hybridfree/eevblog-posts huggingface dataset:
Wifi extend? - Page 1
Forum section: electronics / beginners

author: jjrbus
author_rank: Contributor
timestamp: October 25, 2024, 03:20:18 pm
content: Greetings me again. I am weak on electric, even worse with electronics and computers. I have a Honda EU2200I generator with Blue tooth. I use the generator in an aluminum box, well vented. The blue tooth signal is hit and miss inside the box. It will work not work, short range. As near as I can figure the blue tooth is inside a sealed modual about 3 inch by 2 inch by 1 inch thick inside the generator.Any search I try online brings up blue tooth extenders which are not going to work. I am curious could I wrap wire around the modal and run it outside the box to pick up the signal or is there any other tricks? The generator is controlled by a cell phone app if that helps. I could just try it but the modal is a bit of a pain to get to.https://play.google.com/store/apps/details?id=com.honda.power.z44&hl=en_US&pli=1

author: jmelson
author_rank: Super Contributor
timestamp: October 25, 2024, 03:42:15 pm
content: WiFi and bluetooth are totally different systems. (But, both are a form of RF communication.) WiFi generally uses stronger signals than bluetooth. Trying to communicate with a bluetooth device in an aluminum box sounds REALLY hard. I am not in the least surprised you are having major problems. POSSIBLY what you suggest with a wire MIGHT help, but it is likely to still be flaky. Probably the only way to make this work reliably is to pull the bluetooth module out of the generator and make an extension cable so it can be placed outside the box. Another possible way to solve this is to cut a fairly large hole in the box and put a plastic window in the hole. Is the box for sound isolation or fire safety?Jon

author: jjrbus
author_rank: Contributor
timestamp: October 25, 2024, 05:56:20 pm
content: Thanks for the response. Box is for fire, security and lined with acoustic foam for sound dampening. So cutting a hole is out. As mentioned here when the generator is plugged into the RV the signal does seem to be better, which is what made me think of adding a wire. Did not think of relocating the modual, will kick that around for a bit.
WIFI Module Fun Roving Network RN-XV and Sleep Mode Current - Page 1
Forum section: electronics / beginners

author: Veramacor
author_rank: Regular Contributor
timestamp: January 15, 2013, 12:45:09 am
content: Hi All,Anyone had any experience with Roving Network's (now Microchip's) RN-XV?The datasheet says that these wifi modules will only consume 4 micro amps of current in sleep mode.But the best I have gotten with one of these things is about 40 micro amps.I called Roving Networks directly and they confirm what I'm seeing - the extra hardware on the board consumes more than the stated 4 micro amps!So I am over the marketing fib, but I'm seeing something very strange with my pcb design that might be answered by the geniusphere:After attaching my pcb design to the RN-XV board, I see that the current consumption now reads about 500 micro amps in sleep mode. This is very strange. I touch one of the I/O pins with my finger (dont worry low power app!) on the RN-XV, and the current immediately ramps down to about 43 micro amps! Has anyone seen this situation before, where they touch a pin, and the current draw drops?I'm making a guess here and I'm sorry I didn't attach any schematics I guess I'm curious what might cause that to happen. My first guess is trace capacitance, I do have a long trace going from my Microcontroller to the RN-XV.My breadboard version of the circuit does read about 50 microamps, so my guess is that is the best current draw I can get.I can post my PCB layout if requested.Any clues?J
wifi module removal  - Page 1
Forum section: electronics / beginners

author: McGoober
author_rank: Newbie
timestamp: December 31, 2018, 09:26:33 am
content: whats the best approach of removing a wife module from pcb (using hot air station of course) without disturbing smds on the module and around it?it is mounted just like this

author: soldar
author_rank: Super Contributor
timestamp: December 31, 2018, 09:49:11 am
content: Quote from: McGoober on December 31, 2018, 09:26:33 amWife modules, sometimes called "argument modules", can be difficult to deal with. A lot of patience is required.

author: xyrtek
author_rank: Regular Contributor
timestamp: December 31, 2018, 09:59:31 am
content: Are the contacts under the PCB or on the side?If the contacts are under, then maybe try to use a nozzle like the one in the pic to control the air. Obviously tape/protect nearby components and use good flux.It really depends on how much copper is on that PCB area.At the very least I would (if possible with solder wick for ex) try to remove some of the solder and replace it with rework low temp alloy solder.No idea how to help with the wife, you are on your own on that onehttps://www.chipquik.com/store/index.php?cPath=200

author: booyeah
author_rank: Contributor
timestamp: December 31, 2018, 05:29:26 pm
content: Masking the rest of the board with a layer or two of kapton tape is usually pretty effective.The really difficult bit is when there's black gunk adhesive as well under there like in a lot of phones and tablets.
WiFi RF Amplifier?  - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: December 18, 2023, 10:38:15 pm
content: () recent GreatScott video got me thinking about RF amplifiers and using them to convert an indoor 2.4-5ghz wireless access point to an outdoor one with a power of ~5w (which is legal in many countries, IF used outdoors).However browsing AliExpress, it appears that many RF amplifiers appear to be unable to amplify both 2.4 + 5GHz. I think some access points utilize a single antenna to output both 2.4 + 5GHz? Or is it always separate antenna?Has anyone attempted this before?

author: Benta
author_rank: Super Contributor
timestamp: December 18, 2023, 10:46:07 pm
content: Quote from: LooseJunkHater on December 18, 2023, 10:38:15 pmUmm... no.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: December 18, 2023, 10:58:43 pm
content: Quote from: Benta on December 18, 2023, 10:46:07 pmUm, yes for some. Ex, 4W output power.https://www.arubanetworks.com/en-ca/products/wireless/access-points/outdoor-ruggedized-access-points/370ex-series/

author: 807
author_rank: Frequent Contributor
timestamp: December 19, 2023, 12:07:13 pm
content: Quote from: LooseJunkHater on December 18, 2023, 10:58:43 pmThat 36dBm (4W) level quoted is the EIRP power, which takes into account the gain of the antenna, The actual power of the RF amplifier is only around 600mW (28dBm aggregate).
Wifi yagi antenna not working - Page 1
Forum section: electronics / beginners

author: macross
author_rank: Contributor
timestamp: July 12, 2014, 06:14:28 pm
content: So i'm trying to figure out why my homemade yagi antenna does not work. I followed this tutorial exactlybut with my antenna there is no difference at all and to add insult to injury a regular 9dbi rubber duck antenna beats my supposedly 16dbi yagi one. The only fault which could be with my build is that i have used regular rubber duck antenna rp-sma connector for my antenna, because not a single store in my area carries a rp-sma pigtail connector... Also i'm a bit confused why did he connect shield and center conductor to the same piece of wire isn't this a short circuit? Or with RF it works different?

author: rob77
author_rank: Super Contributor
timestamp: July 12, 2014, 06:29:04 pm
content: in that video he's not making a short - the coax shield goes to one end and the center wire to the other end of that element made of the thick wire.btw.. the length of that element is critical - few centimeters off and you might be out of the gamebut anyways... i'm not an RF expert, but that seems to be wrong.. i think you should use some kind of impedance matching between the coax and the yagi element.

author: macross
author_rank: Contributor
timestamp: July 12, 2014, 06:34:24 pm
content: Quote from: rob77 on July 12, 2014, 06:29:04 pmThe original author of that video has posted this message about impedance matching:Quote from: andrew mcneil on July 12, 2014, 06:29:04 pm

author: Stonent
author_rank: Super Contributor
timestamp: July 12, 2014, 06:47:26 pm
content: Element size is based on the wavelength of signal.So when you hear someone say "2 meter band" that means the wave length is in the 2 meter range, and if you're using a full wave antenna, it would be about 2 meters in length. Sometimes these antennas are coiled and put inside a tube or in the case of Citizens Band (CB) radio in the US which runs in the high 20 MHz band, the wavelength is very long so the base of the antenna mount usually has a coil of wire that takes up the length and you can adjust the exposed part up or down a few centimeters to tune for best performance.Wifi wavelength is only a few centimeters so all the antenna parts will be around that for a full wave antennal.There's also 1/2 wave, 1/4 wave etc designs but that starts to get outside my level of understanding.

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 12, 2014, 08:48:54 pm
content: The impedance of a folded dipole is ~ 300 ohm, so why he did this I don't know.QuoteAs if the laws change when the frequency changes.... sure.There is an easy way to match the driven element to the coax:_____________________| |Tha coax shield at the center of the element, the inner core at the 50 ohm point.

author: rob77
author_rank: Super Contributor
timestamp: July 12, 2014, 09:52:34 pm
content: Quote from: PA0PBZ on July 12, 2014, 08:48:54 pmthanks for that !i learned something useful today
Wilf's Bird Sound Circuit - Page 1
Forum section: electronics / beginners

author: queennikki1972
author_rank: Regular Contributor
timestamp: May 03, 2019, 10:39:36 pm
content: This simple circuit calls for a 74HC14 (x6) chip. Google shows it to be a 14 pin chip but the diagram only shows 2 connections and they are not numbered. The symbol looks like a inverter with only 2 connecting points.Looks simple enough, but can someone explain? Maybe VCC pin to Grnd pinhttp://solarbotics.net/library/circuits/misc_sound_wilfbird.html

author: helius
author_rank: Super Contributor
timestamp: May 03, 2019, 10:48:10 pm
content: The 74HC14 is a hex inverter, meaning it contains six individual inverter circuits. Each inverter has an input (1A, 2A, 3A, 4A, 5A, 6A) and an output (1Y, 2Y, 3Y, 4Y, 5Y, 6Y), and the Vcc and ground on the chip are shared.The circuit schematic also uses six inverters, so it uses all six of the parts in the 'HC14. Since it doesn't matter which is which, they are not labeled except as "U1". If it did matter, then the symbols could be labeled "U1A" through "U1F".

author: wilfred
author_rank: Super Contributor
timestamp: May 04, 2019, 01:34:48 am
content: Who is this Wilf of whom you speak?There was a similar circuit published in Electronics Australia magazine May 1981 that might interest you.https://archive.org/stream/EA1981/EA%201981-05%20May#page/n69/mode/2upI noticed also they were talking about electric cars back then too on page 12.

author: queennikki1972
author_rank: Regular Contributor
timestamp: May 04, 2019, 11:50:10 am
content: Yeah I know, old circuits, but its how I learn. I printed page 71 of this article for the circuit because its a little different

author: Zero999
author_rank: Super Contributor
timestamp: May 04, 2019, 05:11:02 pm
content: Yes, it's a good idea to start with old, proven designs.Regarding the schematic linked to in the first post: not only are the power supply pins not shown, but there's no decoupling capacitor. Connect a 100nF capacitor between pins 7 and 14, as close to the IC as possible. You may be able to get away without it, especially with the 74C14, rather than the 74HC14 IC, but it's good practise.
will a capacitor discharge through a diode bridge? - Page 1
Forum section: electronics / beginners

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 13, 2022, 02:41:53 pm
content: I have some diodes, I could set it up - but does someone think if it will or not?

author: eugene
author_rank: Frequent Contributor
timestamp: April 13, 2022, 02:50:42 pm
content: Do you mean a storage/smoothing cap on the DC side of the bridge? Only a minuscule leakage current will discharge the caps.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 13, 2022, 02:52:47 pm
content: It certainly would if you connect it in forward bias. If you use the the bridge to retifiy an AC voltage source and then using the capacitor to filter out the ripple then no it won't dischage back to the source.

author: Gyro
author_rank: Super Contributor
timestamp: April 13, 2022, 04:05:36 pm
content: You've been here before...https://www.eevblog.com/forum/beginners/load-between-battery-and-capacitor/msg3826460/#msg3826460

author: eugene
author_rank: Frequent Contributor
timestamp: April 14, 2022, 08:40:26 pm
content: @Capernicus, have you asked aetherist about this?

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2022, 02:12:06 am
content: sorry I dont know how to ask this question properly, I tried to delete this and it came back by accident.Thanks everyone for being nice and helpful, but I need to think about this before I pose the question again...
Will a TO-252-5 breakout board work for plain DPAK ? - Page 1
Forum section: electronics / beginners

author: Back2Volts
author_rank: Unknown
timestamp: January 06, 2017, 02:53:29 am
content: I would like to adapt a DPAK for testing in breadboard. I found the adapter in the picture. Am I right in assuming that it will work?

author: ebclr
author_rank: Super Contributor
timestamp: January 06, 2017, 03:59:58 am
content: You may need a heat sink

author: mmagin
author_rank: Frequent Contributor
timestamp: January 06, 2017, 04:50:50 am
content: DPAK is TO-252. I think the leads on TO-252-5 are narrower, maybe you can fudge it though.http://www.irf.com/package/hexfet/dpakfootprint.pdfhttp://www.infineon.com/dgdl/PG-TO252-5-12-Package_Overview.pdf?fileId=db3a304319c6f18c0119ce64c5187b30

author: Back2Volts
author_rank: Unknown
timestamp: January 06, 2017, 04:52:17 am
content: Quote from: ebclr on January 06, 2017, 03:59:58 amThat would not be a problem. I can glue on something a 9x9x5mm.

author: Back2Volts
author_rank: Unknown
timestamp: January 06, 2017, 05:13:12 am
content: Quote from: mmagin on January 06, 2017, 04:50:50 amI see what you mean. They have to be narrower to fit the additional pins between extremes and center. The DPAK side pins may overlay into the nearest footprint, which would be a problem if the center pin in the DPAK had full length and in turn overlay the same footprint, creating a short. As it is cut short, it will probably work.
Will a TS3A44159 work for me - Page 1
Forum section: electronics / beginners

author: leham
author_rank: Regular Contributor
timestamp: September 24, 2024, 01:38:48 am
content: Hello,I have a few project ideas that involve switching data lines between two devices.An example is switching two USB 2.0 devices on a single port with the only user interaction being flipping a switch essentially.I have a few ideas that are similar in scope, just replace USB with some other interface, like line level audio or a serial interface.I'm looking to stockpile a bunch of TS3A44159 (or any better recommendations) and just use more of them to accommodate the number of data lines ill be switching.Would a 0.5 ohm on resistance be an issue here?Thank you for your time
Will I blow the caps? - Page 1
Forum section: electronics / beginners

author: msknight
author_rank: Regular Contributor
timestamp: August 18, 2021, 05:07:15 pm
content: Here is the current circuit.According to 9.2.3 on the datasheet -https://www.ti.com/lit/ds/symlink/lm386.pdf?ts=1629118788552- the capacitor and resistor combination is to allow to raise from the default 20x to 200x. This is on pins 8 and 1.My question is... if I eliminate the resistor and let it run to 200x, will I blow the 10v capacitors I've used?

author: madires
author_rank: Super Contributor
timestamp: August 18, 2021, 05:28:27 pm
content: The voltage rating for the cap should be a little bit higher than Vcc.

author: msknight
author_rank: Regular Contributor
timestamp: August 18, 2021, 05:30:39 pm
content: Vcc is 5v DCSo it doesn't matter how much I amplify the signal by... which I believe is what is going out through the 1000uF caps... I should be fine.

author: Gyro
author_rank: Super Contributor
timestamp: August 18, 2021, 06:04:05 pm
content: That 100nF directly across across the output looks wrong. It's fairly normal to put a series RC network across the output of an amp (often known as a Zobel network) to improve high frequency stability, but a capacitor alone would, if anything, reduce stability.If you look at the app circuits in the LM386 datasheet that you linked, you will see a series 10R/50nF used. Anything from 47nF to 100nF would be fine.
Will it Follow me - Page 1
Forum section: electronics / beginners

author: IDEAMAN
author_rank: Newbie
timestamp: March 26, 2012, 05:51:12 am
content: I have a 12 volt tool cart that will run but i was looking to make it electronicaly follow me go around corners and stop 10' behind me. There has to be a way to have a sensor on my belt it would follow and control its moving direction any help would be greatthanks

author: Simon
author_rank: Unknown
timestamp: March 26, 2012, 06:11:13 am
content: strap it to a dogs back ? haha.Seriously though to you know the carts route, you will have to make sure you plan the carts movements with the available moving space, is there a predetermined "track" ? or will this be used anywhere ?

author: IanB
author_rank: Super Contributor
timestamp: March 26, 2012, 06:33:17 am
content: This thread seems to be a duplicate of the other one you started. Starting two threads won't get you any more answers than one.

author: Simon
author_rank: Unknown
timestamp: March 26, 2012, 06:51:31 am
content: in that case thread locked ! Thank you Ian.
Will mA go up with the more battery's - Page 1
Forum section: electronics / beginners

author: shane_95
author_rank: Regular Contributor
timestamp: July 02, 2012, 04:16:51 pm
content: for my design, I will need to run 3 9v battery's in series to get 27v to run 10x2.3v LEDs with a 20ohm resistor.My question is, will the mA triple? say from 300mA to 900mA

author: cs.dk
author_rank: Unknown
timestamp: July 02, 2012, 04:18:58 pm
content: Quote from: shane_95 on July 02, 2012, 04:16:51 pmNo - The maximum capacity will only triple, if you put them in parallel.

author: shane_95
author_rank: Regular Contributor
timestamp: July 02, 2012, 04:25:11 pm
content: Ok cool thanks

author: 8086
author_rank: Super Contributor
timestamp: July 02, 2012, 04:32:23 pm
content: You could start a project thread and keep the advice in one place in case you have more questions

author: shane_95
author_rank: Regular Contributor
timestamp: July 02, 2012, 05:05:35 pm
content: Quotei think this is it for now

author: IanB
author_rank: Super Contributor
timestamp: July 02, 2012, 06:28:15 pm
content: Quote from: shane_95 on July 02, 2012, 04:16:51 pmWhat kind of 9 V battery are you talking about? 300 mA is a very heavy load for a standard 9 V alkaline battery. 30 mA would be much more in keeping with the power and capacity of those batteries. Different if you happen to mean a much bigger 9 V battery however.

author: shane_95
author_rank: Regular Contributor
timestamp: July 03, 2012, 03:57:10 am
content: im talking about the standard house hold size

author: IanB
author_rank: Super Contributor
timestamp: July 03, 2012, 04:13:21 am
content: Check out the data sheet:http://data.energizer.com/PDFs/522.pdfWhile a household 9 V battery can deliver 300 mA, the service life will be very short when under such a heavy load. The voltage will also drop steeply. Your 9 V battery will not be 9 V for very long.

author: Psi
author_rank: Super Contributor
timestamp: July 03, 2012, 04:24:44 am
content: Yeah, 100mA is pretty much all you'd want to draw from a 9V.300mA will waste a significant percentage of energy (as heat) and the voltage will dip pretty fast.Ya have to remember that a 9V battery isn't the size you see when you look at it.It's a whole lot of smaller cells inside.The size difference between 3x 9V and 5x AA is about the same but you will get a huge amount more energy from the AAs

author: T4P
author_rank: Super Contributor
timestamp: July 03, 2012, 08:26:13 am
content: they work best with 1k source resistance, any more and it will blurt out pretty quicklyPlease keep in mind that it is actually 6 pieces of AAAA batteries inside

author: IanB
author_rank: Super Contributor
timestamp: July 03, 2012, 03:07:42 pm
content: From your other post with the YouTube video it looks like you are using standard red 5 mm LEDs. These small LEDs only need 10-20 mA to run brightly. If you try to feed them with 300 mA they will certainly be destroyed.For example, here's a sample calculation:Forward voltage = 10 x 2.3 V = 23 VSupply voltage = 27 VRequired voltage drop = 27 - 23 = 4 VRequired current = 20 mA = 0.02 ARequired series resistance = 4 / 0.02 =200 ohms
Will measuring DC on AC setting damage analog multimeter - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: December 28, 2016, 01:14:27 pm
content: I don't remember nor I want to check a book right now. I have a mostly working 6 tube radio from 1961 that I'm probing aroundOn a typical AMM with separate AC and DC ranges, does it hurt it if I happen to measure a lot of AC while set on DC, and vice versa ? I know its fine on my DMM

author: jaromir
author_rank: Unknown
timestamp: December 28, 2016, 02:32:28 pm
content: The problem with higher AC voltage on DC range is that the multimeter needle will not show very much, what can lead you to switch to more sensitive range... up to the point where something may break. Measuring DC voltages on AC range is generally OK, though the measurement accuracy is totally off.

author: David Hess
author_rank: Super Contributor
timestamp: December 28, 2016, 03:53:07 pm
content: Quote from: jaromir on December 28, 2016, 02:32:28 pmCompetently designed digital multimeters have the same overload specifications on all AC and DC voltage ranges if only because they share the same input circuits. For the same reason, neither AC or DC signals will cause damage if the wrong function is used. Even the ohms ranges should be proof against damage from AC and DC signals although sometimes to a lower level because it is difficult to protect the current source from severe voltage overload.

author: jaromir
author_rank: Unknown
timestamp: December 28, 2016, 06:08:15 pm
content: While that's true, OP asked about analog multimeters.Those were often nothing but a galvanometer, bunch of resistors, rotary switch and rectifier.

author: jeroen79
author_rank: Frequent Contributor
timestamp: December 28, 2016, 08:18:07 pm
content: Quote from: lordvader88 on December 28, 2016, 01:14:27 pmThere are different types of analog meters, which one are you using?As mentioned, some analog meters have lower impedance at lower range and the user could end up drawing too much AC current as he switches to a lower range.Otherwise I don't see a problem with the AC itself unless it hits the needle's resonant frequency.
Will most pick and place machines struggle to place this part? - Page 1
Forum section: electronics / beginners

author: king.oslo
author_rank: Frequent Contributor
timestamp: October 14, 2012, 11:59:12 pm
content: I am interested in this part. I can get it reasonably in 100+ quantities.http://www.digikey.com/product-detail/en/MPXM2202AS/MPXM2202AS-ND/4205271. It comes in tubes of 60. It doesn't look very pick and place friendly with that huge port on the top. Plus small standard packaging. These tubes will have to be changed every 60th board, right? Doesnt look very machine assembly-friendly. Have I assumed correctly?2. Second question: data sheet doesn't specify a mnimum voltage supply limit. It only specifies a typical and maximum limit. Am I right to assume it will meet its specs at 3.3V?Thank you for your time.Kind regards,Marius

author: David_AVD
author_rank: Super Contributor
timestamp: October 15, 2012, 12:14:11 am
content: See the note about the 10 -16 V range:QuoteI would assume that it needs a supply between 10 and 16 Volts. Best to ask the manufacturer I think.

author: digsys
author_rank: Unknown
timestamp: October 15, 2012, 12:51:09 am
content: The product manual is there, just need to fish around the links.Supply is ~3-16V and is ratiometric, so higher voltages will just make more heat.VERY unlikely to be auto placed, some stuff has to be done manually. I'd definitely add strong glue to hold it tothe PCB. In fact, those type of devices usually have a method to attach to the PCB. Imagine trying to pull off therubber tube and ripping out the pins.

author: sacherjj
author_rank: Frequent Contributor
timestamp: October 15, 2012, 01:40:44 am
content: Even with the model with side exiting pressure line, I agree with the others. It needs additional support. If your pick and place has epoxy, then using the MPXV2202GP CASE 1369-01 style device, you may be able to automatically place, due to the flat top. Drop it into a blog of epoxy. Assuming the sensor can handle the reflow temp profile safely.
Will my adjustable voltage reference schematic work? - Page 1
Forum section: electronics / beginners

author: warpigs330
author_rank: Contributor
timestamp: June 15, 2021, 01:06:50 am
content: I am making an adjustable voltage reference for a DAC. It is based on the TL431. I want this to be adjustable from roughly 3v to 3.3v. The accuracy of the limits of adjustability isn't too important, just that it has a range. Essentially I have a dac that outputs 3.3v and and amplifier stage that gets that to a bit more than 5v, depending on the tolerance of the resistors it is around 5.12v. I want to trim my DAC reference so I can adjust for part tolerances and get 0-5v out. Will this circuit work the way I want it to?

author: ledtester
author_rank: Super Contributor
timestamp: June 15, 2021, 04:05:50 am
content: With regards to C10, have a look at:"Understanding Stability Boundary Conditions Charts in TL431, TL432 Data Sheet"https://www.ti.com/lit/an/slva482a/slva482a.pdf?ts=1623729444831Figure 1 shows the regions of stability when driving a capacitive load.With V_KA = 3.3V, you'll want to have a larger C_L, like maybe > 5uF.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 16, 2021, 02:07:40 pm
content: No, you wont get the adjustment range you want even with no load.Why not use a fixed ref and take care of the gain or offset in in software?EG REF19x from AD. Have look at this as well LT6650.Try this.https://www.ti.com/tool/TL431CALCI'm not sure the FB is of much use here.This circuit pumps up your 3.3V to 5v making life easier for the TL431. It can manage a few mA of load. You need to clock it in the Mhz range. Of course all the load current comes from the driver- a small mosfet or even a gate output say.

author: fcb
author_rank: Super Contributor
timestamp: June 16, 2021, 02:23:35 pm
content: Watch out for stability with the TL431, there is a zone (depending on mfr, part, etc..) around 10nF to 1uF where they oscillate quite badly.

author: KT88
author_rank: Frequent Contributor
timestamp: June 17, 2021, 04:18:53 pm
content: The input voltage needs to be higher than the output voltage. The shunt reference must take some current (within spec). The input resistor must be able to carry both reference- and load current without drooping below the specified output voltage.In this case it would be best to tie the input to your 5V-rail...CheersAndreas

author: Kleinstein
author_rank: Super Contributor
timestamp: June 17, 2021, 04:46:57 pm
content: Unless one needs the 3.3 V for something else too, why not run the DAC with 2.5 V and than do a x2 amplification. x2 is nice, as 2 equal resistors is easy and often quite stable. If really needed fine trim could be at the x 2 part.TL0431 is cheap, but hardly better than what one finds as DAC internal reference, or with a decent 3.3 V voltage regulator.
Will SimCom 7000G work in USA? - Page 1
Forum section: electronics / beginners

author: sztelf
author_rank: Newbie
timestamp: April 03, 2024, 07:12:34 pm
content: Hello,I'm from Europe, and I'm making project for my US friend. I have module LilyGo ESP32 + SIM7000G (G like Global). After purchase I seen that it not support "LTE"... Module is working good in my European country, it connects to internet, can send sms. Will it work (connect to internet and send sms) in USA? Can't find any info, only some outdated things... If it will work in US any sim card of any carrier can be used?

author: m k
author_rank: Super Contributor
timestamp: April 13, 2024, 07:23:45 pm
content: USA is different.There are LTE networks, but that is not universal.European lands are more or less populated.USA has so remote places that wireless is not available at all.

author: aliarifat794
author_rank: Regular Contributor
timestamp: April 15, 2024, 03:08:30 pm
content: SIM7000G Supports LTE, GPRS, and GPS cummunicaion. If your friend's area has GPRS network coverage, they can use SIM7000G.

author: Emo
author_rank: Regular Contributor
timestamp: April 15, 2024, 03:26:54 pm
content: HiThe Simcom7000G version supports following bandsGlobal-Band LTE CAT-M1: B1/B2/B3/B4/B5/B8/B12/B13/B18/B19/B20/B 26/B28/B39;Global-Band LTE CAT NB-IoT1: B1/B2/B3/B5/B8/B12/B13/B17/B18/B19/B20/ B26/B28;GPRS/EDGE 850/900/1800/1900MhzIf an operator does have a network running one of the above modes/bands than it will be possible to use it.NB. This IoT targeted modem does not support regular LTE, only LTE-M1 or NBIoTEric
Will strain resistance will go up - Page 1
Forum section: electronics / beginners

author: A2
author_rank: Contributor
timestamp: August 08, 2014, 06:54:08 pm
content: I have a strain gauge of 1000ohm, with 50000 microstarin & GF=2 it can exhibit a change of 100ohms.Do strain resistance value will always go down i.e 1000-100 = 900ohms.or it can go above 1000 ohms. Like 1000+100 = 1100ohms

author: fcb
author_rank: Super Contributor
timestamp: August 08, 2014, 07:12:58 pm
content: Depends on the direction of the strain. One way it's resistance will increase - the other it will decrease. 1000ohms is the nominal value.

author: A2
author_rank: Contributor
timestamp: August 10, 2014, 12:18:06 pm
content: 1. I am using strain gauge from vishay whose datasheet i have attached.2. I know that in compression resistance decrease & vice versa.3. But in datasheet it says only, strain range = 5%. For gf = 2 & R = 1K, total change in resistance will be 100ohms.Now does that resistance will go 100 ohm down(i.e 900ohm) in case of compression& in case of tension it will go up 100 ohm (i.e 1100 ohm) to show maximum strain i.e5% or 50000 microstrainThis is what i am asking?

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: August 10, 2014, 01:27:01 pm
content: most things I've see strain gages glued to don't do +/-5% strain - or at least not twicefor good force measurement you usually use a metal structure in its linear elastic recovery range, which is less than 0.5% strainand most measuring devices are used with a safety factor to not permanently bend the completed load cellso you most often end up with less than 0.1% resistance changeof course if you are into destructive testing/plastic deformation you may see more

author: fcb
author_rank: Super Contributor
timestamp: August 10, 2014, 06:15:30 pm
content: Read:http://www.vishaypg.com/docs/11506/gageser.pdfWhilst +/-5% is the limit, I would be nervous about subjecting a strain gauge to a tenth of that (and maintaining any sort of accuracy), I think the adhesives would also be a problem.And in answer to your (specific) question: yes
Will the RT4812 boost converter work when Vin is only 0.25V below Vout? - Page 1
Forum section: electronics / beginners

author: MicroControllerGuy
author_rank: Newbie
timestamp: April 16, 2020, 09:31:46 pm
content: Hi,under Electrical Characteristics in the RT4812 datasheet the Test Condition for Vout is specified as:VIN < VOUT - 0.2VI take this to mean that I can design for a constant Vout of 4.1V from RT4812 for a Vin up to 3.85V.(See page 4 ofhttps://www.richtek.com/assets/product_file/RT4812/DS4812-07.pdf)Have I understood this correctly?I'm concerned that a 0.25V "head room" is too little for this boost converter (and boost converters in general) and that the boost converter will boost Vout beyond 4.1V.Some facts about my design:- I plan to run the RT4812 from a LiFePO4 battery pack, and while charging the pack voltage will max out at 3.85V.- The maximum voltage my load can handle is 4.2V, i.e. I must limit the boost converter's output to 4.1V.Please let me know if I have understood the Test Condition of the data sheet correctly. Unfortunately I don't have a RT4812 chip I can measure on.Thank you!

author: Segasonicfan
author_rank: Newbie
timestamp: July 01, 2020, 06:38:13 am
content: I actually sell boost converter PCBs of this chip. Yes, everything you described sounds like it should work. However, be prepared for some slight deviation on the output voltage under heavy loads.Let me know if you'd like me to take some test measurements of my board for you.
Will this battery bank circuit work with these batteries? - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: March 03, 2018, 10:24:35 am
content: I took these batteries out of an old laptop battery pack:It's a parallel array of four 3.7v lithium-ion cells (it was originally used in series in the laptop). Each one is at 4.2v. I tried to connect this to a small single cell power bank circuit, but for some reason, some component on the circuit released the magic smoke after a few minutes (which confused me, because when I connected it to a single cell, the circuit worked properly.Anyway, I want to get a power bank circuit for this, because this is currently lying around, and all of these cells combined made a 42 wh pack. Would something like this (http://r.ebay.com/ufzmfL) work if I connected this battery pack directly to it? Would it have all the needed protection for the batteries?

author: ogden
author_rank: Super Contributor
timestamp: March 03, 2018, 11:10:25 am
content: Quote from: skillz21 on March 03, 2018, 10:24:35 amIt depends. That power bank module is sized for 18650 Battery which is usually in 2..3 Ah (6..10WH) range. Most charge controllers have charge safety timer which dos not allow charge to be longer than some predetermined time. It may simply shut-off after 4 or 8 hours or whatever timeout time is. Your problem is that your pack is20x4x bigger than 18650 and obviously will need longer time for that poor controller to do the charge job. So... your mileage may vary. There's slight problem about protection circuit which is undersized for your pack, but it's IMHO minor problem.Try it if you can afford it, share your results.

author: skillz21
author_rank: Frequent Contributor
timestamp: March 03, 2018, 11:15:01 am
content: Quote from: ogden on March 03, 2018, 11:10:25 amThanks for that, I'll try to buy that and have a look... but will it be safe? All the necessary protection for over discharge and overcharge?

author: ogden
author_rank: Super Contributor
timestamp: March 03, 2018, 11:38:54 am
content: Quote from: skillz21 on March 03, 2018, 11:15:01 amI can't tell you that - have no experience with that particular controller. Overcharge protection for sure, overdischarge most likely. You shall investigate - try to find PCB pictures where IC markings are visible, check datasheets to see what kind of protection particular controller IC offers. When you buy it - do not leave unattended for first runs, check how it does it's job.  42WH is s**tload of energy - be safe. Note that I modified battery sizing info in original post as well.

author: skillz21
author_rank: Frequent Contributor
timestamp: March 03, 2018, 12:57:35 pm
content: Thanks for the info, I'll have a look.
Will this battery be ok to swap with the dead one? - Page 1
Forum section: electronics / beginners

author: josh1073
author_rank: Newbie
timestamp: May 22, 2017, 10:47:11 pm
content: Hi, my dash cam started turning off randomly and the fault has been traced to a duff battery. What i want to do is change the battery with one that is working so it will not turn off when i am driving.The one that is in the camera that has bitten the dust is a li-po 3.7v 300mah i have a 3.7v li-on battery that will fit that i have taken it out a bluetooth receiver I am not sure if it will be safe to put in as i dont want it to blow up. Any help would be great.

author: Audioguru
author_rank: Super Contributor
timestamp: May 22, 2017, 10:57:08 pm
content: The battery might blow up or catch on fire if you connect its polarity backwards or short it. The wires should be red and black on the original and replacement batteries.

author: josh1073
author_rank: Newbie
timestamp: May 23, 2017, 08:15:00 am
content: Ah, so i can replace the lithium polymer battery that is in the camera with a lithium ion battery i have lying around?

author: Rerouter
author_rank: Super Contributor
timestamp: May 23, 2017, 09:21:29 am
content: In general yes, but if your jury rigging something, use a protected li-ion cell,Also be aware that if they are using a charge managing IC like they do in some GPS's (similar devices internally), you will want similar capacity or you may hit a timer limit which means it never charges, if its just a generic charger IC, you could well throw a 2200mah 18650 in a socket on the back and have it last much longer.
Will this BMS design work? - Page 1
Forum section: electronics / beginners

author: Yanagibashi
author_rank: Newbie
timestamp: July 18, 2019, 09:32:07 pm
content: I have spent the last few weeks creating this schematic but I've never done something like this before so I have no idea of verifying if something like this will work, and I was wondering if anyone here could provide some insight or point me in the right direction
will this circuit work as intented? - Page 1
Forum section: electronics / beginners

author: ahmed_eshra
author_rank: Newbie
timestamp: August 04, 2015, 04:09:49 pm
content: My question is will the following circuit work as an automatic pump control.sorry for the terrible design.if i connect the analogue pressure sensor in the primary connection in the circuit after a motorized pump,and the secondary sensor before the pump, and the motor leads between the motor and the mains ,will the following happen?---------------------------------------------1-if the difference between the pressure at each side of the pump is lower than a pre-set value by pot 1(which means someone opened the tab), then the relay should close the circuit ,leading to the pump being run.2-if the difference between the pressure at each side of the pump is higher than a pre-set value by pot 0(which means someone closed the tab), then the relay should open the circuit ,leading to the pump shutting off.please don't flame me for a major design and just point it out.if it would work can someone help me make a breaboard design with recommendations for parts to be used.i need to measure the difference between pressures as sometimes the water increases it's pressure or decreases it.also thanks in advance and sorry for improper formatting and language,still new to the forum.
will this circuit work?  - Page 1
Forum section: electronics / beginners

author: Sounduser
author_rank: Contributor
timestamp: June 16, 2015, 12:51:13 pm
content: I've got an rgb party light that flashes to music.It's basically LEDs that are switched on the low side by a microcontroller.I want to connect it to some rgb led strip.Will this circuit work?Thanks.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: June 16, 2015, 03:35:25 pm
content: If the GND-terminals are connected, yes.The P-channel MOSFET can be replaced by a small signal BJT.

author: Sounduser
author_rank: Contributor
timestamp: June 16, 2015, 08:14:33 pm
content: Okay. Just a straight swap with a pnp transistor. No extra resistors?

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: June 17, 2015, 10:44:29 am
content: Yep, you already have your base resistor, just emitter to 12v and collector to your MOSFET gate.

author: Sounduser
author_rank: Contributor
timestamp: June 20, 2015, 11:31:23 am
content: What value resistor would you use?Thanks guys.
Will this design work well? - Page 1
Forum section: electronics / beginners

author: king.oslo
author_rank: Frequent Contributor
timestamp: January 15, 2012, 10:18:50 pm
content: Hello there,I am making a switch mode power supply. I am finding it challenging. It has a LM25116 buck controlled by PWM from a PIC18F4550.I understand from the datasheet of the LM25116, that a voltage higher or lower than 1.215V on the FB pin alters the the duty cycle of the buck either up or down. As a result Vout is altered.I thought that the best way control this by MCU was to use an op-amp with Unity Gain Differential Amplifier configuration where I input 1.5-4.2 voltage to correspond to Vout of 1.5-4.2. The inverting input has to be 1.215 lower than the non-inverting: f(Vout) = .199 * Vout.I just wonder if my solution is good, or if it can be improved. I find at least one problem. But I am not sure how to solve it. I mostly need help with the feedback circuit inside the blue ellipse at the moment. The rest of the circuit is nowhere near completion.Any critique is much appreciated. When I listed to Dave talk about his design, I am often surprised about things that I did not know.Thank you very much for your time!Kind regards,MariusPS: This is the LM25116 datasheet. On page 13, the Error Amplifier is discussed.http://www.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=snvs509c&fileType=pdf

author: amspire
author_rank: Super Contributor
timestamp: January 15, 2012, 11:56:57 pm
content: Any reason for using that regulator?The reason I am asking is that it gives you no access to the internal 1.25V reference. If the micro could use the same reference as the power controller, then it could use the PWM to do purely relative adjustments. I suppose you are assuming that you can correct for errors between the two references via the ADC input, but this adds another control loop and it can affect the stability.It could work, but I suspect you may be able to find a friendlier regulator chip.It looks like that regulator needs external compensation, so it could be a fair bit of work getting it stable over the the whole voltage range.100 ohms resistors in the amp circuit is way to low. 10K would be better.Richard.

author: king.oslo
author_rank: Frequent Contributor
timestamp: January 16, 2012, 03:21:39 am
content: Thanks for that.Which regulator do you recommend?If I increase from 100R to 10K, the voltage divider Vout will be altered. Correct? How can I ovcome this?Thank you for your timeM
Will this destroy my "car's" side window controller? - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: August 16, 2022, 03:19:32 pm
content: In my cabin scooter is there a button for rolling up and down the side windows, this does only work if the ignition is on.I have sometimes forgotten to roll the windows up and my remote-key does nothing.therefore, have I thought of making a simple circuit that sends power to the side window motor and make it roll up the windows.I had imagined the motor roll up the windows when the ignition is off and the side window electronic is turned off.will it destroy the electronic to connect an external power source t power the motor when the normal windows power is off?

author: Ian.M
author_rank: Super Contributor
timestamp: August 16, 2022, 03:27:56 pm
content: Probably. Most H-bridge motor drive circuits have back-EMF suppression diodes across the output transistors so your circuit will back-feed the car's switched 12V supply, and the suppression diodes wont be able to handle the resulting current.

author: FriedMule
author_rank: Frequent Contributor
timestamp: August 16, 2022, 04:24:51 pm
content: Hmm I am not sure I get it all, but 12V that runs the wrong way into the original circuit is what I think I understand?So unless I can avoid both circuit been connected to the motor at the same time, should I forget about it?A SPST with NC and NO could be the solution?

author: Manul
author_rank: Super Contributor
timestamp: August 16, 2022, 05:17:33 pm
content: The correct way would be to switch motor pin 1 to either car controller or battery positive. There will be no backfeeding then. So you just need to rearrange the schematic.Note: above valid only if motor negative is ground. If not, then you need double pole relay, to switch both motor pins to either car controller or to battery.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 18, 2022, 06:36:45 pm
content: The master window switch in a car does exactly that, no magic smoke.

author: jpanhalt
author_rank: Super Contributor
timestamp: August 18, 2022, 06:47:20 pm
content: 1) My Ford allows the windows to work while the motor is off, so long as the key is not removed.2) Wouldn't allowing the windows to work with no key and off make it easier for thieves to get in? Sorry for my ignorance. I don't know quite what a cabin scooter really is. Is it lockable?3)Why do you need to power off circuit only to be active when the scooter is off?Just leave it active all the time and wire it to the battery with an "always on" circuit (cigarette lighter in older cars was always on). Modern cars call that an accessory circuit. Cigarette lighters promote bad habits, so they cost extra.
Will this measure V and I from different sources? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 04, 2013, 06:41:57 pm
content: Will these Chinese digital volt / amp meters measure voltage and amps from different places? IE, measure mains input voltage to a power supply, and filament current to a valve from a transformer, in the same supply simultaneously?http://www.ebay.co.uk/itm/180929324693?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649Can't be sure these will do what I need.... thanks!

author: Andy Watson
author_rank: Super Contributor
timestamp: December 04, 2013, 06:58:52 pm
content: Provided you use the current transformer, and your filament is driven with AC, I would say yes.

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 05, 2013, 02:10:43 pm
content: Thanks for that. Luckily I have discovered a friend who has a spare unit like this and I can borrow it and check it out. Cheers