hybridfree/eevblog-posts huggingface dataset:
Advice on making a SON-8 to DIP board - Page 1
Forum section: electronics / projects

author: DrG
author_rank: Super Contributor
timestamp: July 31, 2020, 03:28:31 pm
content: I have started to investigate an RV-3028-C7 RTC. My first impressions are that it looks pretty good, but that is not the question/issue.I am considering making a SIMPLE breakout (to DIP) board for the chip. I have never made a board before or, more accurately, not a board like this. Yes, many years ago, I etched a few board using pens and decals and ferric chloride.I have soldered SMTs to DIP breakouts before using an iron and dragging. A TSSOP24 is probably the most “delicate” that I have done. I have a hot air capability on my station.I am using an old version of Eagle (and do not want to go to diptrace or anything else unless absolutely necessary).Here, specifically is what I want to accomplish:That simple breakout is part of their evaluation board.https://www.microcrystal.com/fileadmin/Media/Products/RTC/Demoboard/RV-3028-C7_Demo-Board.pdfAll I want is that portion and I started to figure out how to make pads in Eagle and then I started to wonder how I would solder the chip, IF I made such a board.I do have some Chipquick solder and flux with a syringe.Do I simply apply the solder (I have no stencil) and hit it with a hot air gun? Obviously, I am not going to be directly on the pads. Would that work? That, in general, is my question.I also add that I am aware of one SON-8 to DIP board (actually they have two versions).https://www.icbreakout.com/collections/breakout-boards-son-small-outline-no-lead/products/son-8-breakout-board-3x2-mm-0-5-mmIt might work but I don’t think that the measurements are exactly as in the recommended layout, but close.https://cdn.shopify.com/s/files/1/1690/2801/files/ICB00160_Dimensions.pdf?1137012631354654133Would it just not be worth the effort to make a whole board if that would fit the bill (the cap is a bypass and could be elswhere close to the chip)?Here is the recommended pad layouthttps://www.microcrystal.com/fileadmin/Media/Products/RTC/Datasheet/RV-8803-C7.pdfAnyone have some guidance/ advice?
Advice on signal cables - Page 1
Forum section: electronics / projects

author: StarFishPrime
author_rank: Contributor
timestamp: March 02, 2014, 04:54:43 pm
content: Hi FolksI'm building some earth field magnetometers with school kids. These will have a magnetometer sensor buried undergound outside the lab. I need to bring in two signal lines and take out a 5V supply and would like to use shielded cables. The signal lines will carry voltage pulses at some 100 kHz so don't need co-axial.Can anyone recommend a reasonably priced make or specification of cable that may be used as I am new to all this. It would be most convenient to have a single multicore cable.CheersIanstarfishprime.co.uk

author: KJDS
author_rank: Super Contributor
timestamp: March 02, 2014, 05:11:45 pm
content: The cheap way to do it is with some outdoor telephone cable, twisted pair rather than screened, but fit for use outdoors. eghttp://www.ebay.co.uk/itm/50M-BLACK-OUTDOOR-TELEPHONE-EXTENSION-MODEM-CABLE-WIRE-/230380410579?pt=UK_Computing_CablesConnectors_RL&hash=item35a3be16d3Alternatviely you could use a steel wire armoured (SWA) four core cable, eghttp://www.ebay.co.uk/itm/SWA-Cable-Per-Meter-4-core-SWA-Cable-4mm-4-core-/171025953286?pt=UK_BOI_Materials_Supplies_Electrical_ET&hash=item27d1f0f206Those were the first links I found on ebay, others are available. ...I'd be cautious about using anything that's not designed for outdoor use underground.

author: SeanB
author_rank: Super Contributor
timestamp: March 02, 2014, 05:39:24 pm
content: Underground rated Cat5 network cable, or if it is only going to be short term ( less than 5 years) regular network cable ( shielded or unshielded) inside a 20mm PVC electrical conduit will work. 4 pairs and you can use common network termination boxes at both ends and regular cabling inside. Just use large radius bends underground and place a pull wire in the conduit as you assemble it, or just use a fish tape to pull it through. Make sure you use PVC glue generously on all the joins and keep the open ends sealed from water ingress and it will be fine. If you think you need to expand later you can pull new cable through and not have to dig. If you are in a frost area bury below the frost line, or in other areas bury deeper than 30cm ( 1 foot) down in a narrow trench.
Advice on TVS Diode Selection for High-Frequency FPGA Protection - Page 1
Forum section: electronics / projects

author: Neitsab
author_rank: Newbie
timestamp: February 12, 2025, 11:53:43 am
content: I'm working on an FPGA-based fluence counter project (Z-turn Board V2 Xilinx XC7Z020) that requires designing an electronic board with three high-frequency input signals:3.3V BNC TTL input. 5V BNC TTL input that is converted to 3.3V TTL using a level shifter. NIM input at -0.8V that is converted to 3.3V TTL using a level shifter.I need to protect the FPGA—specifically, the outputs from the level shifters (which are at 3.3V/0V)—using TVS protection diodes or others protection. I need to protect my FPGA from Electrostatic Discharge (ESD). Given that these signals are high-frequency (in severeal Mhz like 10MHz) I know that I need a very low very low parasitic capacitance to avoid signal degradation.Which TVS diodes (or integrated multi-diode circuits) or others components are best suited for this application? What key parameters (stand-off voltage, breakdown voltage, clamping voltage, capacitance) I should focus on for protecting these signals?The maximum voltage of the FPGA pin input is here (Screenshot_1) : Zynq‐7000 SoC DC and AC Switching Characteristics

author: thinkfat
author_rank: Unknown
timestamp: February 12, 2025, 01:00:45 pm
content: 10 MHz doesn't seem to be a lot. I would think USB protection circuits.

author: aeg
author_rank: Regular Contributor
timestamp: February 13, 2025, 02:26:39 am
content: You only need ESD protection on connections to the outside world. If the connection between the level shifter and the FPGA is internal to your circuit, then there is no way for it to receive an ESD zap.As for protecting the level shifter input, a series resistor would be a good start.
Advice on where to add S-Video output lines to Betamax player? - Page 1
Forum section: electronics / projects

author: Orihalcon
author_rank: Contributor
timestamp: December 02, 2024, 10:23:03 pm
content: Hello all, I want to try "S-Video Output Modding" a Sony SL-HF900 Super Betamax player, but I need help determining where I'd need to actually tap luma and chroma for the mod (and if any other components need to be added such as 0.1uf capacitors to the chroma and luma lines).I've attached a truncated service manual that only shows information that should pertain to an S-Video mod. I can see several candidates of where you'd tap as the service manual does show various separated chroma and luma signals. The ones we are interested in are the "PB" chroma and luma levels as that is for "Playback". "REC" levels aren't useful here because that would be levels to record onto a tape and these days betamax is mainly used to capture video from rather than make new betamax recordings.Would love to try different suggestions and I'll report back if the S-Video mod was successful!

author: coromonadalix
author_rank: Super Contributor
timestamp: December 04, 2024, 02:40:30 am
content: you received answers on this forum i thinkhttps://www.digitalfaq.com/forum/vcr-repair/14789-betamax-video-mod.html

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 04, 2024, 03:04:56 am
content: If you're trying to archive videos, consider a mod to digitize the raw signals instead.https://github.com/oyvindln/vhs-decode

author: Orihalcon
author_rank: Contributor
timestamp: December 04, 2024, 10:19:07 pm
content: Nah, nothing useful in those replies. hence why I'm posting here where there's more likely to be an EE that is familiar with composite/S-Video circuit design. I feel like all the information needed to come up with the solution is present in that attached PDF, I just do not have the expertise to know how to hook it up exactly without harming the equipment or if additional components should be placed in line and why.

author: jh15
author_rank: Frequent Contributor
timestamp: December 04, 2024, 10:28:40 pm
content: An external comb filter? In some video displays, years ago, the comb filters did a great job internally. I wonder if there are external comb filters to split the luma and chroma signals.

author: Benta
author_rank: Super Contributor
timestamp: December 04, 2024, 10:58:31 pm
content: Quote from: Orihalcon on December 02, 2024, 10:23:03 pmCould you explain the rationale for this "mod"?In my experience, the S-Video output from VCRs is not as good as the normal CVBS, and my reconding/conversion devices often complain.S-Video is great when delivered directly from the source (eg, video cam), but inferior in other situations.
Advice pls for simplest 12V/5Ah bat. charger - Page 1
Forum section: electronics / projects

author: Chriss
author_rank: Frequent Contributor
timestamp: August 07, 2023, 11:51:55 am
content: Hi!I have to make a most simplest charger for a lead-acid 12V/5Ah battery.My idea is to use a regular switching mode power source 12V/2A this model: PSA-12/2H.In series with the battery I would put a res ~47Ohm/9W. This res should lower the current not to "burn" the battery.What do you think?I know and I'm familiar does this circuit is not a good charger but I need simple as possible.I'm not sure about the PSU, would this type of PSU make the job?Even if it is 12V rated?I know I should have a voltage around 14.xxV and I=5Ah/20...Any suggestion I would really appreciate.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 07, 2023, 12:04:59 pm
content: 12V floating seems too low.Lead-acid 12V batteries are to be charged at 14.4V top (exact value depends a little with the batt temperature), or floated at about 13.8V.

author: Chriss
author_rank: Frequent Contributor
timestamp: August 07, 2023, 12:08:27 pm
content: Would a DC to DC step up converter maybe help?

author: Psi
author_rank: Super Contributor
timestamp: August 07, 2023, 12:09:42 pm
content: Simplest option would be a 13.8V power supply. That is a common voltage for this exact reason. 13.8V is the float charge voltage for a 12V SLA.And an "inrush current limiter" in series. It's basically just a resistor but is low resistance at normal temperature and becomes high resistors if it gets hot.It's not the best option, but it is very simple.You might also want a diode in series, so the SLA cannot backfeed into the PSU when the charger is connected to the battery but not plugged in to the wall. Otherwise it will slowly drain the battery into the charger circuit.A better option for cheap but not too cheap is probably something from aliexpress for a few dollars. Like one of those DCDC converters that has both voltage and current regulation. Then you can set it for 13.8V and whatever amps makes sense and have it between your wall adaptor and the battery. Probably still want that diode though

author: Chriss
author_rank: Frequent Contributor
timestamp: August 07, 2023, 12:28:46 pm
content: Thank you guy's for your guck help.In the main time I found a really clean solution for me.I found a this charger with everything in it : TS-1012CThis will help me a lot.

author: Psi
author_rank: Super Contributor
timestamp: August 07, 2023, 01:41:00 pm
content: Quote from: Chriss on August 07, 2023, 12:28:46 pmI could be wrong, but TS-1012C looks like its for charging Lion cells not Lead Acid

author: tunk
author_rank: Super Contributor
timestamp: August 07, 2023, 01:53:49 pm
content: Many SMPSs use a TL431 plus voltage divider to set output voltage.You may be able to modify it to output e.g. 13.8V.A 47Ohm/9W resistor seems a bit on the high side.
Advice Re: Sourcing Driver for COB LED - Page 1
Forum section: electronics / projects

author: BangDroid
author_rank: Newbie
timestamp: March 17, 2024, 08:37:47 am
content: Hi everyone I am just wanting some advice for a driver for a 10W LED I have. I don't have any specs for the LED unfortunately other than 10W and the listing stated 12V, but I don't know what they means as a driver is constant current so the voltage will vary, I believe. It appears to have 9 chips inside if that's helpful in defining characteristics.I previously had a driver for this LED but it started to slowly blink like many chinesiums do, it's even potted in epoxy so I couldn't even dig it out to replace a cap.I bought a replacement LED driver after 2 attempts of sales being cancelled, it's been months of me trying to replace this LED driver. The previous one worked well for about 1 year before the blinking started.The new driver is extremely dim, it's barely useful, whereas the old driver would make the LED shine very bright and it needed a small heat sink.Attached images show the drivers, top is the old one that blinks, new one that's too dim is bottom. And the 10W LED (the illumination here is not from the driver, but a battery to show the LED chips inside)Would something like this be suitable (https://www.aliexpress.com/item/1005003660953855.html) the 8-12W variant?

author: MarkT
author_rank: Frequent Contributor
timestamp: March 17, 2024, 09:19:23 am
content: That's likely a 3x3 array of 1W dies, so about 10V and 1A, standard white 1W dies are about 3.2V 300mA, so perhaps use 12V supply and 2W 2.2ohm series resistor?Your old unit seems to be a 12V constant voltage supply without a series resistor - no wonder it cooked and failed, it would have been over-stressed due to high current. It probably cooked the LED dies too...The new unit is a 300mA constant-current supply - but your LED requires 1A or so, so its dim.So either 12V plus series resistor or 1A constant-current supply, not either of the one's you have...
Advice wanted on 200W+ main powered led driver idea - Page 1
Forum section: electronics / projects

author: Bendba
author_rank: Regular Contributor
timestamp: July 17, 2018, 12:33:43 pm
content: Hi,I have a heap of 10W led chips and am considering building a high power LED flood light powered from the main.I know there are plenty of very well designed and documented circuits out there.But this came to mind:Simply rectify the main, and inserting an inductor and Schottky diode to form a closed loop, allowing free wheeling when switching off the MOSFET...Hey! I reinvented the buck converter.Is there any particular reason not to use that simple of a circuit when driving power LEDs? Of course, you would want to add a current sensing/protection and eventually a temperature sensing.Yet in the few power LEDs I bought, they use much more complex circuits, even if there isn't always a main insulation. But despite the complex circuits, they still flicker?Thanks in advance for pointing to the obvious issue I am not seeing. :-P
Advise me on inductive position sensor IC's - Page 1
Forum section: electronics / projects

author: MrMetthew
author_rank: Regular Contributor
timestamp: March 05, 2018, 02:53:27 pm
content: Hi everyone,I was at embedded world trade fair in Germany last week. I was looking for some 2d/3d hall sensor IC's. But then I stumbled upon a company offering inductive position sensing IC's. This looks very promising to me because of little interference between sensors compared to magnetic sensors. I was just exploring the technology and wondered if any of you knew other companies that offer ic solutions for this. Any other insights on inductive position sensing versus magnetic/hal sensing are welcome!Thanks! Link to see the IC I was talking about:http://www.cambridgeic.com/spacer-ics/product-cam204-icAnother company that seems to offer this:https://www.idt.com/products/sensor-products/position-sensors

author: exmadscientist
author_rank: Frequent Contributor
timestamp: March 06, 2018, 03:36:50 am
content: TI also has their LDC1xxx range. They're very capable sensors, but finicky. If the environment is just right, you can get some impressive accuracy out of them. If the environment is not so good... well, your measurements will tell you a lot about said environment!One of the more interesting things is that there are two viable types of target: conductive materials and magnetizable materials. They have opposite effects on mutual inductance, and therefore on sensor reading. This can make for some interesting debugging.
Advise needed > lightning vs 7824 - Page 1
Forum section: electronics / projects

author: Bloch
author_rank: Unknown
timestamp: November 10, 2010, 06:16:06 pm
content: Hi AllThis is my first post here so be kind to meAt work I have this circut "24V power supply" see drawing.It have been built i many units with no problems.It powers some wind sensors there is very likely to get stiket by a lightning.My problem is that i would like to change it to a LM7824.I need a current limiter and need to make a new PCB and price / speed is always important.Pro.Cheaper time and partsCurent liniterSmaller spaceCon.Will it survive the lightning as well as the old tried circutAnd no i don't have the possibility to get it tested at a lab.

author: tecman
author_rank: Frequent Contributor
timestamp: November 10, 2010, 06:54:48 pm
content: Your existing design has the merits of being robust and inexpensive. The 7824 will give you tighter regulation and current limiting (sort of). It is not true current limiting, but it limits based on thermal, so you will reach some steady state current on an overload. The other caution is that the 7824 have a max Vin of 40 volts, which could be an issue with surges that might occur with lightning. You could add parts to mitigate the surge sensitivity, but the cost will go up.I would be tempted to stay with what you have and just ass a polyfuse (PTC fuse) to the DC line feeding the transistor. Again thermal protection that will limit current. Simple and robust.paul

author: Simon
author_rank: Unknown
timestamp: November 10, 2010, 09:56:35 pm
content: surely R1 needs to come from the positive supply not negative, like that the transistor will just not pass current

author: oPossum
author_rank: Super Contributor
timestamp: November 10, 2010, 11:52:09 pm
content: Current limiting could be easily added to the existing design. A TVS (transient voltage suppressor) may improve robustness.

author: Bloch
author_rank: Unknown
timestamp: November 11, 2010, 06:38:43 am
content: Quote from: SimonThanks. Yes i did miss i a wire.Quote from: tecmanThanks. It is also my gut feeling that the 7824 is not robust enough.I have tried the polyfuse solution.The circuit powers 4 wind sensors.On installation they did an error (shorted) one sensor. Then they did see that they did it wrong. The polyfuse was so hot that the consumption from the 4 sensors did keep the polyfuse hotand newer got reset before they changed the PCB.So the polyfuse is not a fix here.Quote from: oPossumThanks.Why did i not think on that ? I am surely getting a little rusty.I was thinking of adding a current limiter. But thinking in the direction of an extra power transistor+current sensor.Thanks this must be the answer to my "little" problem. Only 3 cheap/easy components more.
Advises on a position sensor detached for the mover - Page 1
Forum section: electronics / projects

author: Yaroooo
author_rank: Regular Contributor
timestamp: October 16, 2019, 11:32:00 am
content: Hi all,I'm looking for a good solution to a problem. I've a moving mechanical part, without cables or anything, that performs a linear motion. I'd like to know position of this mechanical part, without adding anything mechanical to actual system (i.e. rotative encoder or encoder on moving part). What I can do is to add something nearby it.I've excluded things like ToF or vision systems and perform some research. I've found some systems that use, on linear motion, magnetic encoders with sensor on stator and a ferromagnetic material on mover. What I'm aware is that system doesn't use single sensors due very high accuracy.Do someone have idea on what kind of system they use?I'd like a start point where looking for on my researches.

author: soldar
author_rank: Super Contributor
timestamp: October 16, 2019, 11:37:09 am
content: Quote from: Yaroooo on October 16, 2019, 11:32:00 amWhat kind of precision? How many bits?What is the total travel distance?

author: Yaroooo
author_rank: Regular Contributor
timestamp: October 16, 2019, 01:38:07 pm
content: System that I saw is iTRACK from rockwel that provide a precision of +/-0.5mm. This system use a magnet on it's carriage.I'd like a +/-1mm precision within 1.5/2meters. It will be too expensive to place a sensor each 1mm. I suppose they use something like a hall sensor with a range of some mm and than interpolate reading of two or more sensor to get absolute position?I'd like something similar to my system; I can put a magnet on it, but what I'll need to use to know the position of my part? Is there something common and used commercially?

author: senso
author_rank: Frequent Contributor
timestamp: October 16, 2019, 02:04:51 pm
content: Use a laser range finder, point at part, done..If its an industrial application, grab a distance sensor from banner with IOLink and go to town, any laser sensor from Contrinex that talks IOLink, so you can read back the actual position and not just some on/off setpoint cut-off.
ADXL1005 output stability vs. eval-board RC filter. What's the real "don't cross - Page 1
Forum section: electronics / projects

author: jimmystar889
author_rank: Newbie
timestamp: October 06, 2025, 11:03:20 pm
content: I’m experimenting with an ADXL1005 accelerometer (https://www.analog.com/media/en/technical-documentation/data-sheets/adxl1005.pdf) and trying to reconcile its output-load stability note with the EVAL-ADXL1005Z schematic filter.Datasheet rule:“Output amplifier is stable while driving capacitive loads up to 100 pF directly (no series resistor).”“For capacitive loads > 100 pF, add a series resistor ≥ 8 kΩ.”“Output capacitance must not exceed 22 nF.”Eval board filter:Vout ── R1 ──●── R2 ──●──> to rest of chain│ │C1 C2│ │GND GNDWith R1 = 487 Ω, R2 = 976 Ω, C1 = C2 = 3.9 nF.So there are caps on the order of nF, but they're behind resistors, not tied directly to Vout.So what I understand (and where I'm stuck)For a single branch of the filter:The equivalent capacitance at ω:Ceq​(ω)​=C / (1+(ωCR_s​)^2)Load angle ∠Z = -arctan(1/(ωCR_2))I can then compute Ceq and load angle:At 70kHz (close to the datasheet's small-signal output bandwidth)Ceq = 1.65 nF and ∠Z = -29°So C_eq is much larger tthan 100pF, but the phase angle is far from -90° because the series resistors add a substantial real part. This seems to be why the eval network is stable in practice. (Maybe?)Q1 (Main): The datasheet’s 100 pF rule is clearly for a capacitor physically tied to Vout. When caps sit behind hundreds of ohms (like R1/R2 above), what is the recommended stability check on the load as “seen” at the pin?Is a criterion like “∠Z > -45°" at some check frequency fcf_cfc​ (say 70–100 kHz) a reasonable rule of thumb?Q2 (Finding the “break point”):Thought experiment: let R1 → 0 Ω with the filter above. By the Intermediate Value Theorem, there must be some R1 where the load becomes “too capacitive” and stability is lost.How do I compute that boundary from the datasheet info?Does anyone have a better phase-margin-aware criterion ADI would implicitly be using?I'm aware that I may be overengineering this a ton, and can just use the values from the datasheet, but I'd really like to learn how all of these more advanced concepts work. Thanks for the help!

author: mtwieg
author_rank: Frequent Contributor
timestamp: October 06, 2025, 11:59:11 pm
content: So strictly speaking, you're violating the datasheet's recommendation by having a capacitance >100pF without a series resistance of at least 8kohm.But then look at figure 23 of the datasheet, where they have a two-stage RC filter, and the first stage has R=500ohm and C=10nF, which also violates their recommendation.I would bet that the most important thing is that the load impedance on the output amplifier not be capacitive near its crossover frequency (around 70kHz).
Aerosol based switch cleaners - Page 1
Forum section: electronics / projects

author: Richard Head
author_rank: Frequent Contributor
timestamp: February 18, 2014, 12:27:46 pm
content: Does anyone know exactly what is in the aerosol based switch cleaners.The substance looks like a kind of oil and I wouldn't want to spay any oil into a switch of scratchy potentiometer. But it does work.Also, what about the stuff used to displace water in car distributor caps?Is it the same stuff?Dick

author: kolonelkadat
author_rank: Regular Contributor
timestamp: February 18, 2014, 03:25:58 pm
content: if i were to hazard a guess id say they are a combination of something like the following: (varying of course by application requirements (eg flammability, plastic safety))mostlypetroleum naphtha, heavy alkylate (mineral spirits)with a bit of1,1,1,2-tetrafluoroethaneand a dab ofpolyphenyl etherother options would be a mixture of 1,1,1,2-tetrafluoroethane, butane,pentane, and hexaneeta: I had a bit of a poke around and the deoxit line of contact cleaners appears to be mostly either 1,1-difluoroethane or 1,1,1,3,3-pentaflouropropane. then about 5-10% of whatever their "deoxit" chemical is.theres probably 100 more different solutions than what ive put here. Like anything else I guess you will have to look at the data sheets

author: KDC
author_rank: Contributor
timestamp: February 19, 2014, 02:39:29 am
content: Yeah, it really depends on the product and what it's intended usage.The one we commonly at work, one's plastic safe and uses 1,1,1,2-tetrafluoroethane, dichloroethylene and isopropanol.Do a MSDS search for the product you have.

author: Richard Head
author_rank: Frequent Contributor
timestamp: February 19, 2014, 06:19:19 am
content: Thank you for the input.I expect that they work simply as a degreaser.How on earth they manage to "repair" a worn carbon track on a pot still eludes me though.Perhaps the carbon track isn't in fact worn and is just dirty.ThanksDick
affordable analog multipliers ? - Page 1
Forum section: electronics / projects

author: snarkysparky
author_rank: Frequent Contributor
timestamp: November 15, 2017, 04:00:56 pm
content: Looking for analog multiplier for a project. The cheapest I can find is AD633 at $10.00.Anyone know of something closer to the $3.00 - 4.00 region in low quantities.

author: 001
author_rank: Super Contributor
timestamp: November 15, 2017, 04:05:25 pm
content: Check this treadhttps://www.eevblog.com/forum/projects/poor-mans-analog-multiplier/
Affordable Desoldering Vaccum Station Build With Pictures as Requested - Page 1
Forum section: electronics / projects

author: EmeraldPawn
author_rank: Newbie
timestamp: November 12, 2015, 03:13:56 pm
content: My shop needed a good desoldering station but I didn't want to shell out the kind of money they want for one of those units. I built my own that works every bit as good for less than $100.00 I bought the inexpensive Yihua 936B 50W 110V soldering kit online. This is the analog type controller, 4 wire heating element type. I replaced the five pin soldering gun connector base with a six pin type. I added a small 12V connector jack in the back of the unit which will connect to the vacuum pump unit. I had bought the Tenma Desoldering Gun number 72-6406 that is a replacement gun for one of their stations. I chose this type.model as it has a tinned soldering tip, the others usually require flux to desolder, this doesn't. For the vacuum pump I used the Karlsson Robotics Vacuum Pump-12V which has 0-16" vacuum which is more than enough. The trigger of the desoldering gun is basically a series circuit to the 12V connector you installed so when you press the trigger the pump activates. The only caveat is the Tenma gun elements resistance is less than the original pencil iron (16.4 Ohms) so the controller temp is off a tad. That is no big deal as you are desoldering and need the higher temps. This rig was a good easy and money saving project.

author: dan3460
author_rank: Frequent Contributor
timestamp: November 12, 2015, 07:21:10 pm
content: Could you post pictures of it. I have been looking for a de-soldering gun and for me this is only a hobby so shelling out $$$ hurts.

author: EmeraldPawn
author_rank: Newbie
timestamp: November 13, 2015, 04:31:13 pm
content: Hello Dan, thanks for your interest in my desoldering gun project. I have posted the pictures you request.

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 14, 2015, 10:11:51 am
content: Fantastic, thanks for sharing!
Aftermarket POE module device upgrade not working - Page 1
Forum section: electronics / projects

author: 24602
author_rank: Contributor
timestamp: March 03, 2024, 02:04:12 pm
content: Hi AllGot a product that I purchased that didn't have the POE option installed so I would like it to have POE.started with measuring the rail voltage (5V) and purchased this 5V RT5400 POE modulehttps://www.aliexpress.com/item/1005006181940528.html?spm=a2g0o.order_list.order_list_main.17.4d91180264P9zPI have done this to a similar product made by a different manufacture and it worked perfectlyPhotos attached of product trying to add module tooSoldered in the POE module and the device does nothing.Directly powering the 5V rail results in a dead short across the railDesoldered the output side of the module and measured the output pins of the POE module and nothing 0V.The switch doesn't detect the device in any way either.Have swapped module with another oneHave tested ethernet with the other manufactures device with the same POE module and it worksHave tried soldering different resistors on the pads on the input side haven't found a value that would do anythingAny ideas of getting this to work will be great thanks
Again but somewhat different - what's inside of this electric fly swatter? - Page 1
Forum section: electronics / projects

author: inevitableavoidance
author_rank: Contributor
timestamp: November 23, 2017, 02:19:32 pm
content: I came across a video of someone that hacked their electric fly swatter, as I've seen a dozen times, but this one's rather mental. Does anyone know what's inside of this thing?Thank's in advance!

author: Audioguru
author_rank: Super Contributor
timestamp: November 23, 2017, 02:40:43 pm
content: It looks like it has its power boosted a lot. Then its battery will not make many zaps before it is dead.

author: tecman
author_rank: Frequent Contributor
timestamp: November 24, 2017, 02:54:48 am
content: They have a blocking oscillator on the primary of a small transformer. Secondary is configured to charge a capacitor with a diode using the flyback.paul
AGFA PCR II design reuse question - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: July 23, 2016, 11:19:16 am
content: HelloI post this topic here since I dont really have a repair question although the question is about a old piece of equipment.I have a AGFA PCR IIhttp://www.promarketinc.com/pdf/agfapcriiplus-usersguide.pdfhttp://www.recycledgoods.com/agfa-pcr-ii-pcr-ii-film-recorder.htmlhttp://charlescoughlin.com/ebay/110328_agfa/agfa.htmlAs far as I could gather it was used to transfer digital images to film.My question. If you can transfer digital images to a film could something like this potentially be used to make a PCB using photo chemical etching?The only optics that I can see inside is a CRT looking device aimed at a red, green and blue filter wheel. No lenses. On the other side of the filters there is supposed to be a camera. The camera lens focus the image on a film. You can potentially have you own lens and put the small pcb at the film location.And I just realized that such a thing might not not work to etch pcbs because the light will scatter back from the substrate but on the other hand if you use black surface inside the box it should absorb the scattered light and prevent light to be bounced back to the pcb a second time.What do you guys think. Could one use a machine like this to etch pcb with very fine detail?

author: kony
author_rank: Regular Contributor
timestamp: July 23, 2016, 01:01:42 pm
content: Nope, not useable for PCBs. Find yourself DTP studio nearby, they will happily make you laser exposed Ag film in resolution over 4800DPI for peanuts (I pay one nice "Thank You" or 1$ per A4 sheet of exposed and developed film). Only thing that differs from proffesional PCB manufacturing film matrices is the base used - don't rely on its longterm dimensional stability, otherwise it is just about the same.

author: Cicada
author_rank: Regular Contributor
timestamp: July 25, 2016, 10:16:02 am
content: Ok. I think I will then just remove the High Voltage power supply. It is the only re-usable component in it. Doubt it if I can find a use for the CRT display in it. It looks funny though. Completely white on the front face.

author: helius
author_rank: Super Contributor
timestamp: July 25, 2016, 12:11:54 pm
content: These film recorders use white phosphor CRTs optimized for spot size. Very different from any CRT used for viewing.I don't think the light level is enough to expose low-sensitivity etch resist films.

author: jackcolbran@mail.com
author_rank: Newbie
timestamp: February 04, 2018, 01:23:59 pm
content: Hello,Have you still got the Agfa PCR II? Is it for sale?Many thanks,Jack
Agilent 1602B Scope flash dump  - Page 1
Forum section: electronics / projects

author: resoto
author_rank: Newbie
timestamp: August 24, 2023, 05:31:16 am
content: I'm trying to rescue my handheld Agilent Scope/Meter that died during software update. Actually my flash ic M29DW323DB is completly blank. I tried to flash firmware from manufacturer site directly to flash ic but it didn't help.So if someone own this device I would be thankful for flash dump.
Agilent 33250a worth recapping? - Page 1
Forum section: electronics / projects

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: March 18, 2023, 01:41:58 pm
content: Hi all,I bought a 33250a listed for parts for 200usd, the problem where the rams and the PSU, both of the problem have been resolved.I was thinking of recapping the whole device, both psu and instrument board, buying high quality electrolytes and tantalum smd's, what I wonder is if it makes sense changing also the smd tantalums. The board was buillt in 2005 thus is 18yrs old.The total cost of recapping is 70 eur, is it worth it for you?

author: Shay
author_rank: Regular Contributor
timestamp: March 18, 2023, 04:16:09 pm
content: If it was for personal use and it works good, I'd just (maybe) replace the tantalums as those can fail by a short, but replacing the electrolytes wouldn't hurt either.

author: anotherlin
author_rank: Frequent Contributor
timestamp: March 20, 2023, 10:52:52 pm
content: Quote from: NiaDebesis on March 18, 2023, 01:41:58 pmIf that ends up being your "go-to" signal generator, and you end up having 18 trouble free years of usage, then that would be a good investment.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 21, 2023, 03:11:04 am
content: 18 years? Hah, I wouldn't touch it. If the tants were properly spec'd, and I'm sure they were, I'd especially not touch those. You'll just put more wear and tear on the board that it doesn't need. If something breaks, fix it, otherwise, leave it alone. They used good quality parts and unless you see some visual problem or it doesn't meet specs, you'll do more harm than good. I've got similar Agilent equipment at work that's been running 24/7 for 20 years with no problems at all.
Agilent 54831M Oscilloscope Single Trigger Question/Problem - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: October 30, 2022, 11:35:01 pm
content: I have a current probe (Micsig current probe) connected to my Agilent 54831M Oscilloscope and wanted to capture a single trigger maximum startup wave (i.e. current). For whatever reason, the scope will not trigger, but it works perfectly fine with auto trigger.Thinking maybe it was user setup error, I used another oscilloscope (different model) and was able to catch a single trigger.Does anyone know if any odd settings are needed to capture a single trigger on a digital scope? I'm hoping the scope isn't broken, however, it has passed all the self tests and calibration, along with not experiencing any other issues with it until now.

author: bostonman
author_rank: Super Contributor
timestamp: November 01, 2022, 12:24:27 am
content: Think I managed to figure out what was going on.After pushing various combination of buttons, I figured out to select 'single' trigger after selecting my V/div, time base, and trigger point, push 'clear' display, and then 'run'.Once I did this and tweaked the settings, I managed to capture the same waveform as the other model oscilloscope.
Agilent Back to Basics measurement/theory DVD - Page 1
Forum section: electronics / projects

author: marshallh
author_rank: Unknown
timestamp: November 26, 2013, 01:49:25 am
content: Promo data DVD with a collection of appnotes and webcasts/slide shows.These are publicly available documents.http://retroactive.be/B2B.rar613MB ISOSmall capture of the appnote section:

author: BravoV
author_rank: Super Contributor
timestamp: November 26, 2013, 01:51:24 am
content: Thanks, leeching started.

author: nanofrog
author_rank: Super Contributor
timestamp: November 26, 2013, 04:49:16 am
content: Just got an email for a free copy of this from Agilent today.
Agilent E363xA DAC Circuit explaination? - Page 1
Forum section: electronics / projects

author: Magnethicc
author_rank: Contributor
timestamp: October 11, 2025, 07:37:27 pm
content: Hi everyone,I am researching the Agilent E363xA power supply and came across their Digital-Analog Converter circuit and was wondering if anyone could help shed light on the operation of this circuit?I am kinda lost trying to understand what is going on and how they generate the references for the CV & CC loops.My guess is they use the 74HC4051 to choose (by using the 74HC4094 parallel-out data, kinda like a GPIO expander) which OP-AMP will be connected to the AD1851, then they set the relevant output voltage of the DAC to the desired level of CC/CV_REF they want. I am just not sure if this is correct or not.

author: free_electron
author_rank: Super Contributor
timestamp: October 11, 2025, 07:58:48 pm
content: that is a scanning DAC system. The opamps are sample and hold circuits. The 4051 is an analog multiplexer.The load one value in the dac (U12) , select the channel where they want to send that value using the ABC inputs of the 4051 and then pulse the INHIBIT line of the 4051. The moment they pulse that isngal the dac output is essentially connected through the 215 ohm resistor and charges the 0.22uf capacitor of the selected channel./ The TL074 is nothing but a buffer opamp. since it has JFET inputs it does not form a load for the capacitor.They scan the channels in a loop. If you attach a scope probe to Pin 9 or 10 of the DAC you will see a staircase waveform where each step represents the value of a channel.This saves them 7 DACs... they can use one and some cheap opamps. Many multichannel DAC's are internally built like that. Back in the day when these machines were deigned such dacs did not exist. That AD1851 is pretty pricey ... it is a 16 bit Pulse code modulation DAC originally intended for Audio. Back then 16 bit DAC were a rarity. Being a PCM system it can be made perfectly linear

author: Magnethicc
author_rank: Contributor
timestamp: October 12, 2025, 05:22:54 am
content: That is great explanation, thank you very much!Do you know if in todays world, this solution is viable or there are better solutions to save up on DACs?
Agilent IC Chip Inside Scope - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: March 19, 2021, 02:10:11 am
content: Long shot, but I'm working on an Agilent 54831M scope and came across a section of the circuit that's different when comparing the two good channels to the two bad channels.The two bad channels measure nearly identical to each other while the two good channels measure nearly identical to each other. I've traced the circuit and drew what I feel is a correct layout, however, it doesn't make any sense.I've looked for information about the IC which is 1NB7-8477, but haven't found anything except it's an amplifier and some being sold on Ebay. Does anyone know if any information exists about this?Attached is the circuit I've drawn that's essentially the circuit in question. R1 and C1 are two surface mount components that are not marked. I'm reluctant to remove the good ones and measure them, but I feel it may come down to that. C2, C3, and Z1 are also unmarked, but, if you look at my notes at the bottom, those points measure fine. Also, 'good' and 'bad' are referring to the good channels (Ch1 and C4) and the bad channels (Ch3 and Ch4).
agilent power supply  - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: April 28, 2015, 04:17:39 pm
content: HI guys,I have post a part of the circuit from the agilent E3634 ser power supply. please tell me what is the P channel mosfet Q7 is doing here.

author: prasimix
author_rank: Unknown
timestamp: April 28, 2015, 05:16:58 pm
content: I asked the same question some time ago (checkhere). From current perspective I'd like to say that is possibly added as a simple"down-programmer".

author: dom0
author_rank: Super Contributor
timestamp: April 28, 2015, 06:38:09 pm
content: It is. Re. it's location is before the current shunt so as to not measure this quiescent current. This current serves some different purposes, including fast down-programming with light loads and better regulation with light loads, or when a heavy load is disconnected.

author: sorin
author_rank: Frequent Contributor
timestamp: April 29, 2015, 10:14:17 pm
content: I think that is for drawing constant current,the system will not stable with output current =0.

author: bson
author_rank: Unknown
timestamp: April 30, 2015, 06:55:41 am
content: Looks like a protective feature against reverse polarities on the terminals. Like an inductive load, or a battery attached backwards, or the effects of a blown power rail cap.

author: prasimix
author_rank: Unknown
timestamp: April 30, 2015, 07:07:08 am
content: Quote from: bson on April 30, 2015, 06:55:41 amIt employs reverse connected diodes for that...
agilent power supply - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: January 05, 2014, 07:50:57 am
content: I have attached the agilent power supply service manual from page 121 to 125 herewith. I need some clarification , please explain1 . In page No: 121 the power mosfet is drive by a source V2 from the page No:122 via a pnp transistor. I have build the part that provide V2 and it provide around 14.9V which is tied to mosfet gate to drive it. Since it provide fixed voltage of 14.9V how the mosfet is drive for output above 15V since the output is source pin of the mosfet, since the gate voltage relative to mosfet sourve is zero.2 . what that pmos is Q11 is doing in the schematic.please somebody help.

author: sync
author_rank: Frequent Contributor
timestamp: January 05, 2014, 03:07:29 pm
content: The bias supply ground is connected to the positive output side of the power supply. See attachment. So V2 is always a positive voltage to the MOS-FET source independent from the output voltage.
Agilent PSA globetrotter option hacks? - Page 1
Forum section: electronics / projects

author: nexus
author_rank: Regular Contributor
timestamp: January 01, 2022, 07:26:30 am
content: Hi all,Wondering if anyone has had any experience/luck trying to get memory dumps of license keys off of older Agilent PSA series spectrum analyzers. This generation analyzer is obsoleted by the OEM; Keysight won't sell upgrades anymore. So not like I could buy it legit if I wanted to.I'm thinking of buying the upgrade hardware as I've found the appropriate boards on ebay. Once installed as per the retrofit manual, I need to enter the license key accompanying that option and my host ID, like lots of HP/Agilent gear from the time. I believe it runs some sort of Unix as the OS and uses Globetrotter for license key management.Any info or tips would be appreciated.Cheers

author: zrq
author_rank: Frequent Contributor
timestamp: January 02, 2022, 03:16:49 pm
content: Try looking around in the T&M board, I have seen posts about hacking SAs with similar software stack. From a generic point of view, the FlexLM (now FlexNet) licensing is usually weak and can be keygened (for short keys) or patched (for ECC).

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 02, 2022, 04:51:17 pm
content: Send me your HOSTID and an option you want and I will give it a try.

author: nexus
author_rank: Regular Contributor
timestamp: January 02, 2022, 08:58:22 pm
content: Quote from: zrq on January 02, 2022, 03:16:49 pmI did take a look through the T&M board; there are a few suggestions to attack FlexLM. However, I have not been able to find any keygens or other resources to attempt it myself.Also attached pic of what license keys should look like on the PSA.

author: nexus
author_rank: Regular Contributor
timestamp: January 02, 2022, 09:14:30 pm
content: Quote from: PA0PBZ on January 02, 2022, 04:51:17 pmPM sent. Thank you!

author: nexus
author_rank: Regular Contributor
timestamp: January 03, 2022, 07:13:23 pm
content: Just enjoyed a very good read here:https://www.eevblog.com/forum/testgear/enabling-options-on-agilent-esa-series-e4402b-e4404b-e4405b-e4407b/225/Looks like it has been done on older ESA E44XX series analyzers, which run the same type of OS and FlexLM as the PSA E444X. So it definitely is possible with the PSA; not sure if things like "Vendor Name" or the seeds are unique/different for the PSA.

author: zrq
author_rank: Frequent Contributor
timestamp: January 04, 2022, 05:59:00 pm
content: Ah, good old flexlm 12 digits sign. If you can get in touch with the firmware files on your computer and do not bother peeking into some illegal websites, the way of finding out the seed and vendor name is well documented.
Agilent/Keysight U8903A Audio Analyzer teardown and repair attempt - Page 1
Forum section: electronics / projects

author: nexus
author_rank: Regular Contributor
timestamp: May 13, 2024, 11:13:39 pm
content: Hi all,Another video. This one is a teardown/repair attempt of a Agilent/Keysight U8903A Audio Analyzer. This instrument was sent to Keysight to repair physical damage, when it was also discovered that the analyzer portion of the instrument was not working properly.In this video, we take a look at the measurement report and replicate the error on the bench. We also examine the instrument at a closer level and make measurements to begin diagnosing where the problem could be. We then replace several key components in the audio analyzer signal path, but are ultimately unable to resolve the issue with these initial repair attempts.We conclude with some remarks on how the repair could be continued with the proper resources. If there is a possibility for further repairs to be made, a follow up video will be posted.Enjoy:

author: srb1954
author_rank: Super Contributor
timestamp: May 14, 2024, 01:03:17 am
content: Makes you wonder about the competence of the firmware engineers at Keysight if they write S/W that outputs such implausible values such as Tera volt readings or attenuation readings of -700dB.

author: nexus
author_rank: Regular Contributor
timestamp: May 17, 2024, 05:24:55 pm
content: It is strange how these insane readings do not register as errors. The unit also passes self test as well.I am beginning to suspect that the embedded DRAM could be a culprit as well. A friend suggested heating/cooling memory while running the unit to see if error condition changes.I ordered all DRAM used on the board, might just replace outright and see what happens.