hybridfree/eevblog-posts huggingface dataset:
Fuse ratings?! - Page 1
Forum section: electronics / projects

author: V_King
author_rank: Regular Contributor
timestamp: December 02, 2021, 11:35:14 am
content: Hello, sorry if it is a wrong section, not really sure where would this go.I am wiring up MeanWell TDR240-24 PSUs and need to pickup the input fuses. The manual recommends either slow blow 4A cartridge fuses or C16/D16 miniature circuit breakers. That is a lot of difference in current rating for a 0.69A input current protection. Or am I not understanding something?Screen dump from the MeanWell manual is in the attachment.Thanks

author: Alti
author_rank: Frequent Contributor
timestamp: December 02, 2021, 12:19:37 pm
content: Quote

author: Zero999
author_rank: Super Contributor
timestamp: December 02, 2021, 03:22:25 pm
content: Yes, this is normal. The power supply will draw a large current surge, when initially powered, which would blow a lower rated fuse.The fuse is only there to protect against fire. If it blows, it's highly likely it's because the power supply has failed and will require replacement.

author: Alti
author_rank: Frequent Contributor
timestamp: December 02, 2021, 11:03:36 pm
content: Quote from: V_King on December 02, 2021, 11:35:14 amThe circuit breakers are there to protect wiring, not the PSU, and this number of units guarantees nuisance-free operation on power-on. OTOH the fuse is for limiting damages inside of the unit in case of internal mishaps. This is not one or the other.The D16 might not trip below 320A so additional fusing highly recommended. But C16 is for <80A currents so I am guessing that 19 units won't trip it on startup. That is about 4A per single unit which does not make much sense with T4A fuse as it assumes no inrush - for such inrush-free loads there are IEC60127-2/1 fuses which are 3x faster than what they recommend.

author: TheMG
author_rank: Frequent Contributor
timestamp: December 03, 2021, 04:09:51 pm
content: It's not entirely clear but I don't think it's one or the other. What they are recommending, I think, is a fuse for each individual power supply.The number of units per circuit breaker is just for your reference, and is a maximum number of power supplies you can feed from each type of breaker in order to avoid nuisance trips from the inrush current on power up. In other words, up to 19 of these power supplies can be powered from a single 16 amp C or D curve breaker.

author: V_King
author_rank: Regular Contributor
timestamp: December 06, 2021, 11:28:32 am
content: Thanks for all the advise, both fuses it then. As comprehensive as some manuals are, I found fusing sections are always very brief, leading to some misunderstandings!
Fuses - Page 1
Forum section: electronics / projects

author: rockbassist90
author_rank: Contributor
timestamp: September 23, 2014, 01:55:33 pm
content: I have a general question on fuses...I was looking for an SMD style Fuse of 6A...if I were not able to find this sized fuse, wouldn't putting a 1A and 5A in series with one another give the equivalent of a 6A?What would another solution be to this?Thank You in advance.

author: mariush
author_rank: Super Contributor
timestamp: September 23, 2014, 02:04:41 pm
content: No, that doesn't work.Think of the current rating of a fuse like the diameter of a pipe in which water (current) flows. If the water flow is too strong the smallest diameter pipe cracks/breaks and water no longer flows through the pipe.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: September 23, 2014, 02:17:10 pm
content: Remember, the current is the same for series connected components. 6 amperes would flow through the 1 ampere fuse and the 5 ampere fuse, until the 1 ampere fuse blew from having too much current flowing through it.Theoretically, if you had fuses with exactly the correct characteristics, you could put a 1 ampere and a 5 ampere fuse in parallel. 5 amperes would flow through the 5 ampere fuse, and 1 ampere would flow through the 1 ampere fuse. However, this is impossible in practice and wouldneverhappen.Usually, you'd use the next higher fuse size and be sure your other components (including wiring, circuit traces, etc.) could handle that amount of current.
Fuses in series and something else? - Page 1
Forum section: electronics / projects

author: gooseEL34
author_rank: Regular Contributor
timestamp: June 27, 2016, 11:33:51 pm
content: Check the schematic attached. It is from a vacuum tube guitar amplifier. Fuse one is a 3A fast blow that is mounted in a chassis mount fuse holder. The 5A is a fast blow mounted to the pcb. From that fuse you go directly into the AC transformer. My questions:1. What is the fuse in the dotted box that is third in the line? I do not see a corresponding component. Is it something internal inside the AC transformer ??2. Why would someone design an amp with 3 fuses in series?3. Is there a chance the on of switch is fused internally and this is a schematic mistake?Thanks

author: helius
author_rank: Super Contributor
timestamp: June 28, 2016, 12:13:54 am
content: There is no technical purpose to having more than one fuse in series, unless the power cord is non-polarized (in which case, fusing both wires has some use when the primary transformer isolation goes short). But you should consider who the product customer is: if it is someone stupid enough to defeat the fuse by stuffing aluminum foil around it, then having an internal fail-safe with a higher rating may be good insurance.Switches normally do not have internal fuses, but combined switch/inlets often do. Things like this:

author: Pack34
author_rank: Frequent Contributor
timestamp: June 28, 2016, 12:27:13 am
content: Quote from: helius on June 28, 2016, 12:13:54 amI've never done it, but wouldn't one potential reason be to have a fast-blow and a slow-blow? For example, a fast-blow 5A fuse that will immediately fail when exceeded and a slow-blow 3A fuse that could sustain a current over 3A for a couple minutes at a time?

author: Ian.M
author_rank: Super Contributor
timestamp: June 28, 2016, 12:32:36 am
content: Fuse 3 is a thermal fuse - the clue is the 157 deg C temperature rating. It is almost certainly buried inside the transformer in intimate contact with the primary winding and is there to cut the power if the transformer overheats due to being persistently overloaded.Regarding the series fuses, with one concealed on the PCB, well that's just about the minimum to make it reasonably bass player and roadie proof - the designer anticipated some a===hole substituting a chunk of 1/4 UNC bolt for the externally accessible fuse!The limit on the current carrying capacity of a 1/4" steel bolt 'fuse' is the wires desoldering themselves from the fuseholder contacts due to resistance heating, or at least that's what a friend who used one for an emergency field expedient repair of an Army radio told me. . . .

author: Neilm
author_rank: Super Contributor
timestamp: June 28, 2016, 06:29:41 pm
content: I have seen fuses in series were the internal fuse was used by the design engineer to disable part of the system. It was left in to allow this part of the system to fail but allow the rest (supplied from before the fuse) to function.The other possibility is that the PCB with the second fuse came from an existing system that was not re-engineered to remove it.
Fuses & Overvoltage protection in low-voltage - Page 1
Forum section: electronics / projects

author: Diablo2813
author_rank: Newbie
timestamp: May 13, 2019, 03:26:26 pm
content: Hello,I'm sizing a fuse that could handle a surge from IEC 61000-4 5 without breaking.4kV/12ohm 330A peak over linear 1.2us rising and 100us falling5x repeat every 1sI'm looking for information about exceeding maximum voltage and interrupting rating current in this case.I already read this documents :https://www.nh-hh-recycling.de/id-1995-icefa-ilmenau.html?file=files/swissy/Downloads/ICEFA%2040%20Jahre/1995%20Ilmenau/Coordination%20of%20fuses%20and%20overvoltage%20protection%20devices%20in%20low-voltage%20mains.pdfhttps://www.littelfuse.com/~/media/electronics/application_guides/littelfuse_fuseology_application_guide.pdf.pdfThanks in advanceBenjamin
Fuses - Page 1
Forum section: electronics / projects

author: croberts
author_rank: Regular Contributor
timestamp: April 04, 2013, 02:49:56 pm
content: Hello AllThis is more of an FYI than anything else. Recently I referred a forum member to my topichttps://www.eevblog.com/forum/projects/bidirectional-current-monitor-fits-anl-fuse-holder/. This is a design I'm testing for a current monitor that installs in an ANL fuse holder that uses an ATO Style fuse. I also use ATO fuses in the power distribution box for my solar powered lighting system. They responded with a warning about melting ATO fuses based on a youtube video they had seen. This of course concerned me so I wrote to Digikey and asked them to contact Littlefuse for a comment. Below is my inquiry to Digikey and comments from Littlefuse. Since fuses are a part of a lot of designs and the application of fuses apparently (according to Littlefuse) misunderstood by many designers I thought you might find this useful. All the best!My inquiry to Digikey Technical Support"I am using ATO Style automotive fuses in a 12VDC solar powered LED lighting system in my home. I have ordered 15A and 40A fuses from you made by Littlefuse. I participate in an electronics forum at eevblog.com and a member recently referred me to a youtube video warning that these fuses can get hot and melt without blowing if operated for a prolonged period of time near their rated current (no specific fuse manufacturer was mentioned). Naturally I am very concerned about this and wondered if you would contact Littlefuse and find out if this can happen with their ATO fuses and are they safe to use in my application."Comment From Littlefuse Apps Engineer"A note of my own, it is recommended that the fuse be operated at no more than 75% of the nominal current rating, this will assure the fuse will do its job and not melt or open prematurely. Like the statement below from one of the engineers at Littelfuse that for the fuse to open properly the circuit must be able to withstand a 2X fault current. Here is a link to some details around choosing a fuse you can share with the customer. Heat also can affect the fuse as well."www.digikey.com/Web%20Export/Supplier%20Content/Littelfuse_18/PDF/LF_IntroductiontoCircuitProtection.pdfComment from the Littlefuse Product Manager for this product line"This is a point that many designers fail to understand. A fuse (anybody’s) is just a piece of wire that melts open when the current gets up to a certain threshold. If the current is slightly above or below that threshold, the wire will stay intact for a long time (hours) and often result in melting of surrounding components such as a plastic fuseholder or the fuse itself if it is a plastic design. The designer needs to anticipate the magnitude of the faults his circuit is liable to encounter and use careful judgment in selecting the fuse rating. Hopefully, the faults will be around 2X the fuse rating to allow the fuse to melt open in around 1 second."
Fusible Resistor for DClink precharging >20W - Page 1
Forum section: electronics / projects

author: Amper
author_rank: Frequent Contributor
timestamp: January 28, 2025, 06:40:11 am
content: Hi!Im working on a small battery system at 48V DC which works well but needs precharging before the contactor closes. Id like it to be semiconductor free, so no buck or similar. Using a Resistor works, however at 300mA and full system Voltage ill have 15W of losses continuously. Either i use 15W Resistors or i make sure to cut the power in some passive way. There is Fusible Resistors up to 5W but at DC its risky business.Im just asking for some brainstorming if there is good alternatives besides binding a thermal Fuse to a Resistor manually

author: Slh
author_rank: Regular Contributor
timestamp: January 28, 2025, 08:29:33 am
content: You could use a positive temperature coefficient (PTC) resistor likehttps://www.tdk-electronics.tdk.com/en/530034/products/product-catalog/protection-devices/current-protection/ptc-inrush-current-limiters. The resistance increases with temperature so the continuous power will drop as they heat up.They only way to completely cut power is to use another relay or a switch to switch the pre charge resistor in and out.

author: Vovk_Z
author_rank: Super Contributor
timestamp: January 28, 2025, 11:15:16 am
content: I would suggest large size low resistanse NTC too (like 1-10R 15-20D).

author: Amper
author_rank: Frequent Contributor
timestamp: January 28, 2025, 05:47:16 pm
content: I thought about PTC of cause but they have the issue of being very temperature dependent (duh). The operation range for the battery is -20 to 55 °C so a resistor that will precharge the system nicely at 55°C will have almost a short at -20 (or even at 0). This will result in welded relay contacts at some point.

author: floobydust
author_rank: Super Contributor
timestamp: January 28, 2025, 06:20:16 pm
content: You can consider going the other way. NTC minimum resistance is when they are hot. Pleanty of app notes etc. here:https://www.ametherm.com/inrush-current/thermistor-protection-precharge-circuit-lithium-ion-batteriesI note Vishay bought Ametherm June 2024.Otherwise, you need a big resistor and thermal fuse.

author: Amper
author_rank: Frequent Contributor
timestamp: January 28, 2025, 07:16:39 pm
content: NTCs are for inrush current but that is not my issue here. Lets say i have a Charge current of 300mA max (relay contacts at DC). An NTC that draws enough current at nominal conditions and room temperature (or even -20) will have way too low curretnt to heat up and have its desired runaway condition. Furthermore what im concerned with here is thermal protection in a fault case. Using an NTC and having a fault (Device powered by the battery shorted or low impedance) the NTC will not limit anything, it will increase current until it explodes in an exponential runaway, definitely not better than a normal resistor getting to hot.Big resistor and thermal Fuse yes, thats what i said in the opening post but im looking for alternatives, preferably one that is not bodgewiring a thermal fuse to a resistor by hand.
Futaba M202MD15FJ VFD pinout - Page 1
Forum section: electronics / projects

author: Cloud
author_rank: Regular Contributor
timestamp: January 12, 2016, 09:08:29 pm
content: As a late christmas present santa has brought me two Futaba M202MD15FJ 2x20 VFDsBut I am having hard time finding pinout of it. Does anyone know if it is same as for normal 2x20 LCDs?

author: helius
author_rank: Super Contributor
timestamp: January 12, 2016, 10:02:16 pm
content: For the benefit of other readers, this is a display module containing a VFD and a MCU with driving electronics from a 5V supply. It uses "serial or parallel" interface, which means an ASCII (or Japanese ASCII variant) with control characters.

author: Mr.B
author_rank: Unknown
timestamp: January 12, 2016, 10:09:10 pm
content: Attached.Pinout on page 16.

author: helius
author_rank: Super Contributor
timestamp: January 12, 2016, 10:27:30 pm
content: OK according to the datasheet I was incorrect, the controller does not use embedded control characters. The character data is uninterpreted and control is effected by means of command signals (encoded words written to the device) using either "Motorola" (R_W plus CE), "Intel" (_R plus _W), or "Serial" (a kind of 3-wire where the SS is a "strobe" and must transition to low and then high around each 16-bit word)

author: marshallh
author_rank: Unknown
timestamp: January 13, 2016, 12:01:55 am
content: Looks like pretty much a HD44780 compatible

author: Cloud
author_rank: Regular Contributor
timestamp: January 28, 2016, 08:45:47 pm
content: After checking why it wasn't working I have realized, that I was using defect arduinoWell for 10eur per piece I think it is pretty good dealNow I have to find somewhere 2x16 VFD for frequency counter that I am currently making (http://lea.hamradio.si/~s53mv/counter/counter.html)

author: Alfons
author_rank: Regular Contributor
timestamp: January 28, 2016, 09:41:31 pm
content: Quote from: marshallh on January 13, 2016, 12:01:55 amIt is HD44780 compatible.
fuzz buttons - Page 1
Forum section: electronics / projects

author: grouchobyte
author_rank: Regular Contributor
timestamp: September 01, 2016, 05:38:27 pm
content: Does anyone know where I can source some standard large (~100 mil OD) fuzz buttons (not custom) for a client project? If you have to ask what a fuzz button is then you are not any help, sorry.Thanks@grouchobyte

author: Fungus
author_rank: Super Contributor
timestamp: September 01, 2016, 05:50:37 pm
content: What's a fuzz button?

author: rrinker
author_rank: Super Contributor
timestamp: September 01, 2016, 06:19:52 pm
content: I must say, I had no idea that's what they were called, until I Googled it. Very interesting, and I HAVE seen them before, in their use as a grousing contact. Never seen them of any of the other uses they mention. Pretty interesting product - the web site has a complete history and information on how they are made.BTW according to the web site, 100 mil is not a standard size. They go from 90 to 125. 100 would be a custom size.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 02, 2016, 06:46:37 pm
content: Oh, so that's what the the "tinsel" scattered all over the point wiring of one of my old machines was. It was the remains of fuzz buttons (not original but installed later for grounding, it was apparenly operating into the 60s). I just thought they were for scrubbing your soldering iron.
FXO FXS development board - Page 1
Forum section: electronics / projects

author: samy03
author_rank: Contributor
timestamp: September 26, 2019, 07:12:30 pm
content: Hi,I am doing some R&D on FXO and FXS for a project and wanted to get suggestions from you guys to see which is a better development/evaluation board.I have been looking into Silicon Labs FXO FXS stuff and also into Microsemi's chips. I am new into this and have no clue. Is there anyone here who has done any work in FXO FXS or VOIP to PSTN?I would appreciate your suggestions.Thank you
fxSolver - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 30, 2018, 07:32:13 pm
content: This seems like it may be more handy than Wolfram Alpha, specifically for solving equations:https://www.fxsolver.com/I would suppose, usual free-cloud rules apply, don't submit anything you don't want others to read, etc.Tim

author: rstofer
author_rank: Super Contributor
timestamp: May 30, 2018, 08:30:11 pm
content: I'm using Symbolab.com for general equation solving and Desmos.com for graphing. This in support of my grandson's college courses.I also use Matlab and wxMaxima for all of the more interesting work that I want to save and anything involving matrices. Simultaneous equations are a piece of cake with wxMaxima. Very handy for mesh and nodal analysis.Fortran shows up from time to time. I spent some time coding Riemann Sums (integration of functions) and Euler's Method (for solving DEs). Fortran produces an elegant solution to problems of sums and products.I subscribe to Wolfram Alpha but I can't say I have used it very much.Microsoft Mathematics is pretty good.I don't use it but Maple comes up from time to time.This is certainly an improvement over the days of slide rules.
G \$\Omega\$ Input impedance Voltage measuring up to 1kV - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: October 13, 2018, 12:58:20 am
content: I was working on a circuit the other day that measures ac/dc voltage up to 1kV. The input impedance of the circuit is ~2M, so simply connecting any of my DMM's (10Minput impedance) loads the circuit considerably. I do have several 34401A's however the high impedance mode can only be enabled for low voltage ranges.So perhaps I should build a high voltage, high input impedance circuit for the next time I need to make a similar measurement.Can anyone point me to an appropriate app note?

author: EEVblog
author_rank: Unknown
timestamp: October 13, 2018, 01:14:21 am
content: https://www.eevblog.com/forum/projects/hi-z-high-voltage-probe/A contact electrostatic voltmeter might do the business, maybe something like thishttp://www.trekinc.com/products/esd_voltmeters.asp

author: joeqsmith
author_rank: Super Contributor
timestamp: October 13, 2018, 01:36:51 am
content: Quote

author: Jester
author_rank: Frequent Contributor
timestamp: October 13, 2018, 08:24:22 pm
content: I'm envisioning a circuit something like this:R1,R2 are 1%, rated for 3kV working voltageR5, R6 are to match the gain, I would hand pick themOutput drives 34401A, the 10Ginput resistance mode only works on 10V and lower ranges, so this circuit would be used for V > 10VOP07, is not great with lower input voltages, perhaps an alternate with lower input current OPA191?, suggestions?Please critique and suggest ways to improve.
G545 MOSFET power switch alternative. - Page 1
Forum section: electronics / projects

author: warf135
author_rank: Contributor
timestamp: June 20, 2014, 10:42:01 pm
content: Hello All,I'm fixing a laptop that has a blown MOSFET power switch that controls power to the USB ports. Its a G545-B1 in an 8 pin MSOP package (see attached datasheet). I am finding it impossible to find a G545 chip (the datasheet took 3 days to find!) so am looking for an alternative.The TPS2022 from TI has identical pinouts, but (from what i can see) is only available in an SOP package and is active low instead of active high like the G545... Do any of you know of a suitable replacement for the G545?Cheers!

author: JOERGG
author_rank: Contributor
timestamp: June 20, 2014, 11:19:06 pm
content: http://www.ebay.com/itm/1-Piece-New-GMT-G545B1-G545B1P8U-MSOP8-IC-Chip-/271409526355?pt=LH_DefaultDomain_0&hash=item3f3144b653

author: warf135
author_rank: Contributor
timestamp: June 20, 2014, 11:44:21 pm
content: Thanks! I now look silly LOL! I looked on eBay UK, with worldwide option selected and it didn't appear on there... I didn't think to search eBay US!UPDATE: Further research reveals that TPS2065 from TI seems to be very similar and is available from UK supplier, so I've ordered that instead of the original G545 part from China... Should work ok... (guess I'll find out on tuesday!)UPDATE 2: The TPS2065 from TI is a successful replacement for the G545-B1 MOSFET. It's tiny MSOP-8 package was a nightmare for me to work with (with only basic tools and arthritic hands!), but I managed to replace it and its working perfectly.
G'day, Dave, have u got ur 2225 caled? - Page 1
Forum section: electronics / projects

author: TheEENerd
author_rank: Contributor
timestamp: September 19, 2011, 07:10:35 am
content: I've got the same problems. Maybe you can make a video on how to cal CRO...

author: EEVblog
author_rank: Unknown
timestamp: September 19, 2011, 07:44:25 am
content: No, not yet, too many other things to do...Dave.

author: TheEENerd
author_rank: Contributor
timestamp: September 22, 2011, 02:46:28 am
content: Just got it caled, it's simpler than I thought. Just follow SM and adjust a few pots. But SM is essential.

author: EEVblog
author_rank: Unknown
timestamp: September 22, 2011, 04:25:28 am
content: Quote from: TheEENerd on September 22, 2011, 02:46:28 amI still don't have the service manual.Dave.

author: gregariz
author_rank: Frequent Contributor
timestamp: September 22, 2011, 04:42:11 am
content: Quote from: EEVblog on September 22, 2011, 04:25:28 amMaybe there's something similar in herehttp://www.ko4bb.com/cgi-bin/manuals.pldont forget to give it a washhttp://www.ko4bb.com/Manuals/Tektronix/TEKscope_Magazine/Service_Scope_-_Washing_Your_Scope.pdf

author: simmo
author_rank: Newbie
timestamp: September 22, 2011, 06:09:04 am
content: Hmm, not I good idea I think, wouldn't want water in the EHT or power transformer.Actually Dave's video inspired me to calibrate my 2225, easy with the service manual. Calibrating the vertical deflection is particularly easy as you can just use an adjustable voltage source and an accurate multimeter. Actually got me interested in finally getting around to making a function generator. Was thinking about Dave's 0-10Mhz DDS Function Generator, but there seems to be an issue with the PCB on the SC website, but this is off topic.Regards, Simmo

author: TheEENerd
author_rank: Contributor
timestamp: September 22, 2011, 08:00:23 am
content: Quote from: EEVblog on September 22, 2011, 04:25:28 amCheck ur email.
Gain Calculation for LM13700 When Using Linearizing Diodes - Page 1
Forum section: electronics / projects

author: Scr1bbl3
author_rank: Contributor
timestamp: May 13, 2021, 02:12:51 am
content: Hello everyone,I pulled some LM13700 OTAs from an old board and tested them. All voltages, currents, and resistances were measured. I had the expected (approximate) voltage gain using the equation A=(R2/(R1+R2))∗gm∗RL where gm equals 19.2∗Iabc.The problem begins when I use the linearizing diode on pins 2 or 15. The gain goes down substantially, the higher the current (lower resistor values) on these pins, the lower the output. I have used Marston’s equation from the old Nuts and Volts article, Iout=2∗IS∗(Ibias/ID) but the result are way off.Does anyone know of a better way to calculate gain in an LM13700 when the linearizing diodes are used?UPDATE - I just received some new LM13700's and got the same results.

author: Terry Bites
author_rank: Super Contributor
timestamp: May 16, 2021, 10:42:04 am
content: see page 5-6https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiBmOe8gc7wAhVk8-AKHRGTAFsQFjAPegQIERAD&url=https%3A%2F%2Fwww.experimentalistsanonymous.com%2Fdiy%2FDatasheets%2FLM13700.pdf&usg=AOvVaw3UAxJCx4wz4VvVYgwSiDlS
GALI-84 biasing - Page 1
Forum section: electronics / projects

author: LukeW
author_rank: Frequent Contributor
timestamp: October 06, 2014, 08:05:01 am
content: I'm selecting appropriate components for the bias tee etc. surrounding a GALI-84 amplifier operating at 5.8 GHz.I'd appreciate a little bit of peer-review or feedback on the following selection of components.Note the attached image is just the Mini-Circuits reference schematic for the device so you don't have to look it upIC: MiniCircuits GALI-84.http://www.minicircuits.com/pdfs/GALI-84+.pdff: about 5800 MHz in this application. Input/Output transmission lines are 50 ohm.Vcc: Let's say regulated 9V in this application. (Vd= 5.8V nominal voltage drop across the MMIC.)Ibias: 100mA as per datasheet.Rbias: 33.2 ohms 0.5W 1206 1%.Cbypass: Ordinary 0.1uF 0603 ceramic. Multiple capacitors needed or just one as shown in the datasheet?Cin: The MiniCircuits reference board uses 2.4 nF here. How critical is the capacitor's resonant frequency here? And how critical is the difference between an 0603 and an 0402 package?I'm thinking about using a 3.0pF 0402 Johanson 500R07S3R0BV4T - I'm choosing a relatively low capacitance here in order to keep the SRF above the operational frequency, at about 6GHz. Does that sound appropriate? The MiniCircuits reference board appnote does say specifically that the capacitors need to be free of resonance at the operating frequency. But at only 3.0pF, we have 1/(2pi*5.8GHz*C) = 8.3 ohms. Maybe that's a little bit too high, and the capacitance is too low?Cout: Identical to Cin.RFC: The MiniCircuits TB-409-84 evaluation board uses a MiniCircuits TCCH-80 fancy broadband choke as the bias choke.However, I was planning on substituting it for a generic high-frequency wirewound 0603 (or 0402) inductor.Let's say we go for 15 nH, this gives us 2pi * 5.8GHz * 15nH = about 550 ohms, so it's >10x the 50 ohm line impedance.Something like the Murata LQW18AN15NJ00D 15nH, 6 GHz SRF, 0603 package, I think. Or would an 0402 part be better?
Gall bladder coupling - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: August 05, 2024, 02:07:42 pm
content: Check aliexpress. Search for "Gallbladder", its the latest tech.WTF!!"Line Magnetic LM-508IA 805 Electronic Tube Combined Amplifier HIFI HIEND High Temperature Audio Gallbladder Machine" Excess Bile."High Voltage Beautiful Film Gallbladder Coupled Thin Film Capacitor" Gorgeous."British Grey Knight Frozen Edition DCDS3.0 Fever Level Audio Wall Power Line HIFI Gallbladder Power Amplifier Power Cord" Ideal for Audiofoolery."3.5k 35w fully coupled output transformer 300B dedicated OCC single crystal copper transformer dedicated for gallbladder" Oh yeah!"Dual Gallbladder Rice Cooker " cute"Electric Lunch Box With Insulation Plug In Self Heating Steaming Cooking Portable One Pot Four Gallbladder Lunch Box For Workers"- I am tempted here."Diameter 35-36MM, simple and atmospheric, retro circular inlaid watch head, crystal handicraft, clock gallbladder watch core" No idea.And many more Gallbladder items.
GAL/PAL Reversing - Page 1
Forum section: electronics / projects

author: @rt
author_rank: Super Contributor
timestamp: March 07, 2017, 11:03:20 am
content: Hi GuysWith the acquisition of a vintage board it has become desirable to reproduce 3 x 22v10 PALs with stock logicto reproduce a part of the board’s functionality. Company is long gone, and I’m sure nobody cares about the IP any longer.Where have we come with this?Googling did yield an interesting read, but the links for further information are now dead.It went into brute force methods of input to analyse output.Fortunately, the board is low volume production (test board), and the parts could have easily been used wastefully.Cheers

author: amyk
author_rank: Super Contributor
timestamp: March 07, 2017, 11:42:41 am
content: It's either brute force (may take a long time) or decapping and reading the array directly ($$$, I'm not sure if it's possible to read these like that if they're the E/EEPROM version.)

author: BrianHG
author_rank: Super Contributor
timestamp: March 07, 2017, 12:06:13 pm
content: If I remember correctly, for the GALs, they have a read protect fuse. If you have a programmer, you may be able to read them if this fuse hasn't been set. I don't remember any details about programming PALs.Reverse engineering programmer & tools used to exist in the 90s, but, it takes something like running a PC & code for a week or more to workout the internal fuse map from a protected device & such tools were only available from 1 or 2 companies.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 07, 2017, 01:00:02 pm
content: First thing is to try reading as they may not be protected.22V10s are fairly straightforward to reverse as they can't have buried feedback paths. You should also be able to figure out a lot by looking at what the board does in normal operation. It could be that most of the pterms are doing trivial functions.
Galvanometric temperature gauge and varying voltage - Page 1
Forum section: electronics / projects

author: Luis A.
author_rank: Newbie
timestamp: October 20, 2022, 04:10:04 pm
content: Hi everyone; I'm an EE (RPI '83) and hands-on European vintage car enthusiast.I have observed that galvanometer-based gauges in such cars are not affected much by a varying supply voltage from about 10 - 15 volts. Specifically, I am referring to a coolant temperature gauge reading a resistive value from an NTC sensor on the cylinder head.There is no voltage regulator for the dashboard voltage feed as some other vintage cars utilize. In fact, I hooked up the gauge out of the car to a variable power supply which confirmed this self-regulating behavior.How is this accomplished on the gauge?Photos of the gauge attached. Top legs is +, middle is -/ground (for sensor and voltage) and bottom is the other sensor/resistor input.Thanks in advance!Luis

author: inse
author_rank: Super Contributor
timestamp: October 20, 2022, 04:52:40 pm
content: As already visible, the gauge is called crossed coil gauge.There is a good article in (German) Wikipedia explaining the function:https://de.wikipedia.org/wiki/Kreuzspulmesswerkmaybe you can translate it....found it:https://en.wikipedia.org/wiki/Ratio_meter_systemsbut not as good as the German article...jQuote: "The coil is wound from 99.99% pure copper on a wood which was treated with many oxidizers and chemicals.The benefits from using foil inductors comes in the form of less distortion and higher dynamic headroom, when used on crossovers for modern high performance speakers."

author: Luis A.
author_rank: Newbie
timestamp: October 21, 2022, 04:37:48 am
content: Thank you Inse. The google translation is goofy at times ( what is a “rash”??) but I get the idea. Strangely, I didn’t find an equivalent or an even simpler description by searching in English.

author: inse
author_rank: Super Contributor
timestamp: October 21, 2022, 06:03:11 am
content: I found the Google website translation giving a comprehensible result.How did you do it?Rash is probably the wrong translation for needle movement.
Game Raccoon - OHW + FOSS Sega Mega Drive cartridge using SD cards - Page 1
Forum section: electronics / projects

author: MrD
author_rank: Contributor
timestamp: July 28, 2020, 03:27:50 pm
content: Following on from my previous threads1234I've completed my Game Raccoon SD Card flash cart and published the web site.http://www.mrdictionary.net/gameraccoon/The Game Raccoon is a game development interoperability cartridge designed to allow you to test your own Sega Mega Drive or Sega Genesis in-development games on real system hardware.This cart is the end result of my research into hardware design, made possible by the assistance of users on this forum.Each revision has a Technical Report, which is a basic description of how the cart works, with the schematics and EAGLE files available under CERN OHL and the on-board PIC firmware and 68k Flash-resident menu available under AGPL3. *The Misadventures are (very) lengthy blogs about the journey from a blank sheet of paper to Revision 0, and from there to the fully-functioning Revision 1. That's also where you'll find links to the latest software compatibility spreadsheets.* I'm not super attached to the licenses, I'm just sick of dithering about it. You can ask, but if you think you need another license, you're probably good enough to rewrite the code anyway.Please ask me anything! If there's something I've seriously messed up, please let me know. I also need to find myself an artist to work on the cute mascot raccoon animations during the copy operations!I'm not manufacturing or selling Game Raccoon carts, and don't have any plans to right now. The plans are there if you want to see how it works and mess about and make your own.

author: Amnandaoralio
author_rank: Newbie
timestamp: August 11, 2025, 05:34:58 am
content: The Raccoon – OHW + FOSS Sega Mega Drive cartridge using SD cards is a great example of how modern technology can breathe new life into retro gaming. By combining open-source principles with clever hardware design, it makes playing and preserving classic Sega games more accessible than ever.Melon Playground
Game show buzzer using a micro controller - Page 1
Forum section: electronics / projects

author: 4013Dlatch
author_rank: Newbie
timestamp: May 23, 2015, 02:08:37 am
content: HiI'm looking to convert my game show indicator lockout circuit from the original design using 14000 / 4000 series logic to a micro-controller based design, but I do not have a clue what to look for.Here are the system specs:15 contestant switches N.O.15 corresponding LEDs and aux output in parallel1 LED that comes on if any of the above LEDs is lita reset switch to blank the LEDs and reset the latchesa buzzer that beeps 0.5s to 1s when a contestant light is triggered or the timer reaches 0a timer package that has 5 different push button inputsa 5s or 30s on one switch that is selected automatically based on whether or not a contestant has triggered the systema 45s switcha 60s switcha timer pause / hold switcha timer reset switcha 2 digit 7-seg displaythe timer uses a divided 60Hz signal input coming off of the mains transformerSystem requirements:Inputs debouncedtimer display can be driven separatelyLEDs can be driven separatelycurrent systems operate on 8 Volts regulated, with 12 volt AC input clock signal. ( the ability to operate at this voltage is preferableIf I could get info as to what I'm looking for in a micro, in relation to I/O, peripherals, and anything else to consider as I'm totally new to micros.Also I'm not set on a particular companies micros, so I'm game for almost anything as long as the tools are easy to use.Mike

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 23, 2015, 02:59:23 am
content: Probably the most popular microcontroller platform out there now is Arduino.There are a great many people making Arduino clones, some of them <$5Everything you describe is pretty easy to do with Arduino, even with off-the-shelf I/O expander boards, etc.There are many resources available online including example circuits and code, tutorials, and peer-assistance on the Arduino forum.

author: SL4P
author_rank: Super Contributor
timestamp: May 23, 2015, 05:36:43 am
content: I'm interested in what you're doing - I've done a few game control systems ... including a licensed version of Wheel of Fortune... and others for on camera TV production.Not sure where you are located, but if I can be of help, drop a line.You can take these systems as far as you can imagine...I've had networked systems with touch-screens, midi integration (for audio cues), power & DMX (lighting effects), multiple displays, projectors etc...One element that shouldn't be overlooked or underestimated is a (secure) 'pre-game' editor to setup playing conditions etc. -- if your application goes that far.Cheers

author: 4013Dlatch
author_rank: Newbie
timestamp: May 23, 2015, 12:53:17 pm
content: Quote from: SL4P on May 23, 2015, 05:36:43 amthe pre game setup is done with switches.I'm located in Manitoba Canada

author: SL4P
author_rank: Super Contributor
timestamp: May 23, 2015, 09:32:20 pm
content: I guess we're a bit far apart to meet up, but drop a line if up you get stuck... maybe I can help!
Gameboy Advance to HDMI and Cart Emulator Dev Board - Page 1
Forum section: electronics / projects

author: ShakingRumble
author_rank: Newbie
timestamp: August 18, 2023, 12:08:40 am
content: Hey, I was working on this awhile back and put it on the back burner but wanted to get some opinions on it and any suggestions that you guys might have.The goal/idea behind the project is to eventually have a MB replacement for the GBA that includes a good chunk of the mods people try to fit in with the main focus being integrated "flash cart" (both GB/C and GBA) and video-out.This dev board schematic (not at the PCB level yet) that I worked out should hopefully be enough to emulate some cartridges, take the video pixel-perfect scale it and output it over VGA/HDMI (I've already managed VGA with a smaller FPGA connected to GBA so it's included for ease of testing).If you guys need any more details that I might've left out or questions let me know.

author: ShakingRumble
author_rank: Newbie
timestamp: August 31, 2023, 06:42:38 pm
content: Do you guys think I'll get more suggestions if I post over in the PCB sub-forum as well?I'm looking into getting this manufactured and ideally assembled at somewhere like JLCPCB so save on having to try my hand at soldering BGA for the FPGA.I'm also very new to routing so I'd need some advice on handling signals to avoid issues, like with the HDMI.
Gamma and Beta radiation silicon damage data - Page 1
Forum section: electronics / projects

author: mimmus78
author_rank: Unknown
timestamp: October 22, 2014, 09:54:02 pm
content: Anyone has some data (or can point me to some documentation) about damages caused by Gamma and Beta radiation on silicon chips?What's about possibility to damages to EEPROM?

author: Balaur
author_rank: Unknown
timestamp: October 23, 2014, 06:00:06 am
content: Look for "Total Ionizing Dose" (TID) effects.Space electronics is hugely concerned by permanent (TID) or transient (Single Event Effects (SEE) - Single Event Transients (SET), Single Event Upsets (SEU), Single Bit Upset (SBU), Soft Errors, Single Event Latchups (SEL)) effects caused by energetic particles.You will find in the literature a lot of data concerning the TID hardness of devices that are meant for aerospace, military or nuclear industry use, as these devices will have to work satisfactory in radiation-aggressive working environments.Therefore, the devices are qualified by a battery of tests and one of them is usually a TID test that consists in exposing the circuit to a Co-60 source (emitting gamma rays) and measuring the performance/behavior degradation when exposed to increasing doses of radiation.If you are interested in the overall TID mechanism, just search on Google as many researchers work on this. If you need TID data for specific components, you may find this in the component's TID Test Reports (you may have to ask them nicely though). Otherwise, maybe a researcher or NASA/ESA investigated this component and published the results/a paper on IEEEXPLORE or their site.Best regards,Dan

author: mimmus78
author_rank: Unknown
timestamp: October 23, 2014, 12:35:34 pm
content: Hi Dan and thanks your help!Just searched on GOOGLE for TID and found what I was searching ...http://radhome.gsfc.nasa.gov/radhome/papers/nsrec07_Oldham_W40L.pdf

author: tszaboo
author_rank: Super Contributor
timestamp: October 23, 2014, 01:49:05 pm
content: Big manufacturers have rad-hard and space rated products, I would looks for them for any usable data in this sobject. Example:http://www.ti.com/lsds/sites/ti/high-reliability/files/ROM_Logic.pdf

author: David Hess
author_rank: Super Contributor
timestamp: October 25, 2014, 03:21:08 pm
content: Quote from: mimmus78 on October 22, 2014, 09:54:02 pmI have the Harris Radiation Handbook (thick hardcover book with a red and black binding) but I have never seen it available anywhere.QuoteI am just going by memory here. Radiation will cause defects in the floating gate and shift the threshold voltage in a way similar to how erase and programming cycles wear out the floating gate transistors. Eventually this means that existing cells will change state or it will become more difficult or impossible to complete the erase part of the program cycle.
Gamma-Safe Anti-Charge Protection - Page 1
Forum section: electronics / projects

author: katzohki
author_rank: Frequent Contributor
timestamp: February 28, 2018, 11:53:06 pm
content: Hi All,I need to prevent charging of a battery (i.e. stop reverse current flow). It needs to let about 30A flow forward (peak, typical 10A or 2 standby). Diodes just aren't cutting it due to the voltage drop (this was a last second addition and we don't have much margin due to using a single battery cell). I tried some nice low Rdson power MOSFETs with a 3rd pin to activate the gate when the pack is plugged in and they worked great.Unfortunatelythey got destroyed by gamma radiation. We need to sterilize these with about 40kGy gamma.If any of you have any ideas that would help me out I would truly appreciate.Thanks!

author: amyk
author_rank: Super Contributor
timestamp: March 01, 2018, 01:54:21 am
content: Look for "rad-hard MOSFETs"... but 40kGy seems to be quite extreme. Some lead shielding, perhaps?

author: Cerebus
author_rank: Super Contributor
timestamp: March 01, 2018, 02:53:15 am
content: Quote from: katzohki on February 28, 2018, 11:53:06 pmOuch! Somebody's got a big lump of60Co.That's a 40kJ/kg absorbed dose of ionising radiation! That's going to be a big ask for even nominally radiation hardened parts. For instance IR spec their rad-hard MOSFETS for either 100kRads or 300kRads, that's 1kGy or 3kGy in more civilised units.Do you have the possibility of alternative sterilisation techniques such as EtO?

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: March 01, 2018, 10:54:09 am
content: If you have a 'third pin' which can activate a MOSFET, could you use that pin to drive a relay instead?

author: katzohki
author_rank: Frequent Contributor
timestamp: March 01, 2018, 04:20:12 pm
content: Quote from: Cerebus on March 01, 2018, 02:53:15 amThis is why we were thinking we may have got the dosing wrong. Normally 40kGy (max) is what we use for an entire case of units, but we did this test run just with the FETs themselves. I don't know much about dosimetry personally. I have to ask again about EtO, but I think it was out for some reason. I think E-beam would be just as bad.Quote from: blueskull on March 01, 2018, 01:59:47 amThanks blueskull, I'll take a look into these. Hopefully that is a good lead.
GaN transistor in buck converter turning itslef back on?(problem) - Page 1
Forum section: electronics / projects

author: relu
author_rank: Newbie
timestamp: August 20, 2020, 07:23:56 pm
content: Hello dear EEVblog forum members,I have a problem with a buck converter.It is designed using the GS61008 GaN driven by the LMG1205 pre-driver.The problem that appears is that during turn-off of the HS transistor, the transistor turns itslef back on.Please see the attached pictures.The converter, and the measurement points:Layout (GaN devices are on the other side of the board)Scope measurement, where you can see the turn-on:Phisical boardDo any of you have any experience with this?Would appreciate any help with this.Thank you and best regards,Relu

author: julian1
author_rank: Frequent Contributor
timestamp: August 20, 2020, 09:20:29 pm
content: Since noone else is commenting..What is the purpose of the 27p cap. Is it a misplaced boostrap capacitor? It looks like it would just AC couple switching transients onto the HS Fet gate. Also the ringing/ transients look large, does it need a snubber to dampen?

author: relu
author_rank: Newbie
timestamp: August 21, 2020, 06:35:33 pm
content: Thanks julian1 for the question. I have used the 27pF capacitor to try to slow-down the transistor turn-on/off. (togheter with the turn-on / turn-off resistors).Regarding the ringing - you are right I have to place a snubber to dampen these transients, but I had this problem with the turn-on first.In the meantime I found the issue with this - it is in my sub-optimal layout.I was used to consider a GND plane to have the same potential all over, but for the speeds the GaN transistors are switching, this is not the case anymore.I have placed a capacitor right on top of the swiching cell, and the turn-on effect dissapeared. see the images attached.

author: uer166
author_rank: Super Contributor
timestamp: August 23, 2020, 01:24:21 am
content: Looks like some serious speed.. So turns out adding more decoupling capacitance at the input fixed it, although in your first traces the Vgs voltage was below threshold, so it shouldn't have turned on the FET anyway. I guess the probing wasn't 100% correct then and the "real" Vgs was larger than shown in the trace.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 23, 2020, 02:52:37 am
content: This is two layer PCB? Seems dangerously optimistic...With 4 layers, you can make the switching loop vertically oriented, i.e. within the PCB layers, so the current path is very wide and shallow. Here, it's a relatively large and thin (flat) loop, going along the transistors, then running beside them through neighboring ground plane, up to the bypass cap. (Note that there's no direct ground path under or over the switching node, only beside it.) The field is only able to peek through the gaps between copper polys, but that's still enough to total a few nH.Tim