hybridfree/eevblog-posts huggingface dataset:
Office lighting - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: February 15, 2018, 06:43:00 pm
content: I'm trying to design a lighting system for my office. It's a large open room, with high exposed ceilings. There's a single conference table where all the work is done, with the rest of the room being ambiance. It's an office inhabited by engineers, so we want to take the time to build a nice setup.Things we care about:-Quality of the light (Continuous spectrum. I know CRI is a rather simplified metric.)-Dimmable.-Adjustable colour temperature.-No flickering (high kHz PWM or true analogue).Efficiency is unimportant, as we pay a fixed rate for electricity. We're open to any type of fluorescent or LEDs.At first I was thinking of getting a four channel DMX dimmer, and having a mix of high and low colour temperature lights. Then I realized many LED panels have a 0-10V dimming system built in. We could build a controller to automatically adjust the colour temperature based on the time of day, and have a single potentiometer as the user input.Are LED panels very directional? I was considering one or two such panels over the conference table, possibly adding a directional diffuser from a broken LCD monitor. I'm uncertain how to do nice colour temperature mixing though. Would separate fixtures look weird?Does anyone have interesting ideas or suggestions?

author: elecman14
author_rank: Unknown
timestamp: February 15, 2018, 07:01:48 pm
content: You should look at Intelligent lighting stage lights with an RGB led bulb. That would probably tick all the boxes for what you are looking for. They are quite flexible if your needs change and can be re-configured on the fly.

author: Rachie5272
author_rank: Regular Contributor
timestamp: February 15, 2018, 11:31:55 pm
content: We want adjustable colour temperature because bluer light is nicer during the day (closer to sunlight), while redder light is nicer at night (closer to fire, and doesn't suppress melatonin production). And also because we can't agree on a single colour temperature.

author: CopperCone
author_rank: Super Contributor
timestamp: February 16, 2018, 01:30:58 am
content: get the most blue cold incandescent lights and put them in without a diffuser
Offline Flyback (24V,15W) with INN2904K.....sync. rectifier connection? - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: March 04, 2018, 02:48:34 pm
content: Hello,We are using the INN2904K controller to make a 15W, 25V Offline 240VAC Flyback.We are not using the synchronous rectifier facility in the secondary side. As such, will it be allright for us to simply ground the FORWARD pin?The Forward pin is only rated up to 150V and with our turns ratio, the reflected voltage (+leakage spike ring) would result in the FORWARD pin getting overvoltaged if we connect it up to the switching node of the secondary side.INN2904K datasheet:https://ac-dc.power.com/sites/default/files/product-docs/innoswitch-ep_family_datasheet.pdf
Offline Flyback SMPS diode at 120 degrees C  - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: September 15, 2018, 09:41:26 pm
content: Hello,We have designed a 60W PFC’d Flyback LED driver. Output is for 60V LED string.VAC input is 240VAC.The output diode is STTH3010D.When the LED driver is in its plastic enclosure, which is itself inside a metal enclosure, we record 120 degrees on the tab of the diode. This is with the equipment in 22 degrees centigrade ambient. We cannot afford to buy a bigger heatsink than the one that we have for it. And in any case, we couldn’t afford to re-do the board so we could fit a bigger heatsink in. –This is because the extra cost would make our product uncompetitive with already existing offthe shelf products made by huge electronics corporations.The diode datasheet says it is for use up to 170degrees Centigrade at the junction. However, going above 100 degrees Centigrade obviously bares with it the danger of thermal expansion/contraction damage. However, our equipment is only switched on and off once per day.Due to this, do you think that the product will not suffer badly from expansion/contraction damage, due to the low amount of power cycling events? (the product will be on full power for 6 hours per day)The external ambient that the product is installed in has temperatures ranging from -10degC to 24degC.STTH3010D datasheet:https://www.st.com/resource/en/datasheet/stth3010.pdf

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 15, 2018, 11:49:08 pm
content: 1. What kind of heatsinking is there? Try thermal pads to the enclosure.2. What kind of enclosure is there? If it's plain ABS, that has awful thermal conductivity. A more conductive filled resin would be a good idea.Tim

author: Circlotron
author_rank: Super Contributor
timestamp: September 16, 2018, 12:18:16 am
content: How reliable is the competitor’s product and what is their diode temperature?Edit - that a pretty big diode for a small power supply. Why don’t you use a much smaller schottky?

author: Circlotron
author_rank: Super Contributor
timestamp: September 16, 2018, 03:16:40 am
content: Or if a reverse voltage rating of 200V is enough, a MBR20200CT has about half the forward voltage drop of the SiC schottky.https://www.onsemi.com/pub/Collateral/MBR20200CT-D.PDF
Offline PFC'd flyback in "constant off time" control having problem (L6564 IC) - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: July 25, 2018, 08:33:59 pm
content: Hello,We wish to do a Power factor corrected flyback LED driver for a 60W led load. (240VAC input)We wish to use no electrolytic capacitors at all.We also want full dimmability down to 5w, and want it to be power factor corrected all the way down to 15w.We rejected the Boundary conduction mode flyback designs, since their switching frequency gets unfortunately high at light loading.So we chose the Fixed off time control using an L6564 controller . This is described in the app note, AN1792 by st.com (at bottom)First of all, in order to “check out” this fixed off time control method, we bashed together a prototype in the lab. It uses fixed off time control, but this one is just 13W, as we just wanted to see how it worked (the fixed off time control).It worked just as expected for an hour in the lab…worked very well indeed…nice sinusoidal input current from the mains, and no electrolytic capacitors used whatsoever. I was running it, turning it on and off, and happily soldering probes on for all kinds of scope tests.Then I removed it from the AC power source, and instead connected it to our carroll and mennell isolation transformer, and the LNK302 blew up. There’s a short on the “14VPRI” rail, and after disconnecting the 5V regulator, the short is still there, so it looks like the L6564 has gone short.Do you know of any “bad boy” stories about the connection of the L6564 controller in fixed off time mode? Maybe the ZCD pin just isn’t meant to be connected up like this?AN1792…fixed off time control with L656Xhttps://www.st.com/content/ccc/resource/technical/document/application_note/cc/e2/9f/39/ad/27/4d/7e/CD00004484.pdf/files/CD00004484.pdf/jcr:content/translations/en.CD00004484.pdfL6564 datasheethttps://www.st.com/resource/en/datasheet/l6564.pdfWe cant get a response from st.com

author: dmills
author_rank: Super Contributor
timestamp: July 25, 2018, 10:19:07 pm
content: What is it with you and electrolytic caps?It is the LNK302 (Your AUX supply) that you say blew up, so I would be starting there.Your isolating transformer, has some leakage inductance does it?Remember that your 'current clamp', is just that, it cares not a lot what the peak voltage gets to, I would be thinking the classic startup current ring down thing that is so common when you are short on lossy elements in the input section.Regards, Dan.

author: daveshah
author_rank: Unknown
timestamp: July 26, 2018, 08:17:10 am
content: Maybe the UK grid was at 290V during your testing? Or perhaps your isolation transformer?
Offline SMPS PSU Explained... - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 22, 2018, 11:01:03 pm
content: this guy nicked named DiodeGoneWild... now this can make my life much easier...

author: Cliff Matthews
author_rank: Unknown
timestamp: March 23, 2018, 12:37:51 am
content: Yes, he is kind of famous in EU as well (his sitewww.danyk.czpre-dates many others). We listed him on the Big youtubers list.I liked his 3-part series on SMPS that was posted in the Primers section:https://www.eevblog.com/forum/beginners/electronics-primers-course-material-and-books/msg1414958/#msg1414958He has my all time favorite electronic scare video"https://youtu.be/vfixjqWcOwg

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2018, 02:03:49 am
content: Hehehe, notice the perfect fifth* in the hum: it's a three phase arc, so the fundamentals and second harmonics cancel out (give or take imbalance between arcs), while the 3rd harmonics add perfectly in phase (because 120 or 240 degrees, times three, is a multiple of a full circle). When one pair of arcs breaks, it reverts to single phase, giving the second harmonic. (The fundamental cancels out anyway, because the arc is approximately square law.)*An equal-tempered fifth is technically 2^(5/12), i.e., 5 steps on the diatonic scale (an octave divided into 12 pieces by equal ratios). This happens to be very close to 3/2 (i.e., the ratio between 2nd and 3rd harmonics), but not quite equal. Following multiples of 3/2 (up a fifth) and 1/2 (down an octave), you generate the "circle of fifths", which works out evenly on the scale, but ends up a bit out of tune (I think about a half step in total??), because fundamentally, the 12th root of 2 is an irrational number, and cannot ever be represented by a ration number (in this case, a finite product of 3/2 and 1/2 factors). This has been your musical fact for the day.Tim

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 23, 2018, 04:45:47 am
content: Quote from: Cliff Matthews on March 23, 2018, 12:37:51 amaddress locked (for my reference later) thanks
Offline SMPS with two isolated transformers that don't fit on the PCB - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: June 18, 2018, 03:25:03 pm
content: Hello,We have an offline SMPS PCB which needs two transformers on it. Both of these transformers have isolated outputs, so therefore both must “straddle” the mains isolation barrier.The problem is that if the isolation barrier is a straight line running across the PCB, then the two transformers will not fit on the PCB (as shown in the attached diagram).The PCB is too narrow to fit both transformers on.Therefore, we wish to make the mains isolation barrier “bent” as also shown in the attached diagram. –This way we can fit the two transformers on the PCB.However, we worry about noise issues of this unusual shaped isolation barrier. ( noise coupling from primary to secondary side and creating a bigger common mode noise problem). Another point would be where the Y capacitor should go in this “bent” isolation barrier arrangement, so as to best couple noise back to the primary side?Do you believe that this “bent” isolation barrier is OK?

author: Benta
author_rank: Super Contributor
timestamp: June 18, 2018, 03:48:40 pm
content: Meandering the isolation barrier is no big issue.I'd turn your "transformer 1" 90 degrees, simply to avoid inductive coupling between the two (I assume they're the same core type).
Offline Switching regulator start up Current Splat. - Page 1
Forum section: electronics / projects

author: DeanA
author_rank: Regular Contributor
timestamp: July 28, 2020, 01:11:13 am
content: I’ve been tearing my hair out for days trying to find the source of a current splat when my offline switching regulator is enabled. The circuit is a Non-isolated offline 8-12W LED driver based on the HV9931https://www.microchip.com/wwwproducts/en/HV9931.The current splat occurs when the HV9931 is initially enabled by setting the PWMD input high. The attached scopeshots are Mains input voltage on Channel 1 and Mains input current measured across a 10R resistor on channel 2. The current splat only occurs when the bulk capacitor is mostly discharged.I’d be grateful for any insight as to what might be the cause of this issue.
Offset Pattern Dsub Board-Board Pin Header????.......... - Page 1
Forum section: electronics / projects

author: Smokey
author_rank: Super Contributor
timestamp: July 17, 2017, 09:28:12 pm
content: Anyone know if someone makes a board-board pin header that fits in the offset Dsub pattern? Bonus points if you can find a header that fits the 3Row HDDsub like in the attached picture.Samtec said they don't have anything. I really don't want to have to use two actual DSubs to connect these two boards together. That seems like a waste of both money and space.

author: Smokey
author_rank: Super Contributor
timestamp: July 18, 2017, 03:25:34 am
content: Sorry.. One bump for the evening crowd. Of all the things that you would expect to exist, this would be one. This and the 0.1in box version of the DB9, which I remember there being a thread about and it didn't exist either.

author: Smokey
author_rank: Super Contributor
timestamp: August 04, 2018, 06:44:09 am
content: I was looking through my old posts and I was surprised to see that no one had any feedback on this one. I've wished a board to board connector that mated with DSub pins existed on multiple occasions. I can't imagine I'm the only one.

author: qwaarjet
author_rank: Regular Contributor
timestamp: August 04, 2018, 07:11:32 am
content: would individual pins and sockets be ok?https://www.mill-max.com/assets/pdfs/211.pdfhttps://www.mill-max.com/assets/pdfs/158.pdf

author: Smokey
author_rank: Super Contributor
timestamp: August 06, 2018, 11:07:11 pm
content: Ya that would probably be functional, but it's only a half step up from point to point wiring the pads together. For this to be a "production ready" design, it would really need to be one self contained connector part.

author: Gribo
author_rank: Frequent Contributor
timestamp: August 07, 2018, 02:24:47 pm
content: There are VGA to IDC cables if it helps in any way:https://www.alibaba.com/product-detail/VGA-to-12pin-IDC-connector-with_60477249920.html
offset voltage compensation - Page 1
Forum section: electronics / projects

author: nabardwell
author_rank: Newbie
timestamp: April 21, 2020, 11:55:30 pm
content: I have been looking for an op amp that is stable with av=2.25 ish frequency to 100mhz the op amp also has to have very very good large signal response 2VPP at av~2.25 100mhz. It is appropriate to assume RL~1Mohm so 1k AV=2 vs Freq can be ignored and no load scenario can be assumed. I have found a suitable op amp LM7171 but with the large gain intended 4 stages of AV 2.25 the input offset voltage of ~100uV will be too much. I have simulated and tested a unity gain offset voltage compensated op amp with both low impedance offset source and voltage divider offset source. While I am able to get very good offset for a specific voltage the drift over the entire range is quite large and essentially equivalent to the original offset voltage. Does any one have any suggestions on how to get less drift over the entire range.Here at 2v we have very good offset adjustmentHere at -2v we are pretty far out

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 22, 2020, 12:34:21 am
content: All high-speed opamps have about 1 mV offset or more. You can adjust it for some temperature but can't adjust it for all temperature range, except you use additional integrator.If you don't need 0 Hz (DC) then may be you may use a capacitor at the output?

author: nabardwell
author_rank: Newbie
timestamp: April 22, 2020, 12:47:05 am
content: I was planning on being able to amplify both ac and dc signals. The overall gain after 4 stages will be x25 and if I cant compensate the offset voltage on the first two stages to be better than ~50uV I will have over 1.25 mv on the output from the offset voltage. I am most concerned about the offset drift over Vin when I add offset compensation I get a large offset variation over the Vin range +-2v.

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 22, 2020, 12:41:29 pm
content: I think you should look an Art of Electronix great book. There is an example of how to calculate opamp circuits error budget (and ways to compensate offset). Because I'm not sure you can simulate circuit you want before you'll understand how to do.

author: mycroft
author_rank: Regular Contributor
timestamp: April 22, 2020, 03:02:40 pm
content: You can use a composite amplifier where a slow op amp handles the offset compensation of a fast op amp. Take a look at Composite Amplifiers by Jim William in LT AN-21 (https://www.analog.com/media/en/technical-documentation/application-notes/an21f.pdf).

author: nabardwell
author_rank: Newbie
timestamp: April 22, 2020, 08:25:25 pm
content: Using a composite amplifier seems like the ticket I will build this with a max4239 for the offset stage and LM7171 for the gain portion. Thanks for the suggestion.
Ohmmeter Circuit - Page 1
Forum section: electronics / projects

author: Burning Circuits
author_rank: Contributor
timestamp: July 06, 2020, 05:58:07 pm
content: Hi,the attached picture is the ohmmeter stage of a bench multimeter.We have two current sources (IC26 and IC9-B), and an analogue multiplexer (IC8).I don't understand the purpose of IC9-A ... maybe limit the output voltage when there isn't a resistor to probe?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 06, 2020, 07:18:09 pm
content: IC9 is limiting the voltage with little leakage current. It is still odd to used a zener diode at near zero voltage for low leakage.

author: David Hess
author_rank: Super Contributor
timestamp: July 07, 2020, 07:56:04 pm
content: I agree with Kleinstein; the two series zener diodes clamp the output voltage and IC9 bootstraps zener diode D20 for minimum leakage.I think the designer incorrectly assumed that D20 would have low leakage at low voltages without being a low leakage diode; bootstrapping it does lower the leakage but not to the level of a true low leakage diode. I would have used a low leakage diode, or two, in place of D20.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 07, 2020, 08:19:20 pm
content: The choice of IC9A and IC26 is also a little odd: IC9A still has some avoidable input bias and IC26 has quite some noise and drift, even though attenuated by a factor of 5. I would more like swap the two OP.

author: Burning Circuits
author_rank: Contributor
timestamp: July 07, 2020, 08:42:39 pm
content: Quote from: Kleinstein on July 07, 2020, 08:19:20 pmLT1112 don't have a very low input bias current? 250 pA from the datasheet
Oil Filled Dummy Load for DEC H777 power supply - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: June 08, 2019, 03:28:12 am
content: This is a cheap and cheerful method to make a dummy load that will happily dissipate 150 Watts for 15 minutes, which is long enough for most types of testing.It consists simply of PVC piping with end caps, immersed in mineral oil.In this instance, it is used as a fixed load for the H777 power supply used in Digital Equipment Corporation PDP11/04 and PDP11/34 minicomputers.It appears as a fixed load of about 95% of rated current for the four voltage supplies provided by the H777.But the method could easily be adapted for higher power dissipation, or longer operation:-- Thicker tubing, and/or higher volume of oil.- The thing could be weighted down in a bucket of water.- The containing tube could be made of aluminium, with heatsinking and/or fan cooling.- Several standard fixed resistances could be built inside, with Wires be brought out to a switch panel,so that various switch combinations could select a range of different loads.- Even an active electronic load could be immersed inside to extend its specifications.Schematic used for this unit:-Video:-
Oil reminder device (DIY project) - Page 1
Forum section: electronics / projects

author: daisizhou
author_rank: Super Contributor
timestamp: December 04, 2023, 03:41:06 am
content: Hallo every one.I plan to make this oil reminder device in my free time.Currently, I have completed the preliminary parts purchase and hardware wiring connection,Some attachments are still in transit.I haven't written the code yet,Because I haven't confirmed if my hardware connection is correct yet.If you are good at coding and interested in this project, please leave me a message. Thank youIntroductionThis is an oil reminder device,I plan to install it inside the motorcycle dashboard,Obtaining pulse signals through mechanical code table turntable,140 pulses per 1000 meters.The motherboard is Arduino nano,The connection method is shown in the picture,GC9A01 is the display,KEY1 is the time setting button,Press and hold for a long time to start the setting program,Short press the set time，Automatic storage of set values without operation for a long timeKEY2 is the one-way mileage and oil setting button,Short press KEY2 to reset the one-way mileage display,Long press KEY2 to reset the engine oil to zeroThe display interface is shown in the following figure, with the outermost circle indicating the oil lifespan,The pointer rotates from green to red,The red area is 15000-25000 kilometers,When the pointer points to the red area, the entire indicator strip will turn into a red prompt and flash.In the middle is a digital clock display,It is a 12 hour clock,Press KEY1 for a long time, it will flash and enter the setting modeThe bottom line is the one-way mileage display window

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 04, 2023, 12:37:18 pm
content: Quote from: daisizhou on December 04, 2023, 03:41:06 amDid you miss a zero? 1500km translates to 932 miles, insanely short even with conventional oil. 15000km would be more like it, about the recommended change interval for synthetic oil.

author: daisizhou
author_rank: Super Contributor
timestamp: December 04, 2023, 12:46:21 pm
content: I'm really sorry, I forgot that the first digit on the far right is a single digit, it should be 15000-20000.That's right, the engine oil is indeed fully synthetic.

author: daisizhou
author_rank: Super Contributor
timestamp: December 08, 2023, 11:13:50 am
content: Does anyone know how to use SquareLine studio software?I just want to use it to create a system UI as shown in the picture belowI am a beginner and I am not good at software programming, but I have a passion for electronic production

author: daisizhou
author_rank: Super Contributor
timestamp: December 08, 2023, 01:00:17 pm
content: I searched for similar programs and references in various parts.I need to integrate these scattered programs into my project internally.If you could help me catch up, I would be extremely grateful. Thank youDS3231part-->https://howtomechatronics.com/tutorials/arduino/arduino-ds3231-real-time-clock-tutorial/Oil and odometer part-->see attachment(speedometer-source.zip)
OIP3 from IIP3 of ZFL750 question - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: October 31, 2024, 06:12:41 am
content: Hello, I am trying to build equivalent model in systemvue for ZFL750.In the datasheet they only have IP3 point.What is the oip3 of this device?Thanks.https://www.minicircuits.com/pdfs/ZFL-750+.pdf

author: G0HZU
author_rank: Super Contributor
timestamp: October 31, 2024, 01:11:49 pm
content: Quote from: john23 on October 31, 2024, 06:12:41 amThat is a really old part from Minicircuits. This uses very dated technology to achieve a flat 20dB gain across 200kHz to 750MHz from a 15-16V supply. The OIP3 is quoted on the datasheet as +18dBm. In reality, this will probably be the worst case OIP3 and it may achieve closer to +25dBm OIP3 at some frequencies at a guess. The output 1dB compression point is typically +10dBm so it might manage +25dBm OIP3 across some parts of its frequency range.It's not a great part to work with because it is fragile, very inefficient, it has poor large signal performance and the noise figure is relatively high at 6dB. In its day, it would have been viewed differently as it offers a fairly flat 20dB gain across 200kHz to 750MHz from a fairly small footprint and this could have been challenging 30+ years ago. This would make it attractive as an amplifier that could be used in test equipment for example.
OK, help me with this odd requirement for a fuse/circuit breaker: 5mA but 20KV!! - Page 1
Forum section: electronics / projects

author: cvanc
author_rank: Frequent Contributor
timestamp: June 22, 2016, 12:25:00 pm
content: Yup... need to find some kind of circuit interrupter/fuse/breaker that trips at 0.005A and can interrupt 20,000 volts. Any hope of something like this existing as a commercially available item? Thanks...

author: wraper
author_rank: Unknown
timestamp: June 22, 2016, 12:26:36 pm
content: You should shut down generation of that HV, not break HV directly.

author: Gyro
author_rank: Super Contributor
timestamp: June 22, 2016, 06:07:34 pm
content: The simple answer would be a vacuum relay but it's way more complicated than that!The major question is what is the prospective fault current - you might want to trip at 5mA, but what will be the available current into a short circuit? That pretty much decides whether there is any sensible possibility of breaking at high voltage.The second issue I see is current sensing, if you can't do that in the ground return then there are big issues in current sensing a line that it is sitting at 20kV.Edit: The other question is AC or DC. Breaking 20kV at DC is a bigger problem still. You need to supply much more information before anyone can have a reasonable chance of answering it.
Ok to cross power tracks on a 2 layer pcb? - Page 1
Forum section: electronics / projects

author: hummusdude
author_rank: Regular Contributor
timestamp: April 15, 2021, 12:46:11 am
content: I have a 2 layer board with +- 15VDC for op amps and +5VDC for the digital components. I've looked around and found a ton of great info on best practices including videos from Eric Bogatin and Rick Hartley. But I haven't found a definitive opinion about crossing power tracks with signal lines. I know the current return path wants to follow the trace so if I cross a power trace the return current in the ground plane will spread to find the lowest impedance path back to ground.It seems like very short crossings will have a limited impact on the power return path. But will the signal line have issues? I have analog and digital signals as well. I've grouped the analog components away from the digital. I'm just not clear about how much, if at all, I can disrupt the power return path without causing noise in my analog signal. It's not a high speed board...using an Arduino Nano to control the logic.
Oki metcal PS-900 - Page 1
Forum section: electronics / projects

author: embedded.world@aol.com
author_rank: Contributor
timestamp: March 28, 2014, 08:24:25 am
content: I was looking athttp://www.okinternational.com/Hand_Soldering_Systems/id-PS-900/Production_Soldering_System_-_Tip_Hand-pieceI read that it uses innovative technology by maintain constant temperature instead of constant power to iron.1. is its only advantage?2. There is no display for what is tip temperature. So what the tip temperature I don't know. It must be fix for every model. but I didn't find what is fix temperature for model PG-9002. is it advisable to purchase it over conventional temperature controlled irons in which you can any desired temperature of iron you want as compared to PG-900

author: zapta
author_rank: Super Contributor
timestamp: March 28, 2014, 10:20:19 am
content: Like other Metcal products the temperature is determined by the tip. For each tip dimension there are 2 or 3 versions with different temperatures. You can find them herehttp://www.okinternational.com/metcal/english/globalnavigation/products/hand-soldering-systems/tips-and-cartridges/ps-mfr-tipsSome like the Metcal products (I do), others prefer units with temperature setting.
Oktopod Studio - Development Tools for Mechatronics, Robotics & Automation - Page 1
Forum section: electronics / projects

author: milan.romic
author_rank: Newbie
timestamp: May 14, 2015, 03:21:44 pm
content: Hello developers!I want to inform you all about our project Oktopod Studio!Oktopod Studio is an open source development platform for mechatronics, robotics and automation, which enables creating and controlling low voltage electronic devices, models and home applications. /in an extremely simple way/.We designed Oktopod Studio to be as user friendly as possible, which features plug-and-play analog outputs, digital inputs, DC and Servo motor drivers and a graphical user interface for PC and Andriod devices. Using Oktopod Studio you don't need to be a programmer or an electronic expert to make your own robotic projects!Support us onhttp://igg.me/at/oktopodstudio/xand find a perk for you!Please reply about your impression
Old 486 Motherboard, CPU Clock Speed and Crystal Oscillator Freq. - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: August 12, 2014, 06:51:22 pm
content: Hi guys & Dave,Quick question -- I've acquired an old 486 motherboard for my collection and have noticed that there is a 25MHz crystal on-board. It also came with a 486SX 25Mhz CPU installed.I notice there are jumpers on the board which suggests that it also supports 486DX/2 and Overdrive processors (as we know, they came in anything up to 100MHz clock speeds).I haven't got another CPU to test at the moment, but was wondering does that mean that I am limited to a maximum 25MHz CPU clock due to the crystal or will setting the jumpers apply some sort of multiplier to allow faster CPU's to work on this board (i.e.: is this the "hardware" equivalent of setting multiplier ratios before it was done in software through the system BIOS), or will I need to swap out the crystal with a corresponding clock rate to the new CPU?

author: SirNick
author_rank: Frequent Contributor
timestamp: August 12, 2014, 07:31:30 pm
content: From memory, motherboards of that era tended to have a jumper bank somewhere to let you select the clock multiplier.

author: Stonent
author_rank: Super Contributor
timestamp: August 12, 2014, 08:19:33 pm
content: 486 boards typically came with 25, 33, 40, or 50MHz clocks.90% used 25 and 33 with a clock multiplier in the chip, data ran externally at the clock speed of board but internally at a multiple.There was a 486 DX50 that ran at full speed internally and externally but it was rather expensive.I think AMD or Cyrix may have made a 40MHz clocked cpu.There was also the 5x86 processor series by AMD and some others that used a 486 board but could execute as fast as a low end Pentium processor. They typically ran 25mhz or 33mhz externally and 100/133 internally.

author: nctnico
author_rank: Super Contributor
timestamp: August 12, 2014, 08:31:07 pm
content: I think I upgraded a Lecroy LW420A waveform generator from a 486 to a Pentium-I overdrive. That gave the machine a huge speed improvement!Many are for sale on Ebay:http://www.ebay.com/itm/Intel-Pentium-OverDrive-Processor-83Mhz-BOXPODP5V83-/161268093513
AMP fiber connector - Can you identify it? - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: June 15, 2023, 01:12:14 pm
content: Can anyone identify the part number of this AMP fiber optic connector?

author: AndersJ
author_rank: Frequent Contributor
timestamp: June 18, 2023, 05:24:35 pm
content: No response.Trying again.

author: nexus
author_rank: Regular Contributor
timestamp: June 18, 2023, 05:38:20 pm
content: Where did it come from?

author: AndersJ
author_rank: Frequent Contributor
timestamp: June 19, 2023, 06:21:04 am
content: The device is used in a legacy industrial supervision system, needing spare parts.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: June 19, 2023, 08:04:57 am
content: Hi AndersJ,looks a bit like TOS-link to me.Good luck
Old car GPS navigator - what to use it for? - Page 1
Forum section: electronics / projects

author: DeepLink
author_rank: Regular Contributor
timestamp: March 31, 2023, 10:46:38 am
content: I have several old GPS navigators laying around, Garmin and Tomtom'sThese are not used anymore, as I use the smart phone nowSo want to do with these?They have:GPS receiverColour LCDTouch screenSD cardUSB interfaceSome kind of CPUBatteryThis is basically the building block of my other projectsSo how do I make use of these?What are you doing with your old and obsolete GPS navigators?Show us you hacks

author: Bicurico
author_rank: Super Contributor
timestamp: March 31, 2023, 11:47:29 am
content: Some use WinCE and can be hacked so that you get access to the normal WinCE environment. One hack for Garmin consisted in installing the TomTom executable and it's maps, which were better at the time.Still I would consider your devices plain obsolete, as a 100 Euro Smartphone is better in all aspects.

author: DeepLink
author_rank: Regular Contributor
timestamp: March 31, 2023, 12:27:45 pm
content: Yes, for navigation my phone is what I useBut I was thinking of re-using the old Tomtom touch display and maybe the GPS module for other tasksI cant be the first guy with a bunch of old surplus electronics that could be turned into something else

author: darkspr1te
author_rank: Frequent Contributor
timestamp: March 31, 2023, 12:57:27 pm
content: I have a stack of Japanese Dvd navigation units that are almost usless, they do have usable parts but most parts are japanese with no datasheet. so that usually means cpu,gps,viccs controller etc are unknown units and dont have common pinouts. older ones are good source for common led colours and switches and once in a while eeproms/flash chips.Euro and US navigation are a lot easier, as mentioned already theres WINCE units and most common is the MIPS WINCE setup that is based on Micros0fts design board so you will find info on them in XDA forums including sdk's and schematics.super new units may even be android or arm based (like kenwoods are arm and can run droid if you wish) so a kernel hacking kit is you next best bet.some fun linkshttps://keithlard.livejournal.com/180643.htmlhttps://github.com/lgrangeia/tomtom-hackinghope that helpsdarkspr1te

author: David Hess
author_rank: Super Contributor
timestamp: April 01, 2023, 02:20:12 am
content: I much prefer using my independent Garmin navigator because my phone has better things to do, and the Garmin is more user friendly than Google Maps or Waze.
old ceramic ICs, ground trace on surface of package? - Page 1
Forum section: electronics / projects

author: Skaface
author_rank: Contributor
timestamp: September 14, 2024, 10:39:06 am
content: I have a collection of old ceramic ICs, and have always wondered why they have a ground track on the surface of the chip running from the center of the package to the outer perimeter. I can only guess it was used for testing the package in the factory before it was released for sale? I have searched everywhere and haven't been able to find any information about this anywhere! I am sure someone here will know what this is for!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 14, 2024, 11:17:50 am
content: I mean, the shielding is nice, and grounding what would otherwise be unconnected metal is responsible for ESD purposes for example.Tim

author: inse
author_rank: Super Contributor
timestamp: September 14, 2024, 01:25:04 pm
content: The ceramic substrate type with visible traces is especially nice

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 14, 2024, 02:05:07 pm
content: Trace is part of the ring of metal the lid solders too, probably made the gold plating step easier?

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 14, 2024, 02:08:38 pm
content: Hi Skaface,...is there a connection to any pin?Best regards

author: coppice
author_rank: Super Contributor
timestamp: September 14, 2024, 02:19:56 pm
content: Quote from: T3sl4co1l on September 14, 2024, 11:17:50 amThat doesn't explain why they so commonly have a line from the lid to the end of the package, going to an area where nothing else appears to connect. I think someone told me the reason decades ago, but I can't remember what it was.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 14, 2024, 02:32:01 pm
content: Might be for the gold electroplating process

author: Benta
author_rank: Super Contributor
timestamp: September 14, 2024, 04:00:35 pm
content: It connects the lid to the lead frame which carries the die. Very good for shielding and ESD ruggedness.
OLD diy powersupply restore project 1975 - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 13, 2024, 11:34:14 am
content: sometimes i go a little too far :-)this old DC power supply was really a few sec from the trash bin when i got it in..but look here, how nice it is today, full video on restore projecthttps://youtu.be/CKiiuF9A3-U
Old Electromyograph Teardown - Page 1
Forum section: electronics / projects

author: IEvenKnowOhmsLaw
author_rank: Newbie
timestamp: May 27, 2020, 09:41:25 pm
content: I tore down a really old electromyograph I salvaged back in the fall. Unfortunately I've lost a few of the pictures, but here's most of it. I'm particularly curious about the diode packages with the diode symbol on them, I've never seen anything like it. The boards were all the old curvy hand drawn traces, so this would be pretty old. Anyone have a guess on age? 70s? It was all discrete components. Not a single IC by my memory. Could dig the boards out of the salvage pile if necessary.I kind of regret dismantling it now that I have time, but it was totally dead and old enough to be my father soI have about 8 more pieces of old medical equipment if anyone is interested in having a look. Some of it is lab equipment so I'm hesitant to do anything until I know if I could make use of it.

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: May 27, 2020, 10:13:51 pm
content: Gotta love those bridge rectifiers in the last picture. o_O

author: IEvenKnowOhmsLaw
author_rank: Newbie
timestamp: May 27, 2020, 11:21:50 pm
content: Yeah, 5 points to anyone who can identify the package on them!

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: May 27, 2020, 11:50:35 pm
content: Probably germanium. Did you measure the forward voltage?

author: IEvenKnowOhmsLaw
author_rank: Newbie
timestamp: May 28, 2020, 12:00:10 am
content: ~0.55V

author: IEvenKnowOhmsLaw
author_rank: Newbie
timestamp: May 28, 2020, 12:07:44 am
content: side viewedit: Found a datasheet. Still no idea on the year this would be fromhttps://www.datasheetarchive.com/pdf/download.php?id=fb211d090c07cacec0de3117f735155eb613a1&type=O&term=SKE4F1%252F02

author: DrG
author_rank: Super Contributor
timestamp: May 28, 2020, 01:42:15 am
content: I'm guessing the unit is from the 70s. Who was in White Plains NY at that time? Was Teca?You may want to ask this guy, he has a small collectionhttp://www.peterbodnarmd.com/museum-of-electromyography.php

author: IEvenKnowOhmsLaw
author_rank: Newbie
timestamp: May 28, 2020, 02:15:42 am
content: Yes, it is made by Teca. I'm really suprised someone actually collects these. Thanks for the tip! Compared to his models, mine is closest to the 1960's model. I'll try to get in touch with him.

author: Gyro
author_rank: Super Contributor
timestamp: May 28, 2020, 11:52:59 am
content: I see from the speaker mounted by the CRT that it's the 'Machine that goes Ping!'https://youtu.be/arCITMfxvEcA slightly dodgy place to mount a speaker, even if it is shielded.
Old fashioned rotary switch - what for? - Page 1
Forum section: electronics / projects

author: dobsonr741
author_rank: Frequent Contributor
timestamp: June 27, 2023, 04:59:19 am
content: I have a few old fashioned rotary switch, seems to have 12 discrete positions and five connections. Two sliding contacts inside. Not clear how it's decoding a position or making the contacts. Do you know?

author: wasedadoc
author_rank: Super Contributor
timestamp: June 27, 2023, 07:42:01 am
content: Use a continuity tester to determine which bits of metal inside the circle are connected to each of the 5 solder lugs on the outside.Your second photo shows there are two rotating contact that bridge the two inside "rings".From the above you can work out what connects to what in all 12 positions. But as the moving bridges are 180 degrees apart, symmetry means there are only 6 different settings.It is likely that the mechanism which turns the rod which rotates the contacts has two "stops" which restrict the bridges to only 6 of the positions. That is, the external knob only turns 180 degrees.

author: donlisms
author_rank: Frequent Contributor
timestamp: June 27, 2023, 06:24:49 pm
content: Looks like... custom.Assume this switch was designed for a specific application, rather than a nice, neat general purpose configuration. What gets connected to what else will have been for that device, what ever it was.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 27, 2023, 06:47:47 pm
content: yeah not standard ?? you need i think a 12 positionsand do the keying with external wiresnot so surebut youll get a shaft not this internal transparent rotator

author: dobsonr741
author_rank: Frequent Contributor
timestamp: June 28, 2023, 01:04:15 am
content: Ended up buying a universal one. It it to add it to an old instrument, do decode what position the input divider is sitting.
Old flight sim gauge - Page 1
Forum section: electronics / projects

author: georges shed
author_rank: Contributor
timestamp: August 15, 2021, 04:30:18 pm
content: I have an airspeed gauge from an old nimrod simulator that I’m wanting to get working once again.It has a dc motor and a potentiometer as well as a small pcb with a couple op amps. I have reverse engineered the circuit but cannot figure out how to get it to work. Any ideas?

author: james_s
author_rank: Super Contributor
timestamp: August 15, 2021, 07:15:48 pm
content: That schematic is a bit hard to follow, maybe try to redraw it into more of a standard format now that you have the circuit captured. My guess though is that it's a fairly standard servo circuit that compares the setpoint to the voltage on the pot wiper and uses that to control current to the motor. It's probably a standard aircraft gauge and not specifically designed for a simulator.

author: georges shed
author_rank: Contributor
timestamp: August 15, 2021, 08:47:49 pm
content: Thanks for the reply!It’s definitely a simulator gauge because I have worked with a lot of real aircraft gauges and they usually use a flavour of 400hz ac. This gauge also says “for simulator use only” on the side.I redrew the circuit and it makes more sense now. I applied +5v to the pink line. 0v to black and -5v to brown. I hooked up the yellow and green lines to the +-5v also. I attached a potentiometer between +-5 also and connected the output to the orange line. This makes the gauge rotate dependant on voltage of the orange line. Unfortunately below “100 knots” the gauge then rotates all the way to zero and sticks on.So progress has been make, i suspect tinkering around with the voltage values make remedy this. See attached new schematic.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 15, 2021, 09:23:37 pm
content: Probably needs more voltage, +-15V was common for analog electronics in the old days, try +-10V at first. The reference voltage and signal range is probably 0-5V or 0-10V.
Old hardware programming tool - Mitsubishi M37782 - Page 1
Forum section: electronics / projects

author: Cozzmo
author_rank: Regular Contributor
timestamp: July 10, 2021, 03:40:52 am
content: Does anyone have / have access to / know how to program M37782 chip?If you have the tools but its not for sale, I would still interested to organise to pay to have devices programmed.
Old ICs in DEC (Digital equipment Corp) Schematics - Page 1
Forum section: electronics / projects

author: ale500
author_rank: Frequent Contributor
timestamp: November 08, 2015, 04:40:06 pm
content: Looking at DEC's schematics for the PDP-11 (for example) I came across some ICs like the 8640. What are they ? Do anone knows a full part number/datasheet ?From here: Page 24http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp11/memory/MP00672_MS11L_engDrw.pdf

author: SeanB
author_rank: Super Contributor
timestamp: November 08, 2015, 05:02:10 pm
content: Standard TTL NOR gates, so you will have 4 in a 14 pin DIL package. Not a 7402 as it has a different pinout but does the same function. The W package does match the pinout, but that is a flatpack style package, so might be a little difficult to come by.http://www.ti.com/lit/ds/symlink/sn7402.pdf

author: Gyro
author_rank: Super Contributor
timestamp: November 08, 2015, 05:33:19 pm
content: I knew one of my former lives would come in handy one of these daysThe 8640 is an LSI-11 (Qbus) line receiver. Yes, basic NOR gate functionality but input parameters optimized for line receiver use (long 100R terminated ribbons). EDIT: Oops, 120RVin High: 1.7V minVin Low: 1.3V maxIin High: 80uA maxIin Low : 10uA max.Propagation delay 10-35nS.Standard TTL output.It was used alongside the 8881 Quad NAND bus driver and 8641 Quad Unified bus transceiver 8841. You should be fine with alternatives these days, it was pretty slow by modern standards.

author: SeanB
author_rank: Super Contributor
timestamp: November 08, 2015, 05:51:27 pm
content: Even standard TTL would work in many of those applications, though they did tend to blow up in use in some applications. i replaced a good number of 5474's that were still logically functional but which had suffered parametric drift on ythe input and which no longer would switch at TTL minimum logic levels, though they would still work if you pulled up over 4V. leaky input protection diodes from the application abusing them. We found out that you had to use standard TTL, LS or S or F did not work there. No way to redesign either due to regulatory pain. Luckily we did have a lot of stock of them as NOS parts.

author: Gyro
author_rank: Super Contributor
timestamp: November 08, 2015, 06:10:40 pm
content: Actually, they were used on Unibus devices too. I just had a quick scan and you can probably find the info on the chips you need in this book (Chapt 6 onwards):http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/dec/pdp11/handbooks/PDP11_PeripheralsHbk_1976.pdf@SeanB Yes, you could sometimes get away with a lot of devices (EDIT: on backplane only systems that is!), but it got touchy as you got near maximum length (16ft) a bit less if you had multiple backplanes.

author: amyk
author_rank: Super Contributor
timestamp: November 09, 2015, 01:10:20 am
content: DS8640 and DS8641, apparently still produced through the 90s:https://www.engineering.uiowa.edu/sites/default/files/ees/files/NI/pdfs/00/58/DS005805.pdfhttps://www.engineering.uiowa.edu/sites/default/files/ees/files/NI/pdfs/00/58/DS005806.pdf