hybridfree/eevblog-posts huggingface dataset:
Free book on power supply design - Page 1
Forum section: electronics / projects

author: ptricks
author_rank: Frequent Contributor
timestamp: December 11, 2012, 01:14:10 pm
content: Some may already have this. It is a great book/app note from agilent that they released years ago on power supplies. Covers just about everything and it is free !http://cp.literature.agilent.com/litweb/pdf/5952-4020.pdf

author: skipjackrc4
author_rank: Regular Contributor
timestamp: December 11, 2012, 04:10:30 pm
content: Very nice! I hadn't seen that one before.

author: PuterGeek
author_rank: Regular Contributor
timestamp: December 11, 2012, 06:07:53 pm
content: Nice find with some good information! Probably one of the old HP handbooks originally published in the past.I wonder if Agilent will publish such information going forward?It would be a shame if they didn't but perfectly understandable given all of the 'borrowing' in China and elsewhere.

author: bitwelder
author_rank: Super Contributor
timestamp: December 11, 2012, 09:32:08 pm
content: Very nice guide, thanks!I see from the last page that it's: Copyright 1978, 2000 Agilent TechnologiesDefinitely some old HP engineering expertise in there...

author: FenderBender
author_rank: Super Contributor
timestamp: December 11, 2012, 09:49:51 pm
content: If there's one thing that American test equipment companies have over their Eastern competitors, it is good documentation and stuff like this.
Free Fluke "Calibration Philosophy in Practice" book - Page 1
Forum section: electronics / projects

author: robrenz
author_rank: Super Contributor
timestamp: January 06, 2014, 05:55:16 pm
content: I got a email from Fluke about a month ago offering a free copy of Calibration Philosophy in Practice to the first 200 entrants that tell why their company could use the new fluke calibrator and agree to a salesman contact. I promptly applied but told them straight out that I was a hobbyist and a happy owner of a 8846A but I would not be buying a calibrator. But I sure would enjoy studying the book and thanks for making the best 6.5 digit bench meter on the planet.A week later I get a confirmation that I was one of the first 200 and I would receive my book shortly.Arrived FedEx today! Woohoo

author: jancumps
author_rank: Unknown
timestamp: January 06, 2014, 06:29:12 pm
content: Send my regards to the salesmanHappy reading!

author: saturation
author_rank: Super Contributor
timestamp: January 14, 2014, 01:54:14 pm
content: Great! No pdf version?

author: robrenz
author_rank: Super Contributor
timestamp: January 14, 2014, 02:20:14 pm
content: If you google the title you will find several pdf's for the earlier edition. Glad to see you are still around saturation

author: saturation
author_rank: Super Contributor
timestamp: January 14, 2014, 06:55:35 pm
content: Thanks robrenz, back from long vacation and took a while to read 30+ pages of back posts. Finally finished them today. Yes, I have that pdf ?c1970-80 I think 1st Edition.I see one long time eevblog poster has left? Sorry to see, that's a loss.Quote from: robrenz on January 14, 2014, 02:20:14 pm
free Lecroy knobs - Page 1
Forum section: electronics / projects

author: KTP
author_rank: Frequent Contributor
timestamp: July 18, 2012, 02:38:24 am
content: Sorry if this is the wrong forum section...but I am not selling anything...I just took all of the knobs off the front panel of a Lecroy 9400 that is being junked if any of you Lecroy fan boys have missing or broken knobs.I can mail them in an envelope for free...the postage would not even be worth bothering with paypal.Here is what they look like...large and small. Not sure if they fit the 93xx series, but I could measure the potentiometer shafts to check.

author: Psi
author_rank: Super Contributor
timestamp: July 18, 2012, 03:41:10 am
content: We need more people like this.

author: digsys
author_rank: Unknown
timestamp: July 18, 2012, 06:36:19 am
content: My LeCroys 94xx were the first decent DSOs I ever bought. I keep them in perfect condition, so Iwon't take stuff I don't need. IF no-one else wants them and you decide to get rid of them, I'll buythem off you and store them. Pity it wasn't the 9354AL, need parts for those :-)

author: grumpydoc
author_rank: Super Contributor
timestamp: July 18, 2012, 07:09:58 am
content: QuoteThey won't - the 93xx has rotary encoders with a .185" split shaft. As yet I haven't found any supplier of knobs for these. The ones you have look like 6mm or 1/4" shaft for the larger ones and ?4mm shaft for the smaller ones.

author: KTP
author_rank: Frequent Contributor
timestamp: July 18, 2012, 12:15:45 pm
content: The small knobs fit on a 0.114" diameter shaft and the large knobs on a 0.229" shaft. For you backwards people who still use the metric system, I guess that would be 2.9mm and 5.8mm shafts.digsys: Give it a few days...if nobody needs them you can have them. I also have the CRT and a few of the modular power supplies if you wanted them, but they would not be cheap to ship.

author: T4P
author_rank: Super Contributor
timestamp: July 18, 2012, 12:37:36 pm
content: Give me a PM, i am restoring some LeCroy scopes on request, i only need the 5.8mm shaft knobthe original knobs on this certain scope split into two

author: jh15
author_rank: Frequent Contributor
timestamp: July 20, 2012, 02:02:52 am
content: Lecroy were the first digital scopes I used back in '89. After using analog Tek and HP scopes all my life, a digital waveform was fascinating.Their rep was set up in town, and any problems we had they were super about support.I missed the experience until just this spring, when I bought a rigol and have the same feeling when I view my (multicolor!) traces..

author: aj4ks
author_rank: Newbie
timestamp: October 03, 2012, 10:09:24 am
content: I could use one of the small knobs with cap (no marking) and would be thrilled for the chance to pay for the time/materials/effort involved in sending them.Are they still looking for a home?Thanks

author: T4P
author_rank: Super Contributor
timestamp: October 03, 2012, 08:39:33 pm
content: He told me he would send it but it's been nearly 4 months now ...
Free low noise audio preamp design book. - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: August 09, 2025, 08:08:50 am
content: I've just stumbled upon this free book.Lots of useful stuff on low noise preamp design.It focuses on RIAA cartridge amp design but the core topics are relevant to all low noise opamp circuits.www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Vogel_Burkhard/The%2520Sound%2520of%2520Silence.pdf&ved=2ahUKEwjCoOGVov2OAxVUXkEAHe8YOIcQFnoECBcQAQ&usg=AOvVaw38twM30C7mHbregQt3p1K9

author: moffy
author_rank: Super Contributor
timestamp: August 09, 2025, 08:19:49 am
content: Thanks for the link, a quick browse and the low noise BJT chracteristics on page 45 looks interesting.
Free old electronics magazines online - Page 1
Forum section: electronics / projects

author: Deathwish
author_rank: Unknown
timestamp: May 26, 2015, 03:22:03 am
content: Some will already know of this , but some will not. 10 years of old Radio electronics mags with projects, some may still be relevant or even buildable today. So go knock yourselves out even if it is just out of boredom or nostalgia.https://archive.org/details/radioelectronicsmagazine

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 26, 2015, 03:56:16 am
content: And on this website:http://www.americanradiohistory.com/index.htmare searchable PDF archives of ~200 technical/communications magazines including...Popular ElectronicsElectronics WorldRadio Electronics & Electronics NowElectronics IllustratedRadio TV ExperimenterElementary ElectronicsByte MagazineModern ElectronicsHands-On ElectronicsPractical WirelessPractical TelevisionRadio ConstructorAmateur Tape RecordingAudio Engineering/Audio Magazine.Tape Recordingdb magazineStudio SoundHigh FidelityModern RecordingRecording Engineer/ProducerBroadcast EngineeringBM/ETelevision EngineeringMany other broadcasting and media magazines.Electronics Catalogs from Allied, Lafayette, Olsen and othersMostly from the US, but several from the UK and Australia, also

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: May 26, 2015, 05:09:26 am
content: Thanks,I did not know these links. Very interesting !
Free parts form the work dumpster - Page 1
Forum section: electronics / projects

author: 56kuser
author_rank: Newbie
timestamp: February 06, 2025, 01:47:23 am
content: Hey everyone,I recently got my hands on a large batch 400 units (2+ reels) of Fibacom SS808 Android SOMs. These are fully featured modules with dual SIM support, voice capabilities, camera input, and more—all in a compact castellated package which makes hand soldering feasible (There are some pads on the bottom but these seem to be just grounds).The issue? Without the right tools, they’re essentially paperweights. I’ve been trying to reach Fibacom for support —looking for flashing procedures, an SDK, or an Android image—but so far, no response.I’d love to put these to good use for some fun projects, but without a way to flash and configure them, I’m stuck. Does anyone have experience with these modules or know where I could find the necessary tools? Are there alternative methods to get an OS onto them if official support is unavailable? All i can get is the basic datasheet which i have uploaded as reference. I have torn one apart and the module uses the Qualcomm SD450 CPU along with some memory, Cellular frontend etc.Would really appreciate any guidance—otherwise, these chips will just end up as e-waste which feels wrong....Thanks in advance!

author: Terry Bites
author_rank: Super Contributor
timestamp: February 06, 2025, 12:19:54 pm
content: Your modules are likely to conform to an industry standard. That's how the module makers compete after all.I'd start by looking at similar LTE modules.eghttps://developer.tuya.com/en/docs/iot/LTE-hardware-design?id=Kamiiieo4hz57I know SFA of course.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 06, 2025, 01:03:25 pm
content: maybe on XDA forums ?
FreeRTOS based Wireless Sensor Network Communication Protocols - Page 1
Forum section: electronics / projects

author: Mr.D2
author_rank: Newbie
timestamp: September 23, 2014, 03:44:16 am
content: Hello!I am currently making a WSN project that runs FreeRTOS and I am looking for a Communication protocol [modified:library] that can be used alongside the FreeRTOS uOS.I found some references to some, but they are paid extentions to the FreeRTOS kernel. Being this ones:-http://nabto.com/-http://www.freertos.org/FreeRTOS-Plus/embTCP/FreeRTOS_Plus_TCP.shtml-http://www.freertos.org/FreeRTOS-Plus/FreeRTOS_Plus_UDP/FreeRTOS_Plus_UDP.shtmlCan someone help me with some suggestions or pointers of what can i use?Comments and replies are welcome!!Thanks,Diogo Guerra

author: Kremmen
author_rank: Super Contributor
timestamp: September 23, 2014, 05:33:57 am
content: http://www.freertos.org/embeddedtcp.html

author: RichardBarry
author_rank: Newbie
timestamp: September 23, 2014, 08:03:13 am
content: Same question with replies here:https://sourceforge.net/p/freertos/discussion/382005/thread/78ba77df/

author: tggzzz
author_rank: Super Contributor
timestamp: September 23, 2014, 10:05:19 am
content: Do you want a protocol or a device driver, or both?If a device driver, then specify the hardware.If a protocol, then specify the protocol.

author: Mr.D2
author_rank: Newbie
timestamp: September 23, 2014, 05:39:20 pm
content: Hello again,Quote from: RichardBarry on September 23, 2014, 08:03:13 amJust to say that this is also my doing...My network is a cluster of motes that may be applied in 2 different scenarios.- Close range cluster (with a diameter of <500m)- Wide range cluster (with a diameter of 1 to 5km)For this I have at my disposition 2 radios being this ones:- Sub 1GHz - CC1000 (433MHz) - RF- Over 1GHz - CC2420 (2.4GHz) - 802.15.4 Low-rate WPANThe mote microcontroller is a MSP430F5x chip and the transmission rate is very low. Packets are sent when there is an event, so the network must be real-time capable.Quote from: tggzzz on September 23, 2014, 10:05:19 amI need the entire stack library, but mainly the network and transmission layer ones, because the lower ones will need modification (most probably).I was thinking MAC -> IP -> TCPThe cluster will then use a Gateway Node to send the data over ex. Ethernet to a DataBase.
Freestanding tester advice for low frequency jitter measurement 50Hz square wave - Page 1
Forum section: electronics / projects

author: Hgspine
author_rank: Contributor
timestamp: September 15, 2019, 09:43:53 pm
content: I prefer a freestanding piece of equipment that does not require a sound card or computer.Ideally I connect it to the testpoint with the 50Kz square wave and it gives me a numeric readout of jitter.Can anyone tell me a reasonably priced (under $1000 USD) piece of equipment that does this?I don't mind buying it used.Thanks to anyone who can advise.
Freeware or Cheap JEDEC Compiler for PAL16L8/20L8 or GAL16V8/20L8? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: October 30, 2023, 11:29:03 am
content: Hi!I am investigating a General Radio 1689 Digibridge for a Vintage Radio Forum Member, who thinks one or more of the programmed devices may have failed in it!Very fortunately, I got the EPROM dump from k04BB, and the circuit diagrams from another EEV Blog Forum Member have the product–terms for each pin of the PAL16L8 and 20L8 printed on one of the sheets along with their schematic representations, so all I need is a JEDEC Compiler that I can enter the product terms into for each pin – the contents for the two Sine Generator PROMs (74S571s!) are given on the circuit diagrams as well !Can anyone recommend a free or cheap JEDEC compiler I can use please? – Will "Flowcode" do it?Chris Williams

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 30, 2023, 11:40:51 am
content: Maybe?https://hackaday.com/2021/04/15/programming-pals-in-2021/

author: DLJ
author_rank: Contributor
timestamp: October 30, 2023, 12:51:52 pm
content: Chris,WinCupl as pointed at by DavidAlfa is a usefull (FREE) compiler, I find it works better under XP than Win-10.You will also need a suitable device programmer.You should be able to test the PALs fairly easily on a solderless bread board with some LEDS and resistors, see the youtube that DavidAlfa linked to.Good luck.David

author: PCB.Wiz
author_rank: Super Contributor
timestamp: October 30, 2023, 06:29:12 pm
content: WinCUPL works fine here on Win11, in command line mode.WinCUPL can also run simulation vectors and append to the Jed file for testing, tho the challenge is finding a low cost programmer that can actually run test vectors.EETools Chipmax / Topmax pgm many SPLD/CPLD, and support vector testing, work, but they are mid priced.The XGecu T56 looks promising, it can pgm many PLDs, and it has CMOS logic testing, but (currently) lacks the SW upgrade to read JEDEC test vectors.For hobbyist use, there is this SPLD programmer projecthttps://github.com/ole00/afterburnerNo vector test support, (does not connect MCU to all PLD pins) but otherwise appears active and supported.
Freeze spray fixing marginal power-on issue? - Page 1
Forum section: electronics / projects

author: jayalt
author_rank: Contributor
timestamp: March 29, 2023, 10:18:56 pm
content: I was wondering what types of issues can actually be FIXED by a can of freeze spray?My impression is that freeze spray is useful in diagnosing soldering issues since it can cause faulty joints to temporarily break.I am seeing the opposite on a BGA component that has been giving me a bunch of issues upon power on. I seem to be experiencing some type of latch up condition after applying power to my IC. When I take a can of freeze spray directly to the IC, it can power on just fine.The temperature of my component / board is nearly always at room temperature, since it is a low voltage, battery-operated product.Any ideas what could be happening?

author: xrunner
author_rank: Super Contributor
timestamp: March 29, 2023, 10:25:58 pm
content: Besides double-posting this topic, I looked at your post history. You never respond to anyone who asks for more information from you. Why is that?

author: jayalt
author_rank: Contributor
timestamp: March 29, 2023, 11:32:37 pm
content: Quote from: xrunner on March 29, 2023, 10:25:58 pmOops- my bad.Typically I'm not at liberty to share the schematics or layout online. Although I realize the type of open-ended debug questions I generally ask require them for a useful response.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 30, 2023, 01:30:32 am
content: In that case why bother (us) at all?

author: BravoSierraBravo
author_rank: Newbie
timestamp: March 30, 2023, 02:18:36 am
content: I'm new here, but I'll take a shot at this.It is very unlikely that freeze spray will "fix" anything permanently. If the failing component or board trace in question is thermally impacted and breaks contact or shorts out when it gets hot, the freeze spray would only provide a temporary relief of that symptom and the failure mode will return as soon as the temperature rises back to the failure point of the device/board.Freeze spray is quite good for identifying shorted capacitors and diodes, as they will heat up when power is applied. Shoot some freeze spray, power on, watch for what what defrosts first and start troubleshooting there.I just use canned air and hold the can upside down. While I'd prefer to have a FLIR camera, canned air is cheap and I've repaired a lot of boards using it - but it never "fixed" anything.My buck-O-five. Good luck.

author: jayalt
author_rank: Contributor
timestamp: March 30, 2023, 04:51:24 pm
content: Quote from: BravoSierraBravo on March 30, 2023, 02:18:36 amThank you for your input.You are correct and I should clarify further - it doesn't permanently fix the issue. It provides temporary relief. It allows my IC to power up correctly a couple times before things stabilize to room temperature once again. I will check for shorted components.What is interesting is the system itself never rises more than a few degrees past room temperature at any point of operation - I have confirmed on a thermal camera. The system itself is off 99% of the time, and when I do power on I'm running things very quickly.
Frequency counter circuit  - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: January 14, 2016, 07:05:26 pm
content: Hello,can I make a simple frequency counter with cheap microcontroller like 16F84 and 7-segment LED display but it can's measure from Hz up to 200Mhz or more?.Thank you

author: dom0
author_rank: Super Contributor
timestamp: January 14, 2016, 08:24:45 pm
content: Forgot about your own thread already?https://www.eevblog.com/forum/projects/frequency-counter-project-61274/
frequency counter front end - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: June 19, 2014, 09:29:49 am
content: HI,I designed a frequency counter using CPLD that counts upto 50MHZ , but I found problem in designing the analog front end. I know what front end analog circuit does. I go through various frequency counter schematics they all used differential receiver at the front end with ECL. I know it is faster due to non saturation of transistor. most of the theory said that the differential receiver was used for gain and Schmitt trigger. can I used just opamp amplifier and a Schmitt trigger in the front end . Is it work.............

author: tom66
author_rank: Super Contributor
timestamp: June 19, 2014, 10:26:57 am
content: For a 50MHz signal, you could probably use an op-amp, but it will be difficult to design a good amplifier especially if the op-amp will be frequently saturating, like as a schmitt trigger. Why not use a dedicated comparator? You can convert ECL output into ordinary TTL... a quick search brings up this --http://www.onsemi.com/PowerSolutions/product.do?id=MC100ELT25

author: David Hess
author_rank: Super Contributor
timestamp: June 23, 2014, 02:20:09 am
content: If you want to use high impedance passive probes then you will need an FET buffer of some sort.RF frequency counter front ends use limiting amplifiers to create a saturated signal for driving the following logic but DC coupled lower frequency ones use a comparator with hysteresis. If you use a fast enough comparator, then you do not need anything else.It might be worth using an adaptive trigger circuit:http://www.linear.com/docs/4390
Frequency counter IC with I2C/SPI out? - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: March 19, 2014, 04:26:29 am
content: There's plenty of uC-controlled digital oscillator/clock ICs e.g. LTC6904 - but are there any frequency counter ICs designed to interface with micros?I'm toying with the idea of building a replacement / expanded version of a memory unit for an old-ish radio, which in this case requires reading and storing the frequency from a completely analogue VFO. There's many ways of implementing a simple counter in discrete logic, and in this case the VFO frequency is low enough (max ~3.5MHz, and resolution in the 10's of Hz will be fine) that I can count it pretty easily just with a micro, but it got me wondering...If such a chip existed at a reasonable price, I'd be tempted to use it just for the experience.

author: linux-works
author_rank: Super Contributor
timestamp: March 19, 2014, 04:40:21 am
content: divide it down and count that. I've recently heard of the 'pic-div' (search on it) and its an 8pin chip that will divide by 10 or really, whatever you want. seems like a nice little cheap prescaler.once its low enough freq, you can count it in software easily enough using any controller.there is a freq counter 'app' for the arduino and I've been able to read spdif freq's (192khz and higher) reliably with it in pure software with no hw assist.

author: Unknown
author_rank: Unknown
timestamp: March 19, 2014, 05:17:27 am
content: Quote from: linux-works on March 19, 2014, 04:40:21 amYeah, as I said that's more or less what I plan to do. Shouldn't need a prescaler; even an Arduino is more than capable of counting the 2.5~3.5MHz VFO using a timer interrupt.I was more curious to see if such a chip existed, since the opposite is fairly common.

author: linux-works
author_rank: Super Contributor
timestamp: March 19, 2014, 05:38:26 am
content: I know I was able to get into the low mhz range before it could not keep up.

author: dannyf
author_rank: Super Contributor
timestamp: March 19, 2014, 10:42:53 am
content: QuotePick a mcu with asynchronous counter (some PICs but not all of them have that. AVRs don't). Easily 20Mhz or more without external parts, with sufficiently high (internal) prescaler.Then program a spi / i2c slave in it and you are done.

author: jimmc
author_rank: Frequent Contributor
timestamp: March 19, 2014, 08:25:10 pm
content: Take a look at Microchip AN592 for a single chip PIC solutionhttp://ww1.microchip.com/downloads/en/AppNotes/00592.zipA minimalist version with RS232 output ishttp://www.piclist.com/Techref/microchip/freq2rs232-jp.htm,should be easy to port to a chip with I2C, SPI etcThere are a lot of more complex designs derived from Terry Weeder's original with an LCD display eghttp://www.piclist.com/techref/piclist/weedfreq/4bitlcdusart.htmwhich again has an RS232 output.Jim
Frequency Counter IC - Page 1
Forum section: electronics / projects

author: House91320
author_rank: Regular Contributor
timestamp: September 13, 2011, 01:05:22 am
content: dose any one know of an ideally single chip frequency counter ic that outputs and analog spi or 12c signal?

author: Bored@Work
author_rank: Super Contributor
timestamp: September 13, 2011, 06:00:31 am
content: Quote from: House91320 on September 13, 2011, 01:05:22 amAnalog SPI? SPI is digital.12c? Do you mean I2C? That is digital, too.And these days you don't need any special ICs any more. Most garden-variety microcontrollers are good enough for counting. If they can't stand the input frequency you want, add one or a few dividers from a fast enough 74<some letters> series. The days of ECL dividers to get to 100 MHz are gone.The net is full of examples.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 13, 2011, 08:24:12 am
content: Other than what BAW says, frequency? accuracy? amplitude? maximum integration time?

author: Zero999
author_rank: Super Contributor
timestamp: September 13, 2011, 04:45:51 pm
content: Even a basic 8-bit PIC16F505 has a counter capable of 20MHz.

author: House91320
author_rank: Regular Contributor
timestamp: September 13, 2011, 10:17:35 pm
content: Sorry I should have put commas. I figured it out I'm going to use a micro thanks.

author: Gall
author_rank: Frequent Contributor
timestamp: September 15, 2011, 07:00:04 am
content: Depending on the frequency and required accuracy, you may choose between microcontroller, microcontroller with divider/prescaler, CPLD and combintaions of them.If you need analog output, there exist frequency-to-voltage converter ICs.What exactly you want to count?

author: Gadget999
author_rank: Newbie
timestamp: September 16, 2011, 08:20:52 am
content: i have found the arduino (AVR Atmel) works pretty good
Frequency Counter - Page 1
Forum section: electronics / projects

author: Ferroto
author_rank: Frequent Contributor
timestamp: July 01, 2011, 05:32:58 pm
content: I'm currently working on a frequency counter It's all 4000 series cmos chips and it's coming along nicely.Basically its 3 BCD's (Binary Coded Decimal) counters outputting its value into 3 quad d-latch chips (4175) and then outputting into a binary to 7-segment converter, then to 3 seven segment display's.THE COUNTThe wave form you are testing feeds the clock pulse for each BCD which in turn counts the frequency.RANGEThe range is set by a sample wave at 1 hz (or 1 khz depending on what range you want). This will cause the d-latches to latch whatever value the BCD's have once per second. A delay caused by two not gates will give the d-latches time to latch the value before the signal reaches the reset pins of the bcd's reseting the bcd's to zero. and starting the process all over again.The latches now have the frequency as a BCD value.DISPLAYThe value stored in the 3 d-latches can then be fed directly to the 3 bin to seven segment decoder and onto the displays.OVER RANGEIf the carryout bit on the last BCD goes high it means that the frequency counter has gone over range, however this pin will immediately go out as all the BCD's will reset.In order to indicate to the user that an over range has occurred the carryout bit will charge the capacitor C2 which will keep the signal a logical 1 long enough for another cycle to go through. If the frequency is still over range the carryout signal will refresh the charge in the capacitor. The capacitor is simply used to create a delay.The signal from the carry out bit will then go through an LED to indicate an over range has occurred. The signal will then go through a not gate then into an NPN transistor which will then disable the display until the over range issue has been corrected.I'm not exactually sure what I'm going to use for the 1hz clock and the 1khz clock for the range select. So I just have it going to a header right now.The schematic
Frequency dependence of power MOSFT/IGBT internal gate resistance. - Page 1
Forum section: electronics / projects

author: t_pattinson
author_rank: Newbie
timestamp: January 29, 2025, 02:29:28 am
content: Hi all,I have performed measurements using a Bode 100 analyser (yes, it's set up and calibrated properly) of the Cgs/Cge of a few power MOSFETs/IGBTs. The devices are 650V class, TO247 packages.I'm measuring using the impedance analyzer jig (B-WIC) with the collector and the emitter bridged together, measuring from the gate to C+E.The approach is similar to what's done here:https://www.picotest.com/measuring-mosfet-gate-resistance/except without any DC bias, the measurement is done at 0V.I have arrived at a result indicating the internal gate resistance is highly dependent on frequency, reducing by 2x to 10x between 100kHz and 1MHz.At first I considered that this may be a measurement error, because the impedance is dominated by the capacitance. This is mentioned in a few app notes on the topic.Measurement of a ceramic capacitor (2x 2n2) series with a 1R5 chip resistor shows the expected (flat) resistance characteristic. Besides, this should be well within the capability of the Bode 100.Here you can see:Yellow - 650V 50A IGBTLight blue - Another 650V 50A IGBTPurple - 650V SiC MOSFETGrey - 4.4nF ceramic capacitor in series with 1R5I can replicate this result on an LCR meter at 100kHz. The IGBT/MOSFET gate measures a high resistance, the real RC network measures as it should.Investigating further, I adjusted the source level of the Bode 100 from 13dbm to 0dbm to -20dbm. At lower levels, the resistance is flatter with frequencyMeasuring the same IGBT as the light blue traceGreen: +13dbm (as previous)Red: 0dbmPurple: -20dbmI didn't show it here, but the RC network's response did not vary with the applied signal level.So it seems like there is an ac/dc bias effect at play here.My main question is, what is the mechanism that causes this (the variation of the resistance with frequency)? Is it "real"? or somehow an artifact of the measurement setup?I haven't been able to find any app notes on the topic.TIA.
analog audio frequency division for a dynamic signal analyzer? (extending bw) - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: June 02, 2014, 05:07:00 am
content: Is there any practical circuits for analog audio signal division that could be used with reasonable effect in a DSA? I have the parts for a nice pre amp, more accessories would be nice.http://en.wikipedia.org/wiki/Frequency_divider#Analog_dividersThe LTC6943 could be used to build a 0.01% analog multiplier, it seems appealing to use in the wiki circuits. or do these things just mangle real world signals up so bad that its a fools effort?

author: Paul Price
author_rank: Super Contributor
timestamp: June 02, 2014, 06:59:58 am
content: AD633 et al from Analog Devices, MC1494L Motorola avail. on ebayLow distortion, wide freq range.

author: SArepairman
author_rank: Frequent Contributor
timestamp: June 02, 2014, 08:02:37 am
content: Quote from: Paul Price on June 02, 2014, 06:59:58 ambut is it viable? "analog frequency divider" brings up almost nothing on google.not to mention that analog multipliers have a really bad reputation..with the noise specs on those guys it seems that I would be restricted to 60dB dynamic range. mI think this idea is going bye bye

author: mathias
author_rank: Regular Contributor
timestamp: June 02, 2014, 10:18:33 am
content: Perhaps you should Google on "frequency mixer" instead of "analog frequency divider". Usually the input is at least several MHz's, but Mini Circuits also makes the SRA-8+, which can go down to 500Hz on it's RF/LO port. Conversion loss is about 5dB.What frequency range would you be interested in?

author: SArepairman
author_rank: Frequent Contributor
timestamp: June 03, 2014, 05:10:44 am
content: Quote from: mathias on June 02, 2014, 10:18:33 amI would like to possibly triple or at least double my 40khz DSA bandwidth.120KHz FSBW would turn it into a most respectable devices. are there any other adverse effects besides insertion loss and minor distortion?

author: mathias
author_rank: Regular Contributor
timestamp: June 03, 2014, 10:13:14 am
content: Yes, one you won't like... aliasing.If you have the mixer being driven by lets say 100kHz, then you will downconvert not only 100-140kHz -> 0-40kHz, but also the mirror frequencies 60-100kHz -> 40-0kHz. The only way to avoid this is:a) to use a filter that selects which band you want to investigate.b) a heterodyne downconversion.You can find quite a lot of info on this subject on Wikipedia:http://en.wikipedia.org/wiki/Heterodyneandhttp://en.wikipedia.org/wiki/Superheterodyne_receiver
Frequency Generation: Crystals and Ring Oscillators - Page 1
Forum section: electronics / projects

author: Hugoneus
author_rank: Frequent Contributor
timestamp: August 08, 2011, 05:21:52 pm
content: Dear EEVbloggers:After having been away for the past month, I am back producing more videos: (This next Ep. is 55 minutes long!)In this episode Shahriar takes a look at the challenges associated with signal generation for the purposes of timekeeping. More specifically he digs deep into the workings of crystal oscillators and even takes apart some vintage crystals to reveal whats inside! He also shows how this type of circuits can be characterized and compares the performance of a crystal oscillator with that of a ring oscillator under temperature and power supply variations.Please visit:http://www.TheSignalPath.comAlso please consider going to the YouTube channel, leaving a comment rating the videos. This will help us get the Partner status so we don't have to keep splitting the videos up.Cheers!

author: Hugoneus
author_rank: Frequent Contributor
timestamp: August 08, 2011, 10:04:49 pm
content: Please also feel free to let me know what you thought of the episode on this forum.

author: Rufus
author_rank: Super Contributor
timestamp: August 08, 2011, 11:47:29 pm
content: Interesting enough. I had never seen a crystal you could dismantle although I have a couple of glass cased ones.I think your audience target wanders a bit. Someone who needs the difference between a crystal and semiconductor ring oscillator explained is unlikely to know what a spectrum analyzer is, never mind understand what it is showing him.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: August 09, 2011, 12:11:13 am
content: I know what you mean. It kind of wondered a little. Perhaps I should put tags on the videos to describe the level of each video and try to stick to that level.Thanks for the feedback.

author: plesa
author_rank: Frequent Contributor
timestamp: August 09, 2011, 01:51:44 am
content: Thanks for this kind of practical vids. Thumbs up!!
Frequency inverter power supply topology - Page 1
Forum section: electronics / projects

author: stoyanoff
author_rank: Contributor
timestamp: September 16, 2021, 09:19:12 am
content: Greetings! Can I have your opinion on three phase 400V frequency inverter power supply design? In my design I am using a simple transformer(230V/50hz to 4x15V+1x9V) and LVRs(LM317 and LM337) to drive the half-bridges. This schematic is quite cheap, but I am concern about the quality, durability an so on. I`ve notice all frequency inverters on the market are using some modification of flyback converter.Do you think there is a specific reason for this choice? My power supply is quite bigger, but I don`t have problems with generated parasitic frequencies and so on. If I switch to flyback converter it will be smaller but proper transformer is hard to find. My product is designed for specific purpose and I don`t expect high qualities. But it must be as reliable as possible.So which design is better for this app? Which one do you prefer?

author: capt bullshot
author_rank: Super Contributor
timestamp: September 16, 2021, 10:38:34 am
content: You'd better use a 400V primary transformer, as the neutral (to provide 230V L-N) usually isn't available in the typical environment.Other things to consider:For the gate drivers, you'll have quite steep dU/dt (ballpark values 1 ... 10kV / us) on the switching node. If this is tied to a "normal" transformer, it's insulation might break over time. Your transformer (as well as a DC/DC module that one might want to use) must have explicit rating for this high dU / dt, and appropriate insulation ratings to meet CE / UL / whatever.Usually the flyback (or similar) transformers used for gate driver supply are custom made to these requirements. IIRC, TI have some examples of appropriate supplies in their application circuits collection. Maybe Würth (or some other manufacturer) sells transformers that are suitable for these examples.

author: David Hess
author_rank: Super Contributor
timestamp: September 16, 2021, 11:57:19 am
content: Flyback converters are popular when multiple outputs are needed at lower power levels because of their low cost. At higher power levels, other topologies are more cost effective.

author: stoyanoff
author_rank: Contributor
timestamp: September 16, 2021, 12:49:58 pm
content: capt bullshot, these are good suggestions! I ca easily change the input voltage and ask for isolation level up to 10kV. The transformer is custom made.david hess, I am not well familiar with all topologies, so I used flyback as an example.Thanks!PP: By the way, I found a few pulse transformer winding tutorials and I think I can do it! So may be I can try half bridge and see what`s gonna happen.
Frequency measurement  - Page 1
Forum section: electronics / projects

author: namster
author_rank: Regular Contributor
timestamp: November 21, 2019, 11:19:39 am
content: Hi ,what are the techniques for a precision frequency measurement ? , the DATA can be used but i don't think that give a good precision !

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 21, 2019, 12:30:43 pm
content: Precision measurement can be performed using a frequency counter with an accurate time base. There are frequency counters out there which could do the job. Basically you set the counter start and stop using the 1 sec precision pulse and clock it with the input signal.for low frequencies, use a PLL to scale up the frequency before measurement. This gives better precision.

author: FenTiger
author_rank: Regular Contributor
timestamp: November 21, 2019, 12:42:11 pm
content: This article describes a couple of techniques:http://n1.taur.dk/permanent/frequencymeasurement.pdf

author: namster
author_rank: Regular Contributor
timestamp: November 23, 2019, 08:50:48 am
content: thanks for the orientation , I will do some research
Frequency Modulation LTSPICE vs TINA - Page 1
Forum section: electronics / projects

author: bergausstein
author_rank: Newbie
timestamp: July 28, 2018, 02:44:14 am
content: I downloaded a FM circuit from you spice. The circuit was original drafted on TINA-TI simulator(It was doing fine when I simulated it in TINA-TI). I tried to replicate it in LTSPICE and managed to do so. But when I simulated the circuit it was taking too long to show the result. Here are the two circuits from TINA-TI and the one I created in LTSPICE. Any help would be greatly appreciated!http://www.youspice.com/spiceprojects/spice-simulation-projects/radio-circuits-spice-projects/modulators-spice-simulation-projects/fm-modulator-with-a-xr2206/
frequency responce of switched capacitor based amplifier (ltc6943)? - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: January 21, 2018, 11:33:27 pm
content: I have some trouble getting my head around the LTC6943 and switched capacitor devices. In the datasheet, there is a circuit where you can make an amplifier that has gain programmable by frequency. On page 12,http://cds.linear.com/docs/en/datasheet/6943f.pdfWhat is the 3db point of this amplifier?

author: danadak
author_rank: Super Contributor
timestamp: January 22, 2018, 12:40:01 am
content: This might help in a broad sense -http://www.seas.ucla.edu/brweb/teaching/AIC_Ch12.pdfRegards, Dana.

author: Wimberleytech
author_rank: Super Contributor
timestamp: January 22, 2018, 03:34:18 am
content: First see if you can understand the simplest switched capacitor resistor emulation as shown in this figure.During Phase 1, the charge stored on the capacitor is V(1)*C= Q(1)During Phase 2, the charge stored on the capacitor is V(2)*C= Q(2)The change in charge, DeltaQ is Q(2) - Q(1) = C[V(2) - V(1)] or C*DeltaVThat change in charge occurs over the cycle of Phase 1 and Phase 2.The period of Phase 1 and Phase 2 cycle is T. The frequency of this repetition is F=1/T.The charge that transfers between V1 and V2 is DeltaQ and it occurs over the period, T, at a frequency of 1/T.Current is charge per unit time.The average current. i(avg) is DeltaQ/T = DeltaQ*F = C*DeltaV*FSo we have i(avg) = C*DeltaV*FRearranging we haveDeltaV/i(avg) = 1/C*F = R(equivalent)So R = 1/FC and thus depends on frequency and capacitance.This is a valid approximation when your signal of interest is well below the sampling frequency, F.What this shows is that you can implement an equivalent resistance with a switched capacitor!! Very amazing. James Maxwell figured this out in the 1800s!!!Why is it so amazing? Geez...why not just use a resistor???If you use this structure along with a fixed capacitor in a filter structure (for example), the performance is determined by CAPACITOR RATIOS and not on absolute capacitance values. Thus you can implement very precise filters in monolithic form because capacitors can be matched very precisely!![I have glossed over a huge body of material with a simple explanation in hopes of getting you over the hurdle of understanding switched capacitors]

author: CopperCone
author_rank: Super Contributor
timestamp: January 22, 2018, 05:51:02 pm
content: What is well bellow the sampling frequency? 2x like nyquist?Will give the article a read.

author: Wimberleytech
author_rank: Super Contributor
timestamp: January 22, 2018, 05:56:21 pm
content: Quote from: CopperCone on January 22, 2018, 05:51:02 pmAt least 10X. To minimize requirements on smoothing filter, 30X.
Frequency response of 3 series LPF filters - Page 1
Forum section: electronics / projects

author: aiq25
author_rank: Regular Contributor
timestamp: September 21, 2017, 07:40:55 pm
content: Hi.I'm working on a circuit analysis where we have to graph the frequency response of a system. The system has 3 LP filters: first an RC filter, second an op-amp with a capacitor, third is another RC filter.I was able to figure out the frequency response (bode plot) of the three individual filters but I'm not sure how to figure out the frequency response of the entire system. Any feedback would be greatly appreciated. Attached is a block diagram.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 21, 2017, 08:12:34 pm
content: The bode plot is logarithmic scale. Having the filters in series gives the product of the transfer functions. In logarithmic scale this is a graphic addition on the vertical axis.

author: Benta
author_rank: Super Contributor
timestamp: September 21, 2017, 08:38:09 pm
content: ^^^ ThisThat's the beauty of Bode plots. And you can just add the phase responses (which are on a linear y-scale) as well.

author: The Electrician
author_rank: Frequent Contributor
timestamp: September 23, 2017, 07:05:31 pm
content: Quote from: Kleinstein on September 21, 2017, 08:12:34 pmThis is not true in general. In this particular problem, if the opamp is taken to be ideal, the R1/C1 stage is not loaded by the + input of the opamp, and because the ideal opamp output impedance is zero, the third stage doesn't load the opamp stage.If a stage could load its previous stage, the overall transfer function would not be the product of the individual transfer functions. The overall TF would have to be calculated as a complete circuit. aiq25 should be aware of this because a subsequent problem might not be free of loading effects.

author: Dave
author_rank: Super Contributor
timestamp: September 24, 2017, 05:01:38 pm
content: The second stage isn't a proper LPF either, the gain at high frequencies approaches 1, not 0.Assuming ideal opamp, the frequency response functions would be:\[G_1=\frac{1}{1+j\omega R_1 C_1}\]\[G_2=1+\frac{R_3}{R_2(1+j\omega R_3 C_2)}\]\[G_3=\frac{1}{1+j\omega R_4 C_3}\]\[G=G_1\cdot G_2\cdot G_3\]To draw a Bode plot by hand, you first draw the response of each individual filter segment (simple straight line approximations are fine) and then add the responses together for the response of the whole circuit. It is a simple matter of adding the gain responses together (loglog scale, of course) and adding the phase shifts together (linlog scale).I could go in detail about how to draw the individual reponses, butthis sitedoes a way better job at explaining it.
Frequency Response - Page 1
Forum section: electronics / projects

author: Nick_Kimi
author_rank: Newbie
timestamp: January 06, 2016, 03:07:10 pm
content: Hi there,I would like to measure the frequency response of a radio frequency current transformer (as attached) using DSA815 1.5 GHz Spectrum Analyzer. How can I do that? I try a few times, and this is what I got (as attached) and I don't think it represent the frequency response of the sensor.Many apologies for any inconvenience caused.

author: awallin
author_rank: Frequent Contributor
timestamp: January 06, 2016, 03:41:04 pm
content: Do you have a model number for the sensor and a datasheet?Post a schematic of your measurement setup. What are you measuring and how?

author: Nick_Kimi
author_rank: Newbie
timestamp: January 06, 2016, 04:01:33 pm
content: Hi Awallin,Thanks for replying my post.Yes, I do have the model number for the sensor and a datasheet, all the information of the sensor are there. However, the sensor's performance will decrease by time. That is why I want to measure the frequency response of the sensor again. I need to have it in order to validate my results.I want to measure the frequency response of the sensor. I should have something as attached no.1. I followed one of the EEVblog video () but I did not get it.As attached no. 2 is my schematic of the measurement. And I'm not really sure the measurement setup is correct or not.cheers.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: January 06, 2016, 04:09:56 pm
content: Quote from: Nick_Kimi on January 06, 2016, 04:01:33 pmIt is not correct. To measure the response of a current sensor you need at the very least to make reasonably flat the source current frequency response. To do it you have to use a matched load and a coaxial feed. For starters you can use a 50 Ohm coaxial cable from the generator's output with a 50 (47 or 51) Ohm metal film resistor at the end of it, placed in the transformer opening. It would not be a very accurate method but miles better than what you've tried.CheersAlex

author: babysitter
author_rank: Frequent Contributor
timestamp: January 06, 2016, 04:29:35 pm
content: Mr. Smith describes a lot of suitable DIY probes and talks about ther characteristics, one of the simplest:http://emcesd.com/tt080699.htmbabysitter

author: Nick_Kimi
author_rank: Newbie
timestamp: January 06, 2016, 05:34:31 pm
content: Hi Alex,Thanks for replying my post.Oh yeah, it's make sense. As attached is the measurement schematic, is that what you mean right? And then I need to make sure that I use a correct value of resistor, right?cheers.