hybridfree/eevblog-posts huggingface dataset:
Hi, please i which to know if i identified this logic gate equation correctly  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: August 31, 2018, 03:06:01 pm
content: Hi, please i which to know if i identified this logic gate equation correctly

author: rstofer
author_rank: Super Contributor
timestamp: August 31, 2018, 03:12:16 pm
content: Looks good to me!
Hi, please  i wish to know if i interpreted this logic gate equation correctly  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: August 29, 2018, 05:07:15 pm
content: Hi, please i wish to know if i interpreted this logic gate equation correctly

author: rstofer
author_rank: Super Contributor
timestamp: August 29, 2018, 06:07:29 pm
content: Where's your work? Or are you just creating the tables? Yes, they are correct but you don't have one for the 3 input AND gate.

author: Nusa
author_rank: Super Contributor
timestamp: August 29, 2018, 06:39:50 pm
content: You've given the truth table for a NOR gate when there isn't a NOR gate in the problem.The truth table for the OR gate uses A and B as inputs when the inputs in the problem are A and D.No truth table for the 3-input AND.The inputs to the 2-input AND are not A and B, and the output is X. What's the equation for those inputs?Whats the final equation for X?That's my two cents.
Hi, please  i wish to know if the calculations for this summing amplifies is ok - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: June 05, 2018, 04:30:44 pm
content: Hi, please i wish to know if the calculations for this summing amp is ok

author: Wimberleytech
author_rank: Super Contributor
timestamp: June 05, 2018, 05:01:36 pm
content: This is what I get (oops...negative Vout)

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 05, 2018, 05:12:55 pm
content: Quote from: nyame on June 05, 2018, 04:30:44 pmits not ok. just one example.. 900Mv is not 9V. learn the difference between MV and mV (Mega vs milli Volt), Mv (lower case v) is out of context there. 900Mv is 900,000,000v. i'm assuming its 900mV (capital V) which is 900mV = 0.9V

author: rstofer
author_rank: Super Contributor
timestamp: June 05, 2018, 06:27:18 pm
content: Right, your units are way wrong. Note that your worksheet at the top right wants the voltage in terms of -100 mV.All you your signs are wrong, every output voltage is negative. That's one of the features of an inverting amplifier. It the - input goes up, the output goes down.The worksheet accommodates this by stating that you are to specify the result (apparently as an integer) in terms of -100 mV.If you calculate a value of 900 mV, the value is really -900 mV and after you clean up the sign and divide by 100 mV, you get just 9 as an integer.Remember, when the currents sum up at the - input, they flow through the 470 Ohm resistor from left (+) to right (-) and this leaves the right end of the resistor at a lower voltage than the left end. But the left end is at virtual ground or 0V so the right end of the resistor must be negative.I see the numbers are much different than the original problem of a few days ago.

author: nyame
author_rank: Regular Contributor
timestamp: June 06, 2018, 04:57:44 pm
content: thanks, please kindly take a look at this, please is mV

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2018, 05:06:55 pm
content: he's doing it again 810Mv = 8V this is going to be the most difficult problem of the year

author: Wimberleytech
author_rank: Super Contributor
timestamp: June 06, 2018, 05:19:54 pm
content: Here is my VisiCalc solution
Hi, please  i wish to know if this two Boolean expressions are the same  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: August 26, 2018, 04:07:54 pm
content: Hi, please i wish to know if those 2 Boolean expression are the same, using the 16 rows to summaries the logic gate at each steps, and using 4 variable truth table to come out with the SOP, am a bit unclear about the 2 Boolean expression, someone should please help elaborate this to me.thanks

author: Fred27
author_rank: Unknown
timestamp: August 26, 2018, 04:10:53 pm
content: If the truth table is the same then they are equivalent.

author: brucehoult
author_rank: Super Contributor
timestamp: August 27, 2018, 09:22:09 am
content: X is the same for both, so they are equivalent.(and the tables look right to me)
Hi, please i wish to know what this unit represents in endress + hauser DP Flow  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: May 18, 2019, 03:06:51 pm
content: Hi, please i wish to know what this unit represents in endress + hauser DP Flow meters, proline promag 50Value per pulse (1.0000 1/P)

author: Rerouter
author_rank: Super Contributor
timestamp: May 18, 2019, 03:08:48 pm
content: A simple pulse output flow meter will have a rating for X pulses per unit Volume e.g. 440 Pulses per Liter. that is the scaling factor so you know what your meter is actually reading.

author: nyame
author_rank: Regular Contributor
timestamp: May 18, 2019, 03:26:55 pm
content: Thank you for the reply. I know the flow meter can be scaled in a number of pounds per pulse which the unit will appear like this ib/P, scaling gallons per minute, that will appear like this gal/min.But this particular unit I need to understand what it represents.Your explanation is good but am a bit unclear, please can you help me with more elaboration ?Thanks

author: mikerj
author_rank: Super Contributor
timestamp: May 18, 2019, 03:37:07 pm
content: l/P = litres per pulse.

author: nyame
author_rank: Regular Contributor
timestamp: May 18, 2019, 03:52:11 pm
content: Hello thanks for the reply.Following you explaination and looking at the screen I posted it means the flow is configured for 1 litter per pulse ?

author: Rerouter
author_rank: Super Contributor
timestamp: May 18, 2019, 11:05:53 pm
content: Yes, though that would imply it was at one point hooked up to a rather large impeller based flow meter, or that it just defaults to that ratio.
Hi, please what is the default settings of pulse/ gpm in proline promass 40 - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: May 02, 2019, 05:06:39 pm
content: Hello, please what is the default settings of pulse/gpm in proline promass 40 flow meter ?terminal -24 and +25 are used for frequency and pulse generation for this flow meter.the meter does not accept configuration directly except via controllers. now if i wire my PLC to those two terminals to measure the pulses will it generate the pulses automatically without any configuration using it controllers ?Best RegardsEphraim
Hi, pls I need understand how to solve this instrument linear equation detaily  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: September 06, 2019, 07:59:05 am
content: Hi, please I wish to understand how to solve this analogue instruments linear equation detaily, solving it step by step in a basic wayWill appreciate any help.Thanks

author: nyame
author_rank: Regular Contributor
timestamp: September 06, 2019, 08:17:30 am
content: Hi, please I wish to understand how this instrument linear equation was solved in a simplified method. How the answer was achievedWill appreciate any helpThanks

author: TheHolyHorse
author_rank: Regular Contributor
timestamp: September 06, 2019, 08:32:15 am
content: This is some really simple math and nothing fancy at all.20mA - 4mA give you 16mA, which means you have a range of 16mA to represent 0-100%. So 16 divided by a 100 gives you 0.16mA per percent of signal. So you multiply this with the percentage of the signal which in this case is 34.7 which will get you 5.552. And since the range is 4-20mA you just add 4 to offset it back to the 4-20mA range.Just take some time and look at your problems and you'll be fine don't give up because you didn't get it the first time you looked at it.

author: soldar
author_rank: Super Contributor
timestamp: September 06, 2019, 09:41:11 am
content: Quote from: nyame on September 06, 2019, 07:59:05 amPlease crop and edit your images. Some of us have slower connections and do not need to download huge files of poor graphics. In fact, if it is just text you could transcribe it.

author: Zero999
author_rank: Super Contributor
timestamp: September 06, 2019, 09:52:09 am
content: Simply converting to a monochrome PNG saves a lot of bandwidth, with no loss of clarity.

author: GerryR
author_rank: Frequent Contributor
timestamp: September 06, 2019, 10:24:16 am
content: The last statement "The slope-intercept formula...." is the key to what has been done; y + mx +b where m is the slope (16/100) and b is the y-intercept (4). As previously stated, a basic formula for linear applications.

author: GerryR
author_rank: Frequent Contributor
timestamp: September 06, 2019, 10:44:00 am
content: @ Mechatrommer:I guess I was 2 minutes late; hey, great minds work together.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 06, 2019, 10:57:03 am
content: Quote from: GerryR on September 06, 2019, 10:44:00 ami got sleepy when bending my neck 90 degree, but what i'm aware of is your image is up when i hit the post button so i guess i'm the 2 minutes late one. but nevermind i wont bother to correct my graph "de-offsetted" y range. i think yours is more corrected graph. and more detaily explanation will be needed if OP havent attend secondary class topic like ratio, percentage and how area of trapezium is derived.i should have make it clearer(x - a) / (y% - 0%) = (b - a) / (100% - 0%) ... slope or ratio formula... but well...
Hi, trying to upload program from AB 1400 show no response from processor  - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: January 10, 2019, 12:54:00 pm
content: Hi, after implement the following steps to configure my Allen Bradley 1400 programing logic controller, I tried uploading program from the PLC, a got a notification displaying (no respond from processor at selected path/node) please will appreciate any help to rectify this error
Hi, What are some relevant safety legislation in domestic electrical rewiring  ? - Page 1
Forum section: electronics / beginners

author: nyame
author_rank: Regular Contributor
timestamp: August 04, 2018, 04:51:25 pm
content: Hi, please what are some work safe relevant health and safety legislation that maybe applicable when performing domestic electrical rewiring ?

author: Benta
author_rank: Super Contributor
timestamp: August 04, 2018, 04:58:34 pm
content: I'm not sure you'll find anyone here that know the safety codes for Cameroon. But good luck.

author: nyame
author_rank: Regular Contributor
timestamp: August 04, 2018, 05:13:30 pm
content: HI, thanks for the reply, please the questions is focused on OSHA or HSE legislations.

author: rstofer
author_rank: Super Contributor
timestamp: August 04, 2018, 10:02:17 pm
content: Electrically, the National Electric Code plus local modifications. Expect large cities like Los Angeles, Chicago and others to supplement the requirements with far more stringent standards.Safety wise, OSHA is one source but many states have their own codes that are more restrictive than the national codes.Electrically, OSHA standards and state standards refer back to the National Electric Code referred to as NFPA 70.A very brief snapshot of OSHA requirements:https://www.osha.gov/dte/library/electrical/electrical.pdfHere is another:https://www.osha.gov/Publications/osha3075.pdfHere is one for Cal/OSHA - California's version:https://www.dir.ca.gov/dosh/dosh_publications/Electrical_Safety.pdfThis stuff is all over Google but just pulling down documents isn't terribly useful. People spend their entire career dealing with this stuff and it still fails from time to time.

author: Jwillis
author_rank: Super Contributor
timestamp: August 05, 2018, 12:20:28 am
content: Cameroon falls under the French IEC (International Electrical Code). Start your search there.
HID badge readers - Page 1
Forum section: electronics / beginners

author: TianMing
author_rank: Newbie
timestamp: August 02, 2015, 04:03:13 pm
content: Hi, I have a badge reader that I would like to use in a small project in the future. Right now, my problem is understanding the wiring. I have a picture of it below:Hoping someone has an idea of what are the uses of of each wire (I know whats i+VDC and GND of course), especially the DATA0/DATA1 and SHLDI found an installation guide (http://www.hidglobal.com/sites/hidglobal.com/files/resource_files/iclass_c_ins_mu_0.pdf) for an HID reader that may be very similar to the one I have. It contains a little more information about the wiring.I'm guessing the DATA1 (clock) is used for synchronizing purposes? And DATA0 is used to obtain a list of 'users' that the reader will grant access to?Any insight/enlightment is much appreciated!

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: August 02, 2015, 05:15:29 pm
content: This datasheet of the Wiegand interface might help.http://www.ibtechnology.co.uk/pdf/magswipe_dec.PDF
High current 12V regulator need help - Page 1
Forum section: electronics / beginners

author: Maximus64
author_rank: Newbie
timestamp: March 02, 2015, 03:39:45 am
content: Hi all,I'm designing a high current buck boost regulator that can handle at lease 20 amp @12v with input voltage of range 8-20. All have to be in a single rail.Right now, I'm looking at the LTC3780 driver (http://cds.linear.com/docs/en/datasheet/3780ff.pdf) but not sure if it can handle 20A?I don't know much about power supply design so I need your help

author: Psi
author_rank: Super Contributor
timestamp: March 02, 2015, 10:24:46 am
content: 8-24v buck-boost at 12V 20A output is not a simple psu by any means.Selecting a control IC is the simple part.Sadly this is not a beginner level project
Higher Current LM2576 Buck Converter - Page 1
Forum section: electronics / beginners

author: wlamb02
author_rank: Newbie
timestamp: July 22, 2015, 09:15:56 pm
content: I want to modify the LM2576 to output a higher current and generate less heat using a mosfet with a lower Rds(on). Can I just connect the gate to the output? Here is the block diagramhttp://www.ti.com/lit/ds/symlink/lm2576.pdf#Block Diagram

author: Cliff Matthews
author_rank: Unknown
timestamp: July 22, 2015, 09:25:23 pm
content: That's odd, someone else asked that today.. a going trend maybe? I have a bucket of TOP200's I'd like to try doing the same thing with.https://www.eevblog.com/forum/beginners/lm2577-high-current-with-mosfet/

author: commie
author_rank: Frequent Contributor
timestamp: July 22, 2015, 10:10:06 pm
content: The chip you are using has been specially designed for a few parts as possible, hence the pass transistor switch resides on chip and its terminals are not available for output. May I suggest you try a MC33063 chip which will allow you greater design flexibility, the pass transistor are also on chip but the collector/emitter are available for alternate configurations.I used this chip to drive a mosfet awhile back no problem but for other reasons I ended up using a darlington instead.Note, mosfet rds_on figures are a little bit misleading.Hope that helps
High current PCB prototyping service - Page 1
Forum section: electronics / beginners

author: Sigmoid
author_rank: Frequent Contributor
timestamp: November 19, 2014, 10:10:12 pm
content: Hey,I'm looking for a reliable prototyping service that does high current (>2-3oz) 2 sided PCBs. The ones I know only do 1oz, or at least that's what I managed to extract from their website.Any suggestions?

author: LukeW
author_rank: Frequent Contributor
timestamp: November 20, 2014, 02:19:48 am
content: It might be faster/cheaper/easier to only use 1oz copper from any old board shop, leave the solder mask open across the entire high-current power traces, and then thickly tin them with solder?

author: ovnr
author_rank: Frequent Contributor
timestamp: November 20, 2014, 02:41:16 am
content: Seeed does 2 oz copper, but it's somewhat ridiculously expensive compared to 1 oz ($40 for 10 pcs of 5x5 cm boards vs $10 for the same).If it's just for prototyping, leave off the soldermask and add plenty of solder, as LukeW mentioned. If not enough, consider soldering on some heavy copper braid or something.Of course, if youmusthave heavy copper on a SMD board where it's simply impossible to bodge something on, you'll just have to cough up the money.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: November 20, 2014, 03:52:54 am
content: That's not ridiculous at all! AP Circuits in Alberta goes from $55 for 1oz to $577 for 2oz. Guess which process is optimized for prototypes!

author: coppice
author_rank: Super Contributor
timestamp: November 20, 2014, 04:03:54 am
content: Quote from: ovnr on November 20, 2014, 02:41:16 amYou will frequently see a similar price differentials for anything which is not the highest volume option, like choosing your boards with a specific colour of solder mask. Customisation costs.I see a 2oz option for most of the Chinese prototype board makers. If you want something even thicker your choices tend to narrow rapidly, but quite a few people doing high current work choose 2oz these days.Note that 2oz has its downside. Its so good at conducting heat that you may need to be more liberal with the use of thermal lands. However, the holes in the copper around the thermal lands can defeat the whole purpose of using 2oz in the first place.

author: Sigmoid
author_rank: Frequent Contributor
timestamp: November 20, 2014, 04:28:50 pm
content: Thanks.Seeed looks pretty cool. Also, it seems that 20 boards cost pretty much the same money as 5 boards... maybe I'll try selling the surplus on eBay.I got a "free" ATX supply with my Printrbot, and decided to break it out into a high power bench PSU for when I'm not 3d printing. I'd like to make a break-out board that takes a few molex connections, exposes the PSU's rails on post terminals, and does the extra stuff you need to do to keep an ATX supply happy.There are a few ready-made ATX breakout boards you can buy, but those are low power, one I've seen is even fused for 1.5A. The PSU can supply 30A on the 3.3V rail, 25A on the 12V rail, etc... so since I have a high power SMPS, it would be nice to keep the possibility of supplying high power from it.
high current safety--touching spot welders? - Page 1
Forum section: electronics / beginners

author: Jellysfish
author_rank: Newbie
timestamp: September 04, 2017, 07:16:22 am
content: I noticed in a lot of videos of people using those battery tab spot welders they hold the tab in place when doing the welding. Now I know that the electricity is probably just flowing through the path of least resistance and that would be the battery tab an not anywhere near your finger, but at the same time, if you touch one side of a live 120v AC wire you would definitely feel it. Could someone explain to me how this is safe?My hypotheses:I was looking up this safety stuff, and someone mentioned that its the current that kills you not the voltage. It seems like you only need enough V to get the e- to flow through your skin. These spot welders use ~1.5V and ~500-1000A current maybe it's Voltage is just too low. In that case, if you have really sweaty fingers, would this be dangerous?Here's a one of the vids I watched of the guy spot welding touching the leads:https://youtu.be/Ceos88VO6p4?t=446Thank you all for potentially keeping me alive in the future.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2017, 07:28:51 am
content: Quote from: Jellysfish on September 04, 2017, 07:16:22 amNo big deal at the voltages used for tab spot welders.Study this thread for more/better understanding.https://www.eevblog.com/forum/projects/guesses-on-what-i-am-attempting-here/(name now edited/changed by the OP)

author: Fire Doger
author_rank: Regular Contributor
timestamp: September 04, 2017, 11:00:58 am
content: A spot welder is "capable" to supply 1000A. It doesn't mean that if you touch it 1000A will pass threw you.The worst thing that you can get from welding is burn from a heated metal or eye problems from the arc.For safety reasons don't use tools with wet hands, wear safety equipment and inspect your tools for faults (like exposed live wire) once a wile.Its super easy to damage a cable and then touching it if your working area is a mess.

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2017, 10:50:38 pm
content: Up to 1kA passes through the joint, but the voltage is very low. Spot welding is very low voltage, very high current.

author: Psi
author_rank: Super Contributor
timestamp: September 05, 2017, 06:58:12 am
content: Dont let your ring touch the spot welder.Seriously, just think about trying to remove a 500degC ring from your finger. <shiver>Remove it before use, or you will regret it more than not buying bitcoin
High current switching regulator for automotive applications - Page 1
Forum section: electronics / beginners

author: P1X3
author_rank: Contributor
timestamp: April 30, 2014, 05:54:00 am
content: I am working on a powered USB hub for my project, and I am in need of high current 12V to 5V switching regulator.For now, I have been thinking of going with two LM2596 3A regulators split between usb ports.I have been looking at couple from Texas Instruments, Linear Technology, and ST Micro.Out of all, ST Micro has some appealing DC/DC Step-down buck regulators, but I know nothing about their products.Would love to get some ideas or feedback as to what would be the best option. Looking forward at least 8A 5VEdit:LT8612 is really appealing, but if only output was 8A

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 30, 2014, 07:10:53 am
content: Beware that automotive goes up to 60V on transients and usually requires 80V tolerant inputs.Up at 8A, you'll be looking for an external switch type regulator/controller. Possibly just a boring controller, paired with a high side (bootstrap) gate drive chip.Tim

author: P1X3
author_rank: Contributor
timestamp: April 30, 2014, 07:42:02 am
content: Quote from: T3sl4co1l on April 30, 2014, 07:10:53 amWould you say that something like LT3741 will work for my setup?I am not electronics guy, so I heavily rely on application samples and sample circuits provided by manufacturers.http://cds.linear.com/docs/en/datasheet/37411fe.pdfon page 19 there is 5V supercapacitor charger, wonder if that is what I need.20A sure is a lot of power.

author: Psi
author_rank: Super Contributor
timestamp: April 30, 2014, 07:46:32 am
content: I have a 6-24V input, 12V@12A output buck-boost automotive psu here that i bought for a carPC project.It's using a LTC3780.Does synchronize rectification with around 95% efficiency.Datasheet says its ideal for automotive uses.

author: P1X3
author_rank: Contributor
timestamp: April 30, 2014, 04:38:02 pm
content: Quote from: Psi on April 30, 2014, 07:46:32 amCould you tell me the model number of the psu?Maybe I can find a schematic for it so that I don't reinvent the wheel.
High DC voltage conditioning circuit how does it works ? - Page 1
Forum section: electronics / beginners

author: IGBTSiC
author_rank: Newbie
timestamp: June 28, 2024, 10:24:57 am
content: Hi,I have found DC VOLTAGE CONDITIONING circuit in "25kW WolfPACK FM3 Six-Pack Inverter" from Wolfspeed eval board. I do not understand how does it works because I have always use voltage measurement with galvanic isolation e.g. based on AMC1200.DC voltage is not connected with signal ground elsewhere. Why they do not use the parallel resistor Rs (marked in red color on the figure) for voltage droop? Could someone explain how this measurement circuit works ?

author: Andy Chee
author_rank: Super Contributor
timestamp: June 28, 2024, 10:31:40 am
content: This is just a differential amp configuration with a really, really, really big voltage divider.https://www.electronics-tutorials.ws/opamp/opamp_5.html

author: IGBTSiC
author_rank: Newbie
timestamp: June 28, 2024, 10:40:13 am
content: Thanks, but it has no difference that in circuit from wolfspeed they connected resistors R37 and R153 directly to the inputs of OA ? In differential amp. configuration, the R1 and R2 are connected from the source side. The gain will be the same i.e. Vo = R3/R1 (Vin+ - Vin-) ?

author: IGBTSiC
author_rank: Newbie
timestamp: July 01, 2024, 12:49:46 pm
content: I have done the simulation in LTSPICE. Yes exaclly this is the diferntial aplication of OA. Thank you.
high density smd assembly  - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: July 25, 2013, 12:31:44 pm
content: Hi,i have some experience with smd solder with an iron (TQFP, SOIC, 0805) but know i have to solder a pcb with high density smd component, like: qfn, son and 0603 passive and i can have for free the pcb stencil.So i was thinking of using solder paste, in your opinion is better to invest in a homemade reflow oven or a hot air gun?Can you point me some good product?My max budget is 150 euros.Thank you very much for the help.

author: Rerouter
author_rank: Super Contributor
timestamp: July 25, 2013, 12:42:46 pm
content: for high density i would probably say oven, but as for what model or modifications to play with i myself have not had to face that,doing msop's by hot air without a nozzle can be a sod of a job,

author: Falcon69
author_rank: Super Contributor
timestamp: July 25, 2013, 02:48:54 pm
content: I ran into the same problem where the components were either too small for the iron, or I just could not get to the pads with an iron.So, using this information, I built my own reflow oven, and it works great!http://spectrum.ieee.org/geek-life/hands-on/the-poor-mans-solder-reflow-oven/2I bought a $35 Black&Decker 4 element 1500 watt toaster oven from Walmart, and had a go at it. The PID controller cost me about $80.00 from Auburn Instruments (http://www.auberins.com/). I then bought a heatsink and Relay from eBay for about $24, and then I purchased a Data Logger from Vernier (http://www.vernier.com/). I've been really happy with the oven, and it works great! Don't buy a cheap Thermocouple though, you'll get the wrong readings. I suggest buying the ones listed off Auburn's site.You'll need a jigsaw with a metal blade to cut the opening for the PID. It's pretty easy to do.

author: JuKu
author_rank: Frequent Contributor
timestamp: July 25, 2013, 03:44:33 pm
content: Another vote for an oven. My experiences are here:http://dangerousprototypes.com/forum/viewtopic.php?f=2&t=4471.

author: Corporate666
author_rank: Unknown
timestamp: July 25, 2013, 09:37:50 pm
content: Oven is the way to go for sure.But honestly, you don't need a temp controller/thermocouple, etc. It's overkill. I've reflowed tens of thousands of boards in regular toaster ovens and never had any problems. Use the money you save on the controller on an air dispenser for solder paste. You can get them used/cheap in the $80 range. That will let you use off-the-shelf tubes of solder paste and easily assemble any test boards or low volumes. That's what I do and works great.

author: Unknown
author_rank: Unknown
timestamp: July 26, 2013, 05:22:18 pm
content: Thank you. i will invest in the oven.
High end multimeter voltage reference question  - Page 1
Forum section: electronics / beginners

author: Bootalito
author_rank: Unknown
timestamp: December 31, 2017, 02:03:41 am
content: How does a 32bit adc accept a ~7.2V buried zener reference? Is there just a 4:1 precision voltage dividor to get it down to ~2.5V then just software calibrated out? Or do high end multimeters accept a 7.2V reference natively?

author: Andreas
author_rank: Super Contributor
timestamp: December 31, 2017, 05:12:50 am
content: Hello,high end multimeters do not have a 32 Bit ADC.They usually have a multi-slope ADC. (around 24-28 Bit resolution)If you look e.g. at the 34401A service guide you will find that they generate a +/-10V reference out of the 7V by a precision resistor network.with best regardsAndreas
High Fidelity audio amp IC for battery powered projects. - Page 1
Forum section: electronics / beginners

author: jonovid
author_rank: Super Contributor
timestamp: October 09, 2019, 05:58:44 pm
content: what is the best 200Mw audio amp IC for 4 to 6 volt battery powered projects?.without the need for boost converters.I am looking for a high fidelity alternative to the LM386to drive 8 or 4 ohm 1watt to 200Mw speaker and or up to 30 ohms Headphones.be ether stereo or mono or mono bridged output.either stereo or mono IC is ok.I am looking at a single chip solution here with audio analog input gain up to 200 .this can be SMD , but I prefer DIP packages.will not be damaged by hot-plugging or open circuit at the output when powered up.by disconnecting the speaker swapping out the load or plugging in Headphonesmust have good high fidelity - low distortionrun from 4 to 6 voltsI have some PAM8408 audio amp8403 PAM8403 stereo filterless Class-D audio amplifier models.they say its 3watt. way more them I need for the job.here is the ic datasheethttps://www.diodes.com/assets/Datasheets/PAM8408.pdf

author: tooki
author_rank: Super Contributor
timestamp: October 09, 2019, 06:33:38 pm
content: I’ve tested the PAM 8403 and 8406 (IIRC) amps, and while I wouldn’t call themgreat, they’re perfectly adequate for non-demanding applications.Just bear in mind that most Class D amps, like these, use differential speaker outputs, and youcannotsimply bridge the two negative speaker outputs to create the ground of a headphone jack. You must use a resistor network as shown here:https://www.edn.com/design/analog/4313726/Add-headphones-to-a-Class-D-amplifierI’ve tried that circuit with the PAM amps and it works fine.

author: L_Euler
author_rank: Regular Contributor
timestamp: October 09, 2019, 06:53:19 pm
content: I've had really good luck with TI TPA6021A4 2W stereo amplifier chips.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: October 10, 2019, 02:02:57 am
content: TI has a whole lineup of very good audio AMPs. ESP32 might be worth looking at.

author: Audioguru again
author_rank: Regular Contributor
timestamp: October 10, 2019, 03:03:30 am
content: You know what an amplifier does when its volume control is set too high? It clips and produces lots of distortion.An LM386 produces fairly low distortion of 0.2% at 200mW into an 8 ohm speaker when powered from 6V. At 10% distortion its output is 325mW so it has 125mW more distortion. Its output into 4 ohms is about the same.A PAM8403 produces 0.08% distortion at 1.2W per channel into an 8 ohm speaker when powered from 5V. At 10% distortion its output is 1.8W into 8 ohms or 3.2W into 4 ohms.

author: floobydust
author_rank: Super Contributor
timestamp: October 10, 2019, 03:50:17 am
content: Important to note is Class D amplifiers generate strong EMI and are not usable in radio or other applications needing something electrically quiet. The PAM8403 datasheet radiated emissions graph is from 30-1000MHz and expect surprises below that range. PAM8403 is "filterless" but in reality you'd add some EMI filtering on the outputs. Too bad it won't run on 6V batteries.
High frequency circuit design - Page 1
Forum section: electronics / beginners

author: JTW55
author_rank: Newbie
timestamp: January 22, 2013, 04:58:13 pm
content: Can someone please help find the best design over at GRC.comhttps://groups.google.com/forum/#!forum/portable-sound-blasterThankyou

author: Skimask
author_rank: Super Contributor
timestamp: January 22, 2013, 05:11:07 pm
content: Is Mr. Gibson pushing this stuff AGAIN?I used to listen to him and Leo all the time, podcast after podcast after podcast.Then, well, started to get real old, real fast.Steve Gibson pushes this Shields Up! and Spinrite and a handful of other things (e.g. Portable Dog Killer being one of them) and pushes them like they're the latest/greatest thing out there since sliced bread.Not so much. It might be new stuff to the absolute new "young player" (as Dave says), but (I believe) to everybody else in the business, he just rehashes old ideas with new language, reads whats on whatever website happens to be hot that particular day, etc.Him, the ShamWow guy, what's his name with OxyClean, televangilists...they all belong in the same group.
High Frequency DC High Voltage Arc Ignition Generator Inverter Boost Step-Up ? - Page 1
Forum section: electronics / beginners

author: cpuxxx
author_rank: Newbie
timestamp: July 18, 2019, 04:29:43 pm
content: i didnt understand flyback - feedback relationship here clearly. Normally a driver switches here transistor's gate but in here what switches transistor's gate ? Gate is closing and opening so fast as polarized by coil or something like that ? What switches here transistor's gate ?

author: Simon
author_rank: Unknown
timestamp: July 18, 2019, 08:31:28 pm
content: Please do not double post, it really annoys people.
High frequency HV down a twin cable. - Page 1
Forum section: electronics / beginners

author: nsled
author_rank: Contributor
timestamp: April 14, 2025, 05:54:00 am
content: Why can't I transmit HV HF down a twin side by side cable?For example, I have a 10kV module that creates an audible buzz of HV that will transmit down 10m twin cable and arc over at the end.However when I put an arc lighter (inaudible I guess >25kHz) on it, it will arc into the cable but an arc will not appear at the end it seems to just "disappear", obviously it's not magic and the energy is going somewhere. I tried another inaudible HV module, and it didn't arc at the end either and quickly killed it, I guess due to back EMF? This was when rolled into a spool.I unrolled it and it does the same.What is going on?

author: amyk
author_rank: Super Contributor
timestamp: April 14, 2025, 06:05:02 am
content: Capacitive loss? At high frequencies, even very low capacitances become a low-impedance path.

author: mtwieg
author_rank: Frequent Contributor
timestamp: April 14, 2025, 03:07:18 pm
content: "twin side by side cable" isn't a clear description of any cable...10kV is far too much for typical hookup wire, you will need something specialized to avoid dielectric breakdown.

author: jwet
author_rank: Frequent Contributor
timestamp: April 15, 2025, 02:01:32 pm
content: The difference between a low audible AC signal and a high pitch AC audible signal isn't significantly different to HF loss in the coax- these losses are at quite high frequencies (~1 MHz).Its likely that the output impedance of your source is just getting swamped by the C of the line. Your 10 kV source has some grunt, a piezo sparker has a pretty high Z.
High Frequency pwm - Page 1
Forum section: electronics / beginners

author: Mediterraneo
author_rank: Newbie
timestamp: January 18, 2024, 10:41:18 am
content: Hi, it is a pleasure to be here. I'm a beginner in electronics but I'm studying it in college. I need to operate a 3-phase motor with a frequency as high as possible. I've searched on the internet and found this model of PWM: XY-BLDC 3 Phase DC Motor Controller with Hall Brushless 10KHz PWM Motor. It is not clear to me if it is good for my project because mine is a custom-made motor made with electromagnets and it has no hall sensors. I don't know even what kind of speed controller I need to install, probably a potentiometer? If I don't install any the pwm will start with the maximum 10khz frequency? Furthermore someone knows a 3-phase high-frequency pwm even above 10khz? Thank you

author: liaifat85
author_rank: Regular Contributor
timestamp: January 18, 2024, 12:48:44 pm
content: Since your motor is custom-made and lacks hall sensors, this controller may not be suitable.

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2024, 04:48:53 pm
content: More information is required.When you say electromagnets, do you mean it doesn't have any permanent magnets? Is it an induction or synchronous motor with a wound rotor? The usual way to start a synchronous motor is to start off with the rotor excitation short circuited, so it acts as an induction motor, before increasing the rotor current.

author: CaptDon
author_rank: Super Contributor
timestamp: January 18, 2024, 10:59:35 pm
content: Why the requirement "A frequency as high as possible"? You can do PWM easily in the megahertz range but that isn't going to run your motor. What do you assume is a practical limit for your motor? Higher frequency means more heat loss in the PWM circuit. There needs to be a balance between practical and what you think you want.

author: MarkT
author_rank: Frequent Contributor
timestamp: January 19, 2024, 09:18:08 am
content: Often 20kHz is chosen because then it won't create an audible whine. To run this fast the motor controller should be a MOSFET type to keep switching losses reasonable.But without more data about the motor its hard to say if 20kHz is reasonable for it - large motors use lower PWM rates to reduce iron losses.

author: CaptDon
author_rank: Super Contributor
timestamp: January 19, 2024, 02:51:48 pm
content: O.P., any more data??? By "As high a frequency as possible" could you also be indicating the frequency of the rotating field such as a 10,000 RPM motor vs. a 1000 RPM motor?? We need more info to be helpful.
High Gain MMIC AMP - Page 1
Forum section: electronics / beginners

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 26, 2024, 09:02:18 pm
content: I am looking for a very high gain MMIC to amplify -50 dBm signal at 420 MHZ by maybe 30 dB. Are there any such devices?

author: CaptDon
author_rank: Super Contributor
timestamp: February 26, 2024, 09:55:57 pm
content: I should think some wideband devices fitting that description should be easy to find. -50 is way up out of the noise floor so you don't need a super low noise figure and adding 30Db of gain you are still at -20 so it isn't exactly a power device either. I am certain readily available prepackaged devices with SMA connectors exist. Seems like bare MMIC's would be available. 1 50 ohm input lead, 1 50 ohm output lead which gets D.C. power through a choke and a grounded body / substrate. I wonder if any of the wideband devices rated for +10 to +30 DBm would work for you? They are certainly made. Up to 40Db gain blocks.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 26, 2024, 10:06:40 pm
content: I have already used a RF MMIC board and another board with a MAR 6 to achieve this. The signal is minus 70 dBm and I need to bring it up to 20 dBm. I cannot identify the MMIC on the board. It looks like something from ebay and has no identifying marks on it., it looks like a MAR but has much higher gain. I got the board with some other junk and have no idea where it is from really.

author: TimFox
author_rank: Super Contributor
timestamp: February 26, 2024, 11:35:44 pm
content: Mini Circuits has several devices with > 30 dB gain and -1 dB compression at > + 20 dBm.minicircuits.com browse through their huge catalog

author: JXstaystonight
author_rank: Contributor
timestamp: February 27, 2024, 02:47:55 am
content: HMC8410 from Analog Devices. It's a GaAs pHEMT MMIC amplifier offering very high gain and low noise figure in the frequency range up to 10 GHz.
high impedance and EMI - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: September 20, 2017, 03:23:15 pm
content: I was watching Dave Jones video and he mentioned something I dont understand.I think he said that when the scope is in 1M ohm setting,then electromagnetic interference starts coupling with the probes,that they will act as antenas.Is it true that oscilloscope is more susceptible to interference when set to 1 mega ohm than in 50 ohm mode?There are all kinds of intereference,magnetic,capacitive,electromagnetic ( photons ),I am not sure what type he had in mind,he said something about led lights,I guess thats RF photons?Why is there more interference at 1 M ohm setting? Free space have 377 ohm impedance,that should transfer more power to 50 ohm terminated scope.Isnt coax cable supposed to have shielding as standard? Then it should be imune to interference,except the magnetic type unless it have mu metal shield

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 20, 2017, 03:58:10 pm
content: Right, impedance of free space is 377 ohms, and 1M is a lot higher; so what can we conclude? The interference is not electromagnetic, but (near field) electric.Conversely, if we use a low impedance amplifier and a small loop antenna (a ~short circuit), we expect to observe magnetic interference.(The same principle applies to low-frequency-equivalent transmission line properties: below Zo, equivalent inductance is the primary concern; above, equivalent capacitance is the primary concern.)Indeed, these are always near field probes with very odd impedances (very far from 377 ohms). You can only make an antenna near 377 / 2 ohms (give or take geometric factors) when its size is comparable to a wavelength at the frequency of interest: in other words, it's not a near field probe anymore, but excellent for radiated (far) fields as well.Tim

author: Benta
author_rank: Super Contributor
timestamp: September 20, 2017, 04:01:28 pm
content: As you say, the source of EMI radiates a certain amount of power. A fraction of this power arrives at the scope probe, regardless of whether it's 50 ohms or 1 Mohm.However, the scope displays voltage, not power. For this reason, the impact is much higher on the 1 Mohm input, as the same power results in much higher voltage than on the low impedance input.
High impulse voltage from 5W power supply - Page 1
Forum section: electronics / beginners

author: ankurb
author_rank: Contributor
timestamp: January 13, 2018, 01:59:31 pm
content: Hi experts!I'm doing a test with a 3B 5kV power supply U33010?115 and noticed during fast short circuits I'm getting large power impulses of high wattage. It could be my faultly oscilloscope but was wondering if it is possible for the power supply to reach very high wattage output or is there something internally that prevents this. Hoping to pinpoint the problem.I have a capacitor that is going short circuit periodically at time of approximately every 200 us and trying to measure the voltage over the resistor that is in series with it. Goes short for maybe 0.5 us or so. During the 0.5 us I am getting very high voltages hence very large currents over my smaller ohm resistor.Any thoughts would be appreciated.Thanks!

author: jeroen79
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:22:53 pm
content: What exactly are you observing?Post some numbers or scopeviews to make things more exact.Large power and high wattage would be the same thing, high voltage something else.How is your capacitor going short circuit?Connecting an uncharged capacitor to a voltage source could result in a large inrush current.And connecting the charged output capacitor of the power supply to a low impedance load could cause a high discharge current.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 13, 2018, 04:56:53 pm
content: Yes, consider the equivalent circuit of the power supply, which I'm guessing has capacitors on its output.Tim
High Incremental Drain impedance (from the book The art of electronics) - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: October 29, 2024, 12:57:20 pm
content: Hello guys, I don't understand the meaning of this line"The FET has a high incremental drain impedance, giving roughly constant current for VDS greater than a volt or two"from field-effect transistors chapter of the book "The art of electronics".Here what does it means by"high incremental drain impedance"Can anyone help me to understand it?

author: TimFox
author_rank: Super Contributor
timestamp: October 29, 2024, 02:05:26 pm
content: "Incremental impedance" or resistance is simply the derivative (slope) dV/dIof the functionV(I) near the operating point of the device.The operating point is the voltage and current (in this caseVdsandId) when the input signal is 0.For FETs, BJTs, and vacuum pentodes operating as amplifiers, if you make a small change inVabout that point, you get a very small change inI, hence the derivative is high, and the incremental resistance is high.

author: tggzzz
author_rank: Super Contributor
timestamp: October 29, 2024, 02:21:28 pm
content: Quote from: TimFox on October 29, 2024, 02:05:26 pmAnother name is the "differential resistance", unsurprisingly. Occasionally it is known as "dynamic resistance", especially in the context of AC coupled amplifiers.Although not relevant to this thread, the OP might find it useful to keep in mind some devices can demonstratenegativedifferential resistance. Tunnel diodes are the classic example, but there are others.
High Input and Output Voltages L200 - Page 1
Forum section: electronics / beginners

author: matty-q
author_rank: Newbie
timestamp: May 06, 2014, 12:33:26 pm
content: Hi Guys,Could someone Explain what the "L200 HIGH INPUT AND OUTPUT VOLTAGE" figure does? I have been told to use it for my subject. I have read about it but I would like more information.Figure 26 on the link:http://www.circuitstoday.com/wp-content/uploads/2009/03/l200.pdfI have a 100 VA, 30V secondary, 3300 uF Capacitor and a bridge rectifier which has the values Forward Current: 4A,Forward Voltage: 1V.Thanks Matthew

author: w2aew
author_rank: Super Contributor
timestamp: May 06, 2014, 12:47:01 pm
content: Quote from: matty-q on May 06, 2014, 12:33:26 pmOf course we're not going to do your homework for you! You won't learn anything that way. Tell us what you've figured out yourself already. What are you stuck on? Can you see what affect the VZ zener diode is having on the operation of the regulator? If you show us that you've thought about this and have an understanding of how the basic regulator works, then we might give you a hint or two to help you figure the rest of it out.
High pitched noise from USB charger - fixable? - Page 1
Forum section: electronics / beginners

author: atmfjstc
author_rank: Regular Contributor
timestamp: November 30, 2020, 03:28:56 pm
content: I have an Allocacoc Power Cube - basically an extension socket with 2 USB ports included - that makes a very annoying intermittent high-pitched sound while charging most devices. The sound is clearly correlated to the power draw and well within hearing range, I'd estimate about 13kHz or so. I think it always used to be there, but it seems to have become much more noticeable lately.I imagine the DC conversion circuitry in the socket isn't great, but still it's very convenient and I'd like to fix it if possible instead of buying a dedicated charger. Does anybody know if this is possible? Could it be something like a damaged capacitor, or is it a fundamental design flaw?

author: Yansi
author_rank: Super Contributor
timestamp: November 30, 2020, 03:33:22 pm
content: This gets fixed the easiest way by buying a good quality charger.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 30, 2020, 04:06:22 pm
content: Transformer coil whine is too much trouble to be worth fixing.

author: Yansi
author_rank: Super Contributor
timestamp: November 30, 2020, 04:45:37 pm
content: Quote from: Refrigerator on November 30, 2020, 04:06:22 pmCorrection: Phone chargers are not worth fixing. You'll easily spend more resources trying to fix the cheap sh!t than what you'd need to buy new decent one.