hybridfree/eevblog-posts huggingface dataset:
Mixing linear / switching power supplies for multiple voltages - Page 1
Forum section: electronics / projects

author: dexters_lab
author_rank: Unknown
timestamp: December 23, 2015, 10:22:24 am
content: i have a device here that i dont have it's original power supply for, it needs +5v 5.5A and +/- 15v (2.5A for the +15v and 0.5A for the -15v)i want to power it up but i cant make all the rails with the bench supplies have at the moment and i dont want to spent a lot messing around with this...I can make the +/- 15v rails with my two keysight 6632Bs i have alreadyi was thinking i could buy a cheap 5v switchmode adaptor like this for the 5v:http://www.ebay.co.uk/itm/140718635432the power input to the device has a common ground so would all be tied together... any foreseeable issues doing this?

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: December 23, 2015, 10:25:51 am
content: It depends on what the device is doing with the 5V, and how much ripple your 5V switching supply provides.

author: dexters_lab
author_rank: Unknown
timestamp: December 23, 2015, 10:32:21 am
content: the original supply was a switcher, one of these:http://www.fspgroup.com/Catalog_PDF/AC%20Adapters/FSA110P%20Series.pdfspecifically the FSA110P32

author: h3po
author_rank: Newbie
timestamp: December 23, 2015, 05:07:39 pm
content: You could cannibalize an old ATX PSU and bend the 12V rails to 15. Should be doable without messing about too much.

author: tggzzz
author_rank: Super Contributor
timestamp: December 23, 2015, 05:26:29 pm
content: Some switching PSUs (often for "IT" solutions) have one output connected to earth. OTOH, some switching PSUs have fully floating outputs.If you need a negative voltage, then you will need either a fully-isolated regulator or one that is specifically designed to give a negative voltage. Do not connect a +V of on unisolated regulator to the -V of another.
Mixing two high-frequency signals - Page 1
Forum section: electronics / projects

author: delicado
author_rank: Contributor
timestamp: February 24, 2017, 04:36:48 am
content: HiWhen two high-frequency (~25kHz) signals are mixed on an electret mic's diaphragm, will an audible noise be recorded? For this to happen, do the input signals need to be modulated?Thanks

author: amspire
author_rank: Super Contributor
timestamp: February 24, 2017, 05:35:25 am
content: In theory, if two frequencies, say 25Khz and 30KHz are added in a completely linear system, then all you end up with is 25Khz and 30KHz.If there is any non-linearity at all in the microphone diaphram (ie distortion), you will some 5Khz.
mixing two separate tube preamps before Tone stack - Page 1
Forum section: electronics / projects

author: Vucinic
author_rank: Newbie
timestamp: September 07, 2017, 09:55:06 am
content: Hi all,I have a Tubeamp with 4 x ECC83 + ECC81 for PI. My idea is to make two separate preamps with 2 x 2ECC83. in the both cases V2b (V4b) is cathode follower. I Know that in the first stage often mixing is made by resistors.Can someone suggest solution for mixing two preamps before Tone stack an PI.thanks in advance
Mixing USB and battery? - Page 1
Forum section: electronics / projects

author: casper.bang
author_rank: Frequent Contributor
timestamp: November 08, 2014, 09:19:01 pm
content: I'd like to USB'ify some small battery operated (for the RTC) device with a display. My idea is to simply scan the display driver lines with an AVR or so, and then let it be transferred into a host computer over USB. What I am not sure about, is how to mix the two power sources and whether there's something to watch out for. If I connect the USB ground to the negative battery supply, can I just let an input pin of my USB powered MCU read an output pin of the battery powered display?

author: bobcat
author_rank: Regular Contributor
timestamp: November 08, 2014, 11:12:40 pm
content: It depends-1) If the LCD is directly driven by a chip in the device, then no. LCD drive signals are more complicated than just on or off.2) If the LCD has it's own driver chip and receives commands and data from another chip on the device, AND the logic voltage levels match then yes. If the logic voltage levels do not match, then there has to be some sort of level shifting between the battery device and the USB powered MCU. You may be able to interpret the commands a data sent to the LCD module to determine what is being displayed.

author: casper.bang
author_rank: Frequent Contributor
timestamp: November 08, 2014, 11:40:55 pm
content: Quote from: bobcat on November 08, 2014, 11:12:40 pmYeah I suspected that given the 22 pins for 8 segments! A lot of research into LCD multiplexing without me truly understanding the duty and bias thing, has me thinking I need to look for the raw signal before the LCD driver gets involved - bummer.QuoteInterpreting the LCD was my first idea, but as I said above I'm not so sure about it now. Everything is in one chip but there are test-bed points which I am trying to poke at. Seems the logic shifting (3V to 5V USB) is the least of my problems. Anyway thanks for the insight!

author: Jeroen3
author_rank: Super Contributor
timestamp: November 08, 2014, 11:42:45 pm
content: Why not attach a webcam to the pc and have some vision read the lcd?(You can even do that on a high end arm cortex)

author: casper.bang
author_rank: Frequent Contributor
timestamp: November 09, 2014, 08:23:01 am
content: Quote from: Jeroen3 on November 08, 2014, 11:42:45 pmBecause the thing I am interfacing with, is a 15g RSA token generator destined for the pocket.I really just want to attach a USB plug with an ATTiny emulating keyboard HID, where I can transfer the current token with the click of a button. Should not be rocket science, but clearly not as easy as I had originally envisioned. :/

author: Jeroen3
author_rank: Super Contributor
timestamp: November 09, 2014, 05:17:25 pm
content: Isn't that what a yubikey does?

author: casper.bang
author_rank: Frequent Contributor
timestamp: November 09, 2014, 06:02:37 pm
content: Quote from: Jeroen3 on November 09, 2014, 05:17:25 pmYes kind of and that's what I use for my own stuff! This however is for my employer where I have no mandate to change anything.
MK73-1 230527B chip? - Page 1
Forum section: electronics / projects

author: ledtester
author_rank: Super Contributor
timestamp: February 08, 2021, 07:35:07 am
content: Does anyone happen to know what this chip is?

author: ledtester
author_rank: Super Contributor
timestamp: March 24, 2021, 02:28:48 am
content: Update: My current best guess is that it's a MK9173:http://www.s-manuals.com/pdf/datasheet/a/v/av9173%2C_mk9173_idt.pdf

author: Miti
author_rank: Super Contributor
timestamp: March 24, 2021, 03:29:30 am
content: Yeap, that’s the chip. I tried to use it on one of my boards and it is quite jittery. See here:https://www.eevblog.com/forum/projects/modern-equivalent-of-74hc4046-pll/msg3134028/#msg3134028
MKL16Z128VLH4 test board  - Page 1
Forum section: electronics / projects

author: driesp
author_rank: Newbie
timestamp: October 13, 2015, 05:31:35 pm
content: Hi everyoneI'm currently working on an MKL16Z128VLH4 test board.I want to use this to get used to the arm cortex m0.Currently I only have the usb power circuit worked out and I use the ch340g to communicate with the mcu.-Schematic-PCB layoutI would love to get your feedback and I really want to get better.CheersDries p
MLCC capacitor placement question in RF enclosure - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: October 05, 2016, 07:21:18 am
content: Hi guys,For a project we will be using a converter module with a lot of external caps. The system will be in a sandwich type structure - a 1.6mm FR4 PCB between two milled electroplated dural/aluminum blocks as seen in the attachment.There will be a fair amount of M2.5 screws holding the thing together. Since there will be a lot of MLCCs I'm quite paranoid about cracking - placing them next to mechanically tested points is not recommended. The current layout I'm considering is in the picture. The purple is the inner edge of the milled enclosure. The big circular pads are pads for the screws - 2.7mm hole, 4mm copper. The enclosure will not serve any mechanical purpose (no bending or forces present).My question is whether this layout is whether the area where all of the 1206 capacitors and misc components are placed should be considered problematic for this kind of task - it is relatively close to the edge and to a screw. There will be a lot of screws in the thing.I figure that there will be very little stress, so the caps should be safe. Is this a correct assumption? Do you have any recommendations?Thanks,David

author: daqq
author_rank: Super Contributor
timestamp: October 06, 2016, 12:15:42 pm
content: BumpAny advice would be very helpful.

author: ajb
author_rank: Super Contributor
timestamp: October 06, 2016, 01:14:39 pm
content: Well, ultimately it depends on how much the board gets flexed during final assembly, right? I would think that if you're careful to ensure that the board comes out of assembly nice and flat (so make sure top/bottom copper distribution is balanced, and ideally use 4+ layers with internal planes), and you're careful to tighten all of the screws evenly and to a reasonable torque that won't unduly compress the board (probably not much of a problem with M2.5 screws?) you shouldn't have any appreciable flexure of the PCB. Of course I'm not a mechanical engineer, so take that for what it's worth!
MLS3535B chip regulating current on LED lighting PCB? - Page 1
Forum section: electronics / projects

author: badrequest400
author_rank: Contributor
timestamp: November 20, 2023, 02:26:47 am
content: I have an aluminium PCB with LED lights on it and I was hoping it is the kind which has a chip which regulates the current according to a current-setting resistor. There is an SOP8 chip with the marking MLS3535B but I'm not sure that it is a current regulating chip; at least, it doesn't seem like the others I've seen in light bulbs. The resistor next to each chip is 20R which is a higher value that found in other bulbs for current-setting resistors and also it's 1206 which is bigger than you'd expect for such a role as well.What else are these chips likely to be? Could the current/power of the light be reduced by increasing the value of those resistors to, say, 40R?

author: ajb
author_rank: Super Contributor
timestamp: November 20, 2023, 07:18:25 pm
content: It pretty much has to be some sort of all-in-one LED driver IC, since there's bugger all else on the board, and it's running directly from what looks like rectified mains input. It should be pretty easy to trace out the circuitry since that's a single sided metal PCB, that might give you some hints. Changing the resistor value likely would change the programmed current, but without a datasheet it's impossible to say what the relationship is.

author: badrequest400
author_rank: Contributor
timestamp: November 20, 2023, 07:26:11 pm
content: Okay, thanks. I measured the current consumed to be 130 mA with the resistors from the factory. I will make a small change first and observe the change in current so I can be sure about the direction I'm moving before I try again with a bigger change in value. Desoldering will be annoying with it being an aluminium PCB so I guess the easiest thing to do will be to try adding a 470R resistor in parallel.
MLX90365 - Contactless Rotary position sensor problems - Page 1
Forum section: electronics / projects

author: cmcraeslo
author_rank: Regular Contributor
timestamp: March 07, 2018, 09:08:51 am
content: Hey guys.I'm having issues with MLX90365 sensor not working as I imaginedI've attached the schematics I'm using. It's pretty straight forward and basically a copy-paste from the datasheet. What I want is to fix this below the magnet and when magnet rotates, get 0.5 - 4.5V depending on the orientation. What I get is a constant 2.4V on the output, regardless of the orientation or position, or even change if magnet is present or not. I tried two different IC, thinking one could be damaged, but I get same result. What am I missing ?Is there some special magnet needed for this?Part datasheet:https://www.melexis.com/-/media/files/documents/datasheets/mlx90365-datasheet-melexis.pdfI'd really appreciate any pointers.Thanks!

author: saike
author_rank: Regular Contributor
timestamp: March 07, 2018, 10:26:11 am
content: If you are using a round magnet, it needs to be polarised the correct wayhttps://www.kjmagnetics.com/proddetail.asp?prod=D42DIA

author: cmcraeslo
author_rank: Regular Contributor
timestamp: March 07, 2018, 12:29:38 pm
content: Thank you for pointing this out. I ordered different magnets for my project.In the mean time, I tried positioning the magnet horizontally, but it's still the same. Output is always 1/2 of the supply voltage. If magnet is not present, voltage should be out of range probably?

author: cmcraeslo
author_rank: Regular Contributor
timestamp: March 08, 2018, 06:38:27 pm
content: Hey. Still struggling with this.. does anyone have any other idea what to do ? I'm getting half of the VCC voltage on the output, no matter what I do.

author: RABeng224
author_rank: Contributor
timestamp: March 08, 2018, 08:19:18 pm
content: Looks like you grounded the output. The other side of the 20ohm resistor is connected to ground if I’m reading your schematic right.

author: BrianHG
author_rank: Super Contributor
timestamp: March 09, 2018, 01:18:11 am
content: According to the data sheet, pin 4 should be tied to GND, even though in the pin-list, it says 'Not Used'.Change C2 to 4.7nf. Your device may be configured in PWM mode?How have you asked Melexis to configure it?Or, have you programmed it?

author: cmcraeslo
author_rank: Regular Contributor
timestamp: March 09, 2018, 01:10:17 pm
content: Hey.When I removed the 100nF, I got what looks to be a PWM signal. Signal is still not changing with the magnet, but using the rc combination above I cut the frequency so it's pretty obvious that I got half of the voltage on the output. I have not configured this chip, from the datasheet, it looks like default mode is analog, not PWM (page 20 of the datasheet states that out mode 1 is default)
MLX90640 32x24 Resolution Infrared Thermal Sensor test - Page 1
Forum section: electronics / projects

author: faduo2011
author_rank: Newbie
timestamp: December 19, 2018, 09:06:01 am
content: I foud a good Infrared Thermal sensor.That is MLX90640, 32x24resolution.Temperature measurement range : -40℃~300℃IIC communicationIt can used for PCBA hot detect(not like phone PCBA,it is so high integrated);I detect a PCBA. PCBA size：44.6x75mm。use 0603 22R or 100R connect 3.3V to GND，below picture test for your reference

author: faduo2011
author_rank: Newbie
timestamp: December 19, 2018, 11:25:08 am
content: detect hand

author: Miyuki
author_rank: Frequent Contributor
timestamp: December 19, 2018, 12:43:57 pm
content: It look like nice sensor for decent price

author: faduo2011
author_rank: Newbie
timestamp: December 19, 2018, 01:08:29 pm
content: Yes, Price is good, It can used for some Special application. I am thinking about make some videos. If you need this produce, you can buy it it on my ebay shop:https://www.ebay.com/itm/223274591029thanks

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 19, 2018, 01:16:53 pm
content: That's an interesting sensor. Up to 64 Hz too.

author: faduo2011
author_rank: Newbie
timestamp: December 19, 2018, 01:23:32 pm
content: 64HZ need strong MCU to read and handle temperature. I use stm32f401RCT6(84MHZ) mcu,just 4HZ.

author: dmendesf
author_rank: Frequent Contributor
timestamp: December 19, 2018, 03:50:30 pm
content: First of all, congratulations for your nice product. I saw that you also sell a module based on it. It´s very nice. Before I buy it I´d like to know if the source is open so I can change the firmware in the module to do local processing of the image

author: faduo2011
author_rank: Newbie
timestamp: December 19, 2018, 11:31:04 pm
content: hello.Thanks for your follow.The module software is opensource.It reads temperature and send temperature data out by usart. Development environment is MDK 5.26, software include project, you can change your code directly.thanks

author: dmendesf
author_rank: Frequent Contributor
timestamp: December 19, 2018, 11:53:09 pm
content: Nice to know. Where´s the source available?

author: faduo2011
author_rank: Newbie
timestamp: December 20, 2018, 12:33:38 am
content: I want to upload in github, but have some problems.Pls wait, thanks

author: faduo2011
author_rank: Newbie
timestamp: December 24, 2018, 04:16:58 am
content: Hi, about module code, Pls see below link, thankshttps://github.com/SaberOnGo/STM32-Driver-MLX90640-IR-Sensor
MME-BOOT - Complete CAN BUS (MCP2515) XMega Bootloader with AES & Software - Page 1
Forum section: electronics / projects

author: cmcraeslo
author_rank: Regular Contributor
timestamp: January 23, 2017, 04:22:46 pm
content: Hey guys.I've recently migrated one of my devices to CAN BUS which meant that I had to build the firmware upgrade tool for my customers as well. I've looked all around the web and found few different versions, but none so complete that I could use. This is the reason I decided to make one and share this project with anyone that is doing the same.Link to my project:https://community.atmel.com/projects/mme-boot-complete-can-bus-mcp2515-xmega-bootloader-aes-and-software-encrypt-updateFeel free to test & commentThanks

author: Menen
author_rank: Newbie
timestamp: February 24, 2018, 10:57:36 am
content: The bootloader is not going to. There are no can.h files

author: cmcraeslo
author_rank: Regular Contributor
timestamp: February 24, 2018, 05:11:43 pm
content: You can remove the #include "can.h" file and it will compile normally.I've updated the files on the site and you can download it again.
MMwave RFIC, flip chip, 80 GHz or higher? - Page 1
Forum section: electronics / projects

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: December 12, 2017, 02:28:58 pm
content: Hi guys,For my thesis I am working on device interconnects for mmWave applications (above 100 GHz). I was hoping to be able to do a proof of concept by using this new connection technique to connect two mmWave IC's together to form something like a communication link.So I am looking for off-the-shelf available ICs that operate at very high frequencies, preferably above 80 GHz. Analog Devices has some mixers like the HMC7587 and similar. They are however wirebond and not ideal (I would prefer GSG or differential out flip-chip).I know this is a very vague request but I just need a chip (well, ideally 2 but I can do with one and use a probe to take the place of the second) that I can use to show the interconnect is working and can be used.Most stuff at these frequencies uses waveguides (obviously) but the entire point of our research is to offer alternatives to metal waveguides for interconnecting devices at mmWave frequencies.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 12, 2017, 04:25:08 pm
content: I am by no means very knowledgeable about this, but I remember seeing some ICs that at least come close as part of an automotive collision detection radar, as they run in a similar frequency band (just under 80G if I remember right). Not sure how easy it is to get the bare die they use off the shelf, but they're definitely parts that are being produced in large quantities so there may be some availability. Maybe that's a direction to look, at least.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: December 13, 2017, 10:23:15 am
content: Yeah, that seems like a good option to look at. I tried finding some other manufacturer of mixers, and they exist but are all "talk to our sales people to get the datasheets" type things.
MOBA Line interface/protocol - Page 1
Forum section: electronics / projects

author: up8051
author_rank: Frequent Contributor
timestamp: March 15, 2024, 01:02:39 pm
content: Does anyone know what protocol MOBA Time uses to transmit data to clocks via a two-wire MOBA line?I only found information that the line is used for both power and data transmission and that self-correcting codes are used,

author: up8051
author_rank: Frequent Contributor
timestamp: March 17, 2024, 12:18:11 am
content: I only found such information:MOBA Line:AC voltage 15 Vrms, frequency 50 Hz, combined amplitude/frequency modulation, synchronous data transmission with self-correcting rendering code.Information transmission to end devices.
Mobile phone zoom 4 soldering. - Page 1
Forum section: electronics / projects

author: drm
author_rank: Contributor
timestamp: June 26, 2017, 07:43:40 pm
content: Dear ppl.I was wondering if someone tried some of this cellphone zoom lens, as inspection-solderingaid:http://www.ebay.com/itm/8x-Zoom-Optical-Camera-Telephoto-Telescope-Lens-Holder-Kit-For-Mobile-Cell-Phone-/142304612163?epid=605575286&hash=item2122040f43:g:LosAAOSwB-1YvrYrhttp://www.ebay.com/itm/Camera-Phone-Lens-Kit-AUKEY-Clip-On-180-Fisheye-Lens-110-Wide-Angle-Photos-NEW-/172368398565?hash=item2821f508e5:g:wHgAAOSwPCVX-TipIf someone got some success, or think it may be useful to work with SMDs, please share.Thanks.

author: kalel
author_rank: Frequent Contributor
timestamp: June 26, 2017, 08:04:36 pm
content: Quote from: drm on June 26, 2017, 07:43:40 pmWould be interesting to see. I happen to have a low quality cheap version (2-3 dollars or such, I can't remember the exact price). The close distance type.I took some images to try it out. Note that it's old and dusty (didn't really clean it up properly), plus it blocks the light from the phone. This means you need an external light. Since I didn't have external light, images are taken in bad conditions, and they would actually look a lot better if you had some external light pointing straight into the chip.Using a stand for the phone would produce somewhat sharper images, however, the edges being blurred is due to the lens and cannot be helped (more expensive ones might have better lenses). The focused point is tiny, and that is also something that can't be helped with this lens.This type is definitely not useful for soldering, as you need to hold the phone really close, a bit too close.To conclude, with a better quality lens it might work decently (you get a lot of resolution from the phone, better than any cheap microscope from China). With the cheapest lens available, you will likely get something similar to my results.Edit: But how does it compare to a cheap USB Microscope? This one is native 640 x 480 which cost about $16 or so with plastic stand.

author: drm
author_rank: Contributor
timestamp: June 27, 2017, 12:43:37 am
content: The last picture looks great, what is the distance from the lens to the PCB ?

author: kalel
author_rank: Frequent Contributor
timestamp: June 27, 2017, 02:05:52 am
content: Quote from: drm on June 27, 2017, 12:43:37 amIn the last image, that's the maximum zoom mode or maximum macro mode, which basically means almost zero distance from the microscope plastic parts (the transparent plastic on the sides which protects the lens) to the PCB. From the actual lens, I guess there might be a small distance. I don't think it's very useful in standard cases, but perhaps to check for print quality, or material quality (you can see the bumps in the plastic or scratches in aluminum and such). Might be useful to get a really close look at SMD LED chips as well.
Mobility scooter indicators. - Page 1
Forum section: electronics / projects

author: davelectronic
author_rank: Frequent Contributor
timestamp: May 21, 2022, 03:10:14 pm
content: I have a mobility scooter, is a Rascal 388XL a pavement or road going scooter. It has indicators, but there not functioning. I have checked the user manual, and they should be working on this model. The lenses and bulbs are there, but I've discovered there is no molex incoming cable from the wiring loom. So it looks like they where intended to be plugged in, as the female line socket to the switch is present, but not connected up. So my question is, is it possible to get them wired up and functional, and it's the same with the hazard switch, it's fitted, pre wired but not connected to anything,and no where to connect it to. Any ideas how I could get the indicators working would be good. Thanks for reading any thoughts appreciated. The switches are present, so are the indicators lenses bulbs and wires behind the light fittings.

author: davelectronic
author_rank: Frequent Contributor
timestamp: May 21, 2022, 03:11:41 pm
content: More images.

author: davelectronic
author_rank: Frequent Contributor
timestamp: May 21, 2022, 03:14:35 pm
content: I can't get one of the images to post, it's double posted one image. But it has pre wired indicators front and rear, but no where to plug the switches into.
MOC3023 with triac - Page 1
Forum section: electronics / projects

author: hussamaldean
author_rank: Unknown
timestamp: December 20, 2018, 03:18:52 pm
content: Hi all,I want to use MOC3023 with triac for phase angle control using arduino and I am having hard time to trigger the triac with this optocouplerthe schematic is attached (the input is pulses from arduino) and the applied voltage is about 100Vrmsis there something I doing wrong or either optocoupler or triac has an issue ?

author: Benta
author_rank: Super Contributor
timestamp: December 20, 2018, 04:03:45 pm
content: Where are the gate resistor(s)? Also, can an Arduino deliver the 5 mA needed to trigger the device?

author: wraper
author_rank: Unknown
timestamp: December 20, 2018, 04:59:41 pm
content: Your circuit is incorrect. It looks somewhat like SCR circuit but gates and optocoupler are connected wrong.

author: hussamaldean
author_rank: Unknown
timestamp: December 20, 2018, 05:37:51 pm
content: Quote from: wraper on December 20, 2018, 05:01:30 pmcould you please explain and the value shall be power resistor and high voltage capacitors ?

author: Zero999
author_rank: Super Contributor
timestamp: December 20, 2018, 09:37:36 pm
content: The component values are on the schematic.The voltage ratings don't have to be anything special: 400V or so would do, just make sure the capacitors are X-rated: not a porno, but asafety standard.The resistors aren't high power, just 0.5W will do.

author: hussamaldean
author_rank: Unknown
timestamp: December 21, 2018, 09:37:45 am
content: Quote from: Hero999 on December 20, 2018, 09:37:36 pmthank you but the capacitor's values, shall be the same as mentioned or any value will work ?

author: Zero999
author_rank: Super Contributor
timestamp: December 21, 2018, 04:20:13 pm
content: The values aren't super critical, just use the nearest available values.If you're interested in the calculations, refer to the paper linked below:https://www.fairchildsemi.com/application-notes/AN/AN-3003.pdf

author: hussamaldean
author_rank: Unknown
timestamp: December 21, 2018, 05:41:10 pm
content: Quote from: Hero999 on December 21, 2018, 04:20:13 pmthnx for the paper and it is super helpfulthanks once again and I appreciate your help
MOC3063S direct drive of 120Vac relay coil  - Will it survive? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: February 27, 2023, 10:42:38 pm
content: These MOC devices are typically used to drive a Triac, in the circuit below the MOC3063S is directly driving the120Vac coil of a relay (no external) triac.Anyone doing this?See any issues with the drive portion?The relay coil is specified as 2VA with R=3k OhmThis is a zero-cross opto, do you think the snubber is necessary?Assume the relay is okay for the load.

author: Benta
author_rank: Super Contributor
timestamp: February 27, 2023, 11:07:33 pm
content: I don't see any problem with it. But yes, keep the snubber, it's for turn-off.

author: Jester
author_rank: Frequent Contributor
timestamp: March 03, 2023, 06:04:52 pm
content: Quote from: Benta on February 27, 2023, 11:07:33 pmNormally we would always use a Xcap across the 120V MAINS.However in this case if the capacitor were to fail shorted, the relay would simply pickup, current would be limited to about 20mA because of the 120V relay coil.Thoughts on using a 1kV SMT ceramic capacitor for example:https://www.digikey.ca/en/products/detail/w%C3%BCrth-elektronik/885342208021/9345890?s=N4IgTCBcDaIBxwKwGYAsYwAY6bARhAF0BfIA

author: Benta
author_rank: Super Contributor
timestamp: March 03, 2023, 07:23:10 pm
content: Film caps normally don't fail shorted, certainly not an X2 cap. I don't see the issue.

author: Jester
author_rank: Frequent Contributor
timestamp: March 03, 2023, 09:23:09 pm
content: Quote from: Benta on March 03, 2023, 07:23:10 pmI'm wondering if I can get away with a lower cost surface mount ceramic cap?The cap does see line voltage, but it's not actually across the line.
mod ridgit charger 110 to 220v  - Page 1
Forum section: electronics / projects

author: daniel818a
author_rank: Contributor
timestamp: June 16, 2023, 12:09:04 pm
content: hi i need some help with this mod i change the cap from 200v to 400v and the tvr and its powring on and not blowing up but when i plug a battery to charge its not workingi chacked the trnsistor and its not working its 4n60b the resistor going to it its 0.36 Ohms 5% [ Attachment Invalid Or Does Not Exist ]https://photos.app.goo.gl/NJ3d8xwGMG6oViVFA
Modbus map files for Danfoss MCX06d - Page 1
Forum section: electronics / projects

author: 0xB0D
author_rank: Newbie
timestamp: November 16, 2020, 05:38:05 pm
content: Hi.I'd like to use a raspberry PI with a one of these cheap rs485 modules to make a home SCADA systemhttps://uk.banggood.com/5V-MAX485-TTL-To-RS485-Converter-Module-Board-p-912674.htmlI have1. Fronius Galvohttps://www.fronius.com/en-gb/uk/photovoltaics/products/home/inverters/fronius-galvo/fronius-galvo-3-0-12. Danfoss powered air heat pumphttp://www.jifon.se/en-2/The Fronius people provide all the Modbus details you can handle, including json files, csv files - 10 points therehttps://www.fronius.com/en/solar-energy/installers-partners/technical-data/all-products/system-monitoring/open-interfaces/modbus-rtuDanfoss OTOH and their resellers require you to have an account with them before they will release anything to you and so far I've had absolutely no luck getting anybody with an "in" to provide that data.I've even emailed the CEO of DanfossAnybody else have experience and advice on this ?Can I find this elict super-secret data on PirateBay ?This seems weirdly difficult to find data on...
Modded SC502 to work with DC504 to read the Frequency - Page 1
Forum section: electronics / projects

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 08, 2024, 07:03:48 pm
content: I just wanted to share a mod I did to my SC502 TM500 series scope to work with my DC504 counter/timer to count the frequency of the input signal going into my scope without using a T-splitter BNC. I did this by using the internal signal input of pin 16A of the DC504, and pin 16A of the SC502, which is left blank with solder pads for custom mods.Details:In the SC502, I soldered the center conductor of a tiny coax cable to the emitter of Q510, and soldered the shielding to the grounded pin of C510.I then soldered the other side of the coax's center conductor to the customs mod pads in the SC502. You should solder to the 4 pad up from the bottom.In the TM500 unit, I soldered wires to pin 16A from the plug in bay of the SC502 and the DC504.The mod is done.In the images attached, you can see the mod works well up to 15MHz.I'll add other images later.

author: CaptDon
author_rank: Super Contributor
timestamp: February 10, 2024, 02:07:28 am
content: Just remember your probe is now feeding the counter and scope in parallel so the input impedance is radically changed and any probe who's compensation is now adjusted for channel 1 will be hugely over compensated when you use the same probe on channel 2. Also a 10:1 probe will most likely appear as about an 11:1 or 12:1 due to additional resistive and capacitive loading of the counter and Transport Module backplane capacitive loading. It all would be much more critical if you had the SC504 80MHz scope!! I have the SC504 and I love it!! I built an external trigger delay generator and housed it in an old DM502 module. I even kept the rear portion of the DM502 which is the edge connector with isolation transformer and power supply!! Just hacksawed the rear portion of the DM502 PCB off and parted out the forward portion.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 10, 2024, 03:05:08 am
content: Quote from: CaptDon on February 10, 2024, 02:07:28 amI don't think this is a problem though as the signal is buffered in the scope for use in the trigger generator. That's where I'm siphoning the signal off of.But at the same time, I think my mod has a small effect on the scope's performance as I didn't use coax in the TM500 unit so all the AC 60Hz noise from the power supply is being transferred into that wire.I could definitely be wrong though as I don't have as much experience with electronics as other members on EEVblog.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 10, 2024, 03:09:25 am
content: And as promised for more images:https://imgur.com/a/eJ8WUMx

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 10, 2024, 03:11:16 am
content: I forgot to add one more important detail, you must desolder R100 out of the circuit in the DC504. It is a 50-ohm termination resistor, but it loads the buffer circuit in the SC502 too much.Set the coupling to AC inb the DC504 as well. The signal has a DC offset I think.
modding a 1080p webcam for animation & close-up work - Page 1
Forum section: electronics / projects

author: jonovid
author_rank: Super Contributor
timestamp: February 19, 2017, 06:32:57 pm
content: if anybody is interested in re-using old or cheap webcamsplease feel free to add comments or your images of your DIY microscope or telescope mod'si did find many 1080p webcams do not have a focus ring on the lens.but many older 400p webcams do. this mod is about getting a focus at 10cm for electronics images or animation.the Chinese plug n play USB webcam uses a PC as a DVR or take still images.I don't expect anybody to use expensive webcams or camcorders for lens mods like this .I used a cheap chinese 1080p webcam for this project.even a DIY lens adapter for a smartphone can be interesting project, if posted here.
Modding a laminator for PCB - Page 1
Forum section: electronics / projects

author: biotron345
author_rank: Contributor
timestamp: May 21, 2016, 04:03:32 pm
content: I've been doing PCB for some time now using the toner transfer method and a clothes iron. I've just been given a Fellowes laminator (cheap supermarket type). Takes the board well and doesn't appear to struggle. The result is varied but usually good transfer in some place not others. I've looked into altering the motor speed but to be honest I don't understand how this is done. I've thought of a possible alternative solution.........would it be possible to add a switch to the motor to stop it whilst the heating is still on? Thinking of letting the board go in for a second, switching off the motor for maybe 10 seconds, and so on.........?

author: Unknown
author_rank: Unknown
timestamp: May 21, 2016, 06:10:21 pm
content: https://hackaday.io/project/3363-apache-al13p-laminator-one-pass-pcb-toner-xfer

author: biotron345
author_rank: Contributor
timestamp: May 21, 2016, 06:18:18 pm
content: Thanks Steve! Looks a bit daunting but I'll give it a good read!
Modding a purchased product - Page 1
Forum section: electronics / projects

author: pplaninsky
author_rank: Regular Contributor
timestamp: March 21, 2022, 08:17:58 pm
content: Hello,I am hacking a home automation product that drives a 230 VAC load via a relay.The product has 2 PCBs - one is PSU + hot mains side + the relay, the other is a digital PCB connected via pin headers to the PSU board.I want to have a visual clue for when the relay is on. For some reason the manufacturer has missed to incide such feature.I don't want to mess with the mains voltage, so I thought of adding a LED to the GPIO of the MCU (EFM32 Gecko).With 20K resistor to ground, the current through the LED is about 60-80 uA, which is enough to illuminate an efficient red LED.I think this will not affect the switching of the power transistor, but wanted to double check and ask for a second opinion.Please, check the circuit diagram below.Thanks!

author: inse
author_rank: Super Contributor
timestamp: March 21, 2022, 08:40:58 pm
content: Interference with the transistor is not to be expected.But usually the uC should be able to source a couple of mA, so you could afford more current for your LED.

author: pplaninsky
author_rank: Regular Contributor
timestamp: March 21, 2022, 09:26:18 pm
content: Thank you!I will try then 10k or 5k resistor.I don’t need the LED too bright as well.

author: srb1954
author_rank: Super Contributor
timestamp: March 21, 2022, 11:10:27 pm
content: Quote from: pplaninsky on March 21, 2022, 08:17:58 pmAre you sure your schematic is correct?The 1N4148 diode is in the wrong place to protect the transistor against the relay's back EMF. The diode should be across the relay coil not the transistor.

author: Benta
author_rank: Super Contributor
timestamp: March 21, 2022, 11:17:57 pm
content: Why diddling in that place?Two simple solutions:1: neon lamp plus resistor directly over the load. That will give you the best information.2: LED plus resistor across the relay coil. That will give you the 2nd best information.Very old (and seemingly forgotten) rule: "Annunciators/indicators should show what'sactuallyhappening. NOT what the controllerthinksis happening."

author: pplaninsky
author_rank: Regular Contributor
timestamp: March 22, 2022, 07:33:54 pm
content: Hi Benta,as I mentioned, these were the first options come to mind - well not the neon lamp exaclty.However, the relay is on another PCB/Module, which is connected directly to mains.I don't want to mod this encapsulated module. Reasons: high voltage, fire, liability, etc.So the relay is not very accessible, also the power transistor that drives the relay as they are both on this mains module.The load itslef - it is a floor heating valve - located inside the wall in a box in my antre. So, again not feasable.That is why I have chosen just to modify the harmless 3V digiatal board.
Modding an Apple 24" iMac TFT display for external use - Page 1
Forum section: electronics / projects

author: Ferroto
author_rank: Frequent Contributor
timestamp: March 29, 2014, 11:55:40 pm
content: I have an old 24" iMac from 2009, and recently I have built a new gaming PC. The TFT display on the iMac is beautiful and doesn't even compair to the 19" LCD monitor I'm currently running. The problem is that TFT displays are very expensive and ordering a new one is out of the question.I am considering removing the TFT display from the iMac and mounting it to the wall unfortunately the driver board for the TFT display is on the iMac mainboard. I have been reading up on a standard calledLVDS (Low Voltage Differental Signaling)which is the signaling method used by monitor driver boards to talk to LCD's and TFT displays. Since there seems to be a standard for interfacing LCD panels to main boards I was wondering if I could hack a 3rd party driver board and connect to the TFT display using a traditional DVI connector.

author: dave_k
author_rank: Frequent Contributor
timestamp: March 30, 2014, 12:00:54 am
content: Try it, find out if it works and report back here with your results ... ?

author: Fsck
author_rank: Super Contributor
timestamp: March 30, 2014, 12:13:16 am
content: there are kits for this type of idea on ebay, so long as you tell them the OEM and model of the panel.look like this:http://www.ebay.ca/itm/LCD-Controller-Board-DIY-Kit-NTA92C-VGA-DVI-Turn-LCD-Panel-to-Desktop-Monitor-/110942534244?pt=US_Server_Boards&hash=item19d4b0ba64

author: amyk
author_rank: Super Contributor
timestamp: March 30, 2014, 12:51:52 pm
content: If you can find another monitor with a cracked panel of the same resolution and interface, you could salvage the scaler board and other bits from that and use it.

author: PointyOintment
author_rank: Frequent Contributor
timestamp: March 30, 2014, 04:50:33 pm
content: I know any sufficiently recent iMac can take video input through its video port to serve as a monitor. Was yours made before Apple added that feature?

author: Ferroto
author_rank: Frequent Contributor
timestamp: April 01, 2014, 01:17:56 am
content: Quote from: Fsck on March 30, 2014, 12:13:16 amI noticed those on ebay as well, but how do I know the voltage on the high voltage board is ok. I don't have a multimeter that I trust with those voltage levels.Quote from: PointyOintment on March 30, 2014, 04:50:33 pmmine was made in 2009.
Modding Bench Power Supply - Page 1
Forum section: electronics / projects

author: veryevil
author_rank: Unknown
timestamp: July 25, 2010, 01:41:53 pm
content: Hey, guys.It looks like I'm gonna be getting a bench power supply for my birthday next month which should be really nice.The one I'm looking at is the Circuit Specialists Triple Output DC Bench Power Supply 0-30V/0-3A w/Large LCD Display (CSI3003X3) (See:http://www.circuitspecialists.com/prod.itml/icOid/3506)First off is this any good for £135 GBP?Second they also do a 5A version for £175 but provide the schematics for both versions on their American website.3 AMP Versionhttp://www.circuitspecialists.com/pdf/3003X-III_schematic.pdf5 AMP Versionhttp://www.circuitspecialists.com/pdf/3005X-III_schematic.pdfNow looking over the schematics it looks like the only difference is the extra two transistors and resistors per channel on the Adjust boards and R50 next to the digital pot (X9C103) on the control boards which are used to set the output current.I'm guessing both will use the same circuit board so it should be a matter of putting in the missing parts and changing that resistor value to mod the 3A version to the 5A version.What do you guys think? Also spot any other improvements or any other differences?Cheers Steven

author: david77
author_rank: Frequent Contributor
timestamp: July 25, 2010, 01:54:58 pm
content: Looks like quite a classic design for a power supply. I was surprised to see ICL7106's as panel meter drivers.The one thing that might be different is obviously the transformer. That's the most expensive part of a power supply and so it makes sense for the manufacturer to use different types in differently specified units.I would guess that the 3A unit has a 4A and the 5A unit maybe a 6A transformer in it.That is something you have to look out for, otherwise you might fry the transformer when hacking the 3A psu to give 5A output current!I would leave it as it is, to be honest. When do you need so much power realisticly? 3A is plenty and if you need more you can always parallel both supplys to give 6A current. Just my 2ct.

author: veryevil
author_rank: Unknown
timestamp: July 25, 2010, 02:40:17 pm
content: I think you might be right. Looking at the schematics again it looks like the 5 Amp version has a separate transformer for each channel and the 3 Amp version has only a single transformer.Also why is the panel meter driver a surprise?

author: david77
author_rank: Frequent Contributor
timestamp: July 25, 2010, 03:07:47 pm
content: It's just a very old component that's been around since 1978 or so. I'd have thought they'd use some micro nowadays.
Modding mic input to take active output - Page 1
Forum section: electronics / projects

author: cyberfish
author_rank: Regular Contributor
timestamp: April 24, 2012, 12:28:53 am
content: It would be nice if I can get a sanity check from audio-savvy people for a mod I'm thinking about doing.So I am planning to get a camcorder that has an internal omni-directional (presumably electret) microphone, but I want to feed it audio from an external active source (~standard 1Vpp?).From my research, it looks like typical electret microphone circuits looks like this -http://en.wikipedia.org/wiki/File:Electret_condenser_microphone_schematic.pngwhere the microphone is more or less a current source and the drop across the biasing resistor is AC coupled to the input.Does that mean, if I want to drive it with an active source instead (like MP3 player output), I can just remove the biasing resistor to V+? Or should I add some termination?EDIT: It looks like mic level is much lower than line level. How about a 101:1 (eg. 10kohm:100ohm) divider?Thanks!PS. For anyone wondering, this is for recording cockpit video. Ambient sound would just be noise from the engine/propeller, so I want to feed it from the airplane's intercom, so it can record cockpit conversations and ATC comm.

author: SeanB
author_rank: Super Contributor
timestamp: April 24, 2012, 08:28:34 pm
content: It will work, but will be noisy. With the values you propose you do not have to bother removing the resistor to the supply, it will have nearly no effect. Place a mono( or stereo if nothing else is available, you are just using one channel anyway) 3.5mm socket with isolated switch to enable the internal mic to be used if the cable is disconnected. Place the divider in the cable or the 3.5mm plug.

author: cyberfish
author_rank: Regular Contributor
timestamp: April 24, 2012, 09:04:28 pm
content: QuoteThanks!I'll give that a try and see how it goes. Would you suggest another resistor values?

author: SeanB
author_rank: Super Contributor
timestamp: April 24, 2012, 09:11:31 pm
content: Try the ones you proposed, if it is distorted increase the 10k to 22k, or place another attenuator before it, use 2 10k resistors to make another L attenuator.

author: cyberfish
author_rank: Regular Contributor
timestamp: May 18, 2012, 09:12:11 pm
content: I ended up just using a series resistor instead, since someone has done the exact same mod on the same camera (I can't seem to find the link anymore...).Turned out a 33K in series is all it takes. Sounds awesome.
Mode connector on printer psu  - Page 1
Forum section: electronics / projects

author: atgeek
author_rank: Contributor
timestamp: February 21, 2018, 09:46:13 am
content: I've found a printer psu laying around.. It's rated 24V 1A, but measuring the output voltage it was only about 7V. Opened it and found a connector in the output marked as "MODE CONT" as you can see in the attached picture. Shorting it to vcc the 24V come out. Anyone know what's the purpose of this configuration? Maybe a sort of power saving mode?

author: atgeek
author_rank: Contributor
timestamp: February 21, 2018, 08:19:30 pm
content: Nobody?