hybridfree/eevblog-posts huggingface dataset:
Cleaning up vehicle power - Page 1
Forum section: electronics / projects

author: Dragon88
author_rank: Regular Contributor
timestamp: May 13, 2015, 01:44:04 am
content: I asked a question about RF chokes a week or two ago. I ended up making a little RF amplifier board and it works extremely well. I'm now thinking about one or two more designs I'd like to make.One in particular will be for use on vehicle power. I have everything worked out except for power. What should I do to clean up vehicle power and remove the noise? Current draw will be very low, about 60mA, and I'll be connecting at the cigarette lighter adapter. So far I have:- Linear regulator to 10V (stay away from dropout when vehicle is off, avoid excessive dissipation when vehicle is on. I don't care if it drops out at crank)- Schottky for reverse polarity protection- Big parallel electrolytics on input and output of the regulator, plus decoupling capsWhat else should I add? I did find this article:http://linuxcar.sone.jp/reg.en.htmlA series inductor on the input sounds like a fine idea. What about the "DC line filter" and surge suppressor diode? Anything else?Thanks.

author: JimRemington
author_rank: Regular Contributor
timestamp: May 13, 2015, 04:21:28 pm
content: This document explains the requirement for the surge suppressor diode and offers some solutions:http://www.digikey.com/Web%20Export/Supplier%20Content/Tyco_8004/PDF/Tyco_AutoNetwork.pdf

author: Dragon88
author_rank: Regular Contributor
timestamp: May 13, 2015, 05:50:12 pm
content: Thanks. I also found this lengthy article/catalog on TVS diodes by Littlefuse:http://www.newark.com/pdfs/techarticles/littelfuse/TVS_Diodes.pdfLooks like the only issue I'll have is the inductor for the input filtering. I was hoping to stay all surface mount, but I'll need quite a large value. I guess I'll just roll my own toroid for it.

author: DanielS
author_rank: Frequent Contributor
timestamp: May 13, 2015, 11:40:54 pm
content: Here's TI's take on how to protect a DC-DC converter from the transients that may occur in an automotive environment...http://www.ti.com/lit/an/slva464e/slva464e.pdfSee p.4.
clock design that uses 1pps? - Page 1
Forum section: electronics / projects

author: radiomog
author_rank: Regular Contributor
timestamp: January 23, 2015, 11:20:13 pm
content: I have a GPSDO with a 1pps output that i'm not using.I was thinking it would be nice to have my own "accurate" clock in the house that made use of this.My googlefu must be weak, all I found there were clock designs that were incorporated into a GPS receiver.I didn't find a Clock design that existed and would make use of a 1pps input. Now I imagine I could find one of those with a clock design that I liked, and extract the pertinent parts for my own one-off. I would much rather find plans or a kit as I've got plenty of other things to do.anyone know of a clock / design or ideas? I did see some NNTP servers, but those were pretty pricey; and I'm basically only looking for the clock display, not that my own nntp server wouldn't be nice..just overkill.

author: TSL
author_rank: Regular Contributor
timestamp: January 24, 2015, 12:09:22 am
content: Here's a few links to 1pps driven clocks and/or how to's ...http://wa6rzw.homelinux.net/addon/fmt/fmt_2.phphttp://archive.siliconchip.com.au/cms/A_110148/article.htmlhttp://petemills.blogspot.com.au/2011/12/capricious-clock.htmlhttp://www.prc68.com/I/PClock.shtmlhttp://wd6cmu.antennalaunchers.com/gpsclock.htmhttps://threeneurons.wordpress.com/nixie-power-supply/nixie-clock-kit-6-digit-with-dekatron-pendulum/And last but not least...really nice Nixie tube 1pps driven clock kits here...http://www.nixieclocks.de/english/index.phpcheersTim

author: radiomog
author_rank: Regular Contributor
timestamp: January 25, 2015, 02:13:57 am
content: thanks for the reply Tim

author: Pjotr
author_rank: Frequent Contributor
timestamp: January 25, 2015, 09:58:31 am
content: Yes, and the serial output of the GPS module outputs all the time data for you and if it is valid. Just hook up a microcontroller + display to show the time data. Google for "NMEA data"
Clock/Analog Differential pair Polarity Swap, can be done? - Page 1
Forum section: electronics / projects

author: lorth
author_rank: Contributor
timestamp: July 02, 2015, 02:39:20 pm
content: Dear all,I have a LVDS 1.8V Crystal Osc (XO) that has CLK+ and CLK-. (Si590, block diagram attached). Then I use a Clock Distribution IC,AD9511. The inputs are named CLKx and CLKxB, (B = Complementary, as per Datasheet). Then, as you can guess, the input and output pins polarities are swapped...As far as I've read, when polarity is specified on the bus, and you swap,data needs to be inverted.But, what about clocks? I don't see why it wouldn't work but... want to be sure.So, can I connect CLK+ to CLKxB and CLK- to CLKx ?And analog?Thanks!!!!

author: Kleinstein
author_rank: Super Contributor
timestamp: July 02, 2015, 03:23:28 pm
content: Swaping the normal and inverted line ony changes the phase by 180 Deg. As long as the signal directly from the oscillator is not used for something else there should be no effect of swapping the lines.

author: Scrts
author_rank: Frequent Contributor
timestamp: July 02, 2015, 03:58:03 pm
content: Should be no problems at all. You can also phase shift by 180 in the PLL.
Clock from spares - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: February 01, 2019, 02:31:40 pm
content: I had a few spare bits... a clock board from a previous nixie project, which is basically an Arduino Uno with DS3231 RTC, LV and HV supplies..... combined with an 8 digit LED module I had in the junk and a LASER cut case.
Clock gate circuit architecture - Page 1
Forum section: electronics / projects

author: promach
author_rank: Frequent Contributor
timestamp: April 10, 2021, 04:32:43 am
content: Forhttps://www.design-reuse.com/articles/34973/low-power-high-density-clock-gate.html, could anyone explain how the following newly proposed clock gate circuit architecture works ?1. How does it reduces the clock-to-out path by merging the internal latch sequential loop and clock invertors ?2. How does it saves an area of equivalent to 2 inverters ?
Clock input circuit for 0.8Vpp TCXO - Page 1
Forum section: electronics / projects

author: gxti
author_rank: Frequent Contributor
timestamp: May 19, 2013, 10:24:03 pm
content: I have a TCXO that puts out a clipped sine wave that peaks at 0.8V, which I wish I would have noticed before I designed it in. Many TCXOs, in particular the cheap ones, seem to have this type of output, so using a different oscillator isn't feasible. I need to convert that to a 3.3V CMOS signal for clocking a microcontroller. Using a schmitt inverter circuit I had handy seems to work, but the datasheet specifies a maximum hysteresis of 1.2V, and that's just at room temperature, so I don't think I can rely on that.Comparators look promising but ones fast enough to toggle at 30MHz are several dollars each vs the $0.50 inverter. Non-schmitt inverters seem like another possibility, e.g. 74LVC2GU04G. The datasheet only guarantees operation below 0.25xVCC and above 0.75xVCC but presumably the operating point is quite narrow unlike the Schmitt. With feedback it should "hunt" the operating point quite well but can I rely on that behavior over temperature?What are some other ways to square up a 0.8V signal? Frequency will be at most 30MHz, and low parts count is critical. Also, bonus points if the circuit doesn't oscillate on its own without input, since I'd also like to have a separate instance of it as an external clock input. But if necessary I can use a schmitt inverter for that one as it doesn't need to operate down to 0.8V.

author: ddavidebor
author_rank: Super Contributor
timestamp: May 19, 2013, 11:28:16 pm
content: Try what you get with an optocoupler

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: May 19, 2013, 11:44:51 pm
content: What about a fast op amp and a bit of feed forward to give hysteresis?I had a quick look at DigikeyHere is one possibility. ADA4860-1YRJZ-RL7It was $1.70
Clock Propeller - Page 1
Forum section: electronics / projects

author: Mr1234kaki
author_rank: Contributor
timestamp: September 12, 2012, 01:57:29 pm
content: Hi guys!Ive seen some guys posted on youtube a cool project, called clock propeller. Im trying to work on this using my arduino, however i havent start anything yet.Ive look through almost all websites and tutorials, however the best i can find is the source code that i do not understand.Anyone here that have made this clock please help me out!thanks, cheers
Clock through bus level translator is going higher voltage? - Page 1
Forum section: electronics / projects

author: mikejmoffitt
author_rank: Newbie
timestamp: February 22, 2016, 06:33:29 pm
content: I've been working onan FPGA projectfor a while and I finally decided to build a PCB for it. As my FPGA is a 3.3V IO level tolerant one, but it is interfacing with a 5V system, I have 74LCX245s performing level translation.All of my signals are working as expected, with the 5V inputs being translated to 3.3V, but the 12MHz clock is coming out around 8V! Is my scope mis-representing the signal, or is there some strange resonance voodoo going on in my translators? The 12MHz clock is neither a perfect square or sine wave - it's a little dirty - but I'm hoping that's not sucha n important factor here.I can boot up my scope and take a picture a little later once I have it set up again on the bench. My scope is an HP Infinium, which looks to be from the early 2000s as it boots up into Windows 98.

author: marshallh
author_rank: Unknown
timestamp: February 22, 2016, 06:43:01 pm
content: First make sure you are probing correctly. Seeing a much taller clock signal is common if you introduce parasitics (scope ground lead).Since you are dealing with stuff over 1mhz your ground leads should be nowhere to be seen. Use ground clips or better yet since your scope probably has switchable 50ohm input termination build a Z0 probe.

author: mikejmoffitt
author_rank: Newbie
timestamp: February 22, 2016, 08:03:49 pm
content: I will see about finding an appropriate cable to make a Z0 probe. In the meantime, would measuring in 10X mode produce a more accurate result (of course I'd expect to see 500mV instead of 5V)?

author: marshallh
author_rank: Unknown
timestamp: February 22, 2016, 08:15:44 pm
content: 10x should be your baseline, 1x is only really ever useful for slow high precision analog. Infact most better passive probes are 10x only.

author: mikejmoffitt
author_rank: Newbie
timestamp: February 22, 2016, 08:41:13 pm
content: Interesting. I assume my scope should have an option to scale the voltage accordingly, so it can read the proper voltage without me having to multiply it? I may want to look into a nicer probe. The ones I have were $15 and probably perform accordingly.With that in mind, is it safe to guess that my translators probably aren't putting out a higher voltage clock and it'll be totally safe to go my FPGA? In the meantime, since I couldn't empirically prove that the output wasn't high, I put a voltage divider there to provide some naive protection, but I imagine that's going to make my clock perform worse should I end up with a faster one later.

author: Zero999
author_rank: Super Contributor
timestamp: February 22, 2016, 11:13:25 pm
content: Oscilloscopes do have the ability to adjust the vertical scale and providing it's set up correctly there's no need to manually multiply anything.10x probes are better for this kind of thing. I often use 1x though because I mainly work with low impedance, low frequency, low level signals and if gives more resolution and lower noise.
ClockBuilder Pro by Silab. - Page 1
Forum section: electronics / projects

author: MasterT
author_rank: Frequent Contributor
timestamp: October 25, 2018, 01:09:10 am
content: I need to verify registers settings for Si5351, created with my own fast 27-bits approximation algorithm. Unfortunately, I can't run Silab's ClockBuilder Pro on my Linux.Could someone be so kind, that can run software on Win. machine and post a few test arrays with reg. data?Let say, Si5351A, CLK-0 PLLA , Multisynk-0 Integer Mode, XTAL12.345 kHz,1 MHz,123.456789 MHz

author: ebclr
author_rank: Super Contributor
timestamp: October 26, 2018, 07:01:07 am
content: Do atrial on remote Amazon desktop, there you can run windows remotely on your Linux and install sillabs software and run your self

author: senso
author_rank: Frequent Contributor
timestamp: October 26, 2018, 08:55:11 am
content: Virtual machine?You can install Win10 without a key, it will just have the water mark on the bottom right corner..
Clock/sensor signal averaging - Page 1
Forum section: electronics / projects

author: Elandril
author_rank: Contributor
timestamp: August 18, 2018, 03:43:03 pm
content: For a small project with limited space (fixed enclosure) I have to monitor a larger number of fans that keep the installed hardware under somewhat acceptable temperatures. As I'm trying to avoid having to install additional equipment in the already quite full space, I would like to use the onboard fan monitoring of the mainboard to keep an eye of the fans. The mainboard offers three fan connectors which somehow have to monitor 12 fans. So I'd like to connect one row of 4 fans to each mainboard connector. I've designed a small pcb that powers the fans with +12 V and distributes the mainboard PWM signal to the fans. All of that works like a charm. :-)Now I need to find a way to combine 4 square wave fan tacho signals into one for each channel. The tacho output from the fans is designed as a open-collector/-drain output where the mainboard contains the pull-up to +5 V. So the tacho signal is effectively like clock signal. Does anyone know of an IC that can do an average over 2/4 signals or a minimum clock frequency reduction? The frequency would be below 120 Hz (2 peaks per revolution) for the fans. My search on digikey and mouser was not successful. Otherwise I have to do it via a micro.

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: August 20, 2018, 03:34:21 am
content: Quote from: Elandril on August 18, 2018, 03:43:03 pmI like your microcontroller idea. E.g.: measure the frequency of each tacho signal; calculate the minimum of the four frequencies; output a signal with that same (minimum) frequency. If one fan fails, or starts to fail, the output signal "passes on" the failure.Or you could use a more elaborate relationship, between input frequencies and output signal, to suit your system.

author: Geoff_S
author_rank: Regular Contributor
timestamp: August 20, 2018, 09:11:09 pm
content: One hardware option - RC low pass filter the PWM to produce analog voltage and then average using an op amp adder circuit ?
Close loop current sensor - Page 1
Forum section: electronics / projects

author: Alex93
author_rank: Newbie
timestamp: November 19, 2022, 09:05:29 am
content: I assembled a circuit close loop current sensor based on the Hall effect (Shematic). Results of my measurements on pulsed current in attachment (Current sensor _ MY). There is a problem with fluctuations after reaching a constant level.For comparison, I gave similar measurements for original current sensor (Current sensor _ ORIGINAL).Please tell me how to fix this?https://dropmefiles.com/cR4b9

author: moffy
author_rank: Super Contributor
timestamp: November 20, 2022, 10:53:58 pm
content: Sorry, but I have looked at your files and the schematic without the values on it, I know you provided a BOM, is hard to read and follow. It is also a bit difficult to follow as you have, I think, a hall sensor but it doesn't shown what it is magnetically connected to. The inductor or transformer which appears to be where the current is injected also appears as a power source? It is confusing.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 21, 2022, 10:34:14 pm
content: Looks like overshoot. I'd guess your mystery amplifier needs better compensation.Schematic capture CAD is free, use it!
CM4 Carrier Board Design Tips - Page 1
Forum section: electronics / projects

author: wilbrj
author_rank: Newbie
timestamp: January 25, 2021, 06:47:30 am
content: Hello All!This board layout is by far the most complicated I've attempted, at least the first to combine RF, Ethernet and USB. I would definitely appreciate any suggested improvements or heads up if I've made an obvious errormost of the schematic is pulled from the CM4IO board designs with alternate (in stock) components. AIS Rx circuits are also from the open source project dAISy athttps://github.com/astuder/dAISySchematic and Board Layout PDF's can be found belowThanks!
CMAC STP2390C 10 MHz OCXO oscillator - Page 1
Forum section: electronics / projects

author: JBeale
author_rank: Frequent Contributor
timestamp: December 10, 2019, 07:08:38 pm
content: In case of interest. I got one of these 10 MHz ovenized oscillators used from ebay about 5 years ago. I see they are still available:https://www.ebay.com/itm/CMAC-10MHz-ocxo-oscillator-square-wave-sc-cut-STP-2390C-12V/180911738566AFAICT there is literally no data on it available anywhere online. The company that made it still has a pagehttps://cmac.com/but their frequency control products division was sold off to Rakon in 2007.https://www.electronicsweekly.com/news/business/manufacturing/c-mac-sells-frequency-products-business-for-37m-2007-02/This part may date to well before that. They apparently had an extensive printed catalog back in the day, which may still exist in someone's cardboard box under a bench.My unit is crudely hand-marked on the side as a 5V part. It will start up and run at that voltage, but the current draw does not drop over time, as you expect from an oven reaching its temperature setpoint, unless you seal the whole thing in a thick styrofoam box. It runs fine at +9V drawing 84 mA steady-state (when it is in the insulated box). A thermocouple on the metal case inside the styrofoam reports 61 C surface temp. The above current ebay listing says it runs on 12V, and I suspect that's more likely the design point.Running at +9V input, the output is a square wave between 0 and 4.5 V and the frequency matches a GPSDO 10.0 MHz signal at a control voltage of 1.95 V.Checking the control voltage between 0 and +5V, the tuning rate is about +3.1 Hz/volt or 0.31 ppm/volt (slightly steeper around 0V and flatter around 5V).After leaving it running for several days, I compared the 10 MHz OCXO output with a GPSDO output on the scope, and adjusting the control voltage input to keep the edges aligned (a manual PLL) I find the voltage needed varies between 1.9516 and 1.9528 V over a period of 30 minutes, which would be a total frequency change of 3.7E-10. After an hour it is 1.95222 V so there is no obvious drift at this point. The long-term stability of my Trimble 57964-80 GPSDO (also from ebay) should be better than that as long as it stays locked of course, but I don't have anything else to compare its short-term stability at that level.
GSM/GPRS module +CME ERROR: http need relocation (error code 3829) - Page 1
Forum section: electronics / projects

author: txescientist
author_rank: Regular Contributor
timestamp: July 09, 2016, 11:58:03 pm
content: Can someone please explain me what this error means: +CME ERROR: http need relocation.I'm getting it after using AT+QHTTPPOST command on Quectel M95 GSM module.

author: festevao
author_rank: Newbie
timestamp: September 05, 2016, 10:03:25 am
content: I'm having that same error. Have you figured it out?

author: SL4P
author_rank: Super Contributor
timestamp: September 05, 2016, 12:15:28 pm
content: Without knowing the specific module, I'd guess the GPS receiver doesn't have enough signal/satellite coverage to acquire a fix.The docs should explain the message.

author: festevao
author_rank: Newbie
timestamp: September 07, 2016, 11:26:48 am
content: Quote from: SL4P on September 05, 2016, 12:15:28 pmI don't think that's the issue. Using AT+CSQ (signal quality) I get that the RSSI = 29, which is excellent

author: SL4P
author_rank: Super Contributor
timestamp: September 07, 2016, 12:20:25 pm
content: Isn't CSQ only the GSM/GPRS signal level?

author: festevao
author_rank: Newbie
timestamp: September 08, 2016, 03:40:39 pm
content: yes, which is the only signal that matters for making HTTP requests. GPS is not relevant

author: Wilksey
author_rank: Super Contributor
timestamp: September 08, 2016, 03:51:18 pm
content: Does it happen on a particular website?It might relate to a 300 response code, can you see the raw header coming back?

author: SL4P
author_rank: Super Contributor
timestamp: September 08, 2016, 09:15:40 pm
content: Quote from: Wilksey on September 08, 2016, 03:51:18 pmoops. I looked past the QHHTPPOST, and only saw GSM in the first post!

author: SusmitSen
author_rank: Newbie
timestamp: August 09, 2017, 07:45:37 am
content: I am also using Quectel M95 and got the same error code (3829) "http needs relocation" after trying to post data through AT+QHTTPPOST command. This seems to be some problem with the server side coding. I had no problem posting data tohttp://posttestserver.com/post.php.But I got this error when I used my own webpage which puts posted date into a mySql database. However, when I checked the data base, the posted data was nicely sitting there. Thus, while the POST is successful, the modem returns an error. I wonder, how to get around this problem. Any idea, anyone?

author: Wilksey
author_rank: Super Contributor
timestamp: August 09, 2017, 03:50:54 pm
content: I suspect you need to tell the "client" to re-locate when post is complete, i.e. navigate to a "success" page.
CMOS battery connector type - Page 1
Forum section: electronics / projects

author: jdrexler
author_rank: Newbie
timestamp: August 10, 2021, 10:09:00 am
content: Hello,can you please someone help me with identifying following connector (please see attachment)? It's 1.25mm pitch, but only with 2mm height and it's used for CMOS battery. I tried to some connectors from JST, but they are higher.Thank you,Jan

author: jdrexler
author_rank: Newbie
timestamp: August 11, 2021, 07:52:59 am
content: I found it :-). It's from Japan Aviation Electronics Industry.https://www.jae.com/en/connectors/series/detail/product/id=65141&type_code=T1040
CMOS IC - ESD protection  - Page 1
Forum section: electronics / projects

author: EECrAZY
author_rank: Contributor
timestamp: September 14, 2021, 05:15:10 am
content: I was taking apart an ancient IC (1.2 um CMOS n-well process) and came across this ESD protection structure. Any ideas what it can be?With the FOX etched away:Green areas are protruding above field and are likely diffusionsBlack areas appear to be recessed, so I assumed they must be n-wells, but they are way narrower than allowed by design rules for this tech level.These structures are always placed in pairs next to each other, 1 half connects to+5V, another to GND. At another location 1 half connects to pad and another one to +5VIs that an SCR voltage clamp or something else?

author: EECrAZY
author_rank: Contributor
timestamp: September 14, 2021, 09:57:04 pm
content: Could it be a snapback type voltage clamp? So both diffusions are n-type, and black areas are indeed n-wells.

author: amyk
author_rank: Super Contributor
timestamp: September 15, 2021, 12:01:54 am
content: Diodes.

author: EECrAZY
author_rank: Contributor
timestamp: September 15, 2021, 04:27:34 pm
content: Diodes to Vdd rail are typically placed entirely inside of the n-well tub, with p+ anode in the middle and n+ cathode surrounding anode on 3 sides.After quite some googling, found this so called "SNAP" structure which looks nearly identical to my IC and the only reference to structure with n-well inside of n+ I could find. It was noted that both n+ diffusions must be spaced at minimum allowed distance, so "active edges" are as close as possible. So from what I understand, it forms n-p-n structure which "snaps" once certain voltage between closely spaced n+ areas is exceeded.Any one has any insights on these structures and how do they operate and how are they designed? Thanks!

author: TimFox
author_rank: Super Contributor
timestamp: September 15, 2021, 05:37:44 pm
content: Probably not directly relevant to your device:Back in the 1970s, when RCA introduced the 4000 series “COS-MOS” devices, I attended a talk by an RCA sales engineer. He had an anecdote about when he was testing a prototype of a counter MSI. He finished wiring the test jig at the end of Friday, and started taking formal data Monday morning. The device badly failed the clock rate spec. It turned out that he had forgotten to turn on the power supply, and the input protection was passing the low-impedance pulse generator output to the bypassed power rail, which gave an insufficient Vdd for proper operation, but it still worked at low frequency.

author: EECrAZY
author_rank: Contributor
timestamp: September 15, 2021, 11:48:16 pm
content: Quote from: TimFox on September 15, 2021, 05:37:44 pmFunny, I had a very similar situation. +5V power was hooked up to the wrong pin but somehow it was still powering the IC through ESD diodes, output data was unusually noisy and one of the signals was missing (the one which was supposed to be generated by the miswired pin)
CMOS Image Sensor  - Page 1
Forum section: electronics / projects

author: desloz
author_rank: Newbie
timestamp: April 30, 2019, 05:15:55 pm
content: Hello. Is it possible to read only from one line in a CMOS sensor, in order to increase the frame rate (or line rate)?For example, using this sensor from ON Semi ,https://www.onsemi.com/pub/Collateral/AR0134CS-D.PDF.How can I read only the central line, or a group of lines in the center of the sensor? Thank you.

author: Bassman59
author_rank: Super Contributor
timestamp: April 30, 2019, 06:58:07 pm
content: Quote from: desloz on April 30, 2019, 05:15:55 pmPage 3 of the datasheet you posted:QuoteWhich means that you have to set some of the internal registers via I2C to control the region of interest. Those registers are not documented in the data sheet, so you should check ON's website for it.
CMOS Logic Clock Build From Schematics To Breadboard To PCB - Page 1
Forum section: electronics / projects

author: MarioGianota
author_rank: Newbie
timestamp: January 04, 2021, 03:26:00 am
content: Hello all,Just a quick note about a CMOS clock project I initiated about a month ago. I am building a CMOS clock and documenting as much of the build process as possible. There are links to schematics, project details and videos of breadboard tests of the individual modules that make up the clock. I made a short promo video with a free, online video maker. You can view it on YouTube:There are two videos so far on my channel that show the breadboard tests for the individual modules. I am *not* asking for Patreon money, or anything like that. Hope you enjoy the content.The project is hosted on Hackaday, where you can find all the details:https://hackaday.io/project/176063-hackaday-clock-a-day-entry-cmos-logic-clock
CMOS Logic gates - pull up/down? Can the gate O/P directly drive a MOSFET gate?  - Page 1
Forum section: electronics / projects

author: Richard1234
author_rank: Contributor
timestamp: October 10, 2018, 11:33:46 pm
content: Hi All,I'm looking at using some CMOS logic gates for a low-energy project (running off button cells). I'm wondering, with the CMOS gates, the NAND gates output will be hooked up to one of the AND gates inputs. Do I need a pull-down or pull-up resistor on this line? Also, will the AND gates output have enough capability to drive a IRLFL2502 MOSFET?The NAND gate I'm looking at using is the MC74HC1G00The AND gate I'm looking at using is the TC7S08FUThe Transistor the AND gate's output will be on the gate of is a IRLFL2502So:MC74HC1G00 (NAND) O/P ----------------------- I/P TC7S08FU (AND) O/P ------------------------- GATE IRLFL2502 (N CH MOSFET)The dashed lines are where I'm asking if I need a pull-up/pull-down.From what I can see of the datasheets, I don't think I do. Most of the stuff I've dealt with in the past has been microprocessor based. This is my first time playing with logic gates. I thought I'd check before I get some PCBs cut.Cheers,Richard

author: Zero999
author_rank: Super Contributor
timestamp: October 11, 2018, 09:13:47 am
content: The gates you've listed all have push-pull outputs so no pull-up resistors are required.Whether they can drive the MOSFET directly or not, depends on the switching speed. If it's just slow speed, occasional switching, then yes, otherwise a MOSFET driver is required.
CMOS logic OCXO to LVDS converter without adding too much jitter - Page 1
Forum section: electronics / projects

author: twitzelbos
author_rank: Contributor
timestamp: August 26, 2019, 11:09:40 am
content: Dear all,I hope this question hasn't been asked too often before, but I'm hoping this has a very simple answer. I'm trying to convert the output of a CMOS digital output OCXO module to LVDS without adding a lot of jitter to the clock signal. There don't seem to be any dedicated IC for this purpose which makes me think it is as simple as using a LVDS driver and terminating one of the inputs. Am I on the right path here?Thank you very much for your help and experience!Thomas

author: ejeffrey
author_rank: Super Contributor
timestamp: August 26, 2019, 03:42:26 pm
content: TI has a whole family of LVDS <-> single ended logic transceivers, such as the DS90LV027A. I'm not sure how their jitter compares to your OCXO.If you need really low jitter a high speed comparator with LVDS output will probably work better. The LTC6957-2 is a high speed LVDS driver that is mostly intended to be used as a low jitter clock sine->square converter. It is probably overkill for your application.

author: David Hess
author_rank: Super Contributor
timestamp: August 26, 2019, 04:21:35 pm
content: If your LVDS driver has differential logic inputs then terminating one input to control duty cycle is exactly what to do. The differential inputs allow common mode noise in the ground and power connections to be rejected unlike with single ended logic. This implies being careful about ground loops between the single ended output from the oscillator and the conversion logic which is what differential inputs allow.If I could not take advantage of differential inputs on the LVDS converter, then I would use a single point ground to the oscillator and carefully regulate the common supply voltage to the oscillator and LVDS converter. It may be sufficient to LCR decouple the power supply to remove high frequency noise but supply voltage drift will cause jitter over long time periods.
Cmos switch cap circuit in Pspice - Page 1
Forum section: electronics / projects

author: bb551188
author_rank: Newbie
timestamp: December 04, 2013, 07:50:26 pm
content: Hi all I'm trying to implement the attached switch cap circuit.I have the op amp par working if I just put in a AC signal, but as soon as I put in the switch cap part, I get:ERROR(ORPSIM-15138): Convergence problem in transient analysis at Time = 42.30E-06.Time step = 421.0E-21, minimum allowable step size = 1.000E-18These voltages failed to converge:V(N48709) = 4.116V \ 4.116VV(N90511) = 2.382V \ 2.382VV(N51573) = 4.049V \ 4.049VV(VOUT) = 3.141V \ 3.141VV(N101867) = 3.488V \ 3.488VThese supply currents failed to converge:I(V_V22) = -174.07nA \ -173.33nAI(V_V29) = -3.401nA \ -2.968nAI(V_V30) = 41.97nA \ 42.52nAI(V_V31) = -12.73pA \ -36.38pALast node voltages tried were:NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE( VOUT) 3.1410 (N48709) 4.1157 (N48713) 5.0000 (N48725) 1.4192(N48737) .6801 (N48757) .6130 (N48871) 1.6000 (N48889) .7000(N51573) 4.0489 (N60955) 2.5000 (N61751) 1.6000 (N63719) 5.0000(N63797) 2.5003 (N90511) 2.3820 (N101549) 2.5011(N101806) 5.0000 (N101867) 3.4881(N628250) .7000 (N637831) 465.0E-06**** Interrupt ****Can some one help me realize the error?Thanks
CMRR - how to calculate? - Page 1
Forum section: electronics / projects

author: Mark
author_rank: Frequent Contributor
timestamp: May 21, 2020, 02:18:19 pm
content: On the face of it, this should be a simple answer, but a recent enquiry from a customer made me think twice.The customer has requested "CMRR >100dB (bandwidth)".I am not in direct contact with the customer so I can't ask directly, but, what do you think this means?I have a 16bit ADC system with 300VRMS input, digital output, 3kV AC isolation barrier.The method I have used to calculate CMRR (or CMR) in the past has been to apply a DM signal of, say, 150VRMS and observe and record 150VRMS (Vdm) from the digital output.Then, short the inputs and apply a CM input of 150VRMS between those shorted inputs and the protective earth, recording the voltage at the output of the ADC as the observed Vcm.CMRR in dB is then = 20 log (Vdm/Vcm).Given our 16 bit system, doesn't that mean that we need to be seeing zero output when the common mode signal is applied? Otherwise a change in the LSB of our 16 bit system would result in a CMRR of 96dB?Any thoughts would be appreciated. Maybe I'm calculating this wrongly or misunderstanding the customer's requirement. Maybe the customer doesn't know what they are asking for (quite often the requirement specification is based on a competitor's product that they are trying to tie into a contract). I would really like to get to the bottom of this!Thank you for your help!Mark.

author: Marco
author_rank: Super Contributor
timestamp: May 21, 2020, 05:20:31 pm
content: Maybe he just wants some safety margin? Especially if it uses dividers it will drift ... to the point where I think the spec will be hard to reach, this is more in the domain of adirect differential to single ended amplifier.Why not just measure the CMRR of the analogue front end over the required measurement bandwidth? (Also for various temperatures if you want to be complete.) You could put on a jumper to reduce the attenuation a bit just for the CM measurement and still use the ADC output.PS. oh, I guess the whole thing floats so it doesn't need a differential amplifier at all.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 21, 2020, 08:19:11 pm
content: Quote from: Mark on May 21, 2020, 02:18:19 pmat what bandwidth? CMRR is different at different bandwidth.Quote from: Mark on May 21, 2020, 02:18:19 pmwithout looking at the detail of your circuit, i assume it is correct.Quote from: Mark on May 21, 2020, 02:18:19 pmcorrect
CMRR measurement - Page 1
Forum section: electronics / projects

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: February 20, 2013, 12:27:45 pm
content: Hi EEVbloggers,I'm helping some students out with a project and we're doing a bit of head scratching...The project is a differential amplifier which will amplify some pretty tiny differential signals in the presence of some pretty large common mode interference (it is going in an MRI scanner). I've got some questions about measuring Common Mode Gain so we can work out the Common Mode Rejection Ratio.If we put a large common mode signal into the amp (1kHz sinewave) what we get out is not an attenuated 1kHz sinewave but messy glitchy spiky stuff like you'd get out of a SMPS.To calculate the CM gain we know Vin but do we take Vout to be the RMS value of the glitchy spiky signal or do we just look at the 1kHz component of the output signal. i.e. does the CMRR take into account the nonlinearity and distortion introduced by the device under test?Along the same lines; if you were to connect a spectrum analyser up to do this it would give you a graph of gain vs frequency but does it measure the return signal just at the frequency of interest or over the whole frequency range?Cheers!

author: AndyC_772
author_rank: Super Contributor
timestamp: February 20, 2013, 12:58:50 pm
content: It sounds as though your "large" CM signal might be driving your amplifier outside its linear range, in which case it'll no longer work as designed, and the output is essentially undefined.If you ramp up the CM signal from zero, does the output simply produce glitches and spikes of smaller amplitude which gradually get larger as the input increases? Or are they absent until the CM signal reaches some level, then increase in size fairly rapidly?To calculate the useful CMRR for your application, what you need to know is the ratio of the wanted (differential) signal to the unwanted (CM) signal - bearing in mind how the parts of your circuit further down the chain will respond. If, for example, you feed the signal through a narrow bandpass filter, then you're only really interested in the output of that filter as a result of the CM input. If the amplifier's response to a large CM signal has a lot of energy at frequencies which get filtered out anyway, then they're not such a problem.

author: Marco
author_rank: Super Contributor
timestamp: February 20, 2013, 01:31:09 pm
content: Quote from: DenzilPenberthy on February 20, 2013, 12:27:45 pmFix the amplifier and measure again. Once it is actually working you can just ignore THD in the CMRR measurement AFAICS. It would have to be a pretty lousy amplifier for it to make much of a difference.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: February 21, 2013, 10:07:57 am
content: Hi,Thanks for that, I'll get them to see what happens with a smaller input signal. The signal they're using at the moment should be within the allowable input range though so maybe something is broken.Cheers.
CN3722 is not working - Page 1
Forum section: electronics / projects

author: aakash dey
author_rank: Contributor
timestamp: February 02, 2019, 07:33:37 am
content: I want to charge a 2-cell Li-ion battery with CN3722 charging IC. According to my circuit design, the float voltage at the battery terminal should be 8.4V. But, the float voltage is measured as 13.44V when input is of 15V. Also, when I connect the battery,it draws 220mA current for 1 second and after that it goes to 0A. Any idea, why this charging circuit is behaving like this?

author: ebastler
author_rank: Super Contributor
timestamp: February 02, 2019, 07:44:50 am
content: Please don't cross-post the same question in multiple threads.Anybody wants to comment -- I'd suggest to focus on the identical thread in the "Beginners" section.

author: aakash dey
author_rank: Contributor
timestamp: February 02, 2019, 07:49:38 am
content: Ok. I will take care of thar from next time.
CNC Speed Control - Page 1
Forum section: electronics / projects

author: Roze
author_rank: Contributor
timestamp: March 04, 2019, 03:59:56 pm
content: Hi,I recently bought a Spindle motor with speed controller from china, link below. And now my plan is to replace the supplied pot with some logic to be able to set speed from G-Code.Non the less, do anyone have experience with similar speed controllers? If so, is it a voltage or current controlled input? Or is it some other form of control, like 555 based where replacing the pot is far harder?If it is voltage controlled, I was thinking of using a LTC2644 as a bridge from the supplied PWM to a voltage level.Any info is appreciated.//Kind regards.Link to Controller:https://www.banggood.com/Machifit-AC-110-220V-Power-Supply-Speed-Governor-For-ER11-Chuck-CNC-500W-Spindle-Motor-p-1160828.html?rmmds=search&cur_warehouse=CN

author: ThomasDK
author_rank: Regular Contributor
timestamp: March 04, 2019, 05:47:25 pm
content: From one of the reviews:QuoteWith the potentiometer at mains potential, it is not just a matter of throwing in a DAC.Note that another version of the controller exists with a 0-10V input for speed control:

author: Roze
author_rank: Contributor
timestamp: March 04, 2019, 06:10:18 pm
content: Thank you for that note, I shall order the proper one then!
CNC spindle motor controller - Page 1
Forum section: electronics / projects

author: conducteur
author_rank: Regular Contributor
timestamp: March 30, 2016, 09:05:34 pm
content: I'm changing the stepper motor controller board for my CNC machine. The old board was connected to the pc using an LPT-cable. I replaced it with the TinyG V8 USB for compatibility reasons.To get it all neat, I plan to make a new case to put all the electronics in a new box. I disassembled the existing case to see what's inside. While i'm busy upgrading the electronics, i want to know if it's possible to let the TinyG board control the spindle motor. But i can't find information about the motor controller. Maybe there's someone here who can? I't would be nice if i can start or stop the motor with the TinyG. (I don't believe this thing is capable of 2.2 kW, but that's another discussion).There are plenty of unconnected terminals, so maybe there's a pwm input and an on/off control input. The green and black wires are connected to the emergency stop button.

author: Koen
author_rank: Frequent Contributor
timestamp: March 30, 2016, 09:20:37 pm
content: Usually, it provides a "0-10V input".

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: March 30, 2016, 09:46:18 pm
content: https://translate.google.com/translate?hl=en&sl=pl&u=http://www.cnc.info.pl/topics63/falownik-vfd-huanyang-dema-zechuan-komunikacja-rs-232-485-vt56979.htm&prev=searchSupposedly you can use the manual from Huanyang HY01D523B for programming

author: conducteur
author_rank: Regular Contributor
timestamp: March 30, 2016, 09:54:59 pm
content: http://www.casogo.com/Manual/D5M%20user%20manual%20V1.0.pdfThanks! I think the Huanyang manual will help me to solve the "problem". I try that tomorrow or later this week!
CnM Secure 3802A Default Admin Password - Page 1
Forum section: electronics / projects

author: paul_g_787
author_rank: Frequent Contributor
timestamp: January 25, 2023, 08:33:08 pm
content: Hey all.Just dug out the loft my old CCTV recorders. Two units both are a CnM Secure 3802A 4 channel HDD recorder with 4 BNC composite inputs.I wanted to test them out and see if they work before giving them away to a friend for his home CCTV but I cannot remember the default password for the "admin" user and have no user manual any more.Absolutely no results online for the model.Originally purchased from CPC farnell in, about 2009 I think.I can boot up and view the live feeds but cannot log in. The only user is "admin" and the password has up to 6 characters.I never changed the factory password when it was new so it should be the same.I tried 000000 123456 which sprung to mind but nope.Any clues?

author: paul_g_787
author_rank: Frequent Contributor
timestamp: January 25, 2023, 09:44:30 pm
content: Dear lord. Just spent all this time trying passwords (since about 8pm) only to guess the code and find out it is 111111I do believe it is now beer o'clock
CNOT photonic gate EM simulation testcase failure - Page 1
Forum section: electronics / projects

author: promach
author_rank: Frequent Contributor
timestamp: March 02, 2025, 08:14:34 am
content: May I ask whyhttps://colab.research.google.com/drive/1DeBtiZzOBVW9lc-hUDVKvtdCv5E3rpWc?usp=sharingfailed 50% of the simulation test (scenarios 2 and 3) ?
Coating/masking of FFC connector before potting - Page 1
Forum section: electronics / projects

author: Niklas
author_rank: Frequent Contributor
timestamp: November 17, 2016, 04:27:10 pm
content: I am considering the possibility to have a horizontal FFC connector on a PCBA that will be potted and used in a high volume automotive application. Depending on the complete assembly, it is tempting to have a flex cable and a connector instead of a rigid-flex PCB. What I struggle with is the risk of having potting compound inside the connecting area of the FFC, so I would like to add some kind of high viscosity protective layer on top of the assembled connector before the potting is done. The potting compound is similar to water and mainly dictated by the chemical environment, so that is not possible to change.Total area to cover is approx 1 square cm and roughly 2 mm height above the PCB surface. Ideally this should be 1 component, with short curing time in room temperature and possible to dispense.Anyone with experience of this?
Coax connector type - Page 1
Forum section: electronics / projects

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 20, 2020, 07:11:41 pm
content: I want to buy a short piece of coax with male and female (an extender) connectors for a wireless camera I have.What do you call this?

author: Monkeh
author_rank: Super Contributor
timestamp: March 20, 2020, 07:15:05 pm
content: SMA. Be careful, because RP-SMA is more common (thanks, FCC).

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 20, 2020, 07:58:37 pm
content: Brilliant! Thanks!<indeed RP-SMA is what I need>
Coaxial as low DC power cable - Page 1
Forum section: electronics / projects

author: abdulbadii
author_rank: Frequent Contributor
timestamp: March 09, 2023, 06:51:46 am
content: How is it if audio coaxial cable is used for low ~ 12-24 V, ~2.5 A DC power delivering cable instead of ordinary one ?is it no disadvantage at all, if any would please help elaborate what that is in detail ?

author: Gyro
author_rank: Super Contributor
timestamp: March 09, 2023, 10:33:53 am
content: Impossible to say without knowingwhatcable you are planning to use. Many audio cables have thin inner cores that won't take 2.5A. Look at the data foryourcable.
COB LED boost driver PCB check? - Page 1
Forum section: electronics / projects

author: Nominal Animal
author_rank: Super Contributor
timestamp: March 22, 2019, 06:41:16 pm
content: Texas InstrumentsTPS 61169is a boost LED driver with PWM control. Because it filters the PWM instead of chopping the LED current at PWM frequency (but instead at 750 kHz to 1.25 MHz), I'm hoping it would not have the coil/capacitor whine, when PWM'd at 16 kHz or so.I've designed a tiny board for one TPS61169 and an ATtiny10 at EasyEDA,here, for driving those cheap 3W COB LEDs (12V/250mA) from fleabay, powered from an USB wall wart (less than 1 A at 5 VDC). I'm hoping I could hand-solder the board together, then program the ATtiny10, and after testing, pot the entire thing using some flexible potting compound. The same board can be used with up to three buttons or potentiometers, or in my case, a rotary encoder with a switch. The board is tiny; just half an inch per side (12.7mm × 12.7mm). (I have verified the TPS61169 pinout. The datasheet is a bit wonky, because although the schematic symbol looks a bit like the actual chip, the pinout is different.)As I am just a hobbyist, and the TPS61169 datasheet says the layout is critical for good operation, I'm wondering if mine is acceptable. Any comments or suggestions?Schematic:Board images:Top and bottom layers, sans silkscreening:
Code Composer Studio bug - Page 1
Forum section: electronics / projects

author: migsantiago
author_rank: Frequent Contributor
timestamp: December 26, 2010, 03:50:34 pm
content: HiAs I'm working with my launchpad, I'm using Code Composer Studio 4.2.1.00004 on Windows 7 Home Premium 64 bits.When I try to highlight some text on the editor, the highlighting goes mad and the on-screen text gets kinda messy.Code:https://www.youtube.com/watch?v=2IWN_JqU6i8I've updated the software two times and have had no luck. Any suggestions?

author: Unknown
author_rank: Unknown
timestamp: December 26, 2010, 06:14:38 pm
content: As it's a closed-source program, all you can really do is report the problem to whoever makes the software. You could try running it in compatibility mode if you think that it's a problem with windows 7 compatibility. Other than that, for now all you can really do is just live with the problem or use a different program.

author: migsantiago
author_rank: Frequent Contributor
timestamp: December 26, 2010, 06:23:18 pm
content: I think it works with Eclipse, so I don't really know if it's open source or anything else.No luck with the compatibility mode for now.

author: migsantiago
author_rank: Frequent Contributor
timestamp: December 27, 2010, 07:51:57 pm
content: I found a workaround to this glitch... just closing the Outline window.