie
timestamp: October 22, 2024, 07:01:27 pm
content: HI All,I am trying to create a PCB for a Qi compatible wireless power receiver with some modifications, so it fits in the container I have. I bought a few universal ones, in the hopes I could reverse engineer and shrink them but that turned out to be more trouble than I first thought. I found a schematic for one on Easyeda (https://oshwlab.com/Zomhad/wireless-2s-power-system-v3) but after checking it I wanted to change some things.Ive included images below of the original, the modified and a highlighted original with my modifications for clarity. I just want to check what I have done hasn't broken anything and that if other pieces can be removed.Dark Blue: not a biggie I just changed the input and output to separate pads.Yellow: Removal of probe points.Red: Removal of LEDsLight blue (Turqoise): This is where I have some questions. Since I remove the LEDs can I just change the +Bat connection on these to GND instead? Do they even need to be there?Green: The TS/CTRL pin leads to some resistors and a thermistor. I dont understand what this is for as I dont know why i would need a sensor like that on the board. Do you think this was added in by the Dev as just an added way of checking something like the probe points? Can it be removed and the TS/CTRL just connected to GND?Thanks in advance for your help
QQ, appropriate value current limiting resistor for TIP31C @ 12v? - Page 1
Forum section: electronics / beginners

author: XOIIO
author_rank: Super Contributor
timestamp: March 25, 2016, 10:03:40 pm
content: Hello all, so transistors are something I've never really needed to use, but I need to use one to take the input from a reed switch to turn on some LED lighting.Anyways, I'm not sure how you go about calculating the appropriately rated current limiting resistor for the base of a transistor, in this case, with the circuit operating at 12 volts.I'm not sure if there's jut a safe go-to option, like 10k, or if it's best to actually calculate it. I had a quick peruse of the datasheet but didn't see anything helpful.

author: michaeliv
author_rank: Frequent Contributor
timestamp: March 26, 2016, 02:02:20 am
content: Input the values into this calculator:http://www.petervis.com/GCSE_Design_and_Technology_Electronic_Products/transistor_base_resistor_calculator/transistor_base_resistor_calculator.htmlHow many amps will your LED draw and what is the voltage on the output of the reed relay ?

author: XOIIO
author_rank: Super Contributor
timestamp: March 26, 2016, 07:45:07 am
content: Quote from: michaeliv on March 26, 2016, 02:02:20 amI believe the reed relay is just a basic one, so it will give the full 12v, the LED's should draw 800ma or so. Even though it is an enclosure I have trimmed down a heatsink to help manage the heat a bit better.

author: XOIIO
author_rank: Super Contributor
timestamp: March 26, 2016, 08:35:33 am
content: Quote from: blueskull on March 26, 2016, 07:49:12 amAlready have the parts, and everything is pretty much mounted up in the case permanently, I'm just waiting on the damn reed switches to come in the mail. If I had thought about it before hand I probably would have grabbed one since it's a pretty small space, though since this transistor is rated for 6 amps I figured it shouldn't get too toasty.

author: XOIIO
author_rank: Super Contributor
timestamp: March 26, 2016, 09:56:18 am
content: Quote from: blueskull on March 26, 2016, 09:36:43 amCurrent output will be 800ma roughly, hency why I figured with a 6 amp rating it probably won't heat up too much.

author: XOIIO
author_rank: Super Contributor
timestamp: March 26, 2016, 10:24:02 am
content: I might have some 23904's or similar kicking around, but honestly, waste current isn't that big of an issue, it will spend 99% of it's time off, it's only going to turn on the lighting when I open the doors for my server rack to work on something or check something, so it will be pretty brief, and the supply is (supposedly) rated at 5 amps.If I was driving it from a microcontroller/arduino, or it was going to be used more I probably would put in the effort to make it as efficient as I could, but in this case it's pretty much only being used since the current rating for the reed relays is half of what I need to drive the whole thing.
QQ Should I connect the AT90USB1286-MU Thermal Pad to ground? - Page 1
Forum section: electronics / beginners

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: May 02, 2019, 03:14:49 pm
content: Hi, I’m new here. I want to make a PCB for a Keyboard and want to use the AT90USB1286-MU. The heat gun is already ordered.Other chips specify in the documentation what to do with the thermal pad but I can’t find it with this chip. Also, can I connect the ground pins to the thermal pad if it should be connected to ground and do I need to connect all ground pins or is one enough?For some reason Kicad doesn’t want to connect to the thermal pad when I pour the ground plane.

author: ataradov
author_rank: Super Contributor
timestamp: May 02, 2019, 11:51:40 pm
content: It says right in the datasheet under the package drawing:Quote

author: ataradov
author_rank: Super Contributor
timestamp: May 02, 2019, 11:59:56 pm
content: Yep. And you do need to connect all ground pins. It may not be as critical for mega, but it is a good thing to get used to, since more powerful chips will need as much grounding as possible.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: May 03, 2019, 05:24:04 pm
content: Thank you very much. With so many pages you have to know where to look. One follow up question: on the backside of the PCB I would leave a bare thermal pad. Would I leave thermal relieves between the ground plane and the thermal pad? As I understand it the thermal reliefs are there so that the copper plane doesn't suck up all the heat when soldering but on the other hand for a thermal dissipation pad you would want as much copper attached as possible.P.S. I ran a reaction diffusion algorithm over the back of the PCB. I think that will be the backside silk screen.

author: ataradov
author_rank: Super Contributor
timestamp: May 03, 2019, 05:28:41 pm
content: Don't worry, AVRs can't dissipate enough heat to be even noticeable. The pad is there purely for mechanical reasons.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: May 04, 2019, 01:10:50 pm
content: Thank you. You helped me a lot!

author: Nominal Animal
author_rank: Super Contributor
timestamp: May 04, 2019, 01:45:40 pm
content: One of the first microcontrollers I ever programmed was aTeensy++ 2.0with an Atmel AT90USB1286-MU. They are still manufactured by PJRC, and widely used. The HalfKay boot loader used in the Teensy++ 2.0 is proprietary (allows uploading a new firmware via a HID connection, thus needs no special drivers installed), and I don't think the gerbers are open either; but theschematic is here.I have not created my own AT90USB1286 board, nor programmed one, except as a Teensy++ 2.0 using the HalfKay boot loader. I basically programmed my Teensy++ 2.0 in Linux, using avr-gcc, avr-libc, and TeensyLoader (for uploading via HalfKay).I do recommend using a Teensy++ 2.0 for prototyping, even if you end up doing your own board, due to the large amount of existing code and examples for your use case.
QR code generate in microcontroller - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: December 07, 2016, 08:21:07 am
content: 1. I have to generate QR code, have string of 100 bytes which needs to be fit in.Controller I am using is Atmega2560 arduino.generated code is to be shown on TFT & to be print on thermal printer also.2. There are few libs on it in C/C++, but all use malloc functions. Is there any simple to use library for this? Any one has worked on it before?

author: hamster_nz
author_rank: Super Contributor
timestamp: December 07, 2016, 08:42:12 am
content: I've used another 2D bar code, PFD417 (https://en.wikipedia.org/wiki/PDF417) on an STM32 controller to display on an LCD. It worked well, and I feel is better suited to lower quality printers than QR codes.On a PC I started withhttps://sourceforge.net/projects/pdf417lib/, and then manually replaced all the unchanging variables (width, height, barcode parameters like ECC) with constants, and rather than generating objects (aka malloc()ing a a structure, populating it, and then returning it's address to the caller) I had just one structure statically allocated. Along the way I generated BMP files and tested reading it with a free PDF417 reader app (https://play.google.com/store/apps/details?id=mobi.pdf417&hl=en) on my phone to make sure I hadn't broken it.Once that was all done and debugged on the PC, then moved it to the STM32 and LCD with zero problems or embedded debugging required.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 07, 2016, 09:11:23 am
content: The mostly use malloc because the input is variable length.You can probably implement malloc, and make it just return one fixed memory block.Have you searched github yet? I did find some C libs in a quick search. Maybe it's something.https://github.com/fukuchi/libqrencodehttps://github.com/tz1/qrduinohttps://github.com/embedded-systems/qr

author: amyk
author_rank: Super Contributor
timestamp: December 07, 2016, 12:07:48 pm
content: Figure out the size of QR code that you'll need, then replace all malloc()s with the appropriate constant-size array.(A lot of code out there needlessly uses malloc() in general, even for constant sizes.)
quad 10-bit digital pot - Page 1
Forum section: electronics / beginners

author: metebalci
author_rank: Frequent Contributor
timestamp: January 17, 2024, 05:40:07 am
content: I saw on a schematic a quad 10-bit digital pot. I only see dual ones with 10-bit resolution in digikey and mouser, anyone knows what could this be ?

author: coromonadalix
author_rank: Super Contributor
timestamp: January 17, 2024, 02:10:10 pm
content: link ?? images ?? crystal ball ?

author: metebalci
author_rank: Frequent Contributor
timestamp: January 17, 2024, 04:42:26 pm
content: https://github.com/anabrid/Model-1/blob/main/hardware/HC/HC%20-%20Schematic.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: January 17, 2024, 05:45:27 pm
content: you have to decipher the source code and or check the librairies to get the ic modelbut a search at mouser like this :https://www.mouser.com/c/semiconductors/digital-potentiometer-ics/?number%20of%20pots=Quadmany candidates up to 256 positions / volume values ... find their datasheets, 10 bits in this case is more than enoughsend them an email, they could tell you witch one it is ??

author: ArdWar
author_rank: Frequent Contributor
timestamp: January 18, 2024, 03:49:05 am
content: Are you sure they're actually monolithic quad 10bit digipot and not just four digipot in a trenchcoat?

author: metebalci
author_rank: Frequent Contributor
timestamp: January 18, 2024, 07:20:32 am
content: Quote from: coromonadalix on January 17, 2024, 05:45:27 pmI know there is lots of quads with 256 positions, but could not find any with 1024 positions.

author: metebalci
author_rank: Frequent Contributor
timestamp: January 18, 2024, 07:26:23 am
content: Quote from: ArdWar on January 18, 2024, 03:49:05 amGood catch. I thought it is monolithic but I think you are right.I did not see a photo of HC module(there is a photo on cover of its manual with 2x of the same board) but the block on the schematic has the same name as in DPT24 module. So it uses multiple single channel AD5293.
Quad Differential Transmitter - Page 1
Forum section: electronics / beginners

author: jeremy0203
author_rank: Contributor
timestamp: August 19, 2018, 05:11:32 am
content: Be easy on me, I am a newb.Trying to build and have a pcb produced of a quad differential transmitter that i can use to send 4 signals over ethernet cable to an already existing quad receiver board. Will be using the AM26C31 driver (http://www.ti.com/lit/ds/symlink/am26c31.pdf) and the receiver uses the AM26C32. I will post a picture of a crude schematic I came up with real quick in Kicad. Is there really nothing to this than the IC and a 0.1uF cap as called out in the datasheet? I have seen a board that is meant to do the same thing and it has resistors on each of the 8 outputs, required? And if so what would be the purpose of those in the circuit? Any help would be appreciated. Thanks.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 19, 2018, 06:37:09 am
content: It's standalone, yes.Mind that you still need a ground between transmitter and receiver. If you're using CAT5 type cable, use shielded cable and tie the shield to circuit ground.Otherwise, get the ground reference off the termination resistor (make a center tap), and use isolated receivers.Tim

author: jeremy0203
author_rank: Contributor
timestamp: August 19, 2018, 09:12:02 am
content: Termination resistors, thanks just read up on that and makes sense for this system.
Quad photodetector amplifier - Page 1
Forum section: electronics / beginners

author: mr_byte31
author_rank: Regular Contributor
timestamp: July 12, 2024, 09:47:07 am
content: Hi Folks,I have a Quad-photodetector and I want to amplify the signal of each quadrant independently but I need to guarantee the same gain for all of them.I thought about using operational amplifier for each quadrant but I know that the gain is dependant on the resistance values which has minor mismatches due to manufacturing process.I also need to add and subtract the values after amplifications.I found some components that can do so ex. LMH32404 and LTC6561. I am just wondering how they are implemented.any hints how to guarantee a constant gain for each quadrant using onvthe shelf components ( op-amp, transistors, R, L , C,..etc) ?

author: Positron Enthusiast
author_rank: Newbie
timestamp: July 13, 2024, 06:53:47 am
content: There’s two easy ways to do this:Live with the gain error from COTS partsMake a calibration test fixture to calibrate the gains and linearity for each board and store it on the board in an MCU etc…if you only need relative accuracy between gains/ channels then this is even easier to make.There are probably hard ways to get more accurate gains off the bat but I dont know how well they work in this application.What I can say is that option 2 - calibrated gains - works very well at low frequency. A good way to do it would be reed relays to a programmable current source (common to each analog frontend). Step the current source through the gain stages for each amplifier and boom, gains are calibrated. Recalibrate it on a timer or temperature differential. (Say 5-20 deg C depending on application requirement). Analog switches may work depending on system specs. Environmental sensors and mcu are dirt cheap nowadays. The current source can be a DAC feeding opamps. Just take enough averages to get an accurate gain measurement.

author: dietert1
author_rank: Super Contributor
timestamp: July 13, 2024, 07:03:40 am
content: Yes, probably one needs to calibrate the four channels for equal gain, as the detector will also introduce deviations.Our first series of pulse oximeters had transimpedance amplifiers with adjustable gain. 10 KOhm digital potentiometer chips were used to divide the ampilfier output before feeding the 1 MOhm transimpedance resistor.Regards, Dieter

author: Kleinstein
author_rank: Super Contributor
timestamp: July 13, 2024, 09:14:53 am
content: The gain is set by the resistors and sensitivey / area of the detector parts and the optics (e.g. case) in front. The normal 1% resistors should be good enough in most cases. It depends on the application if an extra fine trim af the gain is needed - I see little need for very good matching. If needed there are resistor arrays with very good matching (e.g. 0.01% ), but this is likely over-kill. 0.05% matching is possibly with the cheap ACAS series (thpough not 1 M).

author: mr_byte31
author_rank: Regular Contributor
timestamp: July 15, 2024, 09:32:16 am
content: Let me give it a try and measure the errors from low error resistors.
Quadrac vs Alternistor - Any difference? - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: February 07, 2018, 05:45:27 pm
content: Rolling something like an Elenco XP-625, but they used an older Quadrac sold by Teccor (who was bought by LittelFuse). I want to upgrade the part to 12amp and 600v PIV, but LittelFuse now calls them an Alternistor and puts the LED suffix on the new parts..The new PDF says it's OK for motor loads (ie: tranformers), so is this Alternistor and LED lingo all basically new marketing wank?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 07, 2018, 06:27:01 pm
content: No they are not the same part at all. The original part includes an embedded diac in the gate so to replace it if that part no longer exists you need a triac AND an external diac.I dont know about marketing w*nk but Littlefuse have simply charecterised that part for LED lighting systems, nothing wrong with that is there ?

author: Cliff Matthews
author_rank: Unknown
timestamp: February 07, 2018, 09:08:43 pm
content: Got it now.. and the slightly renumbered Q6012LTH1LED costs $1 more too (still don't know why they give the name alternistor when it's really just a triac. Maybe old people (like me) were thinking "triode" instead and gave it a new name.

author: tautech
author_rank: Super Contributor
timestamp: February 07, 2018, 09:17:13 pm
content: Quote from: Cliff Matthews on February 07, 2018, 09:08:43 pmAlternistor whilejustbeing a triac is a special type.The term has been around for decades, Google it.I first came across them in MIG welders where they're used for highly inductive loads.Now much of this type of gear is of inverter type design theirfeaturesare not called for so much.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2018, 09:55:25 pm
content: I really learned something new today. Thanks tautech!

author: Cliff Matthews
author_rank: Unknown
timestamp: February 07, 2018, 10:46:14 pm
content: So an alternistor (hi-com traic) and a diac is what's needed in the schematic. I snagged an NXP appnote on 3Q triac's..
Quadrature oscillator - Page 1
Forum section: electronics / beginners

author: bonzer
author_rank: Regular Contributor
timestamp: July 07, 2020, 05:46:17 pm
content: Hello everyone! Please help to understand a curiosity.Here we have a famous two integrator quadrature oscillator.It doesn't allow a full control of barkhausen condition because it is in open loop always about -180° (for any frequency).T(jw) = 1/[(jwRC)^2]= -1/(wRC)^2So it isn't that good because my RC makes my T(jw0) = -1 only in magnitude but phase is always -180.I just wanted to let you know that - I know this so we don't talk about this again. So with real components you couldn't get precise -1 and you'd rather have instability or decreasing to zero. Therefore some components are used like optocouplers or two zenner diodes on the inverting amplifier etc to change the gain and get stable amplitude. (you can find solutions for that online)The reason why I posted here this circuit is to ask you about another thing.When I have my real integrator circuit my op amp introduces a little phase shift error epsilon (see attachment) because of the influence of that differential Vd voltage which is not null and is +90° compared to the output voltage because of that pole introduced by the op amp. I know the best is to have that Vd as small as possibile but anyway let's immagine I can't deal with that and it still has an effect.In open loop I have 2epsilon and thefore when I connect the loop in the point I marked there in the attachment I could have some consequences because of that.My question is what exactly happens in terms of distortion? Is it really dangerous? I think it could give you a frequency that is slightly different but I don't know.Actually there exist some ways to avoid this error but anyway let me know what you think about this and how it changes the result.
(Sloved)Quality 9-30v powerbank? - Page 1
Forum section: electronics / beginners

author: sam1275
author_rank: Frequent Contributor
timestamp: September 25, 2016, 04:23:15 pm
content: Hi everyone.I need a portable power for a project, the output 9-30v are all okay, and only need 0.5-1 amps max occasionally(normal current are lower), but all I can find online are Chinese rubbish, could anyone recommend me a quality one?Thanks!

author: Zbig
author_rank: Frequent Contributor
timestamp: September 25, 2016, 07:33:17 pm
content: I've never heard the term "powerbank" used outside the scope of 5V ones used for charging USB-powered devices. What exactly do you have in mind and what stops you from using bare battery pack and implement the charging, voltage regulation and low voltage cutoff yourself within your project?Also, speaking about "Chinese rubbish" does sound a bit silly these days...

author: sam1275
author_rank: Frequent Contributor
timestamp: September 26, 2016, 04:10:24 am
content: Quote from: Zbig on September 25, 2016, 07:33:17 pmThanks, if they really don't exist, of course I can use a battery pack.Admit or not, Chinese products are really low quality whatsoever...

author: Zbig
author_rank: Frequent Contributor
timestamp: September 26, 2016, 06:41:01 am
content: You do realize that everything is made in China these days, right? Are you trying to say there are no good quality products available at all anymore?

author: sainter
author_rank: Regular Contributor
timestamp: September 26, 2016, 07:05:35 am
content: Any wireless drill battery and buck/boost converter will solve your problem.

author: sam1275
author_rank: Frequent Contributor
timestamp: September 26, 2016, 12:58:44 pm
content: Quote from: Zbig on September 26, 2016, 06:41:01 amI don't mean "made in China" is bad, of course there are many big brands manufacture things in China's factory, but it's totally different between "Chinese brand" and "Made in China".

author: sam1275
author_rank: Frequent Contributor
timestamp: September 26, 2016, 01:00:22 pm
content: Thank you everyone, I'll find another way to do this.

author: eKretz
author_rank: Frequent Contributor
timestamp: September 26, 2016, 07:18:17 pm
content: Totally hear you on the quality of items from China (designed and manufactured). They are "designed" to maximize profit at the cost of quality. If they have an outside company looking over their shoulder and implementing QC (like Apple, DeWalt, etc. then quality is better, in most cases pretty good. In quite a few cases it's still worse than what was formerly made in the country that originally designed the product though.
Quality composite video wireless transmitter+receiver needed... - Page 1
Forum section: electronics / beginners

author: hap2001
author_rank: Regular Contributor
timestamp: November 21, 2023, 02:14:24 pm
content: Hi friends.I need recommendation for a composite video wireless transmitter+receiver from a reliable brand.I know there are tons of options from China, but I don't want those, because I'm using expensive camera and monitor, and I don't want to damage them.I don't care whether it use analog or digital RF signal.Any ideas would be good, thanks.

author: m k
author_rank: Super Contributor
timestamp: November 28, 2023, 03:40:34 pm
content: You must give more information.What kind of a composite video, what kind of connections, distance and so on.

author: Benta
author_rank: Super Contributor
timestamp: November 28, 2023, 06:04:05 pm
content: Pull an of old VCR player apart, then you'll have both modulator and receiver/tuner.

author: wasedadoc
author_rank: Super Contributor
timestamp: November 28, 2023, 08:07:57 pm
content: Unless the power units fail such that they connect mains AC to the input or output video connectors there is no way that even the cheapest or nastiest units will damage your video equipment. In the unlikely event of such failure, damage to you or other persons would be your overriding concern!