hybridfree/eevblog-posts huggingface dataset:
DSO Choice: Rigol DS1104Z-S new or Refurb/used Agilent DSOX2014A ? - Page 1
Forum section: electronics / beginners

author: jimjam
author_rank: Regular Contributor
timestamp: June 06, 2014, 03:22:21 pm
content: Both are 100MHz, 4 channelsThere's a glaring difference in the memory depth, so I'm wondering if it actually makes a difference?The usual question - which one should I get? My gut feeling is that Agilent will be a better scope but some of the specs are beaten by Rigol. In real use - does it matter?Rigol:* 100MHz bandwidth, 4 channels* 1GS/s real-time sample rate* 12Mpts standard memory depth* UltraVision multi-level intensity grading display* Up to 30,000 wfms/s waveform capture rate* Up to 60,000 frames real-time waveform recording option* Low noise floor,dynamic range: 1mV/div to 10V/div* Optional serial bus triggering and decoding (RS232, I2C, SPI)* In-built 2 channel 25MHz waveform generator (DS-1000Z-S)* Complete connectivity: LAN (LXI Core device 2011), USB host & device, AUX <--is the LAN optional or standard?* 7 inch WVGA (800x480) display with multiple intensity level waveform displayAgilent:KEY SPECIFICATIONSSee more of your signal more of the timeLargest screen in its class: 8.5-inch WVGA displayFastest update rate of50,000 waveforms per secondDeepest memory:100 kpts standard, up to 1 Mpts optionalMaximum sample rate2 GSa/sDo more with the power of 5 instruments in 1:Best-in-class oscilloscopeIntegrated logic analyzer (MSO, Optional and upgradable with DSOX2MSO)Only hardware-based serial-bus protocol analyzerOnly built-in 20-MHz function generator: WaveGenOnly built-in 3-digit voltmeterGet more investment protectionUpgradability: add bandwidth, digital channels, memory, serial analysis, DVM or WaveGen after purchaseSegmented memoryMask TestingLAN / Video optional

author: Nazareth
author_rank: Contributor
timestamp: June 18, 2014, 08:48:33 pm
content: So, which one did you get and why?Naz

author: jimjam
author_rank: Regular Contributor
timestamp: June 19, 2014, 12:47:05 pm
content: I haven't decided yet. Meanwhile I have expanded the choice to MSOX304A. There's a refurb MSOX3034a on ebay from Agilent themselves. The price is not bad compared to brand new price, but it comes with no probes/accessories and no warranty. I can hunt around for the probes but buying a $4K gear with no warranty.... I'm not so sure about.Then there's the Rigol's MSO1000Z.I am leaning more towards Agilent because it seems nicer to use, compared to Rigol's, but I have only been looking at youtube videos so far. I'm also not sure how much Rigol's fan noise is going to annoy me or whether it'll be fine.

author: Nazareth
author_rank: Contributor
timestamp: June 19, 2014, 05:04:41 pm
content: JJ,For the amount of money you would be forking over then a warranty would be expected. I have the Rigol DS1104Z-S. If I would have known Rigol was going to come out with the MSO1104Z-S then I would have waited. Maybe I can trade up. I wish I could afford an Agilent but I will settle for what I can afford. Good luck on your search.Naz
DSO1062D current measurement possible? - Page 1
Forum section: electronics / beginners

author: tyger
author_rank: Newbie
timestamp: January 09, 2022, 11:03:23 am
content: Hi all,I am hoping to find some voltcraft/handtek owners here.I was looking for a current measure function on my DSO scope but i can not find it. I think it does not exist?

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 09, 2022, 11:35:51 am
content: just buy any current probe. hantek sells under 100usd

author: tyger
author_rank: Newbie
timestamp: January 09, 2022, 12:38:46 pm
content: Doing the measurement is not the issue, but thank you for the info.I just wanted to know if it was possible to do this with a sense resistor.

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 09, 2022, 04:41:20 pm
content: Quote from: tyger on January 09, 2022, 12:38:46 pmOF COURSE!i always do that all the time.

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 09, 2022, 04:42:05 pm
content: just don't connect your EARTH/GROUND wire.or something will smoke.
DSO138 2 pin male connector - what is it? - Page 1
Forum section: electronics / beginners

author: NikJ
author_rank: Newbie
timestamp: February 21, 2022, 04:21:55 pm
content: HiTotal newb & first post. I bought an assembled DSO138 and what to connect it to a 9v battery. What is the male plug that I need for the white 2 pin connector and can I buy it in less that vast quantities?Thanks!

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 21, 2022, 05:21:42 pm
content: Which connector are you talking about, NX2500-02?

author: jpanhalt
author_rank: Super Contributor
timestamp: February 21, 2022, 05:21:49 pm
content: Apparently, you have 2 choices for power. The circular connector and 2-pin connector are wired in parallel.The 2-pin connector is characterized by its pin spacing. My guess is that it is 2.54mm/0.1". Then you need to find a matching plug that is keyed so it cannot be inserted wrong. JST, Amphenol, Molex and others make them. Finding a matching plug for the circular connector might be easier. Center pin is positive.

author: NikJ
author_rank: Newbie
timestamp: February 21, 2022, 05:48:49 pm
content: Thank you! The barrel connector looks like I can buy singles, rather than tens or hundreds of the 2 pin

author: tooki
author_rank: Super Contributor
timestamp: February 21, 2022, 06:40:17 pm
content: The power header is a JST XH connector. One of the most common connectors in the world. Absolutely not something where you’d have to buy hundreds or thousands. Or even tens. You can order a single one from Digi-Key or any number of resellers. And clones are insanely cheap on AliExpress.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: February 22, 2022, 06:06:09 pm
content: Be aware that if you run the DSO138 from a 9V battery, when the battery gets low, you will start to get incorrect waveform levels. If memory serves, it's to do with the negative voltage reference circuitry not working properly below about 7.5V.And regardless of method of power supply, you cannot give it less than 7V anyway because it uses a 7805 regulator for the 5V rail which has a 2V dropout voltage.

author: Gyro
author_rank: Super Contributor
timestamp: February 22, 2022, 06:58:00 pm
content: You would be better to use a 6(or 8 )*x AA battery holder with NiMh rechargeable batteries. The end voltage isn't so much of an issue then because you can just recharge them.I did a write-up on the JYE DSO138 Forum a few years ago on how to reduce the minimum supply voltage. With all modifications, I managed to get it down to 5.4V. Note that Ireallywouldn't attempt this unless you are experienced - particularly the removal of the reverse supply protection diode!https://forum.jyetech.com/viewtopic.php?f=18&t=744EDIT:*I can't remember whether the regulator gets a little too hot at 12V.
DSO138 oscilloscope - Page 1
Forum section: electronics / beginners

author: nForce
author_rank: Frequent Contributor
timestamp: October 16, 2018, 02:50:52 pm
content: Where can I get a power supply for this oscilloscope:https://www.ebay.com/itm/Fully-Welded-Assembled-DSO138-2-4-TFT-Digital-Oscilloscope-1Msps-Probe-B1/382222708181?hash=item58fe3fadd5:g:NTEAAOSw881Zs1d1:rk:2:pf:0?Because I don't get it with the package. I know it's not a good oscilloscope but, when I get use to it I will buy more powerful one.Thanks.

author: IDEngineer
author_rank: Super Contributor
timestamp: October 16, 2018, 03:49:01 pm
content: From the PCB silkscreening it wants 9VDC. A suitable 9VDC wall wart supply is likely hiding in one of your drawers somewhere!I am a bit troubled by a PCB that has been "welded"....

author: Gyro
author_rank: Super Contributor
timestamp: October 16, 2018, 05:25:20 pm
content: If you want true portability, a 9V (6 cell) AA battery holder with Alkaline or preferably NiMh cells works quite well.

author: exe
author_rank: Unknown
timestamp: October 17, 2018, 08:54:44 am
content: I think manual says supply voltage should be in the range 9-12V. Above 12V onboard voltage regulator may overhead (so says manual, afaik).I think mine worked from 8V or something. Below I started to get huge offset errors.

author: Gyro
author_rank: Super Contributor
timestamp: October 17, 2018, 04:14:41 pm
content: I implemented some mods to make mine more battery friendly, specifically for a 9V battery supply. It works from about 5.4V - 11V (ie. down to about 0.9V per cell)...https://jyetech.com/forum/viewtopic.php?f=18&t=744Use at your own risk (particularly the removal of the reversed supply protection)!
DSO138 problem with oscilator - Page 1
Forum section: electronics / beginners

author: bborisov567
author_rank: Regular Contributor
timestamp: July 31, 2022, 05:29:43 pm
content: I got the scope in unknown condition. After powering just shows white screen. At this point i decided to try upgrading the firmware. Soldered the jumpers, connected the ttl tp usb adapter but the stm flash tool didn't find the device. I checked the board for shorts and also checked the power supplies - everithing is ok. Then i measured the frequncy on the quarz and it was around 44kHz, instead of 8MHz. Replace the quarz with another from a scrap board but the frequncy remains the same. Check both 22pF caps and they are also fine. Is there a possiblity of bad mcu?

author: ozcar
author_rank: Frequent Contributor
timestamp: August 01, 2022, 07:18:26 pm
content: By the sound of it, you don't know if the one you got ever worked?I'm not familiar with the DSO138, but I see it mentioned that there is a LED on the board that should blink twice when it starts up. If you are not seeing that then the processor is probably not running.How did you measure the crystal frequency? In any event, the USART bootloader on the STM32F103 used is not dependent on the 8MHz crystal (HSE), it uses internal oscillator (HSI). So, if you are sure that the USB-TTL converter is working, and that your connections and jumpers are correct, then there must be more wrong with it than just the 8MHz oscillator not working.
DSO2D15 - using SCPI via vb.net  - Page 1
Forum section: electronics / beginners

author: mgroz
author_rank: Newbie
timestamp: February 07, 2023, 07:29:53 pm
content: I’m not having any luck talking with the DSO2D15 from Visual Studio (vb.net). I installed the Keysight software and can talk to it. In addition, I installed the hantek application software and can run the scope and generator from my pc.I’ve got the SCPI manual, which is very good, but does not have any examples on how to connect using VISA or dll’s. Does anyone have a small example of how to connect and talk to the scope.Thanks

author: m k
author_rank: Super Contributor
timestamp: February 14, 2023, 02:15:09 pm
content: Maybe Embedded Computing section or Microcontrollers would be a better place.

author: mgroz
author_rank: Newbie
timestamp: February 14, 2023, 04:06:37 pm
content: Was not sure where to post this. Anyhow, I've figured out how to interface with VISA and march forward using SCPI.
DSO3D12 não faz medição em modo Osiloscopio - Page 1
Forum section: electronics / beginners

author: Valdemir Brito
author_rank: Newbie
timestamp: November 03, 2024, 04:07:02 pm
content: Meu Osciloscópio não ta Fazendo medição em modoosciloscópio nas outras funções tudo ok.alguém ja teve esse Problema.

author: Aldo22
author_rank: Super Contributor
timestamp: November 03, 2024, 04:26:20 pm
content: Este é um fórum de língua inglesa.Pode escrever isto em inglês?De preferência no tópico apropriado.https://www.eevblog.com/forum/testgear/another-dsodmm-zeeweii-dso3d12-claimed-120mhz250msps/150/www.deepl.com

author: u666sa
author_rank: Frequent Contributor
timestamp: November 04, 2024, 06:38:03 am
content: Quote from: Valdemir Brito on November 03, 2024, 04:07:02 pmhttps://forum.jyetech.com/viewtopic.php?t=1036
DSP Explanation Paper - Page 1
Forum section: electronics / beginners

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 01, 2018, 08:44:09 am
content: May prove useful:https://www.researchgate.net/publication/261779218_Understanding_Digital_Signal_Processing's_Frequency_Domain?_sg=dV3kEZOAjU0pi2tG8_FP425FyxFUYEJ0hWaawwSLhQqPJbAztcVxPsXgnW5LuKLUL6quSi8PzrZLl85Z8JKdLQ6QubAYCyvZ2gTim

author: hamster_nz
author_rank: Super Contributor
timestamp: July 01, 2018, 08:51:30 am
content: Thanks! It is added to my reading list....

author: Marco
author_rank: Super Contributor
timestamp: July 01, 2018, 11:56:48 am
content: For a very specific audience, it illuminates some gotchas for RF guys already familiar with working with quadrature signals and thinking in the frequency domain when trying to read DSP books.

author: rstofer
author_rank: Super Contributor
timestamp: July 01, 2018, 11:34:08 pm
content: I like the "coax cable"/"ribbon cable" in Figure 1. It cuts right to the chase!
DSP Filters - going from pole-zero diagrams to spectrum plot of a digital filter - Page 1
Forum section: electronics / beginners

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 05, 2016, 09:34:43 am
content: I'm having some difficulties understanding how they go from the transfer function (in the frequency domain) to the amplitude response diagram. I understand going from the transfer function to the pole-zero plot, but the course book then mentions (translated from dutch):"The behaviour of digital or discrete filters in the neighbourhood of poles and zeros is different (.. from that of continuous filters): ln the vicinity of a pole, a local peak will occur in the spectrum, where in the vicinity of a zero, a trench (I don't know what the correct English term for this is) will occur."That all makes sense, but then as examples, they have these plots:And this one:Can someone explain to me how you go from the pole zero plot to the frequency response? Why is the first always 0 except around the two poles, and the second always A high value except at the frequency where the zero's and the poles are? Why is there no negative peak in the first plot around 0 and ws/2?(Dutch custom book for the course by Prof. P. Wambacq at KUL - I hope he doesn't mind me posting images from his book on this forum)

author: whollender
author_rank: Regular Contributor
timestamp: August 05, 2016, 09:25:41 pm
content: Conceptually, as the frequency goes from 0 to +pi (or -pi), you are tracing the unit circle around the origin (e^(jw) = e^(j*0) -> e^(j*pi)), and the magnitude approaches infinity the closer it approaches a pole, and approaches zero the closer it approaches a zero.This is why a pole on the unit circle means that the system is unstable; the transfer function approaches infinity at the frequency where the pole occurs.The first plot is tied to zero by the zeros at w = 0 and w = pi, and gets pulled higher around w = +/- pi/2 by the poles.For the second plot, you can imagine that the further away from the pole/zero pairs you are, the more they cancel out, so the transfer function is constant. However, as you approach the pole/zero pairs, the zero dominates (it's on the unit circle), so the transfer function is pulled to zero.There isn't a negative peak in the first plot because the zeros make the transfer function zero, not negative infinity, or some other value.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 06, 2016, 05:53:30 am
content: That makes a lot of sense. Now that I've also spent more time studying the chapter, I think I'm starting to get a better understanding of what is going on. It was just the wording in the beginning of the chapter that put me off (from that I first thought I should see a flat line, with a bump in the neighborhood of the poles and a negative bump for zeros). I also go thrown off by the "constant" levels which, if I now understand it correctly, are determined by a factor that you cannot derive from the pole-zero plot. So I couldn't quite understand why the first transfer function was zero except around poles, and the second was one.Thanks for the help!
DSP ..Finding gain from frequency? - Page 1
Forum section: electronics / beginners

author: Seán
author_rank: Contributor
timestamp: April 23, 2014, 10:25:50 am
content: Hello,I am trying to teach myself some of the basics of matlab ...my teacher at uni knew the stuff, but just couldn't teach the stuff.Anyway ...hopefully someone can help me ...how can you determine gain from frequency, say for the -3dB point? Of course it can just be read off from the plot produced by matlab, but how do you do it mathematically?Thanks in advance for any help, and sorry if this has already been asked and answered ...I did a (very) quick search and didn't see a similar question.Thanks again.Seán

author: Rerouter
author_rank: Super Contributor
timestamp: April 23, 2014, 10:41:13 am
content: In your case it sounds like you want to model a system, as the -3dB point is in reference to the low pass roll off of the input of a scope, by knowing what your feeding your signal through you can run it through that model and mathematically solve the attenuation,Most models involve the poles and zeros of the system, otherwise known as the transfer function, I myself am not well versed in it, but hope some of this can point you in the right direction,

author: Seán
author_rank: Contributor
timestamp: April 23, 2014, 10:45:36 am
content: That's great, thanks for the info!Seán

author: LvW
author_rank: Frequent Contributor
timestamp: April 23, 2014, 11:25:33 am
content: Quote from: Seán on April 23, 2014, 10:25:50 amHello Sean,the -3dB point is important for all frequency-dependent systems (real amplifiers with falling gain, filters in particular).That means: You always have to calculate the MAGNITUDE of the gain resp. the output voltage (because of phase shift involved).More than that, it is important if you have a 1st order or a 2nd order system.* For a 1st order system (with one single pole) the -3dB point is that frequency for which the MAGNITUDE is 3dB down and the phase shift is -45 deg. At this frequency the real part and the imaginary part of the function under consideration are equal!.* For a 2nd order system (which has two poles) the situation is a bit more complicated. However, in any case, the -3dB point again is the frequency where the MAGNITUDE is 3dB lower than the maximum value.Hope this helps to answer your question.

author: Seán
author_rank: Contributor
timestamp: April 23, 2014, 03:05:17 pm
content: Hi,Thanks for the reply! It does help me.Thanks again.Seán
dsPIC - Calling asm code from C - Page 1
Forum section: electronics / beginners

author: drZoidberg
author_rank: Contributor
timestamp: June 05, 2010, 09:40:42 pm
content: Hi! I'm a student trying to learn digital filters, and i have a problem with c being too slow.I use a dsPIC30F4011, and i want to use the hardware multiplier. But I dont know how to call assembler code from c.Can someone please show me how to call asm from c?Thanks!

author: migsantiago
author_rank: Frequent Contributor
timestamp: June 05, 2010, 11:51:03 pm
content: HiJust add the asm() tags and you're ready to go!Code:asm("TBLRDL , W4");

author: TheDirty
author_rank: Frequent Contributor
timestamp: June 06, 2010, 04:12:55 am
content: Assuming you are using the MicroChip C compiler, then read chapter 9 of the manual.http://ww1.microchip.com/downloads/en/DeviceDoc/51284J.pdf

author: drZoidberg
author_rank: Contributor
timestamp: June 06, 2010, 09:57:48 am
content: Awesome! Ch 9 was just what i was looking for! Thanks!
DT24P Battery Monitor USB Needed. - Page 1
Forum section: electronics / beginners

author: Jwillis
author_rank: Super Contributor
timestamp: October 27, 2021, 11:42:29 am
content: I got thisDT24P battery monitor with BluetoothI'm using for my electronic load I'm building .I would like to add a USB interface to log data . My laptop has no Bluetooth . I could just get a BT dongle but would really like the USB in the final build.I'm not 100% sure exactly what I need to do but I'm thinking I need a UART to USB bridge ( USB to serial UART interface ) ? Something like theFT232RL. Would that be the right direction?I figured out some of the pins and kind of understand what they do . The Blue tooth module is aJDY-23. The MCU is unknown but suspect its a PIC . I think the 5 connections beside the MCU are for programming .At the bottom of the PCB are 5 connections I think I can connect a bridge to . They are labelled on the picture as VCC 3V3 , GND , TX RXD , RX TXD , and pin 28.TX RXD has a signal I took a picture of with the scope . The signal is coming from the MCU TX Pin 22 . The RX TXD connection is set High at 3V3 . The Pin 28 is low at 0V . This set the STAT on the blue tooth but I don't think I need that for USB . So I think I only need the first 4 connections.Am I going in the right direction with all this ?
DT830B reading fluctuates when held in hand - Page 1
Forum section: electronics / beginners

author: nr4ps
author_rank: Newbie
timestamp: March 06, 2022, 09:00:59 am
content: Hello,I am attempting to assemble a DIY multimeter kit that I purchased, but I’m finding that the meter behaves oddly when held in my hand. If it’s just sitting on the table it seems mostly okay, but if I hold the meter in my hand the reading goes wonky (flips through various readings smaller than the correct answer). Interestingly, this happens when reading a DC power supply but not an alkaline battery.Video of behavior:https://drive.google.com/file/d/18d9zarT9AIOlwOapHeYOwWT4P-VMY9UT/view?usp=drivesdkSchematic is attached.I am not exceptionally good at soldering, but it looks to me like I put enough solder everywhere that everything would have a good connection and nothing appears shorted.I tried taping a piece of aluminum foil as shielding in the inside back case and soldering a spring to a point on the PCB connected to its ground. There was evidently a time when the kit included these parts but they seem to have cut them out to save money so you’re seeing my improvisation in the photo. In any event, it didn’t change the behavior.They’ve sent me two bad capacitors, so the quality of the parts is suspect but I tested every component before I soldered it to the PCB—with the caveat that I can’t measure really small capacitance so I was only able to confirm the 100 pF capacitor is not internally shorted (which was the issue with the two defective capacitors that I’ve identified). I’m wondering if it could somehow still be one of the capacitors, though, because it’s interesting that there’s no issue with reading an alkaline battery but there is with a plug-in DC power supply. I get a perfectly steady reading on that 6.4V using these same leads on my Fluke 117, so there can’t be any wild fluctuations happening but it is a plug-in power supply so I expect there’s some noise.Is there anything obvious that could be causing this behavior?
Dual 555 Timer (with inverted signal) for H Bridge Problem - Page 1
Forum section: electronics / beginners

author: z7d8tsg
author_rank: Contributor
timestamp: May 15, 2019, 11:11:35 pm
content: Dual 555 Timer (with inverted signal) for H Bridge ProblemI tried this circuit but it doesn't work. Any thoughts?Thanks,- Dan

author: David Cutcher CEG
author_rank: Contributor
timestamp: May 15, 2019, 11:49:12 pm
content: You say "H Bridge problem."You need to be more specific.What is the problem?Is this a problem for school?What is the expected output?Not enough information here for me to attempt a helpful answer.David Cutcher "Certified Evil Genius"

author: z7d8tsg
author_rank: Contributor
timestamp: May 16, 2019, 12:22:20 am
content: im building an h bridge that uses 2x 555 timer with optocoupler non zero gate crossing (k3011p). It needs to run off of 1x power supply at the end, I will be using voltage regulators to regulate voltage and resistors to split amperes properly. Is for a high accuracy remote carBest,- Dan

author: David Cutcher CEG
author_rank: Contributor
timestamp: May 16, 2019, 05:12:49 am
content: The original circuit, attached, should work. I'm uncertain about where your added lines are connected.Also, as noted on the circuit, this is using a split voltage. You don't indicate that on yours.David Cutcher "Certified Evil Genius"

author: soldar
author_rank: Super Contributor
timestamp: May 16, 2019, 07:50:40 am
content: That circuit could have some serious shoot-through problems.

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2019, 09:38:22 am
content: Quote from: David Cutcher CEG on May 16, 2019, 05:12:49 amThat will work, but not very well. There will be a huge voltage drop of about 6V, given a current draw of a couple of Amps, because of the Darlington pair configuration and the 555's output stage drops over a Volt, on the high side.

author: z7d8tsg
author_rank: Contributor
timestamp: May 16, 2019, 01:00:10 pm
content: How can I make a potentiometer change the frequency while keeping the duty cycles at 50% for both pwm signals?

author: malagas_on_fire
author_rank: Frequent Contributor
timestamp: May 16, 2019, 01:11:52 pm
content: Another space improved idea is using a 556 which consists a chip with two 555 timers sharing the same power source. Drive the mosfets with some transistors between the 555's and the Gate's, "doodle" something for "H bridge DC motor. ".PS: I'm making an assumpcion on driving improperly the H bridge , but more data would be good to assist .

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2019, 01:44:33 pm
content: Quote from: z7d8tsg on May 16, 2019, 01:00:10 pmThe classic is to use the 7555, instead of the normal 555.A 555 timer isn't the best circuit to use to get 50% duty cycle. I'vebuilt the above circuitand it didn't give a perfect 50% duty cycle output. It's better to use an oscillator and divide by two counter. The CD/HEF4013 work quite well.
Dual action switch different gpio pins - Page 1
Forum section: electronics / beginners

author: caquino
author_rank: Newbie
timestamp: May 02, 2015, 10:40:04 am
content: Hi everyone,I'm trying to build something similar to the Amazon Dash Button using an ESP8266 module.The project has a single button interface, when short pressed it goes to the operational mode, when long pressed it goes to the configuration mode.The ESP8266 module will be in deep sleep, and I will trigger the RST pin to wake it up, the problem is that if in keep the button keep being pressed it need also to trigger a GPIO pin.As to wake the module from sleep I need to trigger the RST pin, I can't used it to detect short/long presses as it resets the module, so I need to solve it outside of the firmware.Basically, if you press and hold the button, it will pulse the RST pin and keep the GPIO up until the button is released.I've attached an image of the circuit that I'm trying to build, the LED represents the GPIO pin and the Buzzer represents the RST pinI'm not sure if this will work, looking on the simulator application it appears that will work, but my "you're doing the wrong thing" sensor is triggered.Any help will be highly appreciated.Thanks in advance!
Dual axis HALL Effect Sensor - Page 1
Forum section: electronics / beginners

author: BoloDotDk
author_rank: Newbie
timestamp: June 17, 2017, 03:49:20 pm
content: Hi guys,I am currently designing a joystick for a flightsim and I really like the gimbal on the Thrustmaster Warthog.Does anyone know what HALL effect sensor they use? Or can suggest a alternative sensor. Link to a photo:http://www.simhq.com/_technology3/images/technology_174a_022.jpgI will be using a Leo Bodnar BU0836A 12-Bit Joystick Controller, which I have tested with different buttons, switches, pot's and encoders. Also got a couple of Allegro A1302 HALL effect sensors, but they are only single axis (I guess).
Dual B3603 as 1st power supply - Page 1
Forum section: electronics / beginners

author: shobo
author_rank: Regular Contributor
timestamp: November 23, 2017, 10:33:12 am
content: Hey,I came across a diy power supply with 2 MingHe B3603 modules (The supply is already made) .My question is:is it decent enough for a beginner power supply?module manual:https://www.elecrow.com/download/B3603%20User%20Manual.pdfsupply listing:https://www.olx.ro/oferta/sursa-de-alimentare-ID9MQAN.html#5c7c7443b0If it is decent, can it be powered by a transformer?(rectified and filtered)

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 23, 2017, 10:51:10 am
content: It can be used as a beginner supply, but you should be aware that the output may be noisy. This doesn't matter for some circuits and design, but can be a problem in others.

author: Gyro
author_rank: Super Contributor
timestamp: November 24, 2017, 09:58:27 am
content: There is a long thread covering pretty much all aspects of the B3603 here:https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/Don't be put off by the title!

author: shobo
author_rank: Regular Contributor
timestamp: November 24, 2017, 04:45:06 pm
content: Quote from: Gyro on November 24, 2017, 09:58:27 amYeah read that a few times
Dual Bench Supply - OK to combine isolated grounds? - Page 1
Forum section: electronics / beginners

author: jstarr
author_rank: Regular Contributor
timestamp: December 31, 2013, 09:14:58 pm
content: I am a newbie and learning basic transistor theory by book, video and breadboarding to observe on my DMM and scope. Many schematics call for different DC supply voltages in same circuit with common ground, for example in same circuit both a 5vdc (fixed) and another either 12 or 15vdc. For breadboarding I want to avoid setting wiring two different voltage regulators from a single supply. I have an Instek dual bench supply where the channels are independent and the ground for each channel is isolated from each other and the supply chassis. Will i damage my Instek if both isolated supplies have their isolated ground bound together on the breadboard? Could the each channel's 'ground' be at a different potential than the other and could bringing them together cause damage? I did check the supply and there is no potential difference between the two ground jacks but there are definitely not sharing a common ground in the Instek (resistance >20Mohm between both black banana jacks).Am I being unnecessarily neurotic?tia and happy new yearjohn

author: w2aew
author_rank: Super Contributor
timestamp: December 31, 2013, 09:31:14 pm
content: Floating supplies like this are designed to give you that flexibility. You can tie them to make split supplies, dual positive supplies, pos or neg with respect to ground, etc. So, yes, no problem.

author: digsys
author_rank: Unknown
timestamp: December 31, 2013, 10:40:01 pm
content: As pointed out, it's all fine. When it comes to creating a +/- setup ie Tying the 1st 0V to the 2nd V+ (and making that GND),some institutions don't allow it (even though it's technically OK). You'd need to read up and decide for yourself.But all 0Vs tied together is totally OK.
Dual Comparator Output Is Phase-Shifted - Page 1
Forum section: electronics / beginners

author: epicode
author_rank: Newbie
timestamp: November 11, 2019, 10:57:14 am
content: Hello, I've been working on a boost converter for a long time now and my control system needs to provide two high frequency inverted signals (when one is high the other one has to be low) and I've been using two comparators for that, both of them get a voltage reference (some constant DC voltage) and a triangle wave just that the inputs are swiped so that the required signal can be generated but for some reason the two signals are phase-shifted like the attachment below, I've checked the triangle wave and it is in perfect sync in both inputs.. the op amp is OPA2691I and as you can see in the picture the op amp seems to trigger in a weird way.. any ideas ?

author: dmills
author_rank: Super Contributor
timestamp: November 11, 2019, 01:12:18 pm
content: Um, you are aware that that is a CURRENT FEEDBACK opamp?You cannot use that part as a voltage comparator in the way you seem to be attempting, because the inverting input is a low impedance (few tens of ohms per the datasheet) not high Z like a voltage mode opamp would be.There is a trap in using opamps as comparators anyway in that many of them have an internal back to back diode pair across the inputs, if you want a comparator, use a comparator, there is a reason they exist.

author: epicode
author_rank: Newbie
timestamp: November 12, 2019, 01:22:26 pm
content: Thank you for the reply, I will try changing to LT1720 and see if that makes any differance
Dual H Bridge driver - Datasheet questions  - Page 1
Forum section: electronics / beginners

author: electron42
author_rank: Newbie
timestamp: September 22, 2022, 07:21:32 pm
content: Hi All,I have been looking into using the TC78H660FTG as a motor driver. The datasheet has been attached.My question is how exactly would the speed of each motor be controlled using this IC. I have only previouslyused an l298n with speed being controlled through PWM on the enable pins.This IC has a Stand by a pin which can stop the motor, would connecting a PWM signal into this be a way of controlling speed?The OSCM pins seem to work in conjunction with VREF which detects if the current limit has been reached, however, this is notneeded so I'm assuming it's okay to ground VREF. However, I don't think this relates to speed control.Lastly, what is it meant when in phase mode? I'm aiming just to keep this in input mode.Sorry if this seems stupid, thanks in advance.Cheers,

author: JustMeHere
author_rank: Frequent Contributor
timestamp: September 22, 2022, 08:34:58 pm
content: Standby is slowYou want pins 1, 14, 15, 16

author: electron42
author_rank: Newbie
timestamp: September 22, 2022, 09:54:02 pm
content: Would this speed be controlled by switching MODE and using the phase on the pins you listed?

author: pcprogrammer
author_rank: Super Contributor
timestamp: September 23, 2022, 06:10:14 am
content: To control the speed you have to use PWM on the control pins (IN1A, IN2A for channel1, IN1B, IN2B for channel2). It uses the same pins when in PHASE mode, but the names differ.Read the datasheet and look at chapter 8 for the difference between the two modes. In the IN mode it shorts the motor to break it, in PHASE mode it does not.When using IN mode the control needs to vary between low,low and low,high to go backwards and high,low and low,low to go forward. This means to control the speed you have to enable PWM on only one of the two lines, depending on the direction you want to go in. Making both lines high will apply break to the motor, which will give it erratic behavior.

author: electron42
author_rank: Newbie
timestamp: September 23, 2022, 10:33:38 am
content: Thanks you!
Dual Modulus Prescalar, point and how they work? - Page 1
Forum section: electronics / beginners

author: blueagle91
author_rank: Newbie
timestamp: April 09, 2015, 09:12:31 pm
content: Hello EEVNew hear good to be part of the forum, a simple question.I know how prescaler works. Now i figuered that because of the channel step a dual modulus is required. But if you switch it fast how does the rest of the circuit knows which ratio is used, or the ratio is basicly both in the same time because of switching speed.Basicly how dual modulus orescaler works? Whats the point?
Dual N-Channel Mosfet testing on a PCB - Page 1
Forum section: electronics / beginners

author: kert06
author_rank: Newbie
timestamp: June 29, 2021, 07:30:40 pm
content: Hello.I've found quite a few tips in these forums that has helped me in the past, and i deeply thank every single one of you here who contribute! Today i have ran into a dead end and thought on asking for help here. I'm still really new into electronics and repair, hopefully you can teach me a little.I am sitting on a dead 1080ti and having trouble of testing a dual mosfet. Can't really tell what i am looking for and how exactly to test.Link to the Mosfet:https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi42Y-Wyb3xAhUkmYsKHXa5D9UQFjAAegQIBBAD&url=https%3A%2F%2Fwww.onsemi.com%2Fpub%2FCollateral%2FFDPC8016S-D.PDF&usg=AOvVaw1CztxplZyvCSGXJ4FfZwC3Also, is it possible to kill the mosfet by testing it with multimeter when the gpu is disassembled, unplugged?Thank you for your input!

author: Faringdon
author_rank: Super Contributor
timestamp: June 29, 2021, 07:48:36 pm
content: Use DMM and test Drain to source for resistance…it should be high …beware not to forward bias the diode.Before doing that, meter from gate to source, with black probe on gate…..you should see v high resistance

author: kert06
author_rank: Newbie
timestamp: June 29, 2021, 08:21:54 pm
content: Quote from: Faringdon on June 29, 2021, 07:48:36 pmFrom gate to source with black probe on gate and red on source. - Tested, all 20 of them using the )))) Ω setting, (3 and 4 seem to be connected, so it doesn't look like it matters whether to measure from 3 to 1 or 4 to 1 etc.) The result is infinite (OL) resistance on every single mosfet from red on 3/4 and black on 1 and 8.I use the same setting to test drain to source or switch it to diode(symbol) mode? What do you mean by forward bias? It's important which color probe is on which pin?

author: Faringdon
author_rank: Super Contributor
timestamp: July 01, 2021, 07:42:47 pm
content: yes, you can see the diode in the fet package drawing.Red to anode forward bais's the diode.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: July 02, 2021, 12:31:59 am
content: I'm curious. They're both NMOS. Pins 2, 5, 6, and 7 are connected together, and looking at the pinout, they would be the source for Q1 and the drain for Q2? Likewise, going by that logic, pin 9 (center) would be the source for Q2 and pins 3 and 4 are the source for Q1? So the diodes would prevent current flowing from source to drain?This topology seems strange to me.

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: July 02, 2021, 09:56:59 am
content: Quote from: LoveLaika on July 02, 2021, 12:31:59 amhave a look (for example) here to see why "totem-pole" configurations of two MOSFETs are super useful.https://techweb.rohm.com/knowledge/dcdc/s-dcdc/02-s-dcdc/92
Dual OP Amp implementation Doubt - Page 1
Forum section: electronics / beginners

author: ramonest
author_rank: Contributor
timestamp: July 29, 2017, 07:07:10 pm
content: Hello, I was studying some schematics. There was a dual OP amp IC being used. One of the internal amplifiers was being used as (I belive) signal conditioning before doing a measure with an ADC. I think I understand that part.What I don't understand is that the other OP amp inside the IC was connected: non-inverting to GND, and a 100 kOhm between inverting and output. It isn't connected to anything else, ideally it has no function, but I guess that if they did that it's for a reason. Anyone knows why?(I probably didn't explain myself too well so I'll add an schematic with the circuit.) Dual OP Amp IC is a TL082 if that's usefull.Thanks!

author: Neilm
author_rank: Super Contributor
timestamp: July 29, 2017, 07:15:47 pm
content: It has been connected like that to stop it floating. You don't want chips to be unconnected as they can end up oscillating and causeing all sorts of problems.

author: John B
author_rank: Frequent Contributor
timestamp: July 29, 2017, 11:04:10 pm
content: http://www.electronicproducts.com/Analog_Mixed_Signal_ICs/Amplifiers/Properly_terminating_an_unused_op_amp.aspxThis covers some of the issues.

author: Lee Leduc
author_rank: Regular Contributor
timestamp: July 29, 2017, 11:16:10 pm
content: TI has a good video about this.

author: ramonest
author_rank: Contributor
timestamp: July 30, 2017, 12:01:25 pm
content: That was helpful thank you all!

author: David Hess
author_rank: Super Contributor
timestamp: July 30, 2017, 11:55:15 pm
content: There are a couple of other reasons this is important:1. Terminating the amplifier within its input and output voltage ranges prevents unusual operation and saturation of any stage.2. Some dual and quad parts share bias stages and operating one beyond its specifications or saturating it will affect the others.Sometimes you can break the rules and shut an amplifier off by pulling its inputs outside of its input common mode range but this depends on the design.

author: retrolefty
author_rank: Super Contributor
timestamp: July 31, 2017, 12:01:10 am
content: Of course the same issue applies to CMOS logic chips, unused inputs should be pulled-up/down to prevent problems. Most modern microcontroller chip these days offer programmable pull-up and or down for input pins, making a no cost solution.

author: electrolust
author_rank: Unknown
timestamp: July 31, 2017, 06:24:17 pm
content: Quote from: Lee Leduc on July 29, 2017, 11:16:10 pmunfortunate URL encoding on this one

author: bson
author_rank: Unknown
timestamp: August 01, 2017, 07:10:23 am
content: Quote from: electrolust on July 31, 2017, 06:24:17 pm
Dual OpAmp: mutual impact of the different OpAmps which are in the same housing - Page 1
Forum section: electronics / beginners

author: Bigman
author_rank: Regular Contributor
timestamp: June 27, 2016, 06:08:27 pm
content: Hi,I believe to remember that I was told not to use dual (or quad, etc.) OpAmps, because the two OpAmps within one housing could impact each other quite significantly.I have checked some TI OpAmp specs, but could not find a parameter, which would characterize how prone the OpAmps within the same housing are for a mutual influence.Of course, at the end it will be a question about available space on the PCB, how much noise is acceptable, how I define "significant" etc. ... however, I could image some Dual OpAmps are better "shielded" than others. I am wondering: isn't there any "standard" parameter in the specs, which would tell me how strong e.g for a Dual OpAmp the single OpAmps can influence each other?Thank for all your comments!

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: June 27, 2016, 06:24:58 pm
content: Sure, its called crosstalk.This is a signal from one opamp coupling into another.I just looked in the LT1632 datasheet, they talk about channel separation:Channel Separation VO = – 10V to 10V, RL = 2k 110 127 dBHigh CMRR and PSRR are also necessary in order to prevent unwanted coupling. Also true for singles.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: June 27, 2016, 06:27:55 pm
content: Oh, there is also thermal coupling. That is where one opamp heats up because its dissipating power and affects the operation of the other one in that package.You can read between the lines, so to speak, as to this effect by looking at the matching of Vos and other parameters in the datasheet.E.g.Input Offset Voltage Match (Channel-to-Channel) VCM = V–, V+ (Note 5) 700 3500 µV

author: SeanB
author_rank: Super Contributor
timestamp: June 27, 2016, 08:04:52 pm
content: As well most dual or quad opamps share internal bias circuitry, so if you drive the one opamp into saturation or into slew rate limiting then this will show up on all the others as either a spurious signal or as a DC offset or the output hitting the one power rail while the overload exists. Most common when using the one half as a comparator and the other half as an amplifier, you can get some odd effects as the comparator side switches and this can be only under certain conditions of input signals.

author: danadak
author_rank: Super Contributor
timestamp: June 27, 2016, 09:17:22 pm
content: That spec of isolation is T and F and V dependent, and many datasheetsits not present. Usually however the product engineer would have donesome characterization testing, and sometimes manufacturer will share thatinfo, especially for critical applications. You can ask FAE or rep if there issome specific OpAmp you want to use and is not speced.You can always test for this yourself.......just a thought.Regards, Dana.
Dual Output Power supply - Page 1
Forum section: electronics / beginners

author: technodruid
author_rank: Newbie
timestamp: December 23, 2019, 04:57:58 pm
content: Hi all, just a quick question:I would like two positive voltages output of my power supply I'm designing. Is it OK to wire two secondaries to separate circuits? Or are these transformersrequiredto be wired in series with a center tap?The reason I ask is I am not in need of a +/- supply for the time being, and wish to test circuits ideas which require differing positive voltages.ORIf I want dual, and it is better for the transformers to be wired series/parallel, would it be best to have two transformers? One for each output and have two sets of +/- outputs?

author: Kleinstein
author_rank: Super Contributor
timestamp: December 23, 2019, 05:39:44 pm
content: One can normally use the secondaries like separate supplies. However the isolation voltage between the secondaries may be limited. So some 50 V between the secondaries is usually OK, but not 500 V without special specs for the transformer.It is often easier to build 2 identical regulators and thus allow them to be connected as a +- supply of with a common negative side.

author: technodruid
author_rank: Newbie
timestamp: December 23, 2019, 08:15:40 pm
content: Thanks, so if I'm looking at a 50VA transformer with two 25V secondaries, it should be safe for isolation?

author: Kleinstein
author_rank: Super Contributor
timestamp: December 23, 2019, 09:53:38 pm
content: A 2x25 V transformer should be safe for series or "parallel" connection. Also in more normal use a parallel configuration directly of the coils a real option - so the transformer has to be OK with this. Having the connection only behind rectifiers is not that different.
Dual Polarity Power Supply question - Page 1
Forum section: electronics / beginners

author: huu_tri0101
author_rank: Contributor
timestamp: November 25, 2013, 07:27:19 pm
content: how it works (form transformer to bridged diode) ? I don't know what happen in the transformer with 3 wires out. How the current flow?why we don't use 2 bridged diode (1 for + rail, 1 for - rail)? Does it make any different about current ripple ?

author: IanB
author_rank: Super Contributor
timestamp: November 25, 2013, 07:36:21 pm
content: Quote from: huu_tri0101 on November 25, 2013, 07:27:19 pmWell, you could trace the current flow on the diagram with a pencil and work it out?The transformer is center-tapped, so you can treat the center point as the ground/zero reference and consider the voltages at each end (top and bottom) of the secondary. When the top is positive the bottom will be negative, and when the top is negative the bottom will be positive. You should be able to work out the current flows from there.

author: Shock
author_rank: Super Contributor
timestamp: November 29, 2013, 04:53:39 pm
content: This shows the same type of transformer (ignore the fact it's 18v).