hybridfree/eevblog-posts huggingface dataset:
HDMI to WiFi converter chip - Page 1
Forum section: electronics / projects

author: muthukural001
author_rank: Regular Contributor
timestamp: February 13, 2021, 09:51:07 am
content: Hi All,I am working on designing a HDMI to WiFi converter. Is there any single chip solution for this ?. Can anyone suggest?Thanks and Regards,Muthu

author: MIS42N
author_rank: Frequent Contributor
timestamp: February 13, 2021, 11:03:35 am
content: It is unlikely there would be a single chip solution. ICs usually have one function, you need three functions. There are single chip solutions for HDMI interfaces (eg Analog Devices ADV7627). The ESP8266 has a wifi capability and may be capable of interfacing with it. But the bandwidth of raw video will be a problem. So you'd use something like H.265(HEVC) 4K/60p Small & Low Power Codec SC2M50 from Socionext.Just ideas. I have no expertise in the area.

author: JoeyG
author_rank: Regular Contributor
timestamp: February 13, 2021, 11:11:48 am
content: Why reinvent the wheel - use a chromecast

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 13, 2021, 12:56:03 pm
content: Quote from: JoeyG on February 13, 2021, 11:11:48 amI'm assuming it's the other direction, HDMI in and Wifi out. There are two open source projects based around cheap HDMI capture devices:https://mtlynch.io/tinypilot/https://github.com/pikvm/pikvmFor minimum chip count, the MS2109 used in those HDMI capture devices plus an ESP32-S2 will work but the framerate is going to be low.
HDMI transmmiter phy for Xilinx-Kintex7 FPGA? - Page 1
Forum section: electronics / projects

author: javad2040
author_rank: Contributor
timestamp: April 15, 2020, 11:33:47 am
content: Hi guys,I currently design the FPGA board that contains Kintex-7, 32 Gb DDR3 Memory, tow LAN 1Gb and FMC. The FPGA banks connected accordingly:1- MGT Banks -> FMC2- Three HP Banks -> DDR3 Memory3- One HR banks -> tow LAN 1Gb,4- Four HR banks -> Pin headers and some components.One bank of HR is not connected and i decided to connected it to HDMI 1K Phy.My customer restricted me to using the chip and industrial ic and by searching i noticed that the ADV7511 phy(HDMI Transmitter with ARC), PTN3360D phy(HDMI Level shifter 3 Gbps) and SN65DP159 phy (TMDS to HDMI level shifter 6 Gbps) has used in some Xilinx FPGA evaluation boards.The ADV7511 is commercial (not industrial) and has parallel interfaces and is expensive ic.The PTN3360D is Industrial and has TMDS interfaces and is chip ic but i don't know Xilinx IP-core can handle it and by HR bank can transfer the 1K video data to Monitor(HR banks has 710 Mbps data rate for SDR)!!!.The SN65DP159 phy is industrial and has TMDS interfaces but is expensive ic, also according the ZCU106 Xilinx Evaluation board it connected to MGT banks to support the 4K video.Please help me to find and choose the chip and industrial IC for HDMI Transmitter that supporting the 1k video and connected to HR bank by 3.3 voltage and 710 Mbps throughput.best regards,

author: Scrts
author_rank: Frequent Contributor
timestamp: April 15, 2020, 01:49:11 pm
content: All industrial grade parts will be expensive... You can also check TFP410-EP.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 16, 2020, 04:07:37 pm
content: you can use PTN3363BSMP! it's cheap and Industrial
HDMI zoom/pan dongle? - Page 1
Forum section: electronics / projects

author: nfmax
author_rank: Super Contributor
timestamp: April 01, 2019, 07:31:09 am
content: Does anyone know of a device with an HDMI input and output that can select a window within the input image and magnify it (e.g. by repeating pixels) onto its output? An elderly relative with macular degeneration lost her old video magnifier, which used a builtin CRT display and could do this, in a house fire. The replacement is much smaller and does OCR and text to speech, but doesn't offer simple magnificationReally don't want to have to use a second device like a USB microscope, with controls that are not optimised for the partially-sighted (or in some cases, for any sort of human)It sounds like a pretty simple job for an FPGA with the right IO, but I haven't done anything with FPGAs for nearly 30 years (the very first, original Xilinx chip!)

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 02, 2019, 12:39:30 am
content: Any modern PC should be capable of it as part of the window manager.

author: nfmax
author_rank: Super Contributor
timestamp: April 02, 2019, 07:20:27 am
content: Quote from: NiHaoMike on April 02, 2019, 12:39:30 amIndeed. But although the reader device obviously uses an embedded PC (judging by the time it takes to boot) there is no way to access its window manager.Possibly a Raspberry Pi with an HDMI input board might work in this way - but I have no relevant experience and insufficient knowledge to determine this.

author: PETER ERSKINE
author_rank: Newbie
timestamp: April 02, 2019, 01:50:30 pm
content: Quote from: nfmax on April 01, 2019, 07:31:09 amWindows magnifier should work.

author: nfmax
author_rank: Super Contributor
timestamp: April 02, 2019, 02:10:19 pm
content: THIS IS NOT A PC!It is a standalone visual aid for the partially sighted. There is no access to the internal gubbins
HDTV PSU power transistor replacement (suitable sub?) - Page 1
Forum section: electronics / projects

author: Skimask
author_rank: Super Contributor
timestamp: April 27, 2014, 05:09:20 am
content: Got a 55" Samsung TV for $0.00, didn't work.Opened it up, found a blown cap and fuse. Replaced them. No fix. Found a guy. Sent the board out, got it back, put it in, worked. Looked at the PCB before I put it in, noticed a power transistor (right next to the blown cap of course) had been replaced. Also took my FLIR E4 to the circuit board after letting the TV run for about 1/2 hour that this particular transistor was running about 160F.Q1) Do I dare put a small heat sink on that transistor? Taking care of course not to short out the case or anything...Q2) Do I dare wire up a small-ish fan to push some air around in that area? Wouldn't mount it inside. I'd mount it on the outside, blow the air thru the cooling holes onto that particular transistor and pull a bit of power from the onboard USB ports.Q3) The original transistor is a "KTD2060", triple diffused NPN power transistor. Can't buy them of course... Drilling down thru Digikey, the closest thing I can find to a sub is a 2SC4511.Power ratings are similar, voltages are equal or greater, current ratings equal or greater. Main differences between the two are the DC current gain graphs (higher for the 2SC4511) and transition frequency (12Mhz for the 2SC4511 vs. 8Mhz for the KTD2060). I fully expect this transistor to blow again in the future, eventually. 2SC4511 suitable substitute or not? When the original transistor blows, slap the 2SC in and find out then?
Headers Headache - Page 1
Forum section: electronics / projects

author: Domagoj T
author_rank: Frequent Contributor
timestamp: September 07, 2018, 12:48:14 pm
content: So, we all know and hate those cheap Aliexpress female headers that have stamped contacts. They never seem to make good electrical and mechanical contact. They are dirt cheap though, so I have an embarrassing amount of them in my parts drawers (yes, multiple drawers with just them).However, when I try to build something I'd like to have a bit more prolonged life I opt to use those nice machined ones. This is what they look like:They have round pins and round sockets, are gold plated (inside the socket), make a good firm contact with square male pins (notice how deep the socket is?), they are easy to cut, solder just fine, and are available in the electronics store I pass by every day on my way to work. Unfortunately, there is a catch. They cost around $1.80 per 20 pin header, which means that whatever I plug into them is usually cheaper than the damn headers.I am well aware that good quality stuff costs money, but the amount of them I go through is making a dent in my wallet. I tried searching online for them, but have found only one source:https://www.peconnectors.com/female-headers-machined-.100/The cost is pretty much the same, even with volume discount, but I assume shipping half way around the Earth would probably change that and make little financial sense.Perhaps I just need a good smack over my head, a reality check and realize that I'm just a cheap bastard expecting good quality product for cheap, but that aside, what headers do you guys use?

author: wraper
author_rank: Unknown
timestamp: September 07, 2018, 12:58:54 pm
content: Connfly machined sockets are quite decent and survive hundreds of insertions. Through I stumbled at a few defective among several hundreds where 2 springy inserts were fitted into a single hole.https://www.tme.eu/en/details/zl307-1x20/pin-headers/connfly/ds1002-03-1_20131/

author: Benta
author_rank: Super Contributor
timestamp: September 07, 2018, 02:39:52 pm
content: Try Preci-Dip.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: September 07, 2018, 04:52:42 pm
content: Quote from: wraper on September 07, 2018, 12:58:54 pmI believe those are the exact ones available in my local shop.Quote from: Benta on September 07, 2018, 02:39:52 pmThose guys have some great looking stuff. Thanks.
headphone amp upgrade - Page 1
Forum section: electronics / projects

author: Prime73
author_rank: Regular Contributor
timestamp: March 16, 2014, 11:24:27 pm
content: while the forum was down I had nothing to do (yes, I admit I spend way too much time on the forum) and decided to finish off a simple upgrade I was working on: I've fitted a CDAC+ dac into Objective2 headphones amp and 12V/5V dc down converter (simple lm7805 I had laying around) to power the dac. I had to move USB connector off the dac board to my custom board to get it fit properly into an existing enclosure.

author: true
author_rank: Frequent Contributor
timestamp: March 17, 2014, 04:50:23 am
content: Not a bad looking mod. I keep mine separate and held together with velcro...(Didn't like the HD650, but wouldn't give up my HD600...)

author: Vgkid
author_rank: Super Contributor
timestamp: March 17, 2014, 05:02:06 am
content: How do you like the 02 amplifier, I was tempted to either make one of those, or a Cmoy.

author: Prime73
author_rank: Regular Contributor
timestamp: March 17, 2014, 01:10:42 pm
content: Haven't tried the Cmoy however really like the O2 - I think it's as transparent to my ears as it could be, it drives my 650s just fine and has plenty of power, completely quite.Quote from: Vgkid on March 17, 2014, 05:02:06 am

author: true
author_rank: Frequent Contributor
timestamp: March 18, 2014, 05:50:32 am
content: The O2 is great for most headphone loads. Drives everything I have more than loud enough and distortion free. Even at high gain there is no hiss.I've built some Cmoys, and they don't really compare to the O2, but they are cheaper.Output power is a bit limited though, especially with TLE2426 versions. I was working on a circuit to fix that and to get better battery life while still fitting in the traditional Altoids tin, but never got it done...Just beware the maximum input level on the O2 as it can clip there. For most purposes it isn't a problem, and certainly not as big as others have made it out to be.

author: linux-works
author_rank: Super Contributor
timestamp: March 18, 2014, 05:54:00 am
content: so, whatever did become of that designer? he never revealed his name, what he does for a living, etc. and then he disappeared and has not been heard from since. anyone know what happened to him?

author: dannyf
author_rank: Super Contributor
timestamp: March 18, 2014, 10:29:43 am
content: QuoteAlien abduction?
Headphone detection resistance for smartphones? - Page 1
Forum section: electronics / projects

author: brainwash
author_rank: Frequent Contributor
timestamp: March 11, 2013, 10:15:51 am
content: I'm trying to integrate a 4 pin TRS plug with my Android smartphone and cannot get it to recognize the jack.I thought it was based on a small microswitch inside the plug but it seems it is actually based on some resistance. On my RAZR, pin 3 (ring 2) is the common/ground connection, pin 4 is the microphone.I've tried putting 220 ohm from any output/input to ground and tried also with 1k, shorting pins in all combinations.Measurements on the original headphone set shows 1.5k mic-gnd, 330ohm out-gnd.The easy way would be to buy another headphone set and tear it down but I'm sure I'm missing something and it should just work, given that in general headphones vary widely.

author: brainwash
author_rank: Frequent Contributor
timestamp: March 11, 2013, 10:24:26 am
content: Never mind, stupid user problem.It IS based on physical jack detection, I was just pressing the vol-up/down keys and if no music is playing the 'ding' is played through the phone speaker.Actually the MIC input is not getting detected properly.

author: Things
author_rank: Regular Contributor
timestamp: March 11, 2013, 12:49:59 pm
content: I think the mics work a bit differently in that they have a switch on the headphone cable, which you push to activate the mic (usually). You may have to look into what this switch actually does, whether it disconnects the mic or what. It may also be that the mic is provided with a small biasing voltage, so maybe the phone is looking for a tiny load on the mic pin?

author: jack32
author_rank: Contributor
timestamp: March 11, 2013, 09:46:19 pm
content: i once tried to connect a condenser microphone to my htc desire and could not get it to work. i was sure i had the correct pinout and everything...it could detect headsets and headphones. no chance on microphones. and no chance on faking an headset and just using the mic...

author: brainwash
author_rank: Frequent Contributor
timestamp: March 12, 2013, 07:38:03 am
content: Exactly my problem now. I did not have time to order a headset just to take it apart so I just used "SoundAbout" to force the mic on while headphone are plugged in.Interestingly enough, another headset from HTC also works and it shows 20k in one direction and ~6k in the other direction. The RAZR mic connection is also asymmetric, so this might have something to do with it.Unloaded bias voltage is about 2 volts, if anyone is interested.
headphone socket: which one is right for me? - Page 1
Forum section: electronics / projects

author: exe
author_rank: Unknown
timestamp: October 11, 2025, 04:51:45 pm
content: Hey forum,I'm making a portable device with a speaker and a headphone socket (3.5mm, stereo). I'd like speaker to go mute if I plug headphone.My questions are:- which socket is the right one?- can I make it compatible with headphones with mic?- Do I need a TRS or TRRS socket? I don't plan to use micFor example, I consider is this socket:https://jlcpcb.com/partdetail/XKBConnection-PJ_327STSMT/C319103. But even then I don't understand how I should wire it.

author: A.Huggy
author_rank: Contributor
timestamp: October 11, 2025, 09:09:24 pm
content: You linked a TRS jack which will work fine for headphones without a mic which usually have a TRS plug.Headsets with a mic that use a TRRS plug will still work for listening, but the mic will not work. If your device does not need an audio input line for the mic, you should be fine with the TRS port you linked.The wiring of TRS and TRRS jacks:

author: Whales
author_rank: Super Contributor
timestamp: October 11, 2025, 11:26:14 pm
content: TRRS is backwards compatible with TRS (if you wire it correctly). If you don't care about mics (or inline buttons on earbud cords) then just TRS is enough.

author: exe
author_rank: Unknown
timestamp: October 12, 2025, 03:30:12 pm
content: Thank you very much for answers!Question about the part I linked. What is the function of contact 4? I can't figure it. Is it connected sleeve (same as contact 3), is it a switch?

author: Whales
author_rank: Super Contributor
timestamp: October 12, 2025, 09:16:22 pm
content: Is it this one?Yeah pin 4 is goofy, I have not seen that before.It's almost a "normally open" pin that would short to pin 3 when a connector is inserted, but it's using the drawing style of jack contacts (>) rather than a NO/NC pin (▶). I think it is a normal jack contact and the big rectangular ring needs to be moved left in the drawing.FWIW I've had nightmares looking through incomplete & confusing TRRS datasheets before, I think you're supposed to negotiate with the OEM to make sense of any of it all.

author: exe
author_rank: Unknown
timestamp: October 15, 2025, 03:56:07 pm
content: I got a reply from lcsc, they said: "According to the circuit diagram in the datasheet, pin 4 is the normally closed switch contact pin for plug insertion detection.".> I've had nightmares looking through incomplete & confusing TRRS datasheets before, I think you're supposed to negotiate with the OEM to make sense of any of it all.I feel that too. Something tells me I may end up with re-spinning the board....
Headphones for TV? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: November 29, 2021, 02:57:35 am
content: My Samsung HDTV has no headphone jack. (Yes, it's olde.) The Audio-Out connectors are line-level and non-configurable (ie, no option whether fixed or adjustable with volume control, as some TVs allow) via user settings or in service mode.So I'm trying to figure out how to add a stereo headphone jack between the main PCB's speaker connector and the speakers on the front of the cabinet.The audio channels have no common ground (measuring between left OUT- and right OUT- shows M). TV audio output schematic:How do I go from stereo with no common, to headphones with a common?DigiKey has a discussion of switching audio jacks (TRS, TRRS, etc.), one (SJ-3581NG) showing an isolated DPDT switch in the jack. Datasheet here:https://www.mouser.com/datasheet/2/670/sj_358xng_series-1779199.pdfSo there's plenty of switch poles available, but this doesn't solve my "no audio common".How do I get this done?And no, I don't want a separate digital-to-analog audio module (which means another IR remote).Thanks.

author: james_s
author_rank: Super Contributor
timestamp: November 29, 2021, 04:26:38 am
content: I can't read the number on the amp IC but judging by the way it's wired I suspect that the ouputs are using a bridge tied load configuration which means you won't be able to feed a pair of headphones unless you use a differential amp. Can you tap off of the input or is the volume control part of the amp IC?

author: iXod
author_rank: Frequent Contributor
timestamp: November 29, 2021, 05:03:55 am
content: STA323W. It takes serial digital input and outputs analog audio. Datasheet:https://www.st.com/resource/en/datasheet/sta323w.pdfA closer look at the TV audio:

author: magic
author_rank: Super Contributor
timestamp: November 29, 2021, 05:46:23 am
content: It may be easier to plug an off-the-shelf HP amplifier (or some DIY CMOY thingy) with its own volume control into the line output.

author: james_s
author_rank: Super Contributor
timestamp: November 29, 2021, 05:56:17 am
content: Yeah that's definitely a full bridge output. It might work to pick off just the upper half of each bridge and wire headphones between that and ground. The datasheet lists different component values for bridged vs single ended output though so I don't know if that will work satisfactorily. I suppose you could also transformer couple the speaker level audio signals so you can tie one end of each secondary to a common ground.The external headphone amp is certainly the easiest approach, since the headphones are generally going to be wired anyway maybe it would make sense to just have the headphone amp on a table next to you so you can adjust the volume there?
Hearing Aid Project - Page 1
Forum section: electronics / projects

author: noSun
author_rank: Contributor
timestamp: November 02, 2016, 05:03:19 pm
content: Finished another project....I would like to share.

author: Audioguru
author_rank: Super Contributor
timestamp: November 02, 2016, 10:46:15 pm
content: I had a hearing test and my hearing loss is exactly normal for my age (71). The loss is only at high audio frequencies and low frequencies are fine and do not need amplification. The hearing aids I selected are programmed with the equalization that my hearing loss needs and each hearing aid communicates its setting to the other one when I push a button on either one for music, increased sensitivity, loudness turned down and automatic that slowly reduces background noise but increases the gain to normal when a voice is heard. My hearing aids detect low battery and let me know. My hearing aids are tiny. My hearing aids automatically detect a telephone at one ear then play the equalized telephone sound in both ears.Your opamps do not have the equalization needed for old people. Also your opamps are inverting then they have a low input impedance of only 1k ohm that attenuates the mic signal. The opamps should be non-inverting then they have a high input impedance and no attenuation.
Heart Beat sensor - Page 1
Forum section: electronics / projects

author: vignesh_shan
author_rank: Contributor
timestamp: November 18, 2020, 05:03:00 am
content: Hi ,What are some small size heart beat sensor available in the market ? In apple smart watches they use photoplethysmography technology. Which emits green light to our wrist vein and by measuring the reflected light it shows the heart beat count. Is there similar or any other technology sensor available ??ThanksVignesh.M

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: November 18, 2020, 10:03:20 pm
content: PPG is the only really small solution. For experimentation you can probably pick up one ofthe ubiquitous MAX30102 modulescheaply. There are obviously newer and better ones to use for production.Note that you need to do some calculations to remove noise, e.g. from deformations of the skin, movement of the sensor, etc. Here's an example library that does this:https://github.com/aromring/MAX30102_by_RF

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 18, 2020, 11:56:01 pm
content: There's also EKG but that requires sensing near the chest.

author: trophosphere
author_rank: Frequent Contributor
timestamp: November 19, 2020, 12:27:24 am
content: You can do an EKG just on the wrist to determine heart beat rate, regularity, and R-R interval. The waveform is pretty much useless for anything else such as the other intervals and morphology analysis.Another technology would be a peripheral derivation of ballistocardiography similar to "feeling a pulse in the wrist" in which you have a pressor sensor pressed up against the skin near either the radial or ulnar artery. One could even theoretically use a sensitive microphone pressed up in similar manner to listen for turbulence as the blood flows. One other one off the top of my head would be using a thermal camera to detect subtle changes in temperature as blood flows from the core body out to the capillaries to derive heart rate.
Heart rate sensor? - Page 1
Forum section: electronics / projects

author: chebeba
author_rank: Contributor
timestamp: March 12, 2014, 08:22:04 pm
content: For heart rate sensing, I have seen many products that you wear close to your body, usually as chest straps.I wanted to design a similar sensor into a thingie I'm building.The web has plenty of app notes and DIY descriptions of how to do it when you shine a light through a body part, most of the time a finger. But my Google skills fail me, I cannot seem to find any description of how to do it when you just have proximity, as with a chest strap.Anyone done such a sensor and want to share how it works?

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 12, 2014, 08:35:41 pm
content: Look up EKG and pulse oximeter.

author: chebeba
author_rank: Contributor
timestamp: March 13, 2014, 06:08:34 am
content: OK, seems I need to clarify ;-)Oximetry (in the implementations I have found so far) requires, as I mentioned in the OP, to shine a light through a finger. So you need a ring or clamp or something like that. Not what I am looking for.EKG (in the implementations I have found so far) requires electrodes attached to the skin using conductive wet gel. Not what I am looking for.There are many product that sense heart rate that does not require this (Google "heart rate chest belt"). But I have not been able to find schematics or even textual descriptions on how these sensors work.So my question is basically: How do these chest belts work, I'd like to make a similar circuit.

author: Dago
author_rank: Frequent Contributor
timestamp: March 13, 2014, 06:47:56 am
content: Quote from: chebeba on March 13, 2014, 06:08:34 amThe belt just basically has a couple of electrodes (conducting rubber) that are attached to some very high input impedance op-amp amplifier circuit which amplifies the signal (also has stuff like low-pass filters, 50/60 Hz rejection filters etc. usually) which is then sampled by a microcontroller and after some signal processing you can figure out the heart rate.I think these might be good for what you are doing:http://www.plesseysemiconductors.com/epic-plessey-semiconductors.phpI was thinking of doing something with them for fun at some point.

author: chebeba
author_rank: Contributor
timestamp: March 13, 2014, 12:06:58 pm
content: Thanks, the EPIC looks like a good product for me. A little pricey at EUR 25 per chip for a glorified OpAmp, but that's OK

author: Dago
author_rank: Frequent Contributor
timestamp: March 13, 2014, 01:56:53 pm
content: Quote from: chebeba on March 13, 2014, 12:06:58 pmThe Plessey EPIC-sensors are under 7,5€/piece at Mouser:http://fi.mouser.com/Search/Refine.aspx?Ne=254016&N=1323038+7454634+4290079590
Heat resistant LED light - Page 1
Forum section: electronics / projects

author: honeybadger
author_rank: Contributor
timestamp: August 14, 2019, 02:54:31 pm
content: Hi,I need to make a new LED "light bulb" for high heat environment, 80°C (higher is better).Current (expensive) LED light looks like this:There are banks of LEDs in series connected to the LEDx pins. Zeners seems to be 30V.Is there anything I should improve before I order PCBs?I guess I should put the MOV after the fuse.X2 class capacitors should be fine, what do you think? It is 230VAC powered.
heat shrink tube sizing for cabling - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: January 04, 2016, 08:31:08 am
content: I need to make up some cable using individual wires and cover them in a heat shrink tube. Now my cable diameter will be 4.5mm so is a 6.4mm diameter tube that will shrink to 3.2mm suitable ? or should the shrunk diameter be the same as the cable cores diameter ? I'm looking to have these cables come out "nice"

author: Ian.M
author_rank: Super Contributor
timestamp: January 04, 2016, 08:40:37 am
content: If your core is close to the final shrunk diameter, the heatshrink sleeve will be tougher and more rigid but it may slip on the core. Generally its better to have some reserve 'shrinkability' so the sleeve remains tight.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: January 04, 2016, 08:44:10 am
content: Larger diameter tube will inherently have thicker walls once shrunk to size when comparing say 6.4-3.2mm and 9-4.5mm tube and shrinking to 4.5mm diameter. This will affect rigidity and depending on how many wires and the arrangement of said wires may also result in a slightly rounder finish, using additional layers of heatshrink has the same effect. The 6.4-3.2mm tube will work, and will shrink tight.

author: Simon
author_rank: Unknown
timestamp: January 04, 2016, 08:56:36 am
content: We usually get cables made outside and they come in nice and flexible and soft which is why i suspect they use tubing that is just the right size. I have a maximum of 7 cores so nothing too involved (he says before spending a week cursing just making up the cable before making the loom) but we generally like flexible looms.

author: dmills
author_rank: Super Contributor
timestamp: January 04, 2016, 09:08:21 am
content: Does it have to be heatshink?Hellerman sleeves are what we often use (Get the right tool) and they are generally much nicer then heatshrink for this, or go with the woven sleeving and a short bit of glue lined heatshrink at each end?Regards, Dan.

author: SeanB
author_rank: Super Contributor
timestamp: January 04, 2016, 09:15:09 am
content: You also get different types of heatshrink. Some are more flexible than others, look at the Raychem heatshrink selection to get one that is flexible for your application. If you want expensive look at the PTFE shrinks they offer.http://raychemsupply.com/products/electronics/

author: Simon
author_rank: Unknown
timestamp: January 04, 2016, 09:23:44 am
content: Quote from: SeanB on January 04, 2016, 09:15:09 amI'd be using Raychem (TE) DR-25 type tubing
Heat sink + fan aerodynamics question - Page 1
Forum section: electronics / projects

author: ivan747
author_rank: Super Contributor
timestamp: July 09, 2017, 04:18:09 am
content: Hi!I finally got round to building a lab power supply. I am planing the heatsinking for it, take a look:There is a fan sucking air from the bottom of the case (it will be lifted off with rubber feet. This fan is attached to a nice heat sink. The power transistors are screwed into the heat sink.The air flows from the bottom of the case through the heat sink and is exhausted at the back of the case. I found it rather neat.But, as you can also see, part of the air that we intake is going into the case, raising the internal temperatures.I thought of covering that side of the heat sink, so the air can only escape at the back and system will not be inside an oven.But that still leaves me with no cooling for everything that is NOT the power transistors.I noticed that the outermost fins receive no airflow from the fan, take a look:Lets say that, on the inside of the case I cover the center fins but leave uncovered those fins with no fan forced airflow. And let's say that on the exhaust part of the cooling solution I leave all the fins uncovered... Will a vacuum be created on the fins that don't have forced fan airflow?I was thinking maybe a vacuum forms on them, and that vacuum can force air out of the case interior (provided there are places for air to enter). The reason why I think vacuum can happen is that the fins nearby have air escaping at high velocity, pulling surrounding air along with that exhausted air.Any thoughts, comments or suggestions?Thanks!-Ivan

author: alm
author_rank: Super Contributor
timestamp: July 09, 2017, 04:29:36 am
content: First, be sure to install a fan guard there. Can be one of those wire mesh fan guards that you fix with the same screws as the fan. Otherwise it could lead to some painful fingers when you unsuspectingly reach for something.Even if such an effect would exist, I would not expect it to create any meaningful airflow at the air speeds that you are likely to use. I would turn the fan around so blows air away from the heat sink, have the fan exhaust through the rear, and then suck air through the bottom in near the front. This way air flows through the entire case to reach the fan. You could add plastic sheets to guide the airflow if a particular area needs extra air.
Heat sink grease needed?? - Page 1
Forum section: electronics / projects

author: zupta82
author_rank: Regular Contributor
timestamp: December 29, 2020, 07:53:54 pm
content: Hello everyone, I was wondering if heat sink grease is needed on the aluminum side it does not look like the white oily compound, I was thinking maybe aluminum oxidation. There is a paper insulator between the transistors and heat sink. Here are some pics. I’m just going to shift some gears and take a break from the scope I’m trying to fix. It took 3 weeks for my power transistors to come in the mailThank You

author: Gyro
author_rank: Super Contributor
timestamp: December 29, 2020, 09:14:13 pm
content: Double post. See:https://www.eevblog.com/forum/projects/is-heat-sink-grease-needed/
Heat sink thermal resistance calculation - Page 1
Forum section: electronics / projects

author: tan98010
author_rank: Contributor
timestamp: October 12, 2015, 08:39:16 am
content: Dear all,how do i determine the thermal resistance of an "irregular shape"(such as metal cast casing for an amplifier) heat sink based on the heat sink material, area, and etc....?is there any book or application notes i could refer to please give me some suggestion?

author: oldway
author_rank: Super Contributor
timestamp: October 12, 2015, 09:13:22 am
content: The simplest way is to measure it.You mount a power resistor with metal case on the radiator, you apply it a fixed voltage and you measure the current and the heat sink temperature at equilibrium.It is easy to calculate the thermal resistance knowing the power dissipation of the resistor, the ambient temperature and the heat sink temperature ...

author: tan98010
author_rank: Contributor
timestamp: October 12, 2015, 02:01:45 pm
content: its certainly true to be measured it, but my boss require me to guide the mechanical guys to design an metal cast heat sink that fulfill the specific requirement.so my biggest question is1. what kind of requirement should i gave, such as Such as surface area required or perhaps the thickness of the heat sink.2. how to come up with such a parameter.Any way i am designing an automotive audio amplifier and there is some space constraint as well.
Heat sink's thermal resistance for two or more TO-220 Package - Page 1
Forum section: electronics / projects

author: Syamil
author_rank: Newbie
timestamp: January 19, 2016, 03:22:46 am
content: Hi all,I'm going to design something like thisAssumingRjc = 2 c/WRch = 0.5 c/WPower = 9.6 WOperating temperature at junction = 109 c (Require to maintain the reliability)Operating temperature at case = 90 c (Require to maintain the reliability)So based on this information, the required heat sink thermal resistance would be 5.22 c/W.My question is, if i'm going to mount two TO-220 transistors on a single heat sink (that work simultaneously and dissipate the same amount of power), does the heat sink have to have 2.61 c/W (half of 5.22 c/W)? or i can use 5.22 c/W heat sink?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 19, 2016, 06:26:28 am
content: You need two of 5.22 in parallel. Thermal resistances work just like electrical ones, so yes, you need 2.61.Tim

author: Syamil
author_rank: Newbie
timestamp: January 19, 2016, 01:57:24 pm
content: Thanks Tim!This will be quite a challenge to find a smaller heat sink with such thermal resistance.

author: macboy
author_rank: Super Contributor
timestamp: January 20, 2016, 02:06:48 pm
content: I don't think Tim is right.If you have one device, then your design shows 5.33oC/W is needed.You don't have one device, you have two, so you need to do the the calculations again.You can look at it two ways: Either half the power in each device (the natural way) or consider your two devices to be like one bigger one, which has half the thermal resistance. Same result either way.You have 9.6 W dissipated. So 4.8 W for each device. Re-do the calculations now, and you will see that the temperature difference between each device junction and heatsink is smaller. This is due to having twice the thermal conductivity (two devices conducting) from the junctions(s) to the heatsink. From heatsink to ambient doesn't change; it is still dissipating 9.6 W (not 4.8 W) through it's junction to ambient resistance.Be careful when choosing a heatsink based on these numbers. Heatsink ratings a often based on certain assumptions about airflow, so read the datasheet carefully. You will likely need to derate the heatsink you choose based on non-ideal conditions, so an over-rated heatsink will become necessary.edit: I just realised you may be asking about 9.6 W in each device, not 9.6 W total. In that case, yes, you need a heatsink with half the resistance to ambient as Tim said.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 20, 2016, 03:05:12 pm
content: Good point, the wording is ambiguous...If the two devices are sharing the same load, then the same heatsink size is acceptable. Simply: use whatever heatsink is necessary to dissipate thetotalpower from all devices on it.Tim
Heat sinks: Deciphering thermal pad specifications - Page 1
Forum section: electronics / projects

author: cvanc
author_rank: Frequent Contributor
timestamp: November 26, 2017, 05:20:31 pm
content: I have always been unclear about the ratings of thermal pads, can I enlist the braintrust for some clarity? When you see specifications like this:Thermal Resistivity 0.35°C/W-or-Thermal Conductivity 1.0 W/m-K...Is a high number or a low number 'better'? And by better I mean more heat is passed through the pad to the heat sink.Here's an example that I'm currently working on. I'll attach a Digi-Key sorted list, I hope it comes through OK. Which of these products is the best performer in terms of helping heat move away from my silicon?https://www.digikey.com/products/en/fans-thermal-management/thermal-pads-sheets/218?FV=188006f%2C8dc02a5%2Cffe000da%2C24c00a1%2C24c0015%2C24c0263%2C24c0265&mnonly=0&ColumnSort=-677&page=1&stock=1&pbfree=0&rohs=0&cad=0&datasheet=0&nstock=0&photo=0&nonrohs=0&newproducts=0&quantity=&ptm=0&fid=0&pageSize=25Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 26, 2017, 09:13:55 pm
content: Lower resistance, higher conductivity.1 W/m/K is pretty typical for such materials, with much better (10+) available if you're willing to also pay for it.To do it for any device, use:Rth = thickness / sigma / areaThickness is the compressed figure (the gooier materials compress and squeeze a lot, which BTW, beware of that when it comes to screw torque), and area is the area of the device backside (not the full area of the insulator, unless you're using a heat spreader to cover it too). Sigma is the conductivity.If you're using units of whatever, just plug this into Google and it'll convert everything for you.The technically-correct answer to your question is the solid pyrolytic graphite, or copper or aluminum heat spreader, but I'm guessing you actually want an electrical insulator, too.Tim
Heat spreader - Page 1
Forum section: electronics / projects

author: cncjerry
author_rank: Unknown
timestamp: July 31, 2016, 02:47:27 am
content: This is the second time I was contracted to machine heat spreaders. The first time I thought the person sent me a model that wasn't importing correctly because it loaded into my CADCAM system as 20mm x 15mm. Turned out that was the size. After being anodized to make it nonconductive, it was clamped to a PC board and used to spread heat across several surface mount components on an RF board. I've made small parts before but usually the things I'm machining involve hammers and 8,000lb clamping force vises. I've done a lot of precision work though, like making gears for old clocks, etc.The guy contracted again for heat spreaders and this one pushed the limits. The outside dimensions are 7.5mm x 7.6mm. The small step on the right channel is .2mm high (.0079"). I used a 1/32" end mill to rough out the channels and then finished them with a .015" end mill. To put that in perspective, a lead on a typical ceramic capacitor is .024". For miniature machining, this type of work wouldn't even get me in the contest. I've seen people make working machines that sit on a dime.The picture doesn't do it justice as the tool marks that are visible could be buffed out just by rubbing the part on a piece of paper. I'll leave the finishing to the customer as even 2000 grit sandpaper would quickly spoil the edges.

author: calexanian
author_rank: Super Contributor
timestamp: July 31, 2016, 03:46:56 am
content: Cool. I never have to do anything tiny like that. We just have another shop down the road EDM the small stuff.

author: cncjerry
author_rank: Unknown
timestamp: July 31, 2016, 04:03:12 am
content: I've seen some amazing things done with EDM and if the entry price wasn't so high I would have one. You still have all the typical table problems with backlash, linearity, etc but they cut just about anything (conductive). The total machine time on one of these parts was nearly an hour as the end mills will break just looking at them. All you hear is a little 'ping' and there goes 25 bucks. EDM would have been a fraction of the time as well.

author: David Hess
author_rank: Super Contributor
timestamp: July 31, 2016, 07:05:45 pm
content: I am surprised that a thermally conductive elastic pad is not a more economic solution for him.
heated 2sc1096 in Joule ringer  - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: June 26, 2017, 04:05:18 pm
content: Hi guys ,I am making Joule ringer 2.0 . Want to do in EI core . to light 5w LED lampthere are videosby LIDMOTORshowing low amp draw like 140mAbut here it is heating the transistor ..amp is >700mAthere are 2 changes from main design1)operating for 220V2)transistor is 2sc1096expert comments needed

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 27, 2017, 03:12:58 am
content: There's no good reason to use such a design in 2017. Use a proper PWM controller.

author: bktemp
author_rank: Super Contributor
timestamp: June 27, 2017, 05:56:21 am
content: And going all the way to 220Vac is probably the most inefficient way of powering LEDs.Why not drive the LED directly using a proper constant current boost converter?
Heathkit bench supply mini-restoration - Page 1
Forum section: electronics / projects

author: james_s
author_rank: Super Contributor
timestamp: July 26, 2018, 01:46:14 am
content: I was poking around in my mom's garage and came across the Heathkit IP-2718 I had when I was a kid. I managed to blow something up in it decades ago and then somehow the lid got misplaced. It also has been missing the dual knob for the B supply for as long as I've had it. I ended up snagging a parts unit on ebay for the opening bid with local pickup so I thought I'd restore mine. Well after some cleaning and polishing and a few squirts of control cleaner I soon realized my "parts" unit was in better shape than the one I had planned to fix with the parts. It had an issue though, when shutting it off the A supply would spike up to around 8V briefly, obviously not a good situation. Digging in a bit I found a very cooked looking diode which had been desoldered at one end with a larger Schottkey diode soldered across it on the back of the PCB. I removed that mod and checked the original diode, finding it was quite leaky. I replaced that with a new 1N4007 and found the voltage spike still occurred. More poking around located another leaky diode, replacing that solved the spike. I was about to button things up and call it done when I noticed the ripple on the A supply was quite a bit higher at some settings than the B supply. I then decided to carefully test the short circuit current limiting and found that while the B supply would limit at around 650mA as designed, the A supply would top out at under 200mA. Another half hour of poking around found a tiny solder bridge hidden under a blob of flux between two adjacent joints. I removed the bridge and everything works perfect. I strongly suspect that whoever built this thing in 1977 simply put up with the degraded performance and never had it working quite right, that must have been frustrating as it was otherwise quite well constructed. It's not a spectacular power supply, lacking adjustable constant current mode but it cleaned up nicely IMO and Heathkit brings a certain degree of nostalgia.So now I guess the problem is I still need a knob and lid for the other one! I can make a new lid using the one I have as a pattern but the knob may be trickier to find.

author: bitseeker
author_rank: Super Contributor
timestamp: July 26, 2018, 04:51:11 am
content: Nice restoration, James. Sounds like you're in the market for another parts unit. And so it goes...
Heathkit ID-1590 weather station adapter - Page 1
Forum section: electronics / projects

author: james_s
author_rank: Super Contributor
timestamp: October 28, 2021, 04:21:47 am
content: Some time back I found a neat old Heathkit ID-1590 wind speed/direction console. This is a neat little unit that has a Panaplex neon display for the wind speed and arrows backlit with small incandescent lamps to indicate the direction. The original Heathkit sensor booms are the same as used on the much more valuable weather computers they offered and are as rare as hen's teeth. Being outside on the roof they deteriorated over time or got left behind when people moved or passed away. Modern wind vane sensors are mostly potentiometer based while Heath used 8 reed switches activated by a magnet on the rotating vane assembly. To multiplex 8 switches over 5 wires they divide them into two banks, one for each half cycle of the AC power out of the transformer.I developed an adapter that allows a modern wind vane such as that used by the Davis VantagePro weather station with the old Heathkit console. When the original incandescent lamps are still used the adapter can utilize "phantom power" without requiring a separate power source or any modifications to the console. I designed it on the fly mostly around parts I had on hand so there may be a better way of doing things but this has been working very well. Since I only needed one and assume the market is very small I just built it on a protoboard and didn't bother to lay out a PCB. I'm releasing all of the source into the public domain in hopes that it will be useful to somebody else who has a ID-1590 or similar console.https://github.com/james10952001/Heathkit-ID-1590-adapter
Heathkit IP-20 Regulated Power supply restoration - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: August 21, 2017, 12:06:06 pm
content: Video 1 of 3

author: jcrubin
author_rank: Frequent Contributor
timestamp: August 28, 2017, 12:22:30 pm
content: Video 2 of 3https://youtu.be/h4oqI6-GAkU

author: jcrubin
author_rank: Frequent Contributor
timestamp: September 09, 2017, 01:20:06 pm
content: Video 3 of 3
Heathkit IT-11 Re-calibration with precision resistors - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: July 21, 2016, 01:54:54 pm
content: I put together a list of needed resistor values from Mauser to attain 1% or better at .5 watt for my IT 11 and installed and re-calibrated the device with those values. The results turned out amazing.I also replaced the 9.1 OHM resistor as well.