hybridfree/eevblog-posts huggingface dataset:
load capacitance CL XTAL - Page 1
Forum section: electronics / projects

author: ArCoN
author_rank: Contributor
timestamp: February 21, 2019, 07:46:27 am
content: Hi AllI'am a little confused by this.Does CL means the xtal have that load or does it mean they recommends to load with that value?https://www.jauch.com/downloadfile/5887342ab8f56_49fb800c54cda51a6f44/jxs22wa-20161222.pdfdriver spec attachedCan i skip CL if the xtal is in spec with the driver?I'am tight on spaceThanks

author: Niklas
author_rank: Frequent Contributor
timestamp: February 21, 2019, 10:58:55 am
content: No, you will need the load capacitors and probably also a small series resistor to adjust the drive level to be approx 10uW. ST has a document that describes how to calculate what load capacitance you will need, see link below, but you will have to check the gain margin from the IC that you are planning to use. The series resistor will limit the power dissipated in the crystal so it does not exceed the maximum of 100uW stated in the datasheet. Many older, physically larger, crystal could handle more power, so then it was not that big issue to skip the resistor.www.st.com/content/ccc/resource/technical/document/application_note/c6/eb/5e/11/e3/69/43/eb/CD00221665.pdf/files/CD00221665.pdf/jcr:content/translations/en.CD00221665.pdf

author: duak
author_rank: Super Contributor
timestamp: February 21, 2019, 06:33:08 pm
content: If you want the crystal to oscillate at its specified frequency you have to provide the correct CL. If you look at the equivalent circuit for a crystal, eg.https://en.wikipedia.org/wiki/File:Crystal_oscillator.svgyou can probably see that the value of CL helps determine the actual frequency. If the exact frequency doesn't matter, you might be able to work with what you have.I once ordered some custom crystals for a timebase oscillator that oscillated a few hundred Hz off that of the desired frequency and there was no way I could correct it. I went back to the order form and saw that I had specified the wrong circuit. Oooops!Cheers,
Load cell data logging - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: November 30, 2016, 03:21:28 am
content: I'm using a load cell to measure some experiments, and need a way to record the force. I tried usingthis DAQ from vishay. The hardware seems decent, but unfortunately the software is unusable proprietary crap.Can anyone recommend a device with decent software? I intend to write my own program to use it as part of a lager automated test setup, and store the results in a database. All I need is a decent open API, preferably something with python compatibility.I'm currently looking at labjack devices. It's overkill for what I need, but from the looks of it the software is wonderful, and all open source. Does anyone have experience with these?

author: joeqsmith
author_rank: Super Contributor
timestamp: November 30, 2016, 04:25:24 am
content: I have the cheapest one they make (U3 HV). For the price, it's not too bad. The LabVIEW code works but I advice you if you plan to use it, download it first and have a look. I'll leave it at that. I don't think the one I have would be near good enough to directly talk with a load cell but I assume that you are doing all the filters/amps external anyway.Not a great review but you get some idea what I was doing with it.

author: Rachie5272
author_rank: Regular Contributor
timestamp: December 02, 2016, 05:13:13 am
content: Great, thanks for the review.How about the HX711 ADC? There are lots of cheapmodules like this oneavailable. I only need a single channel, and it's pretty hard to beat the arduino for open source cross compatibility. Does anyone know how this would compare to labjack, or other data loggers?

author: Brutte
author_rank: Frequent Contributor
timestamp: December 02, 2016, 07:58:55 am
content: If you just need a record and not the closed loop control then I suggest using a scope that can save csv voltage samples. As for excitation and gain of a strain gauge - that depends on your soldering skills. Any op-amps with low offset voltage temperature coefficient around?
Load cell design, will this work ? - Page 1
Forum section: electronics / projects

author: opa627bm
author_rank: Regular Contributor
timestamp: May 08, 2020, 05:27:50 am
content: Hi all,I am trying to do a load module that is capable of doing 100~640A load step @ 1600A/usI am doing 16 individual load cells , and each of them is helping with 40A peak and ~ 10A TDC.2 of the load cell will be grouped into a load bank, and we will have 8 load bank current reporting to the MCU(due to limited channel)I am trying to avoid using the summing amplifier at current sense stage (since i have to combine 2 current signals from the 2 CSR into 1 so i can report back to the MCU) and is trying to combine 2 load cells CSR reading through 1 current sense amplifier.My question is, will this work? will the 2 opamp fights eachother because one opamp can clearly affect the current sense read back , and thus cause another opamp to take action, and may ended up in oscillation ?thank youRegards,Li

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 08, 2020, 11:54:56 am
content: They won't fight.Here is some more information about fast electronic loads (maybe you've seen that):1.Design a 100a active load to test power supplies2.A Closed-Loop, Wideband, 100A Active Load
Load cell mechanical design - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: March 17, 2020, 10:28:36 pm
content: Has anyone seen a good resource (app note, text book, etc) for the design of common load cells?In particular I'm interested in building a custom load pin (basically a cylindrical binocular cell). However it would be interesting to look at others.Obviously one can do this from first principles and/or use FEA, however given how common they are I'm surprised I haven't been able to find a 'recipe' book of equations for the dimensions of common types.

author: David Hess
author_rank: Super Contributor
timestamp: March 20, 2020, 05:05:09 am
content: There are such books but offhand I do not remember any names. A thorough search should turn up many but they will not be cheap.
load circuit  - Page 1
Forum section: electronics / projects

author: Alex QW
author_rank: Contributor
timestamp: March 14, 2023, 05:57:55 am
content: Hi all,May I know how this TTL load circuit work as shown in the below diagram?Note that: 1)the red arrow means the microcontroller control signal (1,2)2) Is the TTL output pin (3,4)The circuit is in this link:https://forum.allaboutcircuits.com/threads/ttl-load-circuit.192516/Thank you.Best RegardsAlex.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 14, 2023, 09:50:31 pm
content: Erm. I'm not registering with your website.You didn't give out any information on your circuit there either!A TTL load is an equivalent circuit of a TTL gate input.Have a look at the TTL wiki page.seewww.interfacebus.com/Glossary-of-Terms-TTL-Load-Circuits.html

author: Alex QW
author_rank: Contributor
timestamp: March 15, 2023, 01:23:01 am
content: May I know why they use a lot of diodes in the circuit?

author: Kim Christensen
author_rank: Super Contributor
timestamp: March 15, 2023, 04:30:48 am
content: Attach the picture of your circuit here. Most people can't see it on allaboutcircuits.com since we don't have an account.

author: Alex QW
author_rank: Contributor
timestamp: March 15, 2023, 06:09:37 am
content: This is the circuit diagramNote that: 1)the red arrow means the microcontroller control signal (1,2)2) Is the TTL output pin (3,4)Sorry for any inconvenience as I just joint this forum not so familiar with this feature

author: Terry Bites
author_rank: Super Contributor
timestamp: March 15, 2023, 11:41:10 am
content: The bias resistors set up a current (1.2mA) in the diodes going to ground- this sets VIL for the equivalent gate input plus a diode drop. You then subtract a diode drop ((D604) from this voltage.This sets the lower threshold to a bit over VIL.

author: Alex QW
author_rank: Contributor
timestamp: March 23, 2023, 01:14:19 am
content: how to know that the bias resistors set up a current (1.2mA)?
Load detection - Page 1
Forum section: electronics / projects

author: bmarvo
author_rank: Newbie
timestamp: May 29, 2012, 07:01:56 pm
content: Okay so I'm designing a portable cell phone charger with a battery pack. What I want to do is detect when the phone is connected so I can turnon an LED indicating whether or not the battery has sufficient charge. I immediately think that current sensing on the output is the way to go.So I found this device:http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00283176.pdfI could use something like that with a comparator to detect when the load is attached. It does seem like overkill using a precision device.Anyone know of a more elegant solution?Here is an image of a very basic version of what I'm talking about.

author: chrome
author_rank: Regular Contributor
timestamp: May 29, 2012, 07:53:16 pm
content: Small resistor in line with the power supply going to the phone, measure over this resistor with a opamp in differential mode, feed this to a comparator, done.

author: bmarvo
author_rank: Newbie
timestamp: May 29, 2012, 09:08:12 pm
content: Excellent. Prototyped it and it does the job

author: T4P
author_rank: Super Contributor
timestamp: May 30, 2012, 03:29:08 am
content: What chrome said is basically a current shunt monitor ... like a INA168His solution is cheaper

author: cebrax
author_rank: Contributor
timestamp: September 16, 2012, 08:21:41 pm
content: I am really interested in this. I want to make a detector to detect IC insertion into an 8-pin DIP socket. Whenever the IC is inserted, I want to sense if there is any current flowing into this IC's Vcc pin, and so I will be able to detect an IC insertion (or call it a load connection). However, I want to build this only with transistors. Is this possible?

author: AndyC_772
author_rank: Super Contributor
timestamp: September 16, 2012, 08:52:40 pm
content: Depends on the IC. If it's a CMOS gate, for example, there could be so little current that measuring it could be a real challlenge whatever components you decide to try and use.Do you have a specific IC in mind?

author: cebrax
author_rank: Contributor
timestamp: September 17, 2012, 07:27:36 am
content: Yes, I think it is a CMOS IC. I have a specific IC in mind,X9C102P, but I don't want this detector to be working for only this specific IC, that means I do not want to detect it polling other pins.
Load efficiency - Page 1
Forum section: electronics / projects

author: keshab.patel
author_rank: Contributor
timestamp: May 02, 2015, 10:44:45 am
content: I am working on a rfq where three parameters are there. Nominal load, load efficiency and resultant load. Where resultant load= nominal load *load efficiency. So what is this load efficiency and how does it affects to search a connector or fuse for that load. Please help.

author: Psi
author_rank: Super Contributor
timestamp: May 02, 2015, 10:49:43 am
content: We need more info. What kind of load is this etc...

author: keshab.patel
author_rank: Contributor
timestamp: May 04, 2015, 04:48:31 am
content: Its a power distribution module. and there are all kind of load from motor, solenoid to resistive load. And the power has gone to different ecu. So hard to tell which one is which load.Another thing is what is "take rate " of a connection.
Load sharing mod for the 18650 battery shield v3 - Page 1
Forum section: electronics / projects

author: Peabody
author_rank: Super Contributor
timestamp: May 31, 2020, 11:01:14 pm
content: I submitted a new video to my local OSH group about modifying the 18650 battery shield v3 to add a load sharing circuit:The shield has a circuit design flaw that makes it unsafe to use with projects drawing more than 60mA, and the mod fixes that. The video also presents alternatives for operating safely within the limits of the original circuit without doing the modification.The basic problem is that when the USB charging brick is plugged in, current to charge the battery and power the load all flows through the TP4056 charger IC, which then fails to terminate charging as it should, which could be a safety issue. The load sharing mod has the brick directly powering the load so the charger can behave as it should.I've nicknamed this module as the Shield of Turin because the picture below reminds me of another Turin-related object that's famous for how it looks in the negative.I don't have access to answer comments on Youtube, but can answer questions here.
Load Sharing with TI UC2907 - Page 1
Forum section: electronics / projects

author: elimenohpee
author_rank: Contributor
timestamp: September 13, 2019, 09:53:27 pm
content: Hi all,I have an application where I need to parallel several 30 VDC power supplies to a single load. I've researched high and low and it looks like the only thing available off the shelf is the UC2907 IC from TI. I've read the datasheet and even the application note provided and I'm still unsure how exactly to use the chip. I plan to OR the power supplies together through an OR controller I just haven't figured out how to get the supplies to share the current evenly. Each power supply has a sense feedback to boost their output (required for the chip to actually regulate each supply).Does anyone have any experience with this chip and/or have any suggestions?
Load shut off circuit - Page 1
Forum section: electronics / projects

author: UncookedCorn
author_rank: Contributor
timestamp: November 04, 2023, 05:48:16 am
content: I would like to design a circuit that will shut off the voltage from a battery to a load when the battery voltage drops to a certain value. The load is connected to the 3.7V 3500mAh battery via a switch, and I want the circuit to open the switch when the voltage drops to about 2.8V. What would be the best way to go about this? (I'm thinking some sort of voltage supervisor IC)Below is the circuit for the battery charger, with the TP405 replaced with the BQ2407 and no protection circuitry.

author: Peabody
author_rank: Super Contributor
timestamp: November 04, 2023, 03:00:49 pm
content: The protection circuit provides that function for you automatically. That's its purpose. When battery voltage drops below a certain point, it disconnects the battery's negative terminal from the system ground, which shuts everything off. Your battery may have that protection built in, or if it's unprotected you can use the parts shown in the circuit. But the "standard" undervoltage threshold is about 2.4V. If you really need 2.8V, then you can replace the DW01 with an FS312F-G chip that I think is 2.9V.
Load switch - Page 1
Forum section: electronics / projects

author: fedimakni
author_rank: Regular Contributor
timestamp: February 02, 2020, 09:45:35 am
content: Hello,I want to use a load switch in order to disconnect the battery from the rest of the system. The load switch has a enable pin that could be driven with uC GPIO. My question is while my uC is also in the load side how could it set the enable pin to high in order to enable the load switch while it doesn't get power yet??Thanks for your answers

author: GromBeestje
author_rank: Frequent Contributor
timestamp: February 02, 2020, 09:56:00 am
content: Maybe something like a push button, that overrides the input to the load switch from the power source. WHen pushed, it will temporary allow power to the MCU, giving it enough time to output the signal to the enable pin itself, and keep running when the push button is released.

author: Warhawk
author_rank: Frequent Contributor
timestamp: February 02, 2020, 09:57:46 am
content: You need a path to supply the uC, have a look here for the inspiration:http://panacek.net/post/magsw1a/http://panacek.net/post/magsw2a/TI also has a chip that periodically wakes up the MCU (or triggers the switch) and then it goes back to sleep. Let me google it first.

author: fedimakni
author_rank: Regular Contributor
timestamp: February 03, 2020, 03:10:07 am
content: @GromBeestjeBut that will not be an automated solution. I need an automated solution that's why. Thanks

author: fedimakni
author_rank: Regular Contributor
timestamp: February 03, 2020, 03:13:19 am
content: @WarhawkBut the problem that i need to use the load switch in order to isolate the uC and all the system together. If I supply the power to uC directly from the power source that will not be effective for my device. Thanks
Load Switch: 24V/60A - 100V/20A - Page 1
Forum section: electronics / projects

author: rounin
author_rank: Regular Contributor
timestamp: August 28, 2017, 01:03:51 am
content: I've been thinking about making a load switch - a high side mosfet switch control board that is good for something like 24V/60A up to 100V/20A (without heatsink, more with heatsink) that could be used as a load switch for things like battery protection / changeover, switching heaters, RC car e-stop, pump control, .... I'm also thinking about using this as a part of a large motor controller or battery manager.This one has M4 bolt-down lugs, LTC7001 static switch controller and a ADUM5240 power&signal isolator, and optional inductive load snubber diodes. It requires a few mA of auxiliary 5V power (this could be done with a high voltage regulator, I just didn't think it was necessary to have on board).Anyone interested? I've been looking for a project that I could make a short board or assembly run with. Not sure how much it would cost yet. I'm also kind of playing with how to keep it different/better than eg a Crydom SSR - it might make more sense to make a "smart" one based on the LTC7000, with onboard power measurement / overcurrent protection & microcontroller. The adjustable inrush control on this board is one advantage.Let me know what you think, or if you have ever needed something like this for work or hobby, and if something like an integrated microcontroller would be interesting.

author: rounin
author_rank: Regular Contributor
timestamp: August 28, 2017, 02:18:23 am
content: Something like a SO28 or QFN28 PIC32MM could fit nicely, and allow arbitrary programmable control and feedback.
Load switch vs. Schottky diode for rail reverse current protection - Page 1
Forum section: electronics / projects

author: jars121
author_rank: Regular Contributor
timestamp: December 23, 2020, 10:12:20 am
content: Evening,I'm working on a board which has two potential power inputs:DC barrel jack with a range of 6-22VUSB-C PD port with a range of 5-20VThe USB-C PD controller IC I'm using allows for a DC barrel jack input, which is used to determine whether the USB-C port should sink power (if there is no DC barrel jack power) or source power (if there is DC barrel jack power). I'm trying to determine the best method for managing reverse currents when the USB-C is sinking power. When the DC barrel jack is used, the USB-C sink power path is disabled by the PD controller, and the sink load switch I'm using has reverse current protection, so it isn't a concern at this stage. Rather than assuming a similar load switch design would be optimal for the DC barrel jack circuit, I figured I'd look at the option of a series Schottky diode as well.I've put together the below highly simplified schematics, showing the Load Switch option (Schematic A) and the Schottky Diode option (Option B).The maximum forward current from the DC barrel jack is 10A. The 'DC Enabled' line represents the input to the PD controller which determines whether to enable/disable the sink power path. In Option A, the intent would be to use the Load Switch's POWER_GOOD or similar output to provide this input, while in Option B, I'd use an LDO (or similar) to step down the 6-22V DC input to 3V3 for the PD controller.Any for/against either option would be greatly appreciated
Load switch with Triac and Reed Switch - Page 1
Forum section: electronics / projects

author: Prayer
author_rank: Contributor
timestamp: January 12, 2015, 03:30:36 pm
content: Hi AllI want to make and switch to control light in cabinet. I need to switch 220 VAC with triac and reed switch. I will place a magnet to door and I will place main box across magnet. The maximum lenght is 15 cm between door and main box. I think reed switch will work properly.You know reed switchs are normally open and when magnet is getting closer, reed switch will close. Could you help me to build schematics with NO reed switch ?

author: mij59
author_rank: Frequent Contributor
timestamp: January 12, 2015, 04:29:12 pm
content: Hi,Why don't you use a door or limit switch ?

author: Prayer
author_rank: Contributor
timestamp: January 13, 2015, 07:28:00 am
content: Because already using limit switch solutions but customers have some problems to fix limit switches correctly. Customer want to use easier solution and we will make like this. Do you have any schematic suggestion ?

author: mij59
author_rank: Frequent Contributor
timestamp: January 13, 2015, 07:48:31 am
content: Quote from: Prayer on January 13, 2015, 07:28:00 amNo don't have a schematic at hand, I would go for a of the shelf solution, e.g. a inductive proximity switch, infrared motion detector.If you build a circuit it has to comply to the 220V regulations.

author: Prayer
author_rank: Contributor
timestamp: January 14, 2015, 04:21:17 pm
content: Is there any suggestion for this issue ?
Load switch - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: August 20, 2019, 02:57:34 pm
content: I want to switch 20 V and 200 mA on high side. I can do that with one n-mosfet, one p-mosfet and pull up resistor. Is this manufactured as one single component? Or is there any as cheap load switch as this one integrated in one component. Multi-channel device is welcome.
lobotomized HC-05? - Page 1
Forum section: electronics / projects

author: pmc
author_rank: Contributor
timestamp: February 02, 2020, 01:34:12 am
content: Hi all,I have an HC-05 that used to work and still works fine in "communications mode". In "command mode" it still responds to "AT" with "OK", but now it answers "ERROR: (0)" to any other AT+ command. Including AT+ORGL. Has anyone else seen this? Any ideas how to more authoritatively reset it?HC-05ZS-040hc01.comV2.1This started after I AT+RESET it after setting a new UART bit rate, for whatever that's worth.

author: pmc
author_rank: Contributor
timestamp: February 08, 2020, 04:40:27 am
content: For whoever might find this later:Using a different serial connection fixed it.There was apparently no problem with the unit.Failed for AT/command mode: USB<->Arduino UnoR3 clone<->soft serial<->HC-05Worked: USB serial adapter (PL2303)<->HC-05both 38400bps

author: Ian.M
author_rank: Super Contributor
timestamp: February 08, 2020, 07:07:21 am
content: If you have to do that again and don't have a USB <=> logic level serial adapter handy, you can jumper the Arduino Reset to Gnd to disable all the ATmega I/O pins including RXD and TXD then use the Arduino's on-board USB serial adapter to communicate with youre device. D0 (RX) is data from USB, D1 (TX) is data to USB. Both have 1K series resistors, so if you need 3.3V levels, put a 1K8 pulldown on D0.

author: pmc
author_rank: Contributor
timestamp: February 09, 2020, 09:12:03 pm
content: Yes. And starting there would make more sense than ending up there!
Local reuse centre WIN - Page 1
Forum section: electronics / projects

author: Jebnor
author_rank: Regular Contributor
timestamp: April 18, 2021, 02:43:29 am
content: Nothing to special, but I bought all these at the local reStore for $5 each.Been keeping my eyes open for some.

author: t1d
author_rank: Super Contributor
timestamp: April 18, 2021, 01:52:27 pm
content: Great finds!
Locating Shorts on Power Planes of Multi-Layer PCBs - Page 1
Forum section: electronics / projects

author: marshallh
author_rank: Unknown
timestamp: August 11, 2014, 10:19:23 pm
content: http://www.linear.com/solutions/5297

author: Artlav
author_rank: Frequent Contributor
timestamp: August 12, 2014, 05:26:53 am
content: Neat.I thought it would be something about a thermal camera with a macro lens, while i was reading it. Dunno what gave me that impression.

author: pickle9000
author_rank: Super Contributor
timestamp: August 12, 2014, 05:30:17 am
content: that is cool.

author: Richard Head
author_rank: Frequent Contributor
timestamp: August 12, 2014, 06:17:16 am
content: Interesting approach. I expect a thermal camera would locate the fault very quickly.Just the other day I was using a large electrolytic cap to blow open shorts on a two layer board. Plenty of microscopic shorts to the ground plane, The 0.2mm gap is a bit too small. The cap method is very effective for small shorts that a 3A PSU cannot blow open.From now on I have opted for bare board testing at the PC board manufacturer.Dick

author: Bukurat
author_rank: Regular Contributor
timestamp: August 12, 2014, 08:22:11 am
content: Interesting

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 12, 2014, 08:54:26 am
content: You could probably do it with an audio power amp and a microphone amp.But a thermal imager is quicker!
Locating Triac Datasheet - Page 1
Forum section: electronics / projects

author: electricMN
author_rank: Regular Contributor
timestamp: November 02, 2020, 08:46:08 pm
content: I'm trying to locate a datasheet for this triac. STMicroelectronics T0812NH. TO-220 package. I need to find an equivalent available part to replace it with but without the basic specs it's difficult to do.Thanks!

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2020, 08:51:47 pm
content: the datasheet is available easily : here for example :https://datasheetspdf.com/datasheet/T0812NH.htmlit's a simple 8A 800V triac.

author: electricMN
author_rank: Regular Contributor
timestamp: November 02, 2020, 09:09:23 pm
content: Quote from: kripton2035 on November 02, 2020, 08:51:47 pmThank you very much!I'm not sure why it didn't show up in my searches. I tried numerous searches looking for it. Anyway, thanks!
lockin amplifier switch choice - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: December 31, 2017, 12:15:12 am
content: I am using a lockin amplifier to resolve a signal. I have a choice of switches. The spectrum is approximately200ohm resistance, very low charge injection1 ohm resistance, moderate charge injectionThe lockin is the op-amp type. I see that most lockin designs seem to take priority on charge injection (i.e. using optimos fets).The circuit switches from inverting to non-inverting amplifier. It's averaged by a variable time constant filter bank.200ohms instead of a short seems to be a problem to me, while the charge injection can be canceled out by a trim stage, so whats the deal? My signal bandwidth is like 1KHz, and the lockin frequency is like 40KHzADG1419 2.1 ohm resistance, 50pC injectionorADG1219 - 400fC charge injection, 200 ohm resistancehttp://www.analog.com/-/media/images/analog-dialogue/en/volume-48/number-4/articles/synchronous-detectors-facilitate-precision/synchronous-detectors-facilitate-precision-fig04.png?la=en

author: Kleinstein
author_rank: Super Contributor
timestamp: December 31, 2017, 10:41:51 am
content: In the circuit shown in the link , the switch resistance is not that important as there is just the high impedance input of an OP loading the switch, so I would go for the lower charge injection switch. The very low R_on switches also tend to be slower in switching - this could be a factor at 40 kHz too.I remember the circuit from an old higher grade commercial Lockin: they used 74HC40xx.

author: CopperCone
author_rank: Super Contributor
timestamp: December 31, 2017, 05:38:33 pm
content: Ah yes, I see what your saying. I was thinking more like an inverting amp, so the 200ohm switch would be significant to the feedback resistors, but I guess its connecting to the noninverting pin
Locking board-to-board connector? - Page 1
Forum section: electronics / projects

author: rexxar
author_rank: Frequent Contributor
timestamp: July 12, 2014, 09:42:09 pm
content: I decided that I need to stick a daughter board on this project, and now I need to find a connector for it. However, the board is going to experience a lot of physical shock, so I'm concerned that a regular connector would come loose. Obviously the best thing would be to directly solder the boards together, but it's an optional module, so I want the end-user to be able to purchase it separately and install it themselves, so I need a connector.So, I wonder if there's some sort of locking board-to-board connector I could get that would withstand physical shock? Or maybe I could use some sort of locking standoff, but I'm very limited on space, so I'm not if that's a viable option...Any ideas?

author: mariush
author_rank: Super Contributor
timestamp: July 12, 2014, 10:53:06 pm
content: jst hvqjst jljst mqjst jdfetcCatalogue here:http://www.jst-mfg.com/product/pageview/connector_e/pageview.html#page_num=312Alternatively, there are standoffs/spacers out there, you could just make a hole on each board, screw the standoff on the main pcb and supply the daughter board with a screw to lock the board completely.See for example:http://uk.farnell.com/standoffsM3 screws are super cheap (the ones used on optical drives, floppy drives, ssd drives etc), standoffs with m3 screw thread are super cheap in quantity.It would add some extra work on installing that standoff in the first place.

author: SL4P
author_rank: Super Contributor
timestamp: July 13, 2014, 03:59:43 am
content: ... or those nylon snap-fit standoffs?
Locking connector for radio microphone? - Page 1
Forum section: electronics / projects

author: rektm8
author_rank: Newbie
timestamp: June 26, 2021, 12:01:44 am
content: I'm looking to modify a set of hearing protectors that have an existing audio input (they're electronic), to include a microphone to be used with a radio for communications, However I can't seem to find a suitable connector that matches the overall budget I'm going for. Everything I've come up with is overkill for what I'm trying to do. (hirose connectors or legitimate military grade connectors which cost half what the headset does)I need two conductors (mono) and some kind of locking mechanism, be it a threaded collar or etc, but it needs to be on the smaller side, something around the size of a 5.5x2.1mm DC jack or a 3.5mm audio jack.It doesn't need to be explicitly for audio, any connector that fits the bill from another application will work just fine, I'm just not coming up with anything that is relatively inexpensive.

author: themadhippy
author_rank: Super Contributor
timestamp: June 26, 2021, 12:10:37 am
content: Quote3.5mm jacks with a locking collar are available,as used on some Sennheise gear,no idea were you find them in the states or the price.Another option maybe mini xlr

author: ajb
author_rank: Super Contributor
timestamp: June 26, 2021, 12:18:55 am
content: Switchcraft make 5.5x2.5mm power connectors with a threaded locking collar, they might also make locking 3.5mm jack connectors--it's worth taking a look through their catalog anyway. I've used their locking power connectors and don't remember them being tremendously expensive but it's been a while.

author: Zoli
author_rank: Frequent Contributor
timestamp: June 26, 2021, 04:52:05 am
content: Switchcraft Mini XLR?Or Lemo:https://www.ebay.com/itm/192285362018?hash=item2cc519c762:g:Hn4AAOSwaMpZnC4hThe Mini XLR is betwwe the 5.5X2.1 DC and 1/4" audio jack as size; the small Lemo's are in the same ballpark.
Logarithmic or linear potentiometers for volume and a 3 band EQ - Page 1
Forum section: electronics / projects

author: Pexy13
author_rank: Regular Contributor
timestamp: April 06, 2020, 12:59:20 pm
content: Greetings!I am in a proces of going trough my junk pile to find all the components I need for a Bass guitar preamp.Looking at the schematic and the text that was posted about the project I can't find if I should use logarithmic or linear potentiometers.There should be one for each (volume, treble, bass and mid).The Scehematic is attached below.

author: TimFox
author_rank: Super Contributor
timestamp: April 06, 2020, 01:44:18 pm
content: Usually for amplifier controls, the tone controls (treble, bass, and mid) are linear (sometimes center tapped) and the gain control (volume) is logarithmic. You can make a quasi-log pot from a linear pot with an appropriate load resistor between the wiper and CCW.

author: Pexy13
author_rank: Regular Contributor
timestamp: April 06, 2020, 01:57:18 pm
content: Quote from: TimFox on April 06, 2020, 01:44:18 pmThanks I'll try it out.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: April 07, 2020, 12:52:34 am
content: The way that volume pot is configured, a linear pot is good since the relation of gain using the two halves of the pot is non-linear, actually hyperbolic. Just how well it emulates a log pot is a function of the 47K value against the 10K pot value. You may have to play with the 47K value to optimize this.I'm sure this is what the designer was going for, to begin with.

author: obiwanjacobi
author_rank: Super Contributor
timestamp: April 07, 2020, 06:54:41 am
content: FYI: the -15V on opamp B is on pin 4 not on pin 1 as shown in the schematic (pin 1 is output for opamp A).
logarithmic sweep generator? - Page 1
Forum section: electronics / projects

author: ftransform
author_rank: Frequent Contributor
timestamp: December 10, 2012, 10:25:36 am
content: So I was watching the bode plot analysis and unfortunately I only have a linear sweep.Does anyone have suggestions for a circuit which can do a logarithmic sweep or a cheap suggestion?From -10 to 10 V pp.

author: firewalker
author_rank: Super Contributor
timestamp: December 10, 2012, 10:33:39 am
content: Is there a Voltage Frequency Control input present?Alexander.

author: w2aew
author_rank: Super Contributor
timestamp: December 10, 2012, 04:50:33 pm
content: Quote from: firewalker on December 10, 2012, 10:33:39 amIf so, you can make yourself a simple exponentially rising signal with a simple pulse generator (555 based even), into an RC circuit. Then, buffer this to drive the frequency control voltage input on the FG.
Logging binary data on Android - Page 1
Forum section: electronics / projects

author: mojoe
author_rank: Frequent Contributor
timestamp: May 30, 2016, 03:52:12 am
content: Is there any easy way (preferably a simple app) to capture and store data from a device plugged into the USB OTG port on an Android tablet? The app doesn't need to understand the data, just store it as it arrives. The data is 8-bit binary.I have configured a uBlox LEA-6T GPS module to output ubx raw data on its USB port. I want to capture this data for later post processing with RTKLIB. I'm doing it right now with STRSVR from RTKLIB on Win7. I'd like to use a tablet so I can go portable.It just occurred to me - would a driver for the uBlox GPS be needed, or does Android see it as a Com port if I am simply capturing the incoming data? I know on Win7, to use the uCenter software, a driver is required. The GPS will start spewing data as soon as it is plugged into a powered USB port.I know that I could use Bluetooth and that Android has SPP support, which might make things easier. However, I don't have a Bluetooth enabled GPS, or a Bluetooth module that I could interface with the uBlox GPS I do have. I could always order something, but If I can make this work with what I already have, that would be preferred.All I need is a simple app that has a START and a STOP button. Every time START is pressed, a new file is created and any data coming into the USB port is saved. When STOP is pressed, that file is closed. Pressing START again will open a new file. I don't care whether the data is saved to internal storage or an SD card, although having a choice would be nice.I've done some searching on the net, but haven't turned up anything so far. Thanks for any help.

author: rs20
author_rank: Super Contributor
timestamp: May 30, 2016, 04:05:28 am
content: Check to see whether you can talk to your device over the COM port in Win7 using a normal terminal program, like PuTTy or hyperterminal. Check whether the device appears under devmgmt.msc as a COM port.Even better, try a linux PC and see if it appears under /dev/tty***.Once you have those questions answered, we can start talking about Android. Android does support CDC USB ("USB COM ports"), but whether it works on your phone and whether root is required are tricky questions.
Logic "fan in" - multiple outputs, single input - Page 1
Forum section: electronics / projects

author: TomS_
author_rank: Frequent Contributor
timestamp: January 09, 2017, 05:35:51 am
content: I was just reading through the Wikipedia article about 4000 series logic, and clicked through to an article about fanout (https://en.wikipedia.org/wiki/Fan-out) and I came across something which caught my attention.Specifically this:QuoteIve designed a nice little compact circuit using 4 logic gate chips (with 2 gates to spare) which I was quite proud to achieve, but I have a small section of circuit where I combine 4 outputs into a single net and feed them all in to a single input on another gate.Based on the above, it sounds like I'll need to add a 5th chip with perhaps a quad input OR gate to take all 4 outputs and produe a single output?But why is it that multiple outputs cant be fed in to a single input?

author: MK14
author_rank: Super Contributor
timestamp: January 09, 2017, 05:42:13 am
content: If you connected up multiple outputs together, and some of them decided to produce a logic 1, and others a logic 0. They would electrically fight each other (a bit like a short circuit), potentially overloading the chip(s) and maybe even damaging them.There are outputs called "tristate" or "open collector", which can solve this problem. Tristate can be switched off (disabled), so that things can share, often called databuses e.g. for memory.Open collector means that the outputs can only pull things towards ground, so it does not matter if you connect multiple outputs of that type, together. But it needs a (usually single) pull up resistor.You did the right thing. The OR gate is the way to go.

author: TomS_
author_rank: Frequent Contributor
timestamp: January 09, 2017, 05:50:42 am
content: Quote from: MK14 on January 09, 2017, 05:42:13 amAhhh right...Now that I look a bit more carefully at the datasheet for one particular CMOS device, e.g. a 4071, the output is configured as a totem pole with a P and N junction FET, so when high it sources current, but when low it sinks it. So yes, potential short circuit conditions, and I guess additional OR gate(s) it is!Makes a lot more sense now. Thanks!

author: technix
author_rank: Super Contributor
timestamp: January 11, 2017, 11:47:41 am
content: There are situations where multiple outputs can be connected together in an orderly fashion without a short happening:1. Open-drain outputs don't have the PMOS on the top, and rely on a pull-up resistor instead. This results in a wire-AND situation.2. Tristate outputs with chip select. Tristate output can emit a High-Z state which neither FET turns on. This releases the line and allows someone else to drive the line. A chip select line is often included to allow arbitration deciding who get to drive the line.These are common ways buses are constructed. An example of open-drain bus is I2C. An example of tristate bus is SPI.

author: bson
author_rank: Unknown
timestamp: January 11, 2017, 08:06:38 pm
content: You can also wire up multiple outputs in parallel for higher current capacity. Just make sure they always operate in lockstep.
Logic Analyzer from one channel of your Rigol DS1052E - Page 1
Forum section: electronics / projects

author: pyroesp
author_rank: Regular Contributor
timestamp: December 12, 2013, 10:04:16 pm
content: Hello everyone,I needed a logic analyzer to check a couple of digital I/Os. I don't have one of those fancy €300+ logic analyzers and thought of a way to make one, using the DS1052E.Obviously, I wasn't the first one to think about this idea.http://codeandlife.com/2012/05/16/worlds-simplest-logic-analyzer-for-5/So what you do is a simple buffer and R-2R network to mix the digital I/Os into one single analog signal. Measure the analog signal and stop the oscilloscope when you think you have enough data. Then you simply have to convert the voltages to PCM values.I've done this for the Rigol DS1052E oscilloscope that uses the 1MB of samples, a bit of calculation and some edge detection.The program reads the data from the scope and writes a file that can be opened in OLS (open logic sniffer) software.http://www.lxtreme.nl/ols/As an example, I tested this with a simple 4 bit counter. It looks like this:- Analog signal- OLSHow to use:First thing you have to do is install the National Instrument NI-VISA 4.6.2. I don't know if a higher/lower version would work with this. You'll have to experiment with it.Then connect the scope through USB to your PC.Quick search through the forum can give you a couple of results about how to install the NI-VISA software and scope on the PC.- Rigol DS1052:Enable/Set long memory. Use only channel 1 (disable everything else).Capture and stop the scope, before launching the program.- PC:Run cmd, go to folder containing the exe, run the following command:program_name.exe -channels <uint> -mask <uint> -Vref <float>Channels : number of I/Os you want to debug (for my little test, this was set to 4)Mask : This an OLS data, set it to "2^channels - 1" to see all channels, unless you want to mask some out.Vref : Is optional, set to 5V (default)Program license:http://creativecommons.org/licenses/by-nc/4.0/The source code is included so you can play with it if you want to.No error detection has been programmed, I couldn't be bothered with it.The edge detection is done with a crappy triangle window, Gaussion window would have been better.Hope this can help some of you.If you have any problems with it, let me know.- pyroespPS: There are 2 defines in the code that determine the edge detection. I forgot to add them as an argument when running the program.The precision define, sets the window width, and then there's a threshold.You'll have to change those and compile if you want something else than what I set.

author: dannyf
author_rank: Super Contributor
timestamp: December 13, 2013, 12:27:26 am
content: Get one of those clone logic analyzers from ebay - <$20.

author: nctnico
author_rank: Super Contributor
timestamp: December 13, 2013, 01:51:59 am
content: Many many years (decades!) ago you had oscilloscope multiplexers to have more traces on an oscilloscope. The basic idea is that you multiplex a couple of inputs into one channel while giving each input a different offset.
Logic circuit problem - Page 1
Forum section: electronics / projects

author: 22
author_rank: Contributor
timestamp: June 06, 2017, 12:16:15 pm
content: Hi. I was working on circuit that set SR latch after rising edge of clock signal. It is shown on picture below but I don't know how to calculate the odd number of NAND gates needed in the delay circuit (?) to ensure stable change in SR latch. The pulse driving the S input is needed to be as short as possible but also long enough to ensure stable change in SR latch. The NAND gates are all the same SN74HC00D.

author: donmr
author_rank: Regular Contributor
timestamp: June 07, 2017, 06:08:20 pm
content: You need enough delay to ensure that the "Set" signal passes thru all of logic to the other input of the top NAND gate of the flop.Among other things, your answer will depend on the loads on the Q and QN outputs. You should probably put buffers on these to make the load a fixed value you can calculate. It also depends on the implementation (wire lengths, capacitance, voltage, temp, ......).This is not a very good design style, there are edge triggered flip-flops for a reason.

author: Zero999
author_rank: Super Contributor
timestamp: June 07, 2017, 06:21:23 pm
content: Why use extra gates, when a simple RC circuit will do? If this was on an FPGA then I'd understand, but this a circuit made with discrete logic ICs, so there's no need for the extra gates.

author: 22
author_rank: Contributor
timestamp: June 07, 2017, 11:13:32 pm
content: Since I need at least 5 logic gates (4 gates in one package). That give me 3 unused, so I was trying to use them as a delay circuit.
Logic Clock Frequency Doubler - Page 1
Forum section: electronics / projects

author: veryevil
author_rank: Unknown
timestamp: February 04, 2012, 05:14:02 pm
content: Hey, I'm looking to build a logic clock frequency doubler and have made up the following circuithttp://www.maxim-ic.com/app-notes/index.mvp/id/3327except using a tlv3501 comparator (still 5ns)I am having a problem with it however as I cannot get both the output pules (for the one input) to be the same length. The pulse is correct and is half the width of the input clock but the second is much smaller.This is because the delayed clock signal present at the XOR is shorter than the original clock.My input freq is 576kHzMy C1 = 100nfMy R1 = 5.1kChannel 1 = Input ClockChannel 2 = XOR outputChannel 1 = Input ClockChannel 2 = XOR Input (output from comparator)Does anyone know why my delayed clock is shorter or anther simple method of making a clock doubler

author: deephaven
author_rank: Frequent Contributor
timestamp: February 04, 2012, 05:39:11 pm
content: You could use a phase locked loop, e.g. a CD4046 with a divide by 2.

author: veryevil
author_rank: Unknown
timestamp: February 04, 2012, 06:06:00 pm
content: Wont it take a long time for the PLL to stabilise its frequency and I'm guessing if the input clock stops for 8-16 cycles it will mess up the PLL?What I was looking for is a pulse on the rising edge and a pulse of the falling edge. If I could make this circuit work like in the maxim app note (50/50 duty cycle) then it would be perfectI've tried changing the R1 and C1 values but that only affects the length of the first pulse the second is pretty much the same no matter what.

author: deephaven
author_rank: Frequent Contributor
timestamp: February 04, 2012, 06:25:33 pm
content: Quote from: veryevil on February 04, 2012, 06:06:00 pmWell, it will take a finite time to stabilise, depends what you're looking for. If you use the right type of phase detector, it could cope with the missing clock cycles but it's getting complicated.If you wanted more control of the pulse lengths you could use monostables.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 05, 2012, 08:31:13 am
content: Your RC time constant seems much too high - 5.1x103x 100x10-9which I make to be 510us compared with a cycle time of 1.7us.The only thing which puzzles be a bit is why itisworking - what does the voltage look like on the input to the comparator - it should be swinging through most of the supply voltage.R1 = 1k, C1 = 1nf would be much closer.

author: veryevil
author_rank: Unknown
timestamp: February 05, 2012, 12:57:29 pm
content: Doh! Found my problem. My signal generators TTL output was about 3.8v not 5v. Which meant that the vref on the comparator of 2.5V was no where near the centre of the input signal.Switched over to the 50 Ohm impedance output, set the level to 5v Pk-Pk and offset to 2.5v and the circuit works perfectly.This is a great little clock doubler circuit which means a large part of my system can run at half speed.