hybridfree/eevblog-posts huggingface dataset:
DDR3 RAM IC selection - Page 1
Forum section: electronics / projects

author: VEGETA
author_rank: Super Contributor
timestamp: July 03, 2021, 10:19:59 pm
content: HelloI am working on a design that has a big ASIC which is the main design chip, it requires the use of 4 DDR3 RAM ICs that have speed of 1600 MHz, each one capacity is 4 Gbit, and organization is 256M X 16. It has to be exactly this.The reference design provided by that ASIC uses MT41K256M16TW-107 by Micron which is faster than 1600 but its datasheet says higher speed ones are directly compatible with slower ones. The ref design has EM6GE16EWXD-12H (by Etron) as an official replacement IC.I checked Etron's website but couldn't find that part number but rather found this: EM6HE16EWAKG-12H (the -12H doesn't exist on digikey and similar ones, the -10 one does).The original MT41K256M16TW-107 is very pricey at +15$ each, so I would need like 60$ per one unit which is crazy. I searched for alternatives and found these:D2516ECMDXGJD by Kingston -> doesn't seem to be available easily or at all except digikey "marketplace" (dunno what is this marketplace thing) for ~7$. Don't know about it if it is directly compatible or not.IS43TR16256B-125KBL -> roughly 9-9.5$ on Digikey, a lot better than original one but still I aim for cheaper.EM6HE16EWAKG-12H -> I found this oneherefor a crazy price of <0.35$ per unit but at 1900 quantity! I don't know if this is legit or not.EM6HE16EWAKG-10H -> similar to above one but faster (dunno if it is compatible with slower ones like Micron part), 10.5$ on digikey but not so available.Therefore, I ask your help in searching for a compatible, available, and cheap part to beexactlyas I mentioned above. I don't care about brand or package as long as it works as the Micron part @ 1600 speed or even if it is faster but compatible with slower operation.Thanks

author: VEGETA
author_rank: Super Contributor
timestamp: July 06, 2021, 10:08:26 pm
content: no one is interested? I thought many would help. will wait and see.
DDS function generator - Page 1
Forum section: electronics / projects

author: jeffreyprinzie
author_rank: Newbie
timestamp: January 30, 2013, 06:20:46 pm
content: Hi,I am building a DDS function generator up to 6MHz with a DDS from analog devices.As opamp I use the LT1226 having 1GHz gain bandwidth, enough with Lag lead compensation?All amplitude and DC offset works, but the output buffer still needs to be done.I was thinking about a Class AB push pull emitter follower. The output impedance is 1/gm , so with enough base current, 50ohm output impedance should be possible. The input impedance should not be depend a lot on the output capacitance, because that would change the output pole of the opamp leading to instability.Should I use an open loop buffer or use feedback? opamp or not for feedback. I rather use no feedback for improved stability. The dominant pole must be on the output then, so capacitive load only moves it to the origin.Amplitude max 5Voffset max +-5Vwhat solutions for the output do you propose?Thanks!Jeffrey

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 31, 2013, 10:54:21 am
content: Hi,Look at using the LT1210 for the amplifier / output stage.With LT1210 you will not need an emitter follower output stage.http://www.linear.com/product/LT1210You should have a 50 Ohm resistor in series with the output of the amplifier, so that the source impedance of your function generator is 50 ohms.Jay_Diddy_B

author: bdivi
author_rank: Regular Contributor
timestamp: January 31, 2013, 02:34:47 pm
content: Another approach is AD811I have built a function generator based on MAX038 that is good to 20MHz and the AD811 buffer happily drives 50 ohms with around 12ns rise/fall times.cheers,

author: jeffreyprinzie
author_rank: Newbie
timestamp: January 31, 2013, 03:43:46 pm
content: Thanks,The LT1210 seems to do it well, i will orde one and see.any sugestions are welcome.I now made a class ab output stage which also works, but with the opamp it can be more linear.kr
DDS project - Page 1
Forum section: electronics / projects

author: elektronchika
author_rank: Contributor
timestamp: October 11, 2013, 08:06:28 am
content: Hi all,I have an idea from several years, but I don't have time to complete it. This is the idea - 1 or 2 channel DDS with output frequency 10 to 20MHz, 1Hz precision. The ability to control the amplitude and offset with 1mV precision, with ranges 10Vpp/ +/-10V. Some king of display is needed and buttons to control the frequency, amplitude and offset.It sounds like an ordinary signal generator. I've done the DDS in Spartan 6 FPGA so far, but I'm thinking about how can I control the amplitude and offset. Here are some ideas:AC Signal Offset and Amplitude Control Using a Dual Channel Multiplying DAC and a Single I/V ConverterAmplitude Control Circuit for AD9834 Waveform Generator (DDS)I've worked with Agilent and Stanford research signal generators. But I can hear inside a relay switching when changing the amplitude or offset. Does anyone have an idea how is made the amplitude and offset control in these signal generators? I've seen Dave's teardown Hantek I think generator, but he doesn't say anything about this, or I saw the circuit of it.So, have a nice day you all!

author: dannyf
author_rank: Super Contributor
timestamp: October 11, 2013, 11:07:20 am
content: QuoteYou mentioned some fairly common spec (10-20Mhz, 1Hz precision), you mentioned some difficult spec (10Vpp/, or even +/-10v). You mentioned some impossible spec (1mv precision).You then failed to mention some really important spec, like what kind of distortion you expect the dds to generate, what kind of wave form you want it to generate. what kind of separation you expect ...As to amplitude control: it can be dome sometimes with the chips selected. Otherwise, you can do it outboard, in analog or digital. The analog approach typically requires a pga + an amplitude detection. The digital approach would be to read the amplitude, adc it and then use that to control a digital pga.The spec you picked unfortunately is quick difficult to achieve.

author: elektronchika
author_rank: Contributor
timestamp: October 11, 2013, 01:23:47 pm
content: Well, these are just some numbers, the spec is not critical, because this is a hobby project. Yes, maybe 10mV resolution (I used precision, but I'm wrong) is easier to achieve. My concerns are how to make the amp and offs control.

author: dannyf
author_rank: Super Contributor
timestamp: October 11, 2013, 01:37:33 pm
content: PGA or digital pots can be used to control gains and add shifts, assuming more reasonable spec. or old resistive pot - nothing wrong with that in my view.Resolution is fairly easy to deliver, precision is much harder.
DDS sine wave generator circuit - Page 1
Forum section: electronics / projects

author: seriouscoinage
author_rank: Contributor
timestamp: July 05, 2015, 09:52:25 am
content: I'm designing a sine wave generator using the AD9854 IC for general hobbyist use. There's a lot of pre-made modules available using similar chips, but most don't have any amplification or amplitude control on the board, and I wanted to have a go at designing one myself. I have laid out and etched some simple single-sided PCBs before, but I thought this would be a good way to have a try at getting a proper double-sided board made and trying some surface-mount soldering. I haven't designed such a high-speed circuit before, though, so I thought I'd get some more opinions before I start laying out my PCB and ordering it.I've attached my circuit diagram. The AD9854 is clocked by a 50MHz crystal oscillator, and takes serial input from a microcontroller (the controller circuit is separate from this module.) The DDS output is filtered by an LC reconstruction filter with a cutoff frequency of 10MHz (I usedhttp://www.aade.com/filter.htmto calculate the component values.) The filter output is amplified by an inverting op-amp stage using an OPA690, and the DC offset from the DDS chip is also removed here using a voltage reference chip and a trimpot. The 1K pot allows amplitude control, and another op-amp stage brings the output up to about 6-7Vpp.Are there any flaws with this overall design, or any mistakes in my circuit? Particularly, is it reasonable to expect to get a reasonably clean 10MHz sine wave output? In theory it should be fine, because with a 50MHz clock the first image of a 10MHz sine wave should be at 40MHz, and will easily be rejected by the low pass filter, but I'm not really sure what to expect because I haven't had any experience with this kind of circuit.Also, I know that ground planes are important for high-speed circuit, but which side of the board should the ground plane be on? Is it right to have the ground plane on the underside of the board, and then drop a via down from the component side wherever a ground connection is needed?Any opinions or criticism of my circuit would be appreciated - I think I'm on the right track, but I want to make sure I have some idea of what I'm doing before I go much further.
DE-5000 LCR meter strange behavior - Page 1
Forum section: electronics / projects

author: alexo
author_rank: Contributor
timestamp: February 27, 2017, 02:06:38 pm
content: I measure 100nf ceramic disk caps with a DE-5000. It starts by showing a value of around 65nf and the value indicated keeps increasing over 90 seconds or so to around 85nf.I wonder if anybody has some explanation. My other LCR metter is rock solid from the beginning.

author: TimFox
author_rank: Super Contributor
timestamp: February 27, 2017, 02:15:56 pm
content: What type of ceramic part is this (X7R, Z5U, etc.)?

author: alexo
author_rank: Contributor
timestamp: February 27, 2017, 02:55:23 pm
content: No idea. I bought them on eBay - 1000 pieces. There is a small slip saying " Ceramic disk capacitors, 104PF, Tol +-80/20%, wvdc 50V and T.C. Y5VI tried with other ceramic caps as well and I saw the same behavior. Also, I tried diff frequencies for the meter.

author: TimFox
author_rank: Super Contributor
timestamp: February 27, 2017, 05:02:31 pm
content: "Y5V" is the type of capacitor. These are very non-linear, but I don't know why they would behave better on your other meter.Can you try a film capacitor (polyester or polypropylene) of the same value on your suspect DE-5000?

author: alexo
author_rank: Contributor
timestamp: February 27, 2017, 06:07:07 pm
content: Doesn't do it at all with polystyrene caps. Rock solid. I tried quite a few values as I have about one cubic meter of those in various values , all 500V .I really wonder what's going on here.

author: Nermash
author_rank: Frequent Contributor
timestamp: February 27, 2017, 06:25:28 pm
content: My DE5000 does exactly the same thing with cheapo 100n ceramic caps.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 27, 2017, 07:53:14 pm
content: You'd have to put a scope on it. Those high k ceramics can have huge temperature coefficients, but also surprisingvoltagecoefficients. If the meter changes its excitation voltage for some reason, the indicated value will change. I also assume you don't have your warm fingers holding the cap?

author: alexo
author_rank: Contributor
timestamp: February 27, 2017, 08:05:18 pm
content: I'm not touching the caps while being measured and I pick them up with tweezers. I also left one in like 30 minutes with the meter off to avoid exactly that sort of issue.Beats me how these sort of caps can be usable foranything.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 28, 2017, 06:38:05 pm
content: Anything? Well, they're useful for making a profit for the manufacturers! Very high k ceramics let you get a lot of capacitance in a small space, and sometimes keeping things small is the highest priority.
DE-5000 LCR meter - Page 1
Forum section: electronics / projects

author: Miss Piggy
author_rank: Newbie
timestamp: December 11, 2017, 01:32:47 pm
content: Hi. I want to buy a DE-5000 LCR meter but there is talk about various copies available on the net. There are a few vendors on Ebay. Does anyone know if any of these vendors are genuine?Thanks

author: Freelander
author_rank: Regular Contributor
timestamp: December 11, 2017, 01:58:08 pm
content: Quote from: Miss Piggy on December 11, 2017, 01:32:47 pmNot come across a copy myself, however, all the vendors on ebay are in Japan, so I think you are good to go. (How do I know this ? - I emailed ALL of them to ask for a lower declared value on the customs form - (Just for 'research' of course.) and they will not do it - none of them - it is extremely difficult to do from Japan.Some good prices though !, but , unfortunately, not when you add duty and vat (ipo) etc.

author: dexters_lab
author_rank: Unknown
timestamp: December 12, 2017, 08:05:29 am
content: Quote from: Miss Piggy on December 11, 2017, 01:32:47 pmmine came off ebay from Japan, i can't vouch for current sellers but mine cost me about £90+shipping a couple of years agomost of these meters come via japan and i'd trust a Japanese seller over most others TBH
DE-5000 meter on ebay IET? - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 10, 2013, 11:56:38 pm
content: Is the DE-5000 meter found on ebay the same meter as the IET DE-5000 that dave jones reviewed?http://www.ebay.com/itm/DE-5000-LCR-Meter-LsLp-Cs-Cp-with-D-Q-ESR-parameters-with-TL-21-TL-22-TL-23-/231030210658?pt=LH_DefaultDomain_0&hash=item35ca794062

author: Fsck
author_rank: Super Contributor
timestamp: August 10, 2013, 11:58:16 pm
content: Yes, same item.

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 11, 2013, 12:03:00 am
content: oh mod can delete this sorry I actually found it myself I searched the DER.
De-rating of SPI master clock frequency - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: June 08, 2024, 05:12:50 pm
content: What is your 'de-rating' (setting 'safer' than data sheet) experience in setting 4-wires SPI master clock frequency?The sensor data sheet says 17MHz. Factory support person says 2 to 10MHz. The demo board (which we do not have) is 7_5MHz in driver software (presume 7.5MHz).MCU and sensor within 1.5 inches (50mm). Only MCU and one sensor, 3 volts push-pull I/O. No long wiring to multiple sensors. Cell life limited. We like transfer as fast as safely possible so devices can sleep soonest.Many thanks

author: globoy
author_rank: Frequent Contributor
timestamp: June 08, 2024, 05:30:31 pm
content: Certainly 50mm is not too long for a SPI bus even at 17 MHz.Perhaps the sensor has some tight SPI timing that leads the support person to suggest a maximum of 10 MHz. I'd look at the SPI section of the spec sheets for both the sensor and the micro-controller. Things you want to look at include any clock duty cycle requirements on the sensor and capabilities of the MCU; setup and hold times for both MISO and MOSI both being sourced and received. Perhaps this will explain why the support person said 10 MHz max.But maybe the micro running at something like 16 MHz would work fine with the sensor. If the spec timings lined up, I'd have no worries about running - or at least trying - that rate given a 17 MHz spec'd max.
Dead-bug soldering a 9-ball BGA chip - Featured on Hack A Day too! - Page 1
Forum section: electronics / projects

author: ginbot86
author_rank: Contributor
timestamp: July 12, 2013, 09:50:02 am
content: (obligatory "First Post!" statement here)Hey everyone. I decided to put up a post on here about my adventures with hand-soldering the dreaded BGA chip.My article:http://ripitapart.wordpress.com/2013/06/15/convenient-chips-inconvenient-packages-making-use-of-the-texas-instruments-bq27421-g1-lithium-ion-battery-fuel-gauge-chip/Hack A Day post:http://hackaday.com/2013/07/03/hand-soldering-bga-wafer-chips/I used a small SOIC-to-DIP board to mount the chip, and used 40-gauge magnet wire and some 30-gauge wire-wrap wire for the higher-current pins.

author: amyk
author_rank: Super Contributor
timestamp: July 12, 2013, 10:01:35 am
content: Want to try a bare die next?

author: millerb
author_rank: Regular Contributor
timestamp: July 12, 2013, 01:16:26 pm
content: The epoxy used is definitely important as noted in the article. For this kind of work I drill a hole in the board and embed chips in dental resin cured with a blue light. The material used in composite fillings withstands extreme temperatures, so much so that forensics people can find them intact in the charred remains of airplane crashes. It certainly holds up to the heat of a soldering iron. Good stuff to work with, you have all the time in the world to set your piece and takes only seconds to cure.

author: amiq
author_rank: Regular Contributor
timestamp: July 18, 2013, 02:24:38 pm
content: Quote from: millerb on July 12, 2013, 01:16:26 pmThat looks like interesting stuff - is it possible to cure this resin if it's in a "blob" of say 3-4 mm deep? I've looked on ebay andthere seems to be lots of different types - can you recommend a brand suitable for this type of electronic work?
Dead coil - Page 1
Forum section: electronics / projects

author: itdontgo
author_rank: Regular Contributor
timestamp: September 18, 2014, 12:47:29 pm
content: Using the AOZ1284 one of our products failed testing today. The main input power PTC was opening when under load.After checking everything with a scope and not finding a problem the AOZ1284 450kHz switch mode regulator was loaded heavily with the PTC shorted out and was able to supply well above it's design current. However I noticed during testing the coil was roasting hot. I changed the coil and the unit worked perfectly with the coil running cool even when over loaded.I cracked it open and found it had two coils presumably to get the current rating up. I'm no expert in coils! It could have had some burned enamel I found when I unwound it. Our assembler has made thousands of these boards do you think it could be the oven temperature or would this be a manufacturing fault on the coil. I imagine it is hard to say but would be interested in hearing if it is a common problem.

author: SeanB
author_rank: Super Contributor
timestamp: September 18, 2014, 04:48:04 pm
content: Most likely it was a faulty unit from manufacture, with a single scratched enamel coat, and this was long enough to meet with the next turn during winding. Likely the heat of soldering was enough to flake the thin coat there and cause a single shorted turn which caused your problem. Hard to test for unless you take all units and test them for inductance, Q and loss as part of incoming QC, or do the test at full load during assembly for a few minutes to weed out these faults.
Deadbug or Breakout AD8333 Quadrature Demod? - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 14, 2015, 06:50:48 pm
content: I am looking at the AD8333 for a simple HF ham transceiver. I realize at some point this would need to get layed out on a PCB. At this point in time with SMT I either dead bug, Manhattan style or use some e-bay dip converter board for prototyping chips. This chip comes in something called an LF CSP 32 pin package. What would be my best option for just playing around with it, at this point I want it to work correctly but have no idea how I would lay it out on a PCB withouht using the chip first.http://www.analog.com/en/products/rf-microwave/iq-modulators-demodulators/iq-demodulators/ad8333.html#product-samplebuy]http://www.analog.com/en/products/rf-microwave/iq-modulators-demodulators/iq-demodulators/ad8333.html#product-samplebuy

author: ajb
author_rank: Super Contributor
timestamp: December 14, 2015, 09:12:34 pm
content: 0.5mm pitch. . deadbugging that will be rather tedious, especially if you're playing around and want to make changes. At the same time I don't imagine that adapting it to DIP will be helpful given it's an RF part. Maybe lay out a little PCB that breaks out to larger SM pads on the top with a solid, bare ground plane on the bottom? Then you can solder that down to a larger copper board for building up a Manhattan-style circuit.
dealing with out of spec -12v rail on a power supply - Page 1
Forum section: electronics / projects

author: keitheevblog
author_rank: Regular Contributor
timestamp: February 23, 2015, 03:59:00 am
content: I was trying to use a mini-box picoPSU-120 to power my Commodore Amiga which uses +5v, +12v, and -12v rails. I managed to source the proper square 5-pin DIN connectors, and then I purchased one of these tiny supplies to provide the power.In preparation of using this new supply, I hooked my amiga up to my lab bench supply, the venerable Rigol DP832.http://www.techtravels.org/amiga/amigablog/?p=1414The main issue is that the picopsu-120 power supply is measuring -13.8v on the -12v rail, and I'm wondering about the best way to deal with the out of spec rail.http://www.techtravels.org/amiga/amigablog/?p=1419I was planning on adding two diodes in series to drop the voltage, but I wonder if this is voltage difference is consistent.I could add another LDO regulator, but I'm not sure if this is best plan of attack.I'm welcome to any suggestions.ThanksKeith

author: sleemanj
author_rank: Super Contributor
timestamp: February 23, 2015, 04:15:41 am
content: A quick google reveals that the original supplies only handled 100mA on the -12v rail, so pretty much anything would be fine I imagine, a 7912 probably the easiest best option.

author: mij59
author_rank: Frequent Contributor
timestamp: February 23, 2015, 05:45:12 am
content: Download the service manual of the Amiga and check what the -12V rail is use for.So far I found that the -12V powers the opamp of the audio part, so -13,8V shouldn't be a problem.The 7912 needs at least 2.5V between in and output to properly regulate.

author: Ice-Tea
author_rank: Super Contributor
timestamp: February 23, 2015, 06:12:29 am
content: You might wanna checkout the original PSU as well. Probably a rectified trafo, in which case -13,8 is already more accurate than what was there in the first place

author: Christopher
author_rank: Frequent Contributor
timestamp: February 23, 2015, 06:55:18 am
content: It's probably some kind of a minimum load problem. As the load goes up a bit the voltage should droop back down to 12v. Try a high power resistor across the rail

author: keitheevblog
author_rank: Regular Contributor
timestamp: February 23, 2015, 09:33:30 pm
content: The -12v rail is used for the opamp of the audio and the RS232 serial drivers. The serial drivers are good to -15v. I can't find the opamp on the schematics, unless it's integrated into one of their custom chips.The original PSU was right around -12v. It was much better.Yes, the actual idle draw on the -12v is somewhere around 25ma. Could be higher during use, although 100ma is likely the maximum.Could I place a 1/2 watt 330 ohm resistor across that rail? It appears that would yield a draw of 36ma, and produce just under 1/2 watt.I ordered an TI LM2990T-12 which has extremely low dropout, especially at the currents I will be dealing with.How's this sound?Thanks
Dealing with parasitic power on signal wires - Page 1
Forum section: electronics / projects

author: calzap
author_rank: Frequent Contributor
timestamp: October 02, 2024, 08:27:17 pm
content: I have a pumping station on a canal that is about 0.4 km from a pond that receives the water. There is a pump house next to the pond that pumps water from the pond. Recently, I designed and installed a status display for use in the pump house that is to show the status of the pumping station. Among things to be displayed is 24 VAC (the control voltage used at the pumping station), flow switch, pressure switch, overload, wrong power voltage, and timers. Status to be indicated by LEDs being lit or not by 24 VAC coming into the status display box from the pumping station. The signal cable is buried tray cable with 6, 18 ga. conductors. Conductors have been checked for continuity and that they are not in contact with each other. Resistance of conductors has been checked and is correct for copper conductors of that size and length. Extra length of the cable is in 2-3 coils in terminal boxes at each end.If power is on for the pump controller but the pump and timers are not running, the 24 VAC LED is on at full brightness as expected. However, several of the other LEDs, which should not be lit, are on dimly. The voltage on the various wires to the LEDs is in the 10-24 VAC range when the wires are disconnected from the dimly lit LEDs. The pump, pump controller, timers, etc. are all working perfectly.My guess is that some of the signal wires are picking up power from the 24 VAC power wires in the signal cable. I plan to use a variable resistor and multimeter to determine how much power is actually transferable … likely not much, the LEDs were dimly lit. Question is what to do about it:a. Putting bucking resistors on the LED wires might do it … or not.b. Another approach would be to convert the 24 VAC signals to DC in the terminal box at the pumping station. The status-indicating LED assemblies are rated 12-24 VAC or DC.c. Another approach would be to use small 24 VAC relays in the terminal box at the pumping station and a DC power supply in the status display enclosure in the pump house.Other ideas?Mike

author: Phil1977
author_rank: Frequent Contributor
timestamp: October 02, 2024, 09:39:49 pm
content: I´d first try solution a) - probably a 1k resistor in parallel to each LED solves the issue.If that´s not enough you can try b), but take care you have some smoothing behind the rectifiers, else the coupling in the cable does not go away.As a last resort you could put relays into the display box.Did you care about grounding and lightning protection? Pure status displays are not very delicate, but cables between buildings always carry some risks.

author: moffy
author_rank: Super Contributor
timestamp: October 02, 2024, 11:58:17 pm
content: Probably a small load resistor across the LED's wires, it doesn't take much to get them partially glowing.

author: calzap
author_rank: Frequent Contributor
timestamp: October 04, 2024, 08:56:45 pm
content: Thanks for the replies. 1K resistors across the LED leads did the trick. Mike
Dear EEV, phone to audio. - Page 1
Forum section: electronics / projects

author: abalducci
author_rank: Newbie
timestamp: March 09, 2019, 01:10:05 pm
content: Dear EEV blog readers,I've tried to think how to make this post not too complicated. Basically I want to interface a standard audio out/in jack to a standard telephone line. To give the gist this is part of an open-source accessibility project I've been wanting to make for my grandmother in the US. Voice activated dialers exist but they are very expensive and limited on the private market. Plus not everyone has the vision capable of using such features on a modern cell phone. I can handle the software side, but am struggling as to how to interface the line properly. I've seen a few schematics online for say old versions of DIY answering machines, but don't know what to trust. I am also not sure where to look up the specs. I'd like it to be non VOIP for accessibility purposes/broad adoption.Can anyone help me out ?(you will get credit for your contribution)Best,- Anthony

author: LapTop006
author_rank: Unknown
timestamp: March 09, 2019, 01:32:41 pm
content: When done for broadcast use these are known as "Telephone Hybrids", looking by that name may be helpful.
Death to serial mice! (Windows) - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: July 09, 2020, 07:26:00 pm
content: Yes, we've been fighting this for decades.You plug in some serial device into a Windows box and Windows says, "OMG, it must be a serial mouse!"Yes, you can disable the service, but it might get turned on behind your back.All of this stuff is protected with the Windows SFC.My solution is to copy and edit \Windows\INF\msmouse.infRemove anything that you distrust, especially sermouse and anything that isnotHID.Then you need to "takeown" of the destination, copy the file over and "icacls" it to have only read permission.Finally, go to devmgmt.msc, View > Show Hidden Devices and delete anything that you don't like.

author: james_s
author_rank: Super Contributor
timestamp: July 09, 2020, 07:32:44 pm
content: I don't think I've ever seen this. What kind of devices are getting recognized as serial mice?

author: Renate
author_rank: Super Contributor
timestamp: July 09, 2020, 07:43:40 pm
content: Quote from: james_s on July 09, 2020, 07:32:44 pmAbout anything that spits out a few chars.USB GPS units that just spit out NMEA when they are plugged in are one case.I'm not sure about the current state of things but Windows used to actually poke devices to see if they quacke-ed like a mouse.Present case: A Digilent CMOD A7 that Windows would snarf the serial debug interface.

author: Renate
author_rank: Super Contributor
timestamp: July 09, 2020, 08:00:50 pm
content: Erm, well, kind-of works.Now it won't load a driver for a mouse, but it still keeps squawking about SERENUM\BALLPOINT\8&12DE5EC0&1&0000.Sheesh.

author: ArthurDent
author_rank: Super Contributor
timestamp: July 09, 2020, 08:09:03 pm
content: This isn't a new problem and not just USB but other serial ports as well. Anyone who has used a GPS receiver with an RS232 port and a mouse has probably tried to use the mouse and found that the pointer has jumped randomly to some other location on the screen. If the GPS puts out some data string every second this 'psycho' mouse will drive you nuts. Sometimes not turning on the serial device until after the computer has booted and recognized the real mouse will prevent this. Here's what one company said about this in 2011.https://www.sealevel.com/support/how-to-fix-crazy-mouse-syndrome-with-usb-serial-adapters/

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 09, 2020, 08:22:14 pm
content: Quote from: james_s on July 09, 2020, 07:32:44 pmI've certainly seen it, back before I abandoned Windows, but an adequate fix was to give it a boot-time option to disable automatic serial mouse detection: the actual drivers were smart enough to not cause problems.MarkMLl

author: Renate
author_rank: Super Contributor
timestamp: July 09, 2020, 08:33:59 pm
content: Brilliant!(That is an "advanced" function of the serial driver and is not found on the stock COM1.)Also, it's not just a question of boot time if you are unplugging and resetting devices.
Debalance and buffer an audio signal with one chip? - Page 1
Forum section: electronics / projects

author: mkiijam
author_rank: Regular Contributor
timestamp: June 21, 2023, 06:33:58 am
content: Hi Guys,So I need to convert a balanced audio signal to a unbalanced one and buffer, that is, not increase it's level for use with the next stage. Just send the output back to the negative input like normal for buffer? Or does the fact that I need to use the NEG in make things more complicated?

author: gnuarm
author_rank: Super Contributor
timestamp: June 21, 2023, 07:39:35 am
content: Quote from: mkiijam on June 21, 2023, 06:33:58 amI recommend a simple circuit where each input, has what is essentially a voltage divider, with the input on one end of the divider, the middle point to the two inputs and the other end of the dividers to ground for the positive input and the output for the inverting input.For a gain of 1, all four resistors can have the same value. Maximum common mode rejection is optimized with maximum matching of the resistor values.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: June 21, 2023, 07:48:14 am
content: Hi,https://www.digikey.de/de/products/filter/verst%C3%A4rker-f%C3%BCr-spezialanwendungen/771?s=N4IgTCBcDaICYEsBmSCmAnVA7ALgghgDYAEmAxqggG4YgC6AvkApick one. ;-)

author: John B
author_rank: Frequent Contributor
timestamp: June 22, 2023, 09:53:17 pm
content: INA1650 by Texas Instruments. It can do what you want for 2x balanced signals, ie a left and right signal pair. No need to match resistors, which won't even be anywhere near as accurate as what's onboard the chip. There's also a single balanced input version.

author: gnuarm
author_rank: Super Contributor
timestamp: June 22, 2023, 09:56:14 pm
content: Quote from: John B on June 22, 2023, 09:53:17 pmInstrumentation amps also have high impedance inputs, which do not require connections to any of the gain setting components. So the high input impedance is maintained and provides nearly no impact on your signal source.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 23, 2023, 11:58:22 am
content: Audio line matching transformers: Great cmrr vs f and very, very low noise.Expensive as a rule.The electronic version is a "line receiver".https://www.ti.com/audio-ic/amplifiers/line-receivers/products.htmlhttps://www.analog.com/en/product-category/audio-line-drivers-and-receivers.htmlhttps://thatcorp.com/balanced-line-receiver-ics/I thinks that's all of them.You can DIY eg sound-au.com/project51.htmOr go pro, my pick is the reasonably priced INA137.I'd avoid instrumentation amps, they are often have very poor noise specs, low bandwidth and cost more than a line receiver.
Debugging AVR-based embedded systems on Linux in 2022 - Page 1
Forum section: electronics / projects

author: navnav
author_rank: Newbie
timestamp: February 12, 2022, 12:20:10 pm
content: Bloom (https://bloom.oscillate.io) can interface with pretty much all of the latest debug tools with AVR support:- Atmel-ICE- Power Debugger- MPLAB Snap- MPLAB PICkit 4- Curiosity Nano Evaluation Board- Xplained Mini Evaluation Board- Xplained Nano Evaluation Board- Xplained Pro Evaluation BoardBloom exposes an interface to the connected AVR target via a GDB server. Any IDE with remote GDB capabilities can interface with Bloom, and thus be used to debug the AVR-based system. Or if you prefer to just use the GDB CLI, that's also fine.Bloom supports over 200 8-bit AVRs. See the complete list athttps://bloom.oscillate.io/docs/supported-targetsAs well as a GDB server, Bloom also provides an optional GUI called Insight. As the name suggests, Insight provides insight into the connected target:A few of the functions Insight provides:- Access to target memories - specifically, internal RAM & EEPROM- Access to all known target registers in the data address space, along with the ability to write to them (whilst execution on the target is halted).- A visual representation of the target and the current state of its GPIO pins.- The ability to manipulate (toggle) GPIO output pins (users can click on an output pin, whilst execution on the target is halted, to toggle it HIGH/LOW).Bloom's source is open for anyone to access. It's published under the LGPLv3 license.
Debugging Vcc GND shorts on PCB - Page 1
Forum section: electronics / projects

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: February 09, 2020, 06:03:55 am
content: FriendsI just wanted to share one method to debug Vcc to Ground shorts on PCBs.Many a times, we get a board back from assembly and find that the supply is shorting to ground. The bare PCB does not have the short, so it can only come from some component. If the VCC and GND are both power planes, and there are hundreds of components like ICs, decoupling caps soldered on them, it is very difficult to debug this.For e.g. if a 0 Ohm resistor is used instead of a capacitor. Often, thermal analysis would not yield the point of short.This may be a known method to many, but I just want to share it with anyone who is new.Steps1. Connect the VCC and GND points from the board to a power supply which is set to CC mode.2. Feed a reasonable current which will not melt the board. 1A is a reasonable value for many boards.3. Use a multimeter in voltage mode. Connect the negative terminal of the multimeter to the ground terminal on the PCB.4. Probe multiple Vcc points with the multi-meter and record them on the gerber file. The L1 layer or Top Assembly layer printed on paper is the easiest way to record the voltages.5. The readings will usually be in several milli volts.6. After recording sufficient points across the board (10 to 20 points will suffice in most cases), draw a contour of the equipotential points.7. The centre of the contour with the lowest potential, will be the point of the short.8. The current flowing on the Vcc plane will cause a voltage gradient with its minima at the point of short to the Ground.This is the cheapest way to detect the short. This is suitable for dead shorts. Shorting through ICs can be debugged by this, but there is a risk of component damage.Comments are welcome...
decade counter, moving switch position - Page 1
Forum section: electronics / projects

author: artis
author_rank: Newbie
timestamp: October 29, 2022, 08:30:31 am
content: I need a row of switches, about 30 to be exact and the idea I need is to have a "moving OFF position" much the same way a "LED chaser" works where you have a moving ON position. Only unlike in a LED chaser where one diode comes ON at any given time and the positions changes continually to resemble a running light, in my case I need for all the switches to be ON continually while some 2 to 3 switches are OFF and this position changes the same way the ON position would change in a "running light". Now the simplest running LED light circuit I see is a decade counter IC 4017 coupled with a "clock" frequency supplied from a 555 chip.This circuit would be fine as I can parallel more than one 4017 IC to get more outputs but the 4017 "pulls up" one output at a time only. This means that I only get one switch at a time action. Ideally I would need at least one switch to always be OFF while the next one turns OFF and only after that the last one turns back ON. So 3 switches involved at any time. My idea is this, I could use the 4017 IC and 555 counter , I would have to use P mosfets because the 4017 pulls the active output to +ve so that would correspond to switching OFF, while the inactive outputs are at ground so for P mosfet they would be ON. I am thinking of adding some delay to the gate in order to accomplish that more than 1 switch is OFF at any given time. Say the 4017 pulls the next mosfet OFF but the previous one is also still OFF and only comes back On after the 4017 has moved one position ahead. I am not sure how this would translate to frequency but the linear OFF position should ideally travel across the switch row at some 1000 km/h or bit more. Sound alot but shouldn't be anything particular for the speeds at which semiconductors can be switched, although i am not sure how to calculate the position moving speed into actual frequency of the moving OFF/ON position, can someone help with that?

author: Circlotron
author_rank: Super Contributor
timestamp: October 30, 2022, 12:31:59 am
content: Sounds like you need a PIPO shift register.https://www.allaboutcircuits.com/textbook/digital/chpt-12/parallel-in-parallel-out-universal-shift-register/

author: Terry Bites
author_rank: Super Contributor
timestamp: October 31, 2022, 07:14:39 pm
content: Invert the output lines unless an output is active- that turns out the selected LED when the count arrives. To have a switchable invert/ non-invert function on any output use an XOR gate.Or cascade XORS to get the function you want.Get aload of 8 >1 muxes. Read the switch inputs from one set of muxes stick an arduino with a LUT or two (or n) in the middle and output to the LEDs through more muxes.A couple of roetary encoder for speed and patterns- Bob's your uncle (or possibly your real dad).You can also read and write using shift registers to reduce the wiring burden.
Decap a chip - Page 1
Forum section: electronics / projects

author: ataradov
author_rank: Super Contributor
timestamp: July 08, 2014, 04:01:12 am
content: Is there a way to decap a chip without destroying it? The chip is dual-die system, where smaller (top) die talks to the bottom die over SPI. The goal is to sniff the traffic. So the chip must remain on the board during the procedure.I'm not trying to do anything bad, quite the opposite. There are security keys exchanged over that bus. I wonder how easy it would be to sniff them for the potential attacker.

author: LukeW
author_rank: Frequent Contributor
timestamp: July 08, 2014, 04:10:54 am
content: It's not clear from your post - is the chip in a common black epoxy package?Usually it's done by mechanically grinding off as much epoxy as you can without risking damage to the die or bond wires, and then using a nitric acid etch to get the rest off.http://www.bunniestudios.com/blog/?page_id=40http://www.cl.cam.ac.uk/~sps32/mcu_lock.htmlhttp://www.rampantapathy.co.uk/12c508a.html

author: ataradov
author_rank: Super Contributor
timestamp: July 08, 2014, 04:23:39 am
content: Yes, it is a standard QFN-48.Actually, mechanical grinding on its own might do the trick. If done carefully enough, it might expose bonding wires.

author: c4757p
author_rank: Super Contributor
timestamp: July 08, 2014, 04:24:47 am
content: Any chance of sniffing it with an EM probe? You can make quite narrow close-field ones. Of course, it'll take a lot of work to get the signal out of the noise.

author: ataradov
author_rank: Super Contributor
timestamp: July 08, 2014, 04:32:32 am
content: Quote from: c4757p on July 08, 2014, 04:24:47 amThat's a good idea!Quote from: c4757p on July 08, 2014, 04:24:47 amAny links? The chip is 7x7 mm, inner die is probably half that size.

author: free_electron
author_rank: Super Contributor
timestamp: July 08, 2014, 05:02:55 am
content: Dissolve cavity in fuming nitrous acid. Stick it in a socket on a probe station. A couple of picoprobes will do the trick. Piece of cake. Takes an hour to do tops. I used to probe chips all the time. Our central lab can decap a chip in under 15 minutes without damage.
Decent online simulator? - Page 1
Forum section: electronics / projects

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: March 25, 2015, 01:46:59 pm
content: Does anyone know of a good or at least decent web sim? I've been using Part Sim but it's buggy as hell. It would be nice to have access to a decent online sim (free to use) that would let me try out circuit schematics.

author: klr5205
author_rank: Regular Contributor
timestamp: March 25, 2015, 02:10:38 pm
content: Why does it need to be online?LTspice is very good (and free) but it requires installationhttp://www.linear.com/designtools/software/#LTspice

author: senso
author_rank: Frequent Contributor
timestamp: March 25, 2015, 02:17:20 pm
content: Maybe to use during exams, it was a thing a couple years ago at the university..

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: March 25, 2015, 02:17:51 pm
content: Thanks for that. I've never used LTSpice before, but will give it a go.

author: Marco
author_rank: Super Contributor
timestamp: March 25, 2015, 02:51:01 pm
content: LTSpice is a wonderful project ... but I find Simetrix easier and far less likely to run into convergence problems, the free version is limited in nodes but for basic circuits it will suffice.
Decent stackable header - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: March 21, 2018, 04:08:17 pm
content: Well, my 2x20 stackable female header arrived from eBay and it is junk. The pins are not 0.025 square pins and bend very easily....Does anyone know/recommend a place for stackable header that is like what I see on STM32 dev boards (it is too sharp, but it is strong)?

author: ajb
author_rank: Super Contributor
timestamp: March 21, 2018, 06:37:19 pm
content: Samtec make just about any form of header you could ask for. They're pretty generous with samples if you only need a couple, I'm not sure about moderate quantities.

author: JXL
author_rank: Regular Contributor
timestamp: March 21, 2018, 06:48:09 pm
content: This one works well for me:https://www.ebay.com/itm/HQ-2x20-Pin-40P-2-54mm-0-1-Female-Header-Long-Pin-12-2mm-/301663671419?hash=item463c8e547bFor other sources search for "PC104 stackable headers" on ebay

author: alank2
author_rank: Super Contributor
timestamp: March 21, 2018, 06:59:48 pm
content: How rigid/strong are the pins? I ordered some like this:https://www.ebay.com/itm/281394575257The pins are all bendy just from handling them...

author: JXL
author_rank: Regular Contributor
timestamp: March 21, 2018, 07:12:04 pm
content: The pins are strong. They are almost square. My measurements indicate about 0.025" x 0.022".

author: alank2
author_rank: Super Contributor
timestamp: March 21, 2018, 07:17:39 pm
content: Excellent; thank you; I'll give those a try!
Deciphering other's prototypes: Mystery NIM module - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: January 20, 2020, 10:32:43 pm
content: Hey all!I've recently scored a NIM bin full of Ortec spectroscopy amps/analog delay/gating and HV bias stuff, which I believe has been used for gamma spectroscopy at a hospital once.Here's the strange part: There is one home-brew prototype module in the rack. It is a single width NIM box with 6 BNC's and a switch on the front, two BNC's on the back and a big ribbon cable crudely cut off.See attached pictures. It would be interesting to figure out what it's supposed to do.Here's what I know:- It has two input channels, going through the OP07 op amps on top of the perfboard, and two bnc's just heat shrunk to nothing, likely from test setups.- The BNC's are just labeled (with pencil) (top-bottom) 0,1,2,3, trig. Last one has no ID. The toggle switches between pos/neg.- Two BNCs on the back are labeled bit 0, bit 1-The 74LS320 clock generator is driven by a 10 MHz crystal, and feeds LS592 timer, whose preset bits are fed to the ribbon connector.-Two of the voltage regs (78/7915) aren't used ? PSU in is +-12V and is regulated to 5V for the logicIt looks a little incomplete but again, this was a working instrument, as far as I know, not some leftover from a university project, so it must be assumed the module preformed some task in its current state. Since this is a energy spectrometer (probably) it would make sense if there was some sort of ADC involved.Could this be some sort of crude, discrete delta/sigma ADC?I don't think getting the module working is an option, but it would be interesting to know what's going on.I hope you think so too!--Chris

author: ChristofferB
author_rank: Frequent Contributor
timestamp: January 20, 2020, 11:44:55 pm
content: From the IC's, it actually looks like a Wilkins type ADC. From what can be seen in this block diagram (attached).I found a great scanned book "Nuclear electronics laboratory manual" published by the IAEA:https://www.iaea.org/publications/786/nuclear-electronics-laboratory-manual-1989-editionAnd WOW. it is a great resource. First of all it's a complete analog/digital electronics introductory book, but always with the focus on nuclear/particle like instrumentation. Secondly, a lot of specific circuits and functions like single/multichannel analyzers, spectroscopy amplifiers, pole zero cancellation circuits etc.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: January 21, 2020, 09:39:11 pm
content: After some preliminary analysis, it seems the heart of this thing was whatever was on the other end of the ribbon cable.. The input amplifiers feed directly into the cable, so does the preset bits from the counter and the two BNC's on the back.The only function that looks like it would be working is that a pos/neg trig pulse would produce a fixed lenght TTL pulse on the lowest front BNC.Either way I don't think I'll sacrifice more time on it. I just wanted to be sure the only value of this is to reuse the box and BNC's.It was an interesting excersize, anyway!--Chris