hybridfree/eevblog-posts huggingface dataset:
crystal oscillator - Page 1
Forum section: electronics / beginners

author: stilwellj1983
author_rank: Newbie
timestamp: December 08, 2013, 12:20:24 am
content: I work in the telecom industry and I would lie to create a signal generator with a 2 pin crystal oscillator. I have a 10.000 Mhz and a 20.000 Mhz. I have been looking online for types of crystal oscillator signal generator. I have found different schematics and built one that uses a four pin but I would like to build one that uses a 2 pin crystal oscillator to reduce size.

author: Zero999
author_rank: Super Contributor
timestamp: December 08, 2013, 12:36:14 am
content: There is no such thing as a two pin crystal oscillator.A two pin crystal is just a resonator. You need to add an amplifier to make an oscillator.By the time you've made the oscillator, it will take up more space than just buying a four pin crystal oscillator which contains the crystal and the amplifier.

author: stilwellj1983
author_rank: Newbie
timestamp: December 08, 2013, 12:39:18 am
content: Quote from: Hero999 on December 08, 2013, 12:36:14 amthank you for the information

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: December 08, 2013, 03:15:45 am
content: If you want to have a bit of control over the frequency and output level then an oscillator made from discrete parts (though it takes up more space) is better than a module.Eg the circuit below with a 10 MHz crystal substituted:
Crystal / resonator circuit - Page 1
Forum section: electronics / beginners

author: int2str
author_rank: Regular Contributor
timestamp: February 17, 2015, 01:34:01 am
content: Alright, I give up....I'm trying to learn how to make a crystal driven circuit as well as a resonator driven one.I've looked into "Pierce oscillators", but can't figure out what makes it "tick".Here's what I have on hand:1x ZTT 16MHz resonator (looks like it's a crystal with built-in capacitors)1x 16MHz quartz crystal1x 74HCU04 hex inverter (since it looks like I need it)+ various resistors (nothing in the mega ohm range though) /LEDs etcIs there a simple circuit i can put together that lets me measure the frequency and analyze it?I've seen a lot of circuits like this:http://upload.wikimedia.org/wikipedia/commons/thumb/2/28/Pierce_oscillator.svg/220px-Pierce_oscillator.svg.pngBut I don't see where one would add power to make it, well, a circuit?Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 17, 2015, 02:00:15 am
content: Power is from the gate's supply/gnd pins (not shown). The resistor is probably ok as low as 100k, but it's usually in the megs, because it's only needed to supply bias voltage to the gate's high impedance input.Detecting frequency without a frequency detector... well, I suppose you can try it like the old timers did -- set up a resonant circuit, detector and galvanometer... but you need to know the resonant circuit is even correct. Lecher lines might be a bit impractical at 16MHz or harmonics, I'm thinking.Frequency counter, oscilloscope or spectrum analyzer would of course be the best choices here.Tim

author: mentaldemise
author_rank: Regular Contributor
timestamp: February 17, 2015, 05:42:49 am
content: I just tried this out with an Arduino crystal I had laying around and seems to work. I don't know much though. I was looking for the same thing myself the other day:http://jaunty-electronics.com/blog/2012/08/simple-oscillator-as-crystal-tester/I found it in another post on here about the same thing.

author: atferrari
author_rank: Frequent Contributor
timestamp: February 17, 2015, 10:47:18 am
content: I recall testing an oscillator built around a transistor. I think it was 10 MHz.In my ignorance, I said, "it is not working" because I expected something like 5V pk-pk. Actually it was much less than that and worked OK. Maybe influence of being used to see square waves of clocks for digital techinques.

author: dannyf
author_rank: Super Contributor
timestamp: February 17, 2015, 12:12:36 pm
content: Since the gate is unbuffered, sticking the crystal across its input/output will get it to oscillate. If that doesn't work, put a 1M - 10M resistor in parallel with the crystal.Cannot be simpler than that.

author: w2aew
author_rank: Super Contributor
timestamp: February 17, 2015, 02:18:39 pm
content: Have seen my video on building a crystal oscillator?

author: int2str
author_rank: Regular Contributor
timestamp: February 17, 2015, 06:22:11 pm
content: Thanks guys!Tried a few more things last night, but came up crickets so far on the logic analyzer.Ordered a scope, so hopefully can learn more about these circuits soon.
Crystal selection - Page 1
Forum section: electronics / beginners

author: viperidae
author_rank: Frequent Contributor
timestamp: March 18, 2019, 02:36:52 am
content: I have a data sheet that doesn't have much in the way of data...https://elinux.org/images/e/e1/UPD72042.pdfI've had a look around for 6.29MHz crystals and all I can find are a handful on mouser. They have 15pf and 47pf resonators.https://nz.mouser.com/Passive-Components/Frequency-Control-Timing-Devices/Resonators/_/N-6zu9h?P=1z0wk1yMy understanding is the 3 pin resonators have built in load capacitors. The data sheet for my device doesn't have any information about load cap values or recommended crystals.Anyone got any advice, other than buy both and see which works?

author: RES
author_rank: Regular Contributor
timestamp: March 18, 2019, 11:36:01 am
content: https://www.arrow.com/en/products/e2sfa16-6.290mtr/ecliptek(but smd)
Crystal sensitivity - Page 1
Forum section: electronics / beginners

author: mayor
author_rank: Regular Contributor
timestamp: March 11, 2015, 11:28:50 pm
content: Hello,I've added a 6pF 32,768kHz crystal to the proper pins of an msp430 controller. Everything checks out, except when I lay the board down or when my finger touches the pins of th uC. The effect I can observe is that my timer just stops. I remove my finger, comes back.Mind you, I have taken as much care with ground as I could on a veroboard, but my question is: is this expected? Anything you can think of to alleviate the problem?TIA!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 12, 2015, 02:28:09 am
content: Patient: "Doctor, it hurts when I do this!"Doctor: "Well then don't do that!"If you must touch it, you could put down some insulating tape. Better still, make a sort of enclosure to keep errant fingers (and wires, and etc.) away from it entirely?The impedance is quite high, because of the nature of the crystal and the low power level it is being driven at. The loading capacitors (6pF, plus whatever the MCU pins are -- probably about as much) are typical of the impedance in the circuit, so, ~10pF at 32kHz is half a megohm impedance. A finger ranges from a series equivalent of a few megs (DC resistance, dry) and fractional pF (not touching, at a distance) to 100-1000 ohms and 100-200pF (direct contact, high frequency), so it's more than enough to load down the oscillator and stall it.Tim
crystal  oscillator help - Page 1
Forum section: electronics / beginners

author: ijchan223
author_rank: Contributor
timestamp: August 05, 2014, 04:06:52 am
content: Hi i damaged a crystal that is on a video card and i can't seem to determine what part i replace it with, i know it is a 27 mhz crystal but can't figure out the capacitance , the original Part has sck27.000n2 on it.any help is appreciated

author: ijchan223
author_rank: Contributor
timestamp: August 18, 2014, 05:19:50 pm
content: can anyone help me with this? Can't seem to find the part reference anywhere

author: KJDS
author_rank: Super Contributor
timestamp: August 18, 2014, 05:22:20 pm
content: Can you tell what caps are on the board at the moment?If not then buy a convenient 27MHz crystal and some suitable caps to go with it. So long as they're within 50% they usually work.

author: German_EE
author_rank: Super Contributor
timestamp: August 18, 2014, 05:46:30 pm
content: The 27 MHz crystal is there because it's an exact multiple of both the PAL and NTSC line frequencies. Because of this I'd be tempted to put any 27 MHz crystal in there because whatever you use the TV will still be able to sync to the card output.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 18, 2014, 07:02:41 pm
content: Are you sure it's a crystal and not an oscillator block?Cause that is what I mostly see on video cards:

author: ijchan223
author_rank: Contributor
timestamp: August 19, 2014, 09:43:31 pm
content: i am assuming that it is a crystal because it only have 2 legs. The i think it is used to sli the video cards together in this case because the card passes all test but just won't sli together. I can't really tell what the component values are because they are all surface mount. here is a picture for reference, i can take one of my own if you like, to see the components closer but they aren't marked

author: wraper
author_rank: Unknown
timestamp: August 19, 2014, 09:49:16 pm
content: Just put any crystal you can get. If it do not work (very unlikely), change load capacitors to different value. You can also desolder them and measure.

author: ijchan223
author_rank: Contributor
timestamp: August 19, 2014, 10:48:04 pm
content: the reason i posted here is because it didn't work, but after swapping around the cards around, and putting the one that has a new crystal up as the primary card it workedI don't see how it mattered but i guess as long as it works i am happy, thanks for the suggestions. going to run the system in this configuration for a few weeks to make sure that is solved the problem

author: wraper
author_rank: Unknown
timestamp: August 19, 2014, 10:58:40 pm
content: IMO it is driver related issue, not crystal.

author: ijchan223
author_rank: Contributor
timestamp: August 21, 2014, 07:07:58 pm
content: Quote from: wraper on August 19, 2014, 10:58:40 pmYou are correct, the actual issue isn't the crystal replacement. The problem is that i moved my soundcard to a different PCIe slot that is causing some conflicts. Thanks for all the input.
Crystals, PPM, and I think I'm bad at math - Page 1
Forum section: electronics / beginners

author: Rendman
author_rank: Newbie
timestamp: April 02, 2013, 11:00:32 pm
content: Hi all,Got a question, I found this formula for determining what the min/max f for the specified f. I run it for 32768 hz and it tells me the minimum can be 32759.808 and the maximum can be 32776.192. Is that correct? Here the formula:deltaF = (f x ppm)/106Thanks!

author: c4757p
author_rank: Super Contributor
timestamp: April 02, 2013, 11:02:13 pm
content: PPM means Parts Per Million. Just think about it - you don't need to find a formula to do this computation.

author: Rendman
author_rank: Newbie
timestamp: April 03, 2013, 12:16:02 am
content: Duh, okay. Figured out my +/- values. Determined that the square wave I was generating was WAY out of spec. A little fiddling with the OCR register and all is well. Thanks.
Crystals   - Page 1
Forum section: electronics / beginners

author: Aztlanpz
author_rank: Regular Contributor
timestamp: January 19, 2018, 02:30:26 am
content: How small do they make Crystals?Aztlan

author: danadak
author_rank: Super Contributor
timestamp: January 19, 2018, 02:34:19 am
content: What frequency range do you need ? Size, depending on frequency, canbe quite different one xtal to another.Regards, Dana.

author: Aztlanpz
author_rank: Regular Contributor
timestamp: January 19, 2018, 03:04:25 am
content: For a crystal of 16MHz.
CSI GBX Pro GPS Receiver Choosing Proper Antenna  - Page 1
Forum section: electronics / beginners

author: Johnny10
author_rank: Frequent Contributor
timestamp: November 09, 2018, 10:38:29 pm
content: Playing with a new find.Looking for the proper antenna.I have an Aeroantenna Technology AT-575-59o Antenna and a SCP1350/Warlock Antenna.The Warlock doesn't seem to work havent tried the Aeroantenna.I am very new to GPS.
Cubesat type application: Should I ground the PCB stack to the external chassis? - Page 1
Forum section: electronics / beginners

author: logancane
author_rank: Regular Contributor
timestamp: May 14, 2021, 01:04:16 am
content: Pretty much as the question states. In this case, the application is a high altitude balloon, but we are connecting the PCB's like how they do in cubesats. That is to say the PCB's will be connected via PC/104 to an aluminum block/ground plane. My question is, should I electrically connect or isolate this ground plane from the external chassis that is exposed to the atmosphere? I am trying to minimize noise in the circuit.Cheers everyone.

author: MikeK
author_rank: Super Contributor
timestamp: May 14, 2021, 02:18:19 am
content: Won't the chassis act like an antenna?

author: David Hess
author_rank: Super Contributor
timestamp: May 14, 2021, 10:09:09 am
content: Test instruments with metal chassis faces the same problem. The chassis should never be floating with respect to the circuit because static charge could build up and especially so in your application. If no ground plane is used, then a single point ground is usually the best option and if possible, should be at the signal ingress/egress. With a ground plane, every standoff might be connected to the chassis.In applications where a direct low impedance connection is not feasible, some provision should still be made to bleed off static charge like an inductor or resistor between the chassis and the single point ground. Often in this case a bypass capacitor is also used to make an RF connection, or a breakover (?) capacitor which acts as a spark gap.

author: nfmax
author_rank: Super Contributor
timestamp: May 15, 2021, 07:53:32 pm
content: Are lightning strikes a possibility? The voltage at different points of the external chassis will be different, because of the lightning current flowing through the structure. You need to talk to an expert though, not me.
Cuk converter, why its not popular ? - Page 1
Forum section: electronics / beginners

author: BravoV
author_rank: Super Contributor
timestamp: January 24, 2012, 02:35:20 pm
content: I mean compared to other popular types like buck, boost or buck-boost ?Is it because of the cost ? I assume those transfer capacitor ?Please be gentle, I'm just starting to read this and merely touching this topic's surface, yes, I'm a noob.From the output ripple point of view, this particular topology has advantage right ?Any insight or your comment will be appreciated.

author: Neilm
author_rank: Super Contributor
timestamp: January 24, 2012, 07:46:57 pm
content: It is (in my experience) generally because of the requirements of the situation. I generally either have an output voltage that is either lower than by supply or higher than my supply, so I choose a buck, boost or fly-back as appropriate. I can only think of a couple of times that I have had a situation where by output voltage can be both higher and lower than the input - generally when designing battery operated circuits with an output in the region of the battery voltage.YoursNeil
Curious about Potentiometers and Tuning coils use all 3 terminals - Page 1
Forum section: electronics / beginners

author: RJSV
author_rank: Super Contributor
timestamp: June 26, 2022, 06:53:30 pm
content: Hey!Going through my (precious) Forrest Mims book, started getting curious, about motivation for using all 3 terminals in many common circuits...In the case of a Tuning Coil, many circuits literally have a short-circuit negating a portion of coil, while adjusted position 'selects' the remaining coil turns. Same idea for Potentiometers, usually keeping all 3 terminals in circuits.Am I missing that some measure of contact noise gets worse, when sliding motions cause near-open connection, or, worse, if middle slider (briefly) loses any contact ?Otherwise, why not just use (most) circuits having only 2 connections, for controlling volume, or controlling tuner inductance.Thanks

author: Terry Bites
author_rank: Super Contributor
timestamp: June 26, 2022, 07:45:27 pm
content: A potentiometer is a 3 terminal device, a variable voltage divider rather than a single variable resistor. A pot can be connected as a variable resistor if you need one. Why make two types of product when one will do both? Its unusual to see a variable resistor out side of gain, time or frequency preset applications. The same three terminals on an inductor are there for the same reason.Wiper noise is only a problem in old, dirty or cheap and nasty pots. Or the pots from hell... thesliderpot. Tying one end to the wiper is a good idea, an open circuit is an entry point for noise and leakage currents.

author: MikeK
author_rank: Super Contributor
timestamp: June 26, 2022, 08:55:05 pm
content: Ask yourself what happens if the wiper, even briefly, fails to make contact in a 2-terminal application. Like a 2-terminal pot in a variable power supply...What happens to the output voltage? And can the connected device handle that situation?...Should it have to?
Curious active filter topology - Page 1
Forum section: electronics / beginners

author: ConnorGames
author_rank: Regular Contributor
timestamp: October 21, 2014, 02:20:18 am
content: I was just browsing the web and encountered a strange looking active filter, and have no idea what topology it is or what kind of thought process would be required to create such a filter. Could someone enlighten me about this filter? What topology is it?I'm just curious and trying to broaden the pool of filter types I have to work from when I'm designing something.I have attached a quick and ugly ltspice sim. Sorry the components are all bunched up!

author: mazurov
author_rank: Frequent Contributor
timestamp: October 21, 2014, 02:47:31 am
content: T-network? They need very low frequency for which component values become very large.

author: LvW
author_rank: Frequent Contributor
timestamp: October 21, 2014, 07:55:52 am
content: Quote from: ConnorGames on October 21, 2014, 02:20:18 amRegarding the topology - it is a special form of a third-order Sallen-Key lowpass with unity dc gain - and rising ac gain.I didn`t check the gain response (for the given values) - however, it looks "strange" (if the display is correct).Remark (edit): You shouldn`t overlook that the part of the original circuit (from D. Johnson) - as sketched by you - is not driven by a low-impedance source (as in your simulation) but by a high-resistive signal source.
Curious if this a TSOP1738 - Page 1
Forum section: electronics / beginners

author: RobH
author_rank: Regular Contributor
timestamp: December 05, 2020, 10:27:14 am
content: I bought what is supposedly a TSOP1738 for a circuit I was going to try.https://www.electronicshub.org/wp-content/uploads/2017/04/IR-Receiver-Circuit.jpgWhen I connected the TSOP1738 as per the schematic and applied 5v, it got quite warm, so I disconnected to power.I have attached a picture of the said device and I'm curious to know if it is actually a TSOP1738, as it looks different to the pictures of them online .If it's of any use, there is what maybe a serial number under the dome: AY443. I googled this but there were no links for it.Thanks

author: exe
author_rank: Unknown
timestamp: December 05, 2020, 11:25:16 am
content: It seems there are different receivers with different pinout:https://microcontrollerslab.com/tsop1738-ir-receiver-pinout-examples-arduino-applications/. Look how similar devices have mirrored pinouts.For example, this module looks like yours:https://www.aliexpress.com/item/33001722129.html. It's hard to see traces, but possible. Look where GND is located.So, may be there are different receivers on the market that look similar?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: December 05, 2020, 11:31:08 am
content: It looks like there is a type number lasered between the lens and the pins.Maybe you can read it when you change lighting conditions.

author: RobH
author_rank: Regular Contributor
timestamp: December 05, 2020, 06:53:15 pm
content: Quote from: Doctorandus_P on December 05, 2020, 11:31:08 amYes the number is AY443, as said in my op

author: RobH
author_rank: Regular Contributor
timestamp: December 05, 2020, 06:58:44 pm
content: Quote from: exe on December 05, 2020, 11:25:16 amThanks for the links and I connected the one I have like the one in the 1st link, with GND on the left as you look at the front of the TSOP1738. But it could be that the GND is on the right??

author: exe
author_rank: Unknown
timestamp: December 05, 2020, 08:05:37 pm
content: Quote from: RobH on December 05, 2020, 06:58:44 pm

author: wraper
author_rank: Unknown
timestamp: December 05, 2020, 08:23:31 pm
content: Certainly not TSOP1738 since it has completely different package of larger size and different pin arrangementhttps://www.batronix.com/pdf/tsop17xx.pdfReceiver probably is sort of compatible with TSOP 1738 but has different pinout, quite likely the same as thishttp://www.farnell.com/datasheets/2049301.pdf

author: Benta
author_rank: Super Contributor
timestamp: December 05, 2020, 08:33:15 pm
content: Looks like a Vishay Minimold type IR receiver. Or a ripoff.
Current activated switch - Page 1
Forum section: electronics / beginners

author: m8
author_rank: Newbie
timestamp: March 04, 2015, 02:40:02 pm
content: Need to switch on my extractor fans/hoover any time any of the workshop tools are turned on Router table saw chop saw. Has anyone had any experience with this type of current switch PleaseMike

author: Seekonk
author_rank: Super Contributor
timestamp: March 04, 2015, 02:47:50 pm
content: Common solution is a go/nogo self powered relay. These are usually 10A with a toroid you place the sense wire through. Don't have 10A, just pass multiple loops through the coil. Most motors have a high current surge so even 3A easily pulls in a relay. Trouble is you usually need a timer relay so the fan operates for a minimum of 5 minutes so you aren't short cycling the fan all the time.

author: m8
author_rank: Newbie
timestamp: March 04, 2015, 03:10:58 pm
content: That's what we used to use but cant find a source of them in 110v/240V at the moment - as to the timer that's easy have those available already but unfortunately need to find them in 110V now to do the same job

author: Seekonk
author_rank: Super Contributor
timestamp: March 04, 2015, 03:38:47 pm
content: Here is one of the self powered relays I was talking about that requires no power connection. This can then be used to switch on a timer relay. They also offer powered versions that have a timer built in.www.rke.com/item/ac-current-relays/go-no-go-ac-current-sensing-relay/mcdr?

author: MLXXXp
author_rank: Frequent Contributor
timestamp: March 04, 2015, 06:51:45 pm
content: Maybe you could use one of those "smart" power bars that have a built in current activated switch. When current is drawn from the "master" outlet, other outlets are switched on.E.g.http://www.smarthomeusa.com/smart-strip-power-strip-automatic-switching-surge-suppressor/

author: SeanB
author_rank: Super Contributor
timestamp: March 04, 2015, 07:28:26 pm
content: Current sense relay, or a simple series resistor with a thermal switch attached to it, so that when it gets hot it turns on the output. Put a non resettable thermal fuse in series with the supply for safety, and if you use a ceramic cased resistor on a heat resistant ( mica sheet with high temperature terminals on it, and all connections crimped or screw connectors) base you can use a 200C safety fuse, and a 80C NO resettable Clixon as the output switch.

author: m8
author_rank: Newbie
timestamp: March 06, 2015, 09:34:34 am
content: Smart Power bars not an option - I need to switch 20A using a contator and timed off as well. As to the thermal option - I might as well monitor the voltage drop across the resistor or even put an opticla Isolator in parallel with diode limiters. Another problem is Im in the UK and most of the options commented on are only available in the states and Ive inquired from RKE do they supply here. And the answer is no. Im trying other options at the momement - Thanks so far will keep listeningMikeGD6ICR
Current capacity of wire - Page 1
Forum section: electronics / beginners

author: iceisfun
author_rank: Regular Contributor
timestamp: October 23, 2013, 07:59:32 pm
content: Hello EEVBlogersI have a question about a project I'm working onI am trying to connect some stepper driver + encoder boards with a DB9 interface to a control box, but I don't know how much current I can carry on one of these wires?The current requirement is 3A @ 5v per phase of the stepper motorhttp://www.ebay.com/itm/370423582662

author: Monkeh
author_rank: Super Contributor
timestamp: October 23, 2013, 08:07:33 pm
content: Not 3A by a long shot.

author: IanB
author_rank: Super Contributor
timestamp: October 23, 2013, 08:12:58 pm
content: Two things constrain the amount of current you can carry in a wire:1. Voltage drop2. Heat generationWith smaller circuits and lower currents voltage drop is the main thing to be concerned about. Simply take the wire you are considering, find out its size (gauge) and length, determine the resistance and then use Ohm's law to find the voltage drop for the current it will carry. See if this voltage drop is within allowable limits. If not, use a thicker wire.

author: 8086
author_rank: Super Contributor
timestamp: October 23, 2013, 08:19:19 pm
content: Google homework:ResistivityOhm's law

author: M. András
author_rank: Super Contributor
timestamp: October 23, 2013, 08:20:52 pm
content: get the db9 connectors and solder some 0.5mm2 wires or 0.75mm2 to it that rs232 or god knows what cable from ebay will have maximum 0.25mm2 wires in it or even thinner

author: Monkeh
author_rank: Super Contributor
timestamp: October 23, 2013, 08:23:58 pm
content: Quote from: M. András on October 23, 2013, 08:20:52 pmBecause 0.75mm² is totally adequate for 5V 3A at 10 feet.

author: Rufus
author_rank: Super Contributor
timestamp: October 23, 2013, 08:44:23 pm
content: Quote from: iceisfun on October 23, 2013, 07:59:32 pmThishttp://www.powerstream.com/Wire_Size.htmis a useful reference.

author: FoXX
author_rank: Contributor
timestamp: October 23, 2013, 09:09:40 pm
content: Very nice link Rufus, thanks

author: M. András
author_rank: Super Contributor
timestamp: October 24, 2013, 03:25:22 pm
content: Quote from: Monkeh on October 23, 2013, 08:23:58 pmi like to oversize things just to be sure

author: Monkeh
author_rank: Super Contributor
timestamp: October 24, 2013, 03:29:24 pm
content: Quote from: M. András on October 24, 2013, 03:25:22 pmOversize? That'sundersized. Do the calculations next time.

author: M. András
author_rank: Super Contributor
timestamp: October 24, 2013, 04:17:57 pm
content: well yeah. my mistake its a serious voltage drop
Current carrying capacity of test leads - Page 1
Forum section: electronics / beginners

author: vjekobalas
author_rank: Regular Contributor
timestamp: September 12, 2021, 05:00:53 pm
content: Is there a way to determine how much DC current at a voltage below 12V the following Uni-trend UT-L10test leads would safely carry ? :https://www.chipoteka.hr/artikl/129950/ispitni-kabeli-2x-banana-4mm-ut-l10-uni-trend-2630403730I wanted to use them for charging some batteries at DC voltages below 12V and currents below 5A.

author: bob91343
author_rank: Super Contributor
timestamp: September 12, 2021, 10:32:29 pm
content: The gauge is important. #18 is probably good for 5 A.

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 12, 2021, 11:30:31 pm
content: UT-L10 is 10 A rated.
Current clamp angle of wire - Page 1
Forum section: electronics / beginners

author: injb
author_rank: Regular Contributor
timestamp: May 16, 2019, 12:54:38 am
content: I have been playing around with a current clamp that I got for my osciioscope, and I've noticed that the reading I get changes quite a bit if I move the clamp or the wire a little. For instance, I was able to get 9A to show up as around 7A just by twisting the clamp so that it wasn't at a perfect right angle to the wire. It was still fully closed.Is this normal? How do you know the true reading? Is the highest reading you get get from it always the most accurate it's capable of?Thanks!

author: David Hess
author_rank: Super Contributor
timestamp: May 16, 2019, 02:59:29 am
content: I always find that this is a problem when the clamp does not close evenly and cheaper clamps cannot close evenly. Good high frequency clamps actually have surfaces polished to optical specifications on their split core for consistent performance.
Current clamp oscillating at 50MHz - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: November 17, 2018, 04:04:25 pm
content: We have a DALI power bus comprising a 15mA current clamp in a 15V rail. (as in attached schematic)As a test, I turned on the transistor, Q4.When I clipped a scope probe (or even a TA041 diff probe ) across the 82R resistor, I sometimes saw a 50MHz sinusoidal oscillation across this 82R resistor, of about 250mV pk2pk.Sometimes I have to grab and release the ends of the probe to “start the oscillation off”.We want to stop this oscillation. Do you agree that a good way to damp out this oscillation is to put an RC series circuit from Collector to base of Q3? ( Values of 10n, 10R)I did this in the lab and it certainly put an end to the oscillation, though we wonder if there is a better way to stop it?NXJ1S1215 datasheet:https://power.murata.com/data/power/ncl/kdc_nxj1.pdfTLV431 datasheet:https://www.diodes.com/assets/Datasheets/TLV431.pdfFMMT491A datasheet:https://www.diodes.com/assets/Datasheets/FMMT491A.pdf

author: Wolfgang
author_rank: Super Contributor
timestamp: November 17, 2018, 09:24:33 pm
content: ... another way would be a resistor between the sense input of the TLV431 and the current sense resistor (say, 1K), plus a small cap between the anode of the TLV431 and the sense input (try a few 100pF).
Current consumption of a FT232 circuit - Page 1
Forum section: electronics / beginners

author: PeterFW
author_rank: Frequent Contributor
timestamp: February 05, 2015, 06:10:13 pm
content: Edit: I forgot the attachment, my apologies.Hello!Since it seems that i misunderstood the usb suspend concept, would someone please tell me how much current the attached circuit should draw with a open jumper?I forgot to give the Resistor a value, it is a 1.6K resistor.With the jumper closed i measure 2.5mA, that is about what the LED current should be.With the jumper open my 0.1mA resolution meter will not register a current.If i understand it correctly, the USB suspend state is entered when no activity on the USB bus is detected for more then 3ms.That means this circuit should only draw a significant amount of current (15mA Operating Supply Current) when data is transferred or something else is talking to the chip.That would mean that, when idling, the chip will consume 100µA worst case.Is this correct?Greetings,Peter

author: 22swg
author_rank: Frequent Contributor
timestamp: February 06, 2015, 09:18:04 am
content: I have USB V and A monitor , with an FTDI232R module attached and with nothing else connected (so no activity) it does not register on the amps display so must be <1ma.Edit Correction , there seems to be an occasional 30ma activity ....

author: bktemp
author_rank: Super Contributor
timestamp: February 06, 2015, 12:04:03 pm
content: I measure 8.7mA when a FT232RL is normally connected with no data transferred and 56uA with only 5V+GND connected.

author: PeterFW
author_rank: Frequent Contributor
timestamp: February 06, 2015, 01:48:10 pm
content: Hello and thank you both very much!I never thought i would one day have to estimate a circuits power consumption in µA.Looks like i have to power the USB-Serial converter from the 5V USB rail.Greetings,Peter
Current Control  - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 02, 2016, 04:27:54 pm
content: 1. I have to control current of a load, so that whenever load increases from 5A it should trip & second there is no reverse current.Operating voltage is 9V to 12.6V.2. I was looking at LTC4358, it says its ideal diode for 5A. Features in it says "0.5?s Turn-Off Time Limits Peak Fault Current".Does that mean it will trip after peak current? What's its value in datasheet? Also will the system auto retry after fault condition?3. Also diode minimum operating voltage is 9V, what if any case error system voltage falls below it? Will the diode shut off or LTC4358 may overheat as its internal mosfet cannot be turn on completely?

author: pyroesp
author_rank: Regular Contributor
timestamp: September 03, 2016, 01:17:35 am
content: 1) Have a look at this :http://electronicdesign.com/power/current-limiter-offers-circuit-protection-low-voltage-dropIt's a current limiter though, not something that disconnects the input voltage. How do you want to switch off the input ? Relay ? Transistor ? ...

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 05, 2016, 05:24:49 am
content: How about using TPS25944A.It gives current limit & provide reverse current protection also.
Current-controlled switch symbol - Page 1
Forum section: electronics / beginners

author: elki
author_rank: Regular Contributor
timestamp: December 22, 2023, 10:04:39 pm
content: Is it a current-controlled switch symbol? I am asking because this one has four legs, while SPICE models that I saw have only two.

author: Jwillis
author_rank: Super Contributor
timestamp: December 22, 2023, 11:22:30 pm
content: According to Pspice it is a Wbreak Current-controlled switch breakout device Model.http://www.ee.cuhk.edu.hk/~ymfung/ppp/pspice/symbol.htmlandhttps://www.pspice.com/passive/switches/current-controlledhope this helps

author: elki
author_rank: Regular Contributor
timestamp: December 23, 2023, 07:22:17 am
content: Thanks. Does anyone know if there is a corresponding symbol in LTspice?

author: Zero999
author_rank: Super Contributor
timestamp: December 23, 2023, 10:28:13 am
content: I normally use a current controlled switch to model a relay. Here's an example.
Current Divider Confusion - Page 1
Forum section: electronics / beginners

author: JacobEdward
author_rank: Regular Contributor
timestamp: March 19, 2015, 01:07:42 am
content: https://youtu.be/hjq1Kf9hiGYI am measuring 4.83 mA across R3 and this is the table I used to calculate what values I should have been receiving... can someone check my math or maybe come up with some ideas of why I'm getting 4 mA less than I should be?______________R1________R2________R3_______TotalVoltage_______12.7_______12.7______12.7_______12.7Current______0.000235__0.000642___0.000863___0.00174Resistance____54000_____19760_____14700___7291.126531I'm following this basic circuit configuration:http://www.allaboutcircuits.com/vol_1/chpt_6/3.html

author: AlfBaz
author_rank: Super Contributor
timestamp: March 19, 2015, 01:12:15 am
content: Assuming you've connected your ammeter in series then most likely you are seeing the effect of burden voltage

author: JacobEdward
author_rank: Regular Contributor
timestamp: March 19, 2015, 01:16:54 am
content: Quote from: AlfBaz on March 19, 2015, 01:12:15 amYes, the ammeter is in series, thanks, forgot to mention that in the description

author: IanB
author_rank: Super Contributor
timestamp: March 19, 2015, 02:54:25 am
content: Note that 0.000863 A is 0.863 mA. Given that you appeared to measure 4.83 mA, something is far more wrong than you state in your post.You really need two meters here so that you can measure both voltage and current at the same time without swapping leads around and twisting the range selector.You should test a single resistor. Measure the voltage and current at the same time and calculate the resistance. (Make sure to measure the voltage across just the resistor so the ammeter doesn't interfere with the reading.) Then take the resistance out of circuit and measure the resistance using the resistance range on a meter. Check that they match.After that, try to repeat your experiment, taking great care over every detail.Also, be careful with that big ass lead acid battery. One false move and you will let the magic smoke out of everything in the vicinity, start a fire and burn yourself all in one go.
Current Driver - Page 1
Forum section: electronics / beginners

author: Yossarian
author_rank: Newbie
timestamp: August 31, 2018, 12:58:52 pm
content: Hey Guys,I have a question concerning a project i am doing for University: I am supposed to help build an active magnetic field compensator for an electron microscope.For that i need a current driver (I'm not even sure if that's the right word) that can convert a small voltage (tens of mV) from the sensor into a large current (1+ A). It should also be quite fast and accurate between DC and about 1kHz.I have tried to build a circuit but it's not working so far (i'll try to upload a picture later) and i don't really find a lot of helpful stuff on google neither.I hope you guys can help me out or maybe tell me what to search for.Many thanks in advance.Cheers

author: awallin
author_rank: Frequent Contributor
timestamp: August 31, 2018, 01:28:28 pm
content: If it doesn't need to be ultra-low-noise then look at OPA569here's a board I did a few years back:http://www.anderswallin.net/2014/09/tec-drive-v2/if noise is crucial, look at Libbrecht-Hall or Ericksson circuits for laser constant current drives.https://arxiv.org/abs/0805.0015http://www.submm.caltech.edu/kids_html/DesignLog/DesignLog179/MillerMUSICReadoutDocs/HEMT%20Power%20Supply/Libbrecht%20and%20Hall,%20A%20Low%20Noise%20High%20Speed%20Diode%20Laser%20Current%20Controller.pdf

author: Cerebus
author_rank: Super Contributor
timestamp: August 31, 2018, 02:10:49 pm
content: Quote from: Yossarian on August 31, 2018, 12:58:52 pmDo you have a specifictransconductancethat you're aiming for, i.e. a specific ratio ofcurrent/voltage?A few minutes thinking about that question might jog your memory as to exactly how you might achieve this. (Yes, I am deliberately adopting adidacticstyle rather than offering up any neatly packaged answer(s) as you've admitted yourself that it's your homework.)

author: MasterT
author_rank: Frequent Contributor
timestamp: August 31, 2018, 02:29:30 pm
content: Below 20 kHz any audio power amp, except D-class.

author: David Hess
author_rank: Super Contributor
timestamp: August 31, 2018, 05:13:04 pm
content: So essentially you need a Howland current pump with a power output stage although there are other topologies which may be better.Another way to do it is to use a fixed precision constant current source and then *subtract* another precision current from it with a parallel current source of the opposite polarity. This has the advantage of only requiring one quadrant operation. Usually it would be power intensive but in your case with an inductive load, the required voltage compliance is low so the power is low.Check out figure 142 on page 65 ofLinear Technology application note 47for one implantation of a fast high current voltage controlled current source.
current excited wheatstone bridge - Page 1
Forum section: electronics / beginners

author: mercurial
author_rank: Regular Contributor
timestamp: January 26, 2024, 06:07:13 pm
content: I came across a post on this forum where the consensus was that driving current through a wheatstone bridge was not the preferred way for signal conditioning of strain gauges.Some users cited linearity and some cited temperature related errors.So if I use a full bridge topology (all 4 resistors in the bridge are strain gauges) and somehow mechanically couple the strain gauges such that they are equally affected by temperature and drive the bridge with a 1mA current.Would it still be the non-preferred mode of measuring a strain, what kind of errors does one expect and why?I did a small simulation test and results and attached.

author: voltsandjolts
author_rank: Unknown
timestamp: January 26, 2024, 07:20:08 pm
content: With semiconductor based strain sensors, where bridge resistance increases noticeably with temperature, constant current drive can help maintain temperature stable bridge output. It might be beneficial with metal strain gauges if you are operating over a wide temperature range and you'renotmaking a ratiometric measurement of bridge output.I recommend you use ratiometric measurement and then bridge supply becomes less critical and constant voltage is fine.https://www.eevblog.com/forum/projects/load-cell-(wheatstone-bridge)-excitation-voltage-hurdles/msg3134330/#msg3134330

author: mercurial
author_rank: Regular Contributor
timestamp: January 27, 2024, 03:32:13 am
content: BTW i was thinking of using current excitation of bridge(metal strain gauge) + ratiometric to remove drift errors from current source. I was just wondering what are the cons of current excited bridge vs voltage excited bridge. Are they any? or whether I interpreted the responses in the other posts wrongly.

author: voltsandjolts
author_rank: Unknown
timestamp: January 27, 2024, 08:53:30 am
content: Creating a constant current source may require extra effort and components, and if using a ratiometric measurement I don't see any advantage over voltage drive.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 27, 2024, 11:44:16 am
content: Constant current drive could simplify the wiring / connectors to the bridge, as one does not have to take into account the drop the wires to the bridge, which can be an issue for long wires and high accuracy target combined. It may still be easier to have extra sense wires for the drive than making ratiometric current drive.

author: David Hess
author_rank: Super Contributor
timestamp: January 27, 2024, 01:16:49 pm
content: Practical load cells have a temperature sensitive modulus compensation resistor in series with the excitation which would be defeated by using constant current drive unless sense wires are used, and if sense wires are used, then why bother with constant current drive?The presence of the modulus compensation resistor can be checked by comparing the resistance across the excitation with the resistance across the signal wires.
Current-feedback vs Voltage-Feedback - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 19, 2021, 10:15:40 pm
content: In a previous design of mine, I used theTI LM7171voltage feedback op-amp in an inverting summing circuit, taking two inputs and adding them up and inverting them. I'm revisiting the design with different requirements, so I'm looking at different topologies as a result. I was wondering, when is it recommended to use a current-feedback op-amp over a voltage-feedback op-amp for a circuit? I see that CFAs have high slew-rates and wide bandwidths, and I read about how their BW isn't dependent on gain (compared to the VFAs and the GBP), but as a result, you have more noise with CFAs. Is there a way to reduce the noise with a CFA so you get the benefit of a CFA with less noise like a VFA?

author: magic
author_rank: Super Contributor
timestamp: October 20, 2021, 06:21:39 am
content: Ahem, there is a subtle difference between voltage feedback opamps and "voltage feedback opamps". For whatever reasons, which you would have to ask marketroids about, if those words are spelled out explicitly in the datasheet it usually means a current feedback amplifier with built-in unity gain buffer at IN-.So you have already used a CFA as far as noise is concerned, but without the GBW benefits

author: Terry Bites
author_rank: Super Contributor
timestamp: October 20, 2021, 07:43:16 am
content: AD have a nice paper discussing the pros and cons .https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiV1s_kvtjzAhWH66QKHRawALUQFnoECAMQAQ&url=https%3A%2F%2Fwww.analog.com%2Fmedia%2Fen%2Ftraining-seminars%2Ftutorials%2FMT-049.pdf&usg=AOvVaw0ACIgCjCGcmogDPIFG1sQN

author: magic
author_rank: Super Contributor
timestamp: October 20, 2021, 04:47:40 pm
content: I will add that exact noise specifications should of course be included in the datasheet of any given part.Given the nature of the beast (bipolar transistors running at fairly high bias) I expect CFA voltage noise to be quite competitive, but IN+ current noise may be a few dB higher due to the combined base currents of two transistors. Off the top of my head, not sure how much current noise there is on IN-.Many integrated instrumentation amps use current feedback in their first stage to achieve stable performance across a wide range of closed loop gains. Some of those ICs exhibit very low noise at low source impedance.
current flow - Page 1
Forum section: electronics / beginners

author: m3vuv
author_rank: Super Contributor
timestamp: June 11, 2019, 02:50:23 pm
content: ive been led to belive power flows from neg to positive,so why are diode and transistor symbles like they are as in showingthe oposit? am i misisng something here?

author: soldar
author_rank: Super Contributor
timestamp: June 11, 2019, 03:03:39 pm
content: This has been discussed to death. You can find many threads discussing this.https://www.eevblog.com/forum/beginners/why-not-change-conventional-current-to-electron-current/

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 11, 2019, 03:03:52 pm
content: The technical definition of direction was formed before the physical direction was known, therefore symbols are oriented after the technical direction. Technically holes can "move" by electrons filling the void.

author: garethw
author_rank: Regular Contributor
timestamp: June 11, 2019, 03:15:27 pm
content: Think of holes as positive charge carriers. The lack of an electron is just as powerful a concept as the electron being present.Sent from my iPhone using Tapatalk

author: David Hess
author_rank: Super Contributor
timestamp: June 12, 2019, 01:15:18 pm
content: It was Franklin's fault:https://en.wikipedia.org/wiki/Electric_charge#HistoryHe also posited that when matter contained too little of the fluid it was negatively charged, and when it had an excess it was positively charged. For a reason that was not recorded, he identified the term positive with vitreous electricity and negative with resinous electricity.
Current for MOSFET gate? - Page 1
Forum section: electronics / beginners

author: nsled
author_rank: Contributor
timestamp: June 04, 2024, 05:01:20 pm
content: I've been looking at the IMW65R015M2HXKSA1 MOSFET.https://au.mouser.com/ProductDetail/Infineon-Technologies/IMW65R015M2HXKSA1?qs=mELouGlnn3dwwSVR7zAG%2FA%3D%3DFall Time: 8 nsRise Time: 21 nsGate Charge: 79 nCNow I've been assuming I'll need about 5A of current into the gate to fully switch it on fast enough at 50kHz (maybe 200kHz). Now I've just had the revelation that I'm probably completely wrong. What sort of current will I require to make available for the gate of this MOSFET?

author: jwet
author_rank: Frequent Contributor
timestamp: June 04, 2024, 05:33:10 pm
content: I = Cdv/dt or dQ/dt.If you want to charge 79 nc in your rise/fall times, it would take 3.76A/9.87A. These are maxim peak values for the FET- you don't have to achieve this- this where the metallization on the FET will melt. If you're going to run at 200 Khz, you have a 5 uS on time. You'd like to switch quickly to maintain efficiency- say 1% of that 5 uS or 50 n with currents of 1.58 A rise/fall. This is also a peak current and has a 1% duty cycle, average current is 15.8 mA. If you bypass your high side drive with 1 uF, you'll have pretty decent drive with a bit of droop. This is ok, since the current is not constant, its higher at the beginning and reaches zero after gate charged/discharged. This is standard FET driver territory. Vishay has good app notes on driving big FET's.

author: nsled
author_rank: Contributor
timestamp: June 04, 2024, 06:30:01 pm
content: Ok Excellent thankyou jwet, I was having an awful time trying to find a voltage reg that'd give 5A its good to know it isn't needed.

author: jwet
author_rank: Frequent Contributor
timestamp: June 05, 2024, 04:19:33 pm
content: Didn't mention this, but the stray inductance of this supply and bypass must be kept to a minimum. Also minimize loop area between driver gate, source and driver common with very tight bypassing. Pushing 2 amp 50 nS pulses around takes tight layout to minimize L. Look at rec'd layout if available or consult app notes.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 05, 2024, 04:47:27 pm
content: You'd be wise to be generous with the regulator spec.