hybridfree/eevblog-posts huggingface dataset:
SATA to mSATA questions (along with USB 3) - Page 1
Forum section: electronics / beginners

author: tyguy2
author_rank: Unknown
timestamp: April 26, 2020, 07:54:54 pm
content: Hello all,I've been designing a PCB to connect an mSATA SSD to my computer via a USB 3 connection. I'm using TI's TUSB9261 USB 3 to SATA bridge as the device to connect these two standards. My issue is that all of the documentation (schematic,datasheet,product page) are designed with regular sized SATA devices in mind. I am using an mSATA device, which is supposedly electrically identical to SATA, but I've been having no luck connecting to the mSATA SSD with my current designs (see schematics attached).I can detect the TUSB2961 as a USB device, and have been able to program its SPI flash, so I'm fairly certain the USB front end works correctly. However, there are a few differences I've noticed between the mSATA vs. SATA pinout that make me think I've wired the mSATA header incorrectly. I've left the DAS/DSS pin, DevSlp pin, and Device Detect Pin unconnected. Some research says that DevSlp is an active high pin, which essentially turns the SSD off to save power. However, I've found no information on if it should be tied to ground otherwise, and I've found no schematics on any kind for mSATA to SATA adapters.I've been sure to length match my SATA traces on my PCB, and the run is very short, only about 2cm long. The only other issue I could see would be the capacitors on the RX side of the SATA line, as I've seen some mSATA/ PCIe controllers that don't use them on the RX line. I'm afraid if I remove the caps, however, I'd end up killing the TUSB2961, as it's a very sensitive to over-voltage.Thanks, and any help is appreciated!Edit:Link to mSATA pinout

author: tyguy2
author_rank: Unknown
timestamp: April 27, 2020, 04:41:41 am
content: A bit of an update, making some progress. I think I've been able to narrow down the fault to the USB line instead of the mSATA line, as the chip is putting out a FS/HS suspend signal for its USB line. I'm using anFUSB340to switch between one USB device and the TUSB9261. Looking at the datasheets for the 2 devices, I noticed a difference between the SSTX diff pairs. On the reference schematic, there are 2 capacitors, C13 and C14, to AC couple the TX line (image attached, USB3Frontinref). On the FUSB340 datasheet, however, no such capacitors exist (image attached, FUSB340spec). On my PCB, I have these 2 capacitors, C13 and C14, connected to the SSTX lines of the TUSB9261. If I remove those and short across them instead, would that work? Or would it damage the SSTX pins going into the IC?
Satellite dish interface - Page 1
Forum section: electronics / beginners

author: Croy9000
author_rank: Contributor
timestamp: November 24, 2017, 02:41:43 pm
content: I am working on a hobby project to track signal strength on a DirecTV dish (which wont be connected to a set-top box). These newer dishes have a LNB that can be switched to send one of a few satellites downstream through its RG-6 connection. This switching is done by injecting one of 4 possible combinations of 18V/13V and a 22KHz tone.I have found a TI eval board containing a chip for doing exactly this:TPS65233EVM. It take Vin (J2), and via I²C, outputs the required voltage/signal on VLNB (J13).My question is about connecting that 18V/13V/22KHz VLNB output to my circuit. My naive thought is just tapping directly into the RG-6 signal path like this:I don't do much in the analog domain like this. Can anyone give me tips for any additional considerations (like isolation, impedance issues, etc)? Or should this work fine?Thanks for any help!

author: Gyro
author_rank: Super Contributor
timestamp: November 24, 2017, 04:08:40 pm
content: Pah, in the good old days we used to do it the hard way, we didn't need no chip!It would have been nice to have a compact and efficient off-the-shelf solution like that though.That eval board is designed to feed into the LNB supply pin of a satellite tuner inside the STB. Inside the tuner you have the necessary filtering to pass the supply and 22kHz signal onto the RF input without messing up the input impedance or attenuating the signal.You can probably get way with just a series inductor with a self resonant frequency above the 950-2150MHz IF frequency, probably with a decoupling capacitor between the VLNB and the RG6 shield too (before it goes through the inductor). One of the RF guys may be able to suggest something a bit more scientific.If you're wanting to get further into dish positioners, switches and other data then you should make yourself familiar with the DiSEqC spec. You can do a lot more than just the Lo band Hi Band and H/V polarization selection from your 4 states of LNB supply voltage and 22kHz. DiSEqC works by on/off modulating the 22kHz...https://en.wikipedia.org/wiki/DiSEqC
Satellite Modem 10/100 Ethernet Ports - Page 1
Forum section: electronics / beginners

author: rakeshm55
author_rank: Regular Contributor
timestamp: December 13, 2023, 05:40:23 am
content: Hi,I am referring to attached modemhttps://www.comtechefdata.com/files/datasheets/ds-DMD20.pdfIt has an optional terrestrial interface 4 port 10/100Base T Ethernet port.1. What is the purpose for having 4 ethernet ports? Are they just redundant ports used one at a time.2. Is this a 4 port ethernet switch? Or are they four independent ethernet ports?

author: amyk
author_rank: Super Contributor
timestamp: December 13, 2023, 06:12:10 am
content: It helps if you look at the actual manual:https://www.comtechefdata.com/files/manuals/radyne/modems/mn-dmd20-20lbst.pdfSee Appendix J.
Satronix brand solid state relays: any experience? - Page 1
Forum section: electronics / beginners

author: nidlaX
author_rank: Frequent Contributor
timestamp: January 29, 2016, 12:26:21 am
content: I'm considering using this (http://www.ebay.com/itm/141888710580) Satronix brand SSR for a mains switching application with anticipated 5 - 10 A, 120V resistive load. Has anyone done a teardown of this unit or used it for any application? Is there any reason to choose this over a F(os)aketek?I'm not ruling out dropping $30 for a brand name SSR from Digikey, but it seems like the Faketek is even "good enough" if used conservatively.

author: uncle_bob
author_rank: Unknown
timestamp: January 29, 2016, 02:11:17 am
content: HiThey look as good as any of the odd stuff on eBay.Do note that his 40A rating is an inrush rating (short term load burst). The max resistive load rating on those 40A parts may only be 10 or 20A.If you derate 3X or 5X from there, you really don't have much left.Bob

author: wraper
author_rank: Unknown
timestamp: January 29, 2016, 02:19:35 am
content: Those (Fotek) ebay SSRs are not meeting even half of their specs, complete junk, often with an inferior insulation too. At that price I would just but a triac and an optocoupler which for the same price (if not cheaper) would do the job reliably. Also ebay is full of counterfeit big brand SSRs.QuoteNo, that is BS rating (if for fotek). Nothing to do with actual parameters. For normal normal SSRs this is continuous raring (with a heatsink).This particular Satronix ssr might do the job. At least it have some actual (though Indian) manufacturer (if it is genuine).

author: nidlaX
author_rank: Frequent Contributor
timestamp: January 29, 2016, 03:55:57 am
content: Quote from: wraper on January 29, 2016, 02:19:35 amThat's the only reason I even bother asking. Otherwise, I would just assume it's another Faketek. Checked out the company and there is evidence that their history of existence is legit (web archives show the site with the same products and claims back to 2005). That eBay seller is also the official NA distributor as listed on their website. The remaining question is that of its actual quality and performance.

author: uncle_bob
author_rank: Unknown
timestamp: January 30, 2016, 06:02:40 pm
content: HiIf you can trace the parts back to a licensed (term used loosely) distributor and a manufacturer, that's way better than the average buy on an auction site.Heatsink them well and see how they do. Part of getting things at a low cost is taking at least some risk.Bob
Saving averaged signal with a Rigol DS4034 - Page 1
Forum section: electronics / beginners

author: Klugge
author_rank: Newbie
timestamp: August 23, 2018, 02:46:47 am
content: HiI am trying to save a CSV file using the Average acquisition mode (with the DS4034 it goes up to 8192). However, the data on the CSV file is not actually averaged. It looks pretty similar to what you get using Normal or High Res acquisition.My question is the following: is it possible to save the actual averaged data? If yes, how? If not, is it a specific bug from this oscilloscope or are there some arcane reason that prevents it?I have a hard time believing this Average feature would be just for the display on the oscilloscope. It is listed as an Acquisition mode dammit.Thank you very much for any help regarding this issue.I could upload the files and make screenshots of the tests I made but I think I explained the problem carefully.Thanks
SAW resonator   HP R433M 649 - Page 1
Forum section: electronics / beginners

author: stern0m1
author_rank: Contributor
timestamp: February 14, 2018, 05:34:13 am
content: I see on a PCB a SAW resonator marked HP R433M 649.Any idea where I can find the data sheet to this specific chip?Thanks

author: 0xfede
author_rank: Regular Contributor
timestamp: February 14, 2018, 07:42:33 am
content: Are you looking for this?http://www.dzsc.com/uploadfile/company/860560/201239161254122.pdfBest,0xfede

author: stern0m1
author_rank: Contributor
timestamp: February 14, 2018, 02:04:51 pm
content: Mine is surface mount with 8 pins.Thanks
Saw/Ramp to Triangle and Inverted Ramp/Saw skewer circuit ideas? - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: October 14, 2023, 06:11:22 pm
content: Hi all,I was wondering if there is a circuit to be able, given a triangle wave or a saw wave to produce a continuously variable wave going from a downward ramp saw -> triangle -> inverted saw or upward ramp.I really don't care about whether the input should be a saw or a triangle as I have both of them avalaible.I initially thought to produce the inverted of a saw wave and then try to combine the two ramps (the one going up and the other going down) at the same time essentially making a crossfader circuit of the two ramps to produce a half amplitude triangle but I get zero in the middle which is what one would get trying to add a signal with it's inverted copy.I then thought that I need to delay that by half a period or make the other half of the wave double the frequency of the first half so I can add the two halves essentially getting a triangle.And then I stopped because I guess this is something more difficult to do that I anticipated.I would appreciate any help doing this!From a quick search it doesn't seem to be an ordinary process so there isn't any obvious way to do that..

author: Ian.M
author_rank: Super Contributor
timestamp: October 14, 2023, 06:58:38 pm
content: Integrate a PWM, but you'll also need to servo the PWM high and low levels to maintain output amplitude and mean level at zero. 50% duty cycle gives a triangle wave and the extremes close to 0% and 100% give the rising and falling sawtooths.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: October 14, 2023, 07:01:53 pm
content: By integrating a PWM you mean I need to use an OTA to produce a ramp from a pulse modulated square wave or just pass this square wave thru an opamp integrator? This latter seems simple enoughDo you have any examples?!EDIT: I found this circuit here :https://till.com/articles/VariableSaw/Tried to simulate it but there are quite a few things missing that render it unusable as is..also CA3280s are non existent anymore so I will eventually have to use a LM13700 for the circuit to be able to get built.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 23, 2023, 08:12:14 pm
content: Here's the classic aproach>>>> Control the ratio of charge to dischage of a simple integrator. OTAs indeed!The volts feed back from the comparator control the ramp time. A buffer stops interaction of freq and symmetry controls.You get a rectangular sync output for free.

author: belzrebuth
author_rank: Frequent Contributor
timestamp: March 25, 2024, 07:52:57 pm
content: Do you have any circuit example for this?Thanks!
Sawtooth Wave Generator - Page 1
Forum section: electronics / beginners

author: ArjunSukumar
author_rank: Contributor
timestamp: October 18, 2015, 01:51:45 pm
content: Hi guys,I want to generate a sawtooth wave by charging a capacitor using a constant current source(0.1mA) charging from 0 to 1V. For making the capacitor discharge, i have used a voltage comparator to compare the voltage of capacitor with 1V and if the capacitor voltage reaches 1V, it shud discharge through the transistor connected as a switch. but my problem is capacitor is not discharging,instead of that it is giving a constant value 1V continously. What should I do to discharge the capacitor? Circuit and output obtained (pspice simulated, ideal opamp with power supply 10V) is attached below. Thanks in advance

author: Connoiseur
author_rank: Regular Contributor
timestamp: October 18, 2015, 03:34:54 pm
content: Actually the circuit may be oscillating at almost infinite frequency, that’s why the program is probably not able to show you the waveform.Consider the instant when you switch on the circuit. The capacitor starts to charge to 1V as 1/C integral i(t)dt (which is a linearly rising ramp). The moment it acquires Vcap = 1V + input offset voltage of opamp; the comparator shoots the o/p from –10V to +10V. Transistor turns on and after discharging the capacitor to Vcap = 1V – input offset voltage, the comparator again slams the o/p voltage to -10V.So effectively your circuit is charging and discharging the capacitor between 1+Vio and 1-Vio, so the time constant is incredibly small and zero in ideal case.

author: elements
author_rank: Newbie
timestamp: October 18, 2015, 03:47:04 pm
content: The capacitor can't fully discharge because the circuit charging it is always on. Also, there is a voltage between collector and emitter at saturation that is non-zero !

author: Simon
author_rank: Unknown
timestamp: October 18, 2015, 03:58:54 pm
content: You need a memory element in there like a latch. This is how the 555 timer IC works. Your comparator detects that the voltage on the capacitor has gone over 1 V. So your circuit starts to discharge the capacitor. But as soon as you go under one volt which will happen immediately it switches off again. What you need is something like a latch which is set when you go over 1 V and stays set until you go back down under a certain voltage where it will reset. This is how the 555 does it.Why don't you just use a 555?

author: TimFox
author_rank: Super Contributor
timestamp: October 18, 2015, 04:15:09 pm
content: The comparator needs hysteresis, so that the discharge transistor conducts after the upper threshold is reached, dropping the voltage across the capacitor until the lower threshold voltage is reached. This is how the 555 works in astable mode. Back in the day, the 884 thyratron was used, where the device would conduct until the voltage approached zero and the discharge shut off. Later, the 2N2646 unijunction transistor was used, in a manner somewhat similar to the 555.To get a good sawtooth with the 555, use a current source instead of the normal resistor to charge the capacitor.
sbit data type in mikro C pro - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: July 25, 2019, 11:26:19 am
content: What does it mean by " in a unit" ??

author: Ian.M
author_rank: Super Contributor
timestamp: July 25, 2019, 11:54:28 am
content: A unit, colloquially compilation unit, but officially translation unit is one fully expanded C source file as seen by the compiler *AFTER* all preprocessing is complete. Seehttps://en.wikipedia.org/wiki/Translation_unit_(programming)N.B this has absolutely nothing to do with the MikroC propitiatory and non-standardsbittype orsfrqualifier except that a variable's definition and declaration using them apparently follow the same scope rules as any other C variable.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 25, 2019, 11:55:52 am
content: Unit is a compilation unit, basically the .c file where this line resides in. Declaring something in the unit with the extern keyword means that this unit (the c file), after this line, knows about the existence of such variable, and you can use it, but it is defined somewhere else.
Scale down clock from 24MHz to 10 MHz - Page 1
Forum section: electronics / beginners

author: limata
author_rank: Contributor
timestamp: August 12, 2014, 03:58:31 pm
content: Hi, What is the best way to scale down the clock from 24 MHz to 10 MHz and it has to be phase locked.I am thinking of PLL 24Mhz*5=120MHz, then dividing 120MHz/12 = 10MHz with counter or something else.Are there other ways to realize this?Thanks

author: andy_silicon
author_rank: Regular Contributor
timestamp: August 12, 2014, 04:13:58 pm
content: http://www.idt.com/support/calculators/30702One option is something like the ICS307-02Using the calculator in the link gives the settings to give an ideal conversion.Just use the calculator with 24Mhz as the input and 10Mhz as the output.The result is 0ppm error and minimum jitter.

author: andy_silicon
author_rank: Regular Contributor
timestamp: August 12, 2014, 04:33:46 pm
content: And if you want something which will work standalone.There is the TI CDCE906http://www.ti.com/lit/ds/symlink/cdce906.pdfBut it is limited to 3.3V ( you didn't state voltage requirements )The CDCE906 has eeprom and can be programmed via I2C.( but not as easy to solder - finer pitch )

author: limata
author_rank: Contributor
timestamp: August 12, 2014, 04:39:59 pm
content: Thanks andy_silicon,This is a very flexible solution unfortunately I don't have a microcontroller etc on this adapter board to program this clock source. The only reason I need 10 MHz is that the tektronix AFG only takes 10 MHz input. I simply want to take 24Mhz clock from our data acquisition system, scale it down to 10Mhz, then pass it to the AFG.

author: andy_silicon
author_rank: Regular Contributor
timestamp: August 12, 2014, 04:47:31 pm
content: The cdce906 can be programmed once - the eeprom loads the PLL parameters at power up.Is your 24Mhz LVTTL ? Or TTL ?I guess we need a little more detail from you for advice.You could of course do it with discrete logic :-)

author: limata
author_rank: Contributor
timestamp: August 12, 2014, 05:09:00 pm
content: You are right. I can just use any mcu to program it for once.24MHz signal is from the FPGA in the data acquisition system and it's 3.3V differential buffered output. The AFG can take 10 MHz input with a voltage swing 100mVp-p to 5Vp-p.

author: Andy Watson
author_rank: Super Contributor
timestamp: August 12, 2014, 05:30:51 pm
content: Divide the 24 MHz by 12. Phase lock you PLL running at 10 MHz, using an XOR detector.

author: German_EE
author_rank: Super Contributor
timestamp: August 12, 2014, 06:43:26 pm
content: 24 MHz / 24 = 1 MHz (Reference)10 MHz / 10 = 1 MHz (VCO)Feed these two signals into a phase detector then use the output to drive your 10 MHz VCO. Note that it might be better to divide the 24 MHz signal by 12 then by 2 so that you have a 1:1 Mark/Space ratio going into the phase detector.

author: limata
author_rank: Contributor
timestamp: August 12, 2014, 11:09:42 pm
content: Thank you all for the input. Eventually we go with a lattice CPLD with embedded PLL. It's a little over killed but we happen to have this chip in the lab.
Scales with constant load. - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: December 21, 2017, 07:48:24 am
content: So I have a keg of beer. It's a metal container. The only way for me to tell it's nearly empty would be to try and pull a pint from it. This is irritating.Bathroom scales would tell me fairly accurately how much is left in it, simply by zero'ing it with the empty keg before filling.The downside is bathroom scales typically only turn on, take your weight, 'latch' onto the stabilised reading and then switch off. You have to take the load off and put it back on again to get a new reading. I would need a continous reading... or better yet, the ability to take a spot reading on the press of a button and the device return to power save moments later.I wondered if there was a simple electronics solution.A friend suggested an old analogue gauged spring based scale, but I'm not entirely sure if they would like having a 25Kg weight sitting on them 24/7 in a fridge.

author: SeanB
author_rank: Super Contributor
timestamp: December 21, 2017, 09:13:30 am
content: Loadcell platform will work, and as the temperature is reasonably stable you will have less worry about zero shift with it, and could just use the standard differential amplifier circuit with the amplifier output ( with appropriate scaling for 0.1V/kg)) and a zero pot to apply the required offset for zero on a standard cheap 7106 type LCD display. Or just a MCU reading the diff amplifier output, and doing the scaling and zero offset in software, driving a standard 2x16 display of the same.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 21, 2017, 09:17:10 am
content: Get a digital scale. There are some very hackable ones out there -- they use load cells, mass produced on the cheap!Tim

author: Raj
author_rank: Frequent Contributor
timestamp: December 26, 2017, 12:53:26 pm
content: solve it with mechanics...place a bar of metal under sensor pads and yank it to turn it on
Scaling a signal. - Page 1
Forum section: electronics / beginners

author: jgalak
author_rank: Regular Contributor
timestamp: December 25, 2017, 02:48:46 am
content: I need to rescale an input signal. The source signal is a sine wave with amplitude of about 5 Vpp and a DC offset of 2.5V. In other words, it swings between ground and +5V, centered on 2.5V. I need it to swing between ground and 3.3V, centered on 1.65V. The frequency is in the range of about 1 - 2.5kHz.My first attempt was to use a fractional gain non-inverting opamp amplifier, but that got me a 3.3Vpp signal centered on 2.5V, swinging between .85V and 4.15V (appreciate ox numbers).One idea I had was to AC couple the output of the amp, and then rebias it to the correct offset voltage, using a circuit like the one attached (copied from Learning the Art of Electronics), using the appropriate ratio resistors between 5v and ground.Is there a better way to accomplish this? Maybe with a single step of attenuation and rebiasing?

author: hexreader
author_rank: Frequent Contributor
timestamp: December 25, 2017, 03:01:46 am
content: Won't a simple resistor voltage divider do that job?Something like 1k7 Ohms and 3k3 Ohms.Sounds too simple, so maybe I am missing the point?

author: jgalak
author_rank: Regular Contributor
timestamp: December 25, 2017, 03:25:44 am
content: You mean both attenuate and change the offset? Hmm, yeah, that should work. Almost seems to easy...Especially if I throw a buffer Op-Amp on our or both sides of the divider, to help with loading. The source of the signal is an R2R ladder, so I'd be concerned that without a buffer between it and the divider it would get distorted by the loading.Not sure if I need a second buffer at the other end, the signal is going to be a control signal to an IC, but the data sheet doesn't list input impedance for that pin, just that it's a max current of 20 uA.

author: David Hess
author_rank: Super Contributor
timestamp: December 25, 2017, 03:42:00 am
content: All that is required in this case is a resistor divider with a ratio of 3.3/5.0 so 0.660. A voltage follower could be used at the output to buffer the attenuator.
Scaling of sensor voltage to desired linear output - Page 1
Forum section: electronics / beginners

author: wolfrum
author_rank: Newbie
timestamp: March 23, 2012, 12:46:13 pm
content: I am working on a "opamp" based project where the sensor values vary from 0.7V to 1.9V and this needs to be scaled to trigger another circuit(PWM generator) which operates from 4.7V to 5.3V.Can anyone suggest a nonlinear amplifier for the above. My project involves PID control so I cannot go for discrete amplification using programmable gain amplifier.

author: sacherjj
author_rank: Frequent Contributor
timestamp: March 23, 2012, 01:35:56 pm
content: Quote from: wolfrum on March 23, 2012, 12:46:13 pmI don't think you want a non-linear amplifier. I think you want and amplifier with a gain of (1.9-0.7)/(5.3-4.7) = 1.2/0.6 = 0.5. You also want a DC offset of 5 - (1.9+0.7)/2 = 5 - 1.3 = 3.7 VSo an opamp circuit with gain of 0.5 is pretty simple to calculate. Then you add another chain with a voltage reference. Or some of the better circuit monkeys might be able to show how to do this in one chain.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 23, 2012, 01:36:35 pm
content: Why non-linear? Unless you didn't tell us everything, what you want to do is all very linear. This sounds like a job for an opamp, configured as an adder, adding 8.7V to the signal on input, and with a gain of 0.5. Or first a division by two, and then adding 4.35V.

author: wolfrum
author_rank: Newbie
timestamp: March 23, 2012, 01:56:57 pm
content: Thank you very much got it
Scantronic 500r - Page 1
Forum section: electronics / beginners

author: poleo
author_rank: Newbie
timestamp: May 20, 2017, 07:13:56 am
content: Hi Guys,I have just fitted a Scantronic 500r home alarm system by following the installation instruction.It all appears to work except the transformer gets too hot once the mains supply is connected.Can anybody explain why this happens.Thanks.

author: CJay
author_rank: Super Contributor
timestamp: May 20, 2017, 09:22:46 am
content: How hot is too hot?if it's really overheating it's entirely possible it's faulty out of the box or you've got a short somewhere...Best, simple way to test would be to disconnect all the sensors/bellbox, let it cool down and then see if it still gets too hot, that'd rule out the alarm panel or your wiring/sensors.If you've got a multimeter that'd make life easier to isolate problems
SCART-8 shielded wire for LCD display - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: May 11, 2020, 08:37:13 pm
content: Hi, need to powerLCD display~1meter away from Arduino, 8core cable is enough to run SPI. In the shop they had onlySCART-8(0.08mm3) shielded wire cable. So I was wondering is its thickness enough to run LCD? Or I need thicker cable?
Scattering Parameters of a connector - Page 1
Forum section: electronics / beginners

author: RFbeginner
author_rank: Newbie
timestamp: July 15, 2019, 06:31:30 am
content: hello everyone,I'm trying to deembed some filters on transmission lines and in order to do so i need to figure out the S-Parameters of the connector,i found out the Phases easily, i produced 2 Transmission Lines that are lossless and adjusted to 50Ohm, one of Length L and the other one of Length 2L and used matlab to find out the phases and it works perfectly while comparing the measured and simulated results of my Hybrid but now i'm kinda stuck to exttract the amplitude, does anyone have an idea how i can find that using the two transmission lines that i already havethanks a lot

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: July 16, 2019, 04:33:07 pm
content: Call me naive but couldn't you just perform a Short Open Load Through calibration on the VNA that you used to measure the filter? It will push the reference planes (ideally) to the ends of the connectors so you won't have to worry about de-embedding (unless you're in a situation where you cant re-measure the filter). It's a different story if you're using a test fixture where you can't eliminate it.When you say "phases", do you mean the phase propagation constant? or the total phase change for the length of coax that you're using? That would be the electrical length if its the latter.Either way, you'd need to find both terms of the complex propagation constant, both alpha and beta. Alpha is measured in nepers per meter or about 8.7dB per meter. You can then find alpha, and you already know beta.Am I understanding this correctly? I'm a bit confused by the wording: Are you trying to shift the reference planes to the end of coax connectors, or do you have a filter that you want to remove too?
Scenarios for this current rating on MOSFET drivers - Page 1
Forum section: electronics / beginners

author: kelvne
author_rank: Newbie
timestamp: June 05, 2023, 01:37:32 pm
content: Trying to delete my account [ Specified attachment is not available ]

author: langwadt
author_rank: Super Contributor
timestamp: June 05, 2023, 01:41:37 pm
content: if you want to switch a (big) fet on/off fast you need a lot of current to charge/discharge the gate capacitance

author: srb1954
author_rank: Super Contributor
timestamp: June 06, 2023, 12:18:26 pm
content: And the effective input capacitance at the gate is increased by the Miller effect boosting the effect of the gate-drain capacitance. This Miller effect capacitance can be greater than the static gate-source capacitance thus requiring even more drive current to switch the FET rapidly.A good description of this can be found in the Unitrode application note U-137.

author: Nominal Animal
author_rank: Super Contributor
timestamp: June 06, 2023, 02:55:34 pm
content: And do not forget: the current is only supplied as a short pulse, not continuously.Essentially, the charge \$Q\$ transferred to the gate is an integral of the current with respect to time. The faster you want to completely switch the MOSFET state, the higher the instantaneous current has to be during the pulse.
Schematic and PCB review of HDMI mezzanine card - Page 1
Forum section: electronics / beginners

author: basher4
author_rank: Newbie
timestamp: May 04, 2025, 02:48:11 am
content: Hi, I am designing a mezzanine board for a cheap Kintex 7 FPGA board from AliExpress (https://github.com/rriggs/kintex-7-stlv7325t-board-files) with 2x HDMI input ports. Goal is to be able to capture two 1080p60 streams. However, as this is my first attempt at designing a PCB of any complexity, if all I can get is 720p30 I'll be ok with that.I'm looking for feedback on the schematic and the PCB. I think I have sufficiently ripped off the pynq z1 schematic (https://files.digilent.com/resources/programmable-logic/pynq-z1/pynq-z1-sch-f0.pdf) and already got some good feedback on r/AskElectronics already (https://www.reddit.com/r/AskElectronics/comments/1kbnxdx/schematic_of_a_simple_hdmi_input_board/) but I'd appreciate any extra feedback, even if it's just the way I drew it.I'm quite unsure about the layout. I chose a 6 layer JLCPCB service because it's almost free (less than $4 USD delivered), but don't have a good use for the inner 2 and 3 layers so they are mostly empty. However, the 6 layer process gives me via-in-pad for free, and I used that extensively.I will assemble the board by hand. I have a small hot plate so I want to place components on one side and stick to 0603 or 0402 as much as possible.Here's what I know:- I need to route my TMDS lines with 100Ohm impedance. I used the JLCPCB calculator for that which gave me trace thickness, spacing, and which stackup to use.- I2C lines are routed with single ended impedance of 50 Ohms.- Keep solid ground under high speed lines to have a good return path for the signal.- Keep decoupling caps close to where they're needed.My concerns are:1. TMDS inter-pair skew.I have no clue what HDMI spec allows or how long are the traces from FPGA to the B2B connector. I'm hoping that I can make up for any delays caused by the PCBs in the FPGA fabric.If lower resolutions work, I think I can figure out some sort of one-time link training process, or get access to a fast oscilloscope that will allow me to look at the TMDS signals whizzing past at 1.4GHz.2. I'm not sure where to put the TMDS termination resistors.Is there a way I could meaningfully terminate the signal with the resistors on the top side?I would like to use a resistor network because that should be easier to solder on the underside. Is this a bad choice? I do have enough space for 8 individual 0603 resistors.3. Via in pad for the TMDS lines. Is it a bad idea?4. The layout seems somewhat ugly.Ignoring the silkscreen for now, there's just something about where the components are placed, the odd trace that wiggles strangely, gigantic loop that distributes power...Any pointers, feedback, or help are greatly appreciated. Thanks for any and all help!
Schematic Database - Page 1
Forum section: electronics / beginners

author: LSEI
author_rank: Newbie
timestamp: May 05, 2013, 06:53:14 pm
content: Another beginner would like to obtain a schematic for a Lambda LQD420 power supply. They seem to be rare or nonexistent. Any help. I saw one in a YouTube video so they must be somewhere.TNX

author: rsjsouza
author_rank: Super Contributor
timestamp: May 06, 2013, 10:18:55 am
content: You may want to askthese guysif their manual has schematics. It may be your only option.
Schematic doubts - Page 1
Forum section: electronics / beginners

author: Benjam
author_rank: Regular Contributor
timestamp: May 10, 2022, 02:46:09 pm
content: I was looking at the schematic of this half-bridge driver and came across some confusion.Question: What are the roles of R163 and D20 and R125 in the schematic? What is their significance?

author: Picuino
author_rank: Super Contributor
timestamp: May 10, 2022, 02:55:56 pm
content: R163 and the diode D20 speeds up the switch off of the mosfet.R125 avoid the switch on of the mosfet when the circuit doesn't have signal in GATE_AH1Edit:When you ensure that the mosfet turn-off is faster than the turn-on, you avoid that both mosfets (high and low) can be on at the same time, causing a short circuit.

author: Benjam
author_rank: Regular Contributor
timestamp: May 10, 2022, 04:17:30 pm
content: Quote from: Picuino on May 10, 2022, 02:55:56 pmThank you for your answer
Schematic Editior Software With Hotkeys - Page 1
Forum section: electronics / beginners

author: ZeTeX
author_rank: Frequent Contributor
timestamp: March 18, 2016, 10:39:50 pm
content: I'm looking for easy to use free schematic editor.What I currenly use is LTSpice and its great, easiest and best software I used so far, but it doesnt have alot of symbols e.g screw terminals and such..Most of the schematic editors I tried dont have hotkeys, and you cant click F2 write quickly R press enter and boom a resistor, you need to actually move your mouse click a few buttons and then you will get you resistor, and I hate it, it feels like a simple schematic takes hours to draw. thats what I like about ltspice - I can draw schematics extremely quick.I tried many softwares and all of them are or too simple, or too complicated..

author: suicidaleggroll
author_rank: Super Contributor
timestamp: March 18, 2016, 11:03:25 pm
content: Have you tried KiCAD?A lot of the normal tasks have hotkeys, and you can make your own symbols if you can't find one in the library.

author: c4757p
author_rank: Super Contributor
timestamp: March 18, 2016, 11:08:17 pm
content: Yes, KiCad is (or at least can be) quite keyboard-driven. I like it for the same reason.

author: ZeTeX
author_rank: Frequent Contributor
timestamp: March 19, 2016, 09:31:38 am
content: Quote from: c4757p on March 18, 2016, 11:08:17 pmI'm trying KiCad and it seems like I can learn to use it, But I have one major problem - everything is mirrored, if I move my mouse to the left the sheet moves to the right, also every compoent letter is mirroed like this:Also I have to click end tool on everything and that is just annoying, is there anyway to disable it so it will be like in ltspice where you just right click when you finished?Also when I click the home button the sheet just becomes black and I have to zoom in to fix this (bug)Also everything I click on F3 which I set to "Begin Wire" it just draw random wire and not just switch to the tool.. (other bug).I think I have some technical problems with kicad, time to format this damn crappy windows 10.too many annoying things..

author: c4757p
author_rank: Super Contributor
timestamp: March 19, 2016, 08:31:45 pm
content: ZeTeX, it looks like you've found a pretty ugly bug in KiCad. I can confirm it on my own system, and have filed a report in the bug tracker. If you'd like to follow and see when it gets fixed, you can create a Launchpad account and then subscribe yourself to the bug report here:https://bugs.launchpad.net/kicad/+bug/1559545

author: bson
author_rank: Unknown
timestamp: March 20, 2016, 12:46:25 am
content: Try toggling the trackpad panning function on and then off to reset all the state related to it. This was added quite recently and is great if you use a trackpad, but it might get confused if you enable it with a mouse.
schematic editor tool? - Page 1
Forum section: electronics / beginners

author: techguru
author_rank: Regular Contributor
timestamp: December 09, 2018, 06:14:24 pm
content: Hi to all,I need some schematic editor tools were i could draw the circuit but i do not want to simulate the circuit. I always admire at Behzad Razavi sir book, How the author might drawn to explain the concept. Can i know the software used in the book and free software available for schematic drawing....

author: Kasper
author_rank: Frequent Contributor
timestamp: December 09, 2018, 06:53:48 pm
content: Not sure what is used in that book but for free stuff:KiCAD is good for schematic and PCB.Fritzing seems popular for schematic and I think it can also do breadboard designs, haven't used it myself.

author: Wimberleytech
author_rank: Super Contributor
timestamp: December 09, 2018, 07:04:40 pm
content: Quote from: Kasper on December 09, 2018, 06:53:48 pmFritzing is a very nice tool. I even use it for layout (don't laugh). It is a challenge to get a new device that is not already in the library. Moreover, it is not being maintained any longer. There is at least one guy on the Fritzing forum that will build a custom part if you ask him nicely.I have used Visio for years. It is not free. I have an extensive library of symbols that I have created.Once upon a time, I wrote an engineering textbook (now 3rd edition). We did the figures using Adobe Illustrator (for 2nd and 3rd). Very nice results but Illustrator is not really designed for that purpose and it is not free. However, Inkscape is free and also generates nice output.

author: Zero999
author_rank: Super Contributor
timestamp: December 09, 2018, 10:57:35 pm
content: I use LTSpice for lots of my schematics, even if I don't bother simulating them and edit them in image editing software later.
Schematic for Stepper learning board (as in attached image) - Page 1
Forum section: electronics / beginners

author: amrat.ch@gmail.com
author_rank: Newbie
timestamp: August 10, 2024, 03:12:58 am
content: Hi everyone,Any ever see or have schematic or manual of this attached Stepper learning board ?ThanksAmrat

author: MathWizard
author_rank: Super Contributor
timestamp: August 11, 2024, 04:30:27 am
content: Hi did you take the picture ? What would the zif socket/blue thing be for ?

author: ledtester
author_rank: Super Contributor
timestamp: August 11, 2024, 04:46:55 am
content: I think the ZIF socket is for an microcontroller. You've got a power inlet with a switch, bridge rectifier and bulk capacitor, a crystal with two small caps, and what looks like an RJ45 or 11 jack perhaps for a TTL serial port.Take a pic with the top removed - that would give us a lot more info. I would expect to see something to drive the stepper coils - like transistors or motor driver chips.

author: jpanhalt
author_rank: Super Contributor
timestamp: August 11, 2024, 09:48:28 am
content: I agree, the ZIF is almost certainly for the MCU of one's choice. The LEDs might be related to state, e.g., Example 2 here:http://ww1.microchip.com/downloads/en/AppNotes/00907a.pdfA paper disk attached to an inexpensive stepper gauge (e.g., automotive) and solderless breadboard is what I used when playing with code for them. Adafruit has an inexpensive breakout board, schematic, and code for learning:https://www.adafruit.com/product/2448
Schematic -- one AND gate to mulitple outputs - Page 1
Forum section: electronics / beginners

author: IveGotAPocket
author_rank: Newbie
timestamp: May 01, 2015, 09:23:15 pm
content: Hey guys I took a truth table and made 7 k-maps from it for all of my 7 outputs using only 4 inputs. Next i identified logic gates that appeared in multiple k-map SOP forms. Once that was done i started to make the schematic in diamond lattice.My question is how i can i tie one AND gates output to multiple outputs..says 1,2,3 for example? -the 1,2,3 would correspond to lights on a 7-segments display.I was not sure how to do this as connecting the wires directly is not working...i tried this bus tap which allowed me to connect the wire to output gives me weird output in my spreadsheet, so i know that is probably wrong.Thanks for any help

author: Thor-Arne
author_rank: Unknown
timestamp: May 01, 2015, 10:16:28 pm
content: You can use a diode on each gate output, the diodes can then be connected together.If you're going to drive 7segment displays with AND gates, check that the LED's isn't drawing to much current for the chip.

author: IveGotAPocket
author_rank: Newbie
timestamp: May 01, 2015, 10:26:55 pm
content: Quote from: Thor-ArneThanks! i will go try that nowedit: the software I'm using doesn't seem to have a diode.Quote from: Thor-ArneI defiantly will do that. Is there anything that I'm not doing correctly or could be improved?I will be running the display via a MachX02 board

author: Thor-Arne
author_rank: Unknown
timestamp: May 01, 2015, 10:51:03 pm
content: I'm not doing FPGA's, but diodes is very commonly used in logic circuits so I assumed it was in there.Perhaps there is another way to tie the outputs together, but I'm afraid someone else has to answer that.

author: IveGotAPocket
author_rank: Newbie
timestamp: May 01, 2015, 10:54:00 pm
content: I guess that i will just start a new schematic and do it a longer route..was trying to use the least gates possible but i cant seem to find an answer to my question from any resource lattice diamond has that i can find. Dang

author: Rerouter
author_rank: Super Contributor
timestamp: May 01, 2015, 10:59:40 pm
content: At an educated guess, you would have to use OR gates to accomplish it, but if you are doing this in an FPGA, dont they have a 4 bit mux or similar in there function blocks, allowing you to attack it that way over many, many and gates?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 01, 2015, 11:04:47 pm
content: Boolean addition is implemented with OR gates. You can use diodes, but they kind of suck.. don't expect too much out of them!Note you can complement all the inputs and use NAND gates for the maxterms, then NOR gates for the sums. This is how it's implemented in real chips (PLDs etc.).Tim

author: IveGotAPocket
author_rank: Newbie
timestamp: May 01, 2015, 11:16:35 pm
content: Quote from: T3sl4co1l on May 01, 2015, 11:04:47 pmWord i see what your saying, thanks i will try that. I'm just gonna restart cause its good practice anyway
Schematic or service manual - Page 1
Forum section: electronics / beginners

author: masster
author_rank: Regular Contributor
timestamp: May 07, 2014, 10:44:57 am
content: HiI wondered many times how can Dave Jones find free service manuals for all kind of electronic devices. He only mentions briefly 'I managed to find this or that schematic / service manual'. My search was in vain, the so called 'free' sites proved to be very shady, not free / scam sitesSo I am asking you, is there a free Motherload for schematics and service manuals to help me repair electronic devices? Right now I'm trying to repair a car radio (NewOne AR702) that was supplied with 12V reversed polarity. I replaced what was getting hot or blown (a 1000uF cap, a TDA8571J and a 7808) but still no luck, nothing lits. A schematic would help me a lot.

author: paulhm81
author_rank: Regular Contributor
timestamp: May 08, 2014, 06:44:00 pm
content: I find a lot of service manuals on this site -http://www.eserviceinfo.com/Usually you will have a hard time finding service manuals for noname equipment.Intelegi?

author: masster
author_rank: Regular Contributor
timestamp: May 08, 2014, 07:17:46 pm
content: Thanks for the link.NewOne (http://www.new-one.eu/home) is not a noname Chinese brand, it is a French company founded in 2007. The model AR702 was discontinued, so I contacted them hoping they will share some information, but no luck.Anyone else knows other links to service manuals for all kind of electronic devices?
schematic question - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: April 21, 2022, 08:58:09 pm
content: In the diagram below I have highlighted two areas of interest with red boxes, am I correct in assuming that part of the circuit should be fed a separate 12v source

author: james_s
author_rank: Super Contributor
timestamp: April 21, 2022, 09:00:36 pm
content: I don't believe so. It looks like those are just flags indicating the +12V supply and ground point it is referenced to.

author: TimFox
author_rank: Super Contributor
timestamp: April 21, 2022, 09:11:30 pm
content: I believe the two tags are for the unseen power connections to the ICs on another page, not an external power supply.

author: eugene
author_rank: Frequent Contributor
timestamp: April 21, 2022, 09:19:05 pm
content: That makes sense. VT1, VD1, and associated R's and C form a voltage regulator, presumably 12V.
Schematic Review of Solenoid Control through multiple channels - Page 1
Forum section: electronics / beginners

author: x4ce
author_rank: Contributor
timestamp: August 17, 2024, 06:04:16 am
content: Hi,Please if someone can review the attached schematic. I am trying to control solenoid (12, 15W) from 2 channels of MCU.1. P0.16 will permanently turn on the solenoid using NMOS from 12V.2. P0.18 will turn on the NMOS but the solenoid will be driven by a PWM source through another NMOS.I have selected SI4214DDY-T1-GE3 as a logic level FET and as such added 100 Ohm resistor for current protection along with a pull-down to avoid floating of NMOS. Whereas, the gate of STN3NF06L will be driven by VGS >10V.Please review the schematic for any potential issues and any further suggestion in its improving.Thanks

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 17, 2024, 07:48:46 am
content: I don't think P16 is a problem.I don't see the point of using two FETs for P18, is there any reason why the gate of P18 FET cannot be directly PWM controlled?If it were me, I would not use P16 and put P18 through an AND gate to combine P18 control and PWM control. no need for STN.

author: x4ce
author_rank: Contributor
timestamp: August 17, 2024, 09:08:07 am
content: Quote from: squadchannel on August 17, 2024, 07:48:46 amThanks for responding.These two FET are be turned ON under two different conditions through MCU. In one condition, P16 turns ON the solenoid and P18 remains OFF. In second condition, P16 is off then P18 turns ON and here 3rd (bottom) FET is driven by external PWM source. So, the purpose is to drive the solenoid from external source under 2nd condition.Thanks

author: PGPG
author_rank: Frequent Contributor
timestamp: August 17, 2024, 09:47:09 am
content: Quote from: x4ce on August 17, 2024, 09:08:07 amYou are making AND (External with P18) and then OR of it with P16 at high output current.After converting external signal into your logic level you can do all that at signal level reducing the use of high current output transistors to 1.