hybridfree/eevblog-posts huggingface dataset:
Board with serial capabilities and 12v output? - Page 1
Forum section: electronics / beginners

author: dmg0345
author_rank: Newbie
timestamp: June 22, 2021, 11:31:34 pm
content: I raised a topic about a programmable power supply, the IPS-405, and its non standard RS232 interface.To summarize, this IPS-405 has a 0V to 5V UART, a 12V input to feed some internal optocouplers for isolation and a ground signal.I am not sure if what I am asking for even exists, but I need to communicate via serial with this PSU, is there any USB based cable or any cp2102/pl2303 breakout board that has an UART and a 12V output? Any recommendations? The closest thing I found is an adjustable USB based power supply called EasyVolts, and it also acts like a uart transceiver to communicate with another device through the USB via EasyVolts, however thia product is no longer manufactured, it does what I need.I have some cp2102 breakout boards that also give 5V output, unfortunately this is not enough, I need 12V.

author: Manul
author_rank: Super Contributor
timestamp: June 23, 2021, 12:25:46 am
content: According to the user manual of IPS series supplies, it is RS232, not UART. And 12V seems to be not a supply, but connection to RS232 DTR line from which it gets logic high (+12V) once connected. So it seems you just need USB to RS232 converter.

author: dmg0345
author_rank: Newbie
timestamp: June 23, 2021, 02:28:01 pm
content: Quote from: Manul on June 23, 2021, 12:25:46 amNah, unfortunately not, those 12Volts signal simply feed optocouples for isolation, there is no DTR logic per se. It is proprietary technology: the pins do not match a null modem nor straight cable, and I've been told that this is the cable needed for the IPS-405, PSP-405... power supplies: GTL-232A, however this one is not USB. This is my investigation so far:https://www.eevblog.com/forum/testgear/ips-405-programable-power-supply-rs232-interface/msg3589337/#msg3589337I think it might be possible to use a USB to RS232 converter, using something intermediate to change the wiring to match the PSU, and setting DTR to a high level from software, hoping that it is >=12V.

author: Manul
author_rank: Super Contributor
timestamp: June 23, 2021, 03:20:43 pm
content: Ok, got it. But have you tried to wire it up, like it is shown in the manual? If 12V is for optocouplers, it is probably not important, what exactly is this voltage. USB to RS232 converters has charge pump and produces something lik +- 7-10V. Should be enougth. If no success, take isolated dc/dc converter which you can put inside PSU itself. Or take a 5 to 12V step up (boost) converter and run it from usb together with data converter.
bode of filter - Page 1
Forum section: electronics / beginners

author: naviss
author_rank: Newbie
timestamp: January 03, 2013, 01:06:39 pm
content: Hi,Electronic is not my cup of tea but i have to now the bode of a filter.But i can't find any infos about this filter. can you help me or can you give me some link about this type of filter ?Thanks.

author: Kremmen
author_rank: Super Contributor
timestamp: January 03, 2013, 01:29:35 pm
content: Google "multiple feedback low-pass filter".At these component values corner feqs sit at 553.925 Hz and 510.926 Hz. The slope is 60 dB/decade (3rd order). Phase response corresponds normally to the slope, lagging ~135 degrees at corner.The corresponding poles are at-553.925 +j0 Hz and-248.225 +/-j446.575 Hzwhich gives a damping ratio of 0.485

author: naviss
author_rank: Newbie
timestamp: January 03, 2013, 01:36:08 pm
content: Thank you Kremmen this site is very usefull
Bode plot of opamp integrator - Page 1
Forum section: electronics / beginners

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 06, 2020, 04:53:34 pm
content: HiWhy does the LTspice AC simulation give the phase near the f=0 axis as 180degrees for this opamp integrator?This cannot possibly be right. Surely?The transfer function is – (1/jwC)/ R,Which equals 0 + j (1/wCR)The phase of this is atan {[1/wCR]/0}..this is atan (infinite) which is n.pi/2, where n = +/- 1,3,5,7,9 etcThis cannot possibly be 180 degrees. Do you agree?

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 06, 2020, 05:23:01 pm
content: It is an inverting integrator. (?)Phase will go from 180 to 270 at the corner.I use qucs and it is a bit tricky in graphing phase that goes through the upper/lower limits set by user on the phi graph.But I think it does it correctly.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 06, 2020, 05:34:13 pm
content: Near f = 0 Hz one would see the limited DC gain of the OP and thus a constant gain. So a 180 deg. phase is correct.

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 07, 2020, 11:12:44 am
content: QuoteThanks, you mean if it was a ideal opamp then it would be 270 degs near the f=0 axis?By the way, page 10 of the following has phase near f=0 axis as 90 degrees, not 180 degreesti.com application notehttps://www.ti.com/lit/an/slva662/slva662.pdf?ts=1607167216358&ref_url=https%253A%252F%252Fwww.google.de%252F
Bode Plot - Page 1
Forum section: electronics / beginners

author: Chris Tatler
author_rank: Newbie
timestamp: August 30, 2021, 01:23:15 am
content: Hi all.I'm new to this forum and I was wondering if someone could help me with this bode plot (image attached).I'm just mucking around with filters on the bread board using op amps etc. I have a reasonably good understanding of the phase difference between the input to the filter versus the output at varying frequencies and what to expect, but I am fairly new to doing this kind of analysis and using the test equipment so it's quite possible that I may have set it up wrong. I can't understand why the phase trace on the scope jumps from -180° to +180° when the signal is around -6db. I can't imagine it doing it for real, and I thought it might be something to do with the way the scope interprets the information. If I set up the same thing in LT Spice, it doesn't do it.Attached is a snippet of the filter (part of a bigger circuit for a cross over network) and the screen of the scope bode plot.Thanks

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 30, 2021, 01:32:47 am
content: Chris,There are a couple of things happening here:1) Bode plots are normally log amplitude versus log frequency. Your x-axis is linear.2) When you measure phase you are limited to +/- 180 degrees. For example -185 degrees is the same as + 175. Some equipment may offer 'extended' phase which shows it as a continuous.Jay_Diddy_B

author: Chris Tatler
author_rank: Newbie
timestamp: August 30, 2021, 03:23:40 am
content: Hi,Thanks for your help and quick reply. Yes that does make sense now, its wrapping around it would seem. I was comparing what I was seeing on my scope with what I was seeing in LT Spice, and LT Spice doesn't seem to have the limitation of 180° so was confusing me.Also - I changed my scope to log and it looks a lot better (it defaults to linear so that's why I had it set like that).Good to know.Cheers
Body Metronome - Page 1
Forum section: electronics / beginners

author: EEBlackSheep
author_rank: Contributor
timestamp: December 10, 2011, 03:46:10 am
content: I am a musician. There is a metronome out called a body metronome and uses a vibrating clip rather than a speaker - so the musician "feels" the beat. *very* cool thing. Anyways they are $120 and I can make one way cheaper.I have a couple of eletronic metronomes with ear phone jacks. These emit a square wave(ish) at 5Vpeak for about 5ms duration. I also have scavenged a cell phone vibrator motor from an old phone that takes about 3.5VDC max. I tried connecting the two thinking that the load from the motor would sag the voltage, but nothing happened. So I am guessing one of a few things. I need more current, I need a longer on time, I need a little less voltage.So... I am thinking I should have a sperate power source for the motor - a rechargeable lithium will do. And use a transistor to control the power to the motor, and the transistor can be triggered by the metronome. However, I am unsure about any supporting components or the right spec for the transistor. Also I am unsure how I can increase the on time (although I am not sure if I even need it)thanks for the help.

author: Joshua
author_rank: Regular Contributor
timestamp: December 10, 2011, 04:10:56 am
content: I am also a very involved musician. I will be following this thread closely. This would also probably be great for my students who at the beginning have a hard time grasping the fact you have to play *with* the metronome. Sorry I don't have anything to add, but good luck and I will look forward to progress updates.

author: robrenz
author_rank: Super Contributor
timestamp: December 10, 2011, 04:12:42 am
content: IMO the vibrator motor is not a good choice. Too much time to accerate and decelerate, it would limit the highest frequency you could achieve. A very small voice coil in a mini speaker might work, possibly with a properly sized weight added that would give a sufficient thump you could feel. Others on the forum are more versed in giving advice on the electronic end of it.

author: EEBlackSheep
author_rank: Contributor
timestamp: December 10, 2011, 04:15:43 am
content: Well perhaps humour me and let me find out if this will work or not through experimentation. Any suggestions on the control circuit?

author: EEBlackSheep
author_rank: Contributor
timestamp: December 10, 2011, 01:27:15 pm
content: These guys pulled it off at 100BPM - I only need 150 so I think its quite doable:

author: EEBlackSheep
author_rank: Contributor
timestamp: December 10, 2011, 01:44:43 pm
content: He he - never mind - bought one for my android smart phone. $2.93 - works just great.So much for the guess that it wouldn't work. hah - naysayers. Doom and gloom. Reminds me of a song - "sunny side of the street".Time to go and play.
Bogus constant current tutorial video using 7805 lin vreg?? - Page 1
Forum section: electronics / beginners

author: Axel1973
author_rank: Regular Contributor
timestamp: June 12, 2012, 05:57:17 am
content: on youtube some electronics/radio guy radiofun232 lately posted a video about how to use a lin.V-Regulator 7805 as a constant current source.This is his vid:I think the way he uses the regulator is just the "classic" way for voltage regulation, not constant current, except the "feedback resistor" between IN and OUT.I say he uses the regulator pretty much as a normal voltage regulator and NOT as a Const.Current source. I would expect the resistor between OUT and GND Pin of the regulator.So who is messed up here? Am i ? is his circuit ?What do you guys say about that circuit?a second opinion would be interesting.greetsAxel

author: Axel1973
author_rank: Regular Contributor
timestamp: June 12, 2012, 06:00:58 am
content: PS: check Time 3:40+ to see the circuit im talking about.Axel

author: free_electron
author_rank: Super Contributor
timestamp: June 12, 2012, 07:02:57 am
content: Yeah, it's bullshit.The regulator does not keep the voltage across the resistor comstant. All it does is make 5 volts. The. Reason his lamp burns brighter at 22 volts is because of the alternate path throug the 220 ohm resistor. He succeeds at lifting the 5 volt output throught te resistor.You cant do constant current with this kind of regulator. Use lm317 or lm337

author: Bored@Work
author_rank: Super Contributor
timestamp: June 12, 2012, 01:35:58 pm
content: Oh dear, why do people feel the need to record an eight minute video for a trivial (and wrong) schematic?Of course one can use a 7805 to build a crude constant current source. But not in the way shown. Connect the output voltage of the regulator to a constant load, aka a resistor, cf. Ohm's law. The current through the resistor, plus the regulator's quiescent current is the current from the supply into the regulator (cf. Kirchhoff's current law), and is roughly constant if the supply voltage is large enough, and the regulator is operated within its input voltage rating (cf. Kirchhoff's voltage law).See, no need for an eight minute video.
Boji Stones force field - answers on a postcard please - Page 1
Forum section: electronics / beginners

author: Quantumplate
author_rank: Regular Contributor
timestamp: January 29, 2023, 11:37:44 am
content: Hello,so i just got a pair of these curious rocks which some describe as 'electromagnetically charged' in online blurb. They do exhibit repulsion, very slight, when brought close on their long sides. I can then flip one stone around and still get repulsion, not attraction.I've tested them down to the minimum i can read - 10uT - on my flux density meter, but no reading is evident. I've probed them for resistance. They are conductive and exhibit variable resistance in the kilo to megaohm range depending on the probe position.But what is causing the repulsion? Are they somehow permanently electrically charged somewhere within such that the charge cannot dissipate?It's a mystery i tell you.

author: Gyro
author_rank: Super Contributor
timestamp: January 29, 2023, 12:34:43 pm
content: I can say that the electric charge theory has zero traction. Electrostatic forces are tiny for any safe voltage, even in multi kV electrostatic voltmeters. You say that the stones are conductive, any charge capable of attraction or repulsion would have to reside on the outer surfaces and would be instantly discharged when you touched them.I think this is probably one for the Dodgy Technology section.

author: xrunner
author_rank: Super Contributor
timestamp: January 29, 2023, 12:44:52 pm
content: Quote from: Quantumplate on January 29, 2023, 11:37:44 amLook at Kansas Pop Rocks -https://en.wikipedia.org/wiki/Concretion#Kansas_pop_rocksThey are real rocks, but mostly used for "metaphysical Healing". So ... yea.

author: Quantumplate
author_rank: Regular Contributor
timestamp: January 29, 2023, 02:54:02 pm
content: Quote from: Gyro on January 29, 2023, 12:34:43 pmHaha....thanks for ruling out the charge idea.Well, they seem to be magnetic MONOpoles then with no detectable field. Help!

author: TimFox
author_rank: Super Contributor
timestamp: January 29, 2023, 03:10:16 pm
content: I remember the fuss in 1973 about the discovery of magnetic monopoles in cosmic rays over Sioux City, Iowa.The theory (following Maxwell) that almost everyone on this site learned does not allow magnetic monopoles.Further analysis of the particle tracks in the polycarbonate medium in the balloon experiment determined that they were platinum nuclei.https://physicstoday.scitation.org/doi/10.1063/PT.3.3328covers the history of this and other experiments.(One office at my university put a 60 cm square of LexanTMwith its paper label in the glass window, offering monopoles for sale.)

author: BillyO
author_rank: Super Contributor
timestamp: January 29, 2023, 04:08:07 pm
content: Fill your bath, put them on Styrofoam floats close together, and see if they move apart.

author: Quantumplate
author_rank: Regular Contributor
timestamp: January 29, 2023, 04:39:30 pm
content: Quote from: BillyO on January 29, 2023, 04:08:07 pmDamn, i just tried but my bits of Styrofoam aren't big enough.
Bolyestad's Format methods for Nodes and Mesh Analysis - Page 1
Forum section: electronics / beginners

author: watchmaker
author_rank: Unknown
timestamp: December 22, 2023, 03:40:23 pm
content: These methods are pretty damned powerful. Helps me avoid conceptual confusion caused by overthinking.Maybe I am getting ahead of the course, but these seem to apply to I or V only source ckts. Is it possible to break ckts apart and analyze them separately and rejoin? (Leave out mutuals between Source types until the broken out ckts are reconciled?)Dewey
Book Lab files - Page 1
Forum section: electronics / beginners

author: CraigAB
author_rank: Contributor
timestamp: September 14, 2023, 11:20:23 pm
content: Hi,I own, for a long time now.- Computer Simulated Experiments for Electronic devices using Electronics Workbench. By Richard H Berube- Mastering Electronics Workbench By John AdamsBut I don't have the Lab files.I was wondering if anyone here had a copy of the Disks and the CDROM?Archive.org doesn't have them and the publisher's website doesn't either.Kind regards,Craig
Book recomendation - Page 1
Forum section: electronics / beginners

author: stafil
author_rank: Regular Contributor
timestamp: April 28, 2020, 05:45:11 pm
content: Hi!I have been enjoying Dave's fundamental Fridays videos and was wondering if someone can recommend a book that has all the major basic building blocks circuits.For example something that has the principles of operation of things like voltage regulators, buck-boost converters, window comparators, etc.. Mainly interested in analog circuits.

author: ggchab
author_rank: Frequent Contributor
timestamp: April 28, 2020, 06:51:04 pm
content: Of course, this is very subjective, but I find this book very interesting:"Learning the art of electronics, A Hands-On Lab Course" by Thomas C.Hayes with the assistance of Paul Horowitz

author: schmitt trigger
author_rank: Super Contributor
timestamp: April 28, 2020, 07:18:28 pm
content: Do you like Analog Circuits?If so,Troubleshooting Analog Circuits, by the late analog guru Bob A. Pease, written in the author's witty and colorful language, is a fascinating read. Some fascinating pictures, including one of Bob hurling a desktop computer from atop National Semi's building into the pavement below. With the caption:"I knew that computer would never lie to me again."Along a similar vein,Analog Circuit Design, Art, Science and Personalities, a collaboration of the who-is-who of analog design and edited by the late Jim Williams, is also a must read. Each chapter is written by a different author, and thus the writing style differs. But all chapters are incredibly authoritative, written by leaders and experts of the field.
Book recommendations for [high frequency] PCB layout? - Page 1
Forum section: electronics / beginners

author: ankeakala
author_rank: Contributor
timestamp: September 13, 2020, 09:43:15 am
content: What would be good books to learn about high frequency PCB design? Or an advanced book about PCB design and layout? Or any other source or reference? Not super super high but say 100MHz

author: David Hess
author_rank: Super Contributor
timestamp: September 13, 2020, 10:51:27 am
content: Howard Johnson's books are the first to come to mind - "High Speed Digital Design: A Handbook of Black Magic" and "High Speed Signal Propagation: Advanced Black Magic".

author: Benta
author_rank: Super Contributor
timestamp: September 13, 2020, 03:18:18 pm
content: ON Semiconductor "MECL System Design Handbook", chapters 3 and 7. No longer available onwww.onsemi.com, but can be downloaded for free here:https://www.tiffe.de/Robotron/Bausteinuebersicht/MECL/HB205-D.pdf

author: AndyC_772
author_rank: Super Contributor
timestamp: September 13, 2020, 04:56:15 pm
content: Lee Ritchey - "Right the First Time"https://speedingedge.com/products/right-first-time/

author: Zeyneb
author_rank: Regular Contributor
timestamp: September 13, 2020, 08:37:45 pm
content: Quote from: David Hess on September 13, 2020, 10:51:27 amI do think the first one: "High Speed Digital Design: A Handbook of Black Magic" is quite good. But it is a bit old, nevertheless there is much to learn from the basic principles. I also bought the second one "High Speed Signal Propagation: Advanced Black Magic" But to me it didn't add much. Missing practical guidelines and full of arrogant consultant humor.Another nicer book to learn these things is "Signal and Power Integrity-SIMPLIFIED" by Eric Bogatin.
Book to read before visiting EMC lab? - Page 1
Forum section: electronics / beginners

author: implor
author_rank: Regular Contributor
timestamp: February 14, 2021, 08:00:09 am
content: It there a good book about what is done in a EMC lab?Don't get me wrong, I most likely know 95% already and I have gone to a lab before.But like many ppl it's now years between visits and It would be nice with something as a refresher before a visit.Including:*Common standards*All test including the setups*Check list on what to bring(?)yes, I just get the EN 61000 standard and read them but would be nice with something less dry to read....Any suggestions?
Books and Textbook Recommendations  - Page 1
Forum section: electronics / beginners

author: Vincenzo
author_rank: Regular Contributor
timestamp: May 25, 2021, 07:56:00 am
content: Throughout my decades in electronics and as an EE undergrad and graduate student, knowing which book or textbook to use was a torturous process of research and trial & error that eventually led me to (in my opinion) the best collection of books that I enjoyed studying in the past and learned a great deal from and those that I still go back to right now. Let's share our favorites and make it easier for younger hobbyists and students to find the jewels.Here is a short list my favorite books that enjoyed and still have but rarely use now:
boolean algebra rules again - Page 1
Forum section: electronics / beginners

author: Simon
author_rank: Unknown
timestamp: May 24, 2014, 12:08:21 pm
content: So my BTEC L3 couse has an excersise I need to demonstrate with karnaugh maps the following:1) A+AxB = AWell A+A = Aso it's now AxB=AIs it is me or this cannot be because A AND B = A has nothing to do with the AND truth table and it will depend on B as well not just A.

author: electr_peter
author_rank: Unknown
timestamp: May 24, 2014, 12:24:16 pm
content: I suggest to change "+" --> "OR" and "*" --> "AND".A+AxB = A --> A OR (A AND B) = A. Now go from there.

author: Simon
author_rank: Unknown
timestamp: May 24, 2014, 12:28:54 pm
content: so I have to fulfill the AND operation first ?

author: electr_peter
author_rank: Unknown
timestamp: May 24, 2014, 12:43:35 pm
content: In this context, "AND" operation should be completed first, because it is same as "*" operation in first equation. "*"has higher priority than "+" operation and it implies brackets around A*B."AND" and "OR" are not the same as "*" and "+" in all contexts. Brackets "override" order of logical operations and make it easier to visualise.

author: Zero999
author_rank: Super Contributor
timestamp: May 24, 2014, 12:53:29 pm
content: Yes, AND has a higher precedence than OR, just like in normal algebra division and multiplication are performed before addition or subtraction.http://www.asic-world.com/digital/boolean1.htmlhttp://en.wikipedia.org/wiki/Logical_connective#Order_of_precedence

author: Simon
author_rank: Unknown
timestamp: May 24, 2014, 01:25:38 pm
content: yep something else the course material kindly forgot to mention
Boolean Algebra - Page 1
Forum section: electronics / beginners

author: Cujo
author_rank: Regular Contributor
timestamp: March 31, 2020, 09:32:21 am
content: Is the the correct simplification of Boolean algebra?

author: tggzzz
author_rank: Super Contributor
timestamp: March 31, 2020, 10:26:14 am
content: Your being in Australia makes it unnecessarily difficult for us to see your working. I suggest you turn the picture the right way up

author: radiogeek381
author_rank: Regular Contributor
timestamp: March 31, 2020, 12:03:06 pm
content: You ran into trouble on the second line.AB + A [NOT (B + C)] + B [NOT (B + C)]Is that what you started with?Then notice that things of the formNOT(X + Y)turn into (by DeMorgan's law)(NOT X) AND (NOT Y)andX AND (NOT X) AND (anything at all)disappears.That will get you a fair way along.

author: Cujo
author_rank: Regular Contributor
timestamp: March 31, 2020, 11:46:37 pm
content: I stared with the first line at the top.I thought the second line was right, I used DeMorgan's law: (The complement of sum = product of complements)

author: coolyota
author_rank: Contributor
timestamp: April 01, 2020, 12:17:34 am
content: Solved:
Boombox Radio Circuit confusion - Page 1
Forum section: electronics / beginners

author: Quantumplate
author_rank: Regular Contributor
timestamp: December 12, 2023, 08:37:05 pm
content: This is the front-end going into the mixer circuits of the Sanyo m9998. What's going on with Q103? It appears to need (i would have thought) a PNP here, not an NPN as shown, and the b/e/c voltages don't make sense either! Where's the base emitter 0.6v drop?No doubt it is correct on the diagram and i have some learning to do...Thanks

author: wasedadoc
author_rank: Super Contributor
timestamp: December 12, 2023, 08:44:59 pm
content: 2SC930 datasheet says itisNPN. I expect that if you look at the complete schematic you will find that the supply rail is negative with respect to the 0 volt (often confusingly called 'ground') rail. That would also explain why the drain of the FET goes via coil L107 to that 0 volt rail.Update: Follow the right hand end of R109 to the next page and see the polarity of C319 and C330 and D308 Zener. See the marking +B1 and E against connections 1 and 7 "To Amp".

author: Quantumplate
author_rank: Regular Contributor
timestamp: December 13, 2023, 11:57:13 am
content: Quote from: wasedadoc on December 12, 2023, 08:44:59 pmHi wasededoc, thanks, it makes sense now. What we both initially thought was the 0v rail is in fact at ~7.5v. I'm still puzzled with the base voltage on Q103, but then i see this connection goes to a switch (am/fm switchover), so possibly the e/b/c figures are for the transistor in the non-conducting state?
Boost-Buck Converters and a reference pin - Page 1
Forum section: electronics / beginners

author: roogadget
author_rank: Contributor
timestamp: October 06, 2018, 09:46:51 am
content: I have spent a great amount of time looking for a buck boost converter that outputs 12V.Turns out it requires an external reference of 5V for the PG pin.Do these regulators always require a reference?It seems odd to a beginner (me) that it would require an additional regulator just to use one.

author: aheid
author_rank: Regular Contributor
timestamp: October 06, 2018, 10:00:52 am
content: From the data sheet:QuoteSo seems to me that if you're not interested in low-power mode, you can just tie that pin to ground.

author: sd
author_rank: Unknown
timestamp: October 06, 2018, 11:34:23 am
content: PG 15 O DOutput power good pin. This pin is an open-drain pin. The status of the power-good output is goodwhen this pin is high (1) and has a failure when this pin is low (0)If you don't need PGOOD, just ignore that pin.

author: aheid
author_rank: Regular Contributor
timestamp: October 06, 2018, 10:17:26 pm
content: Quote from: sd on October 06, 2018, 11:34:23 amMan I need to learn to double-check things when posting before breakfast...
Boost converter cant handle loads below 80kohms - Page 1
Forum section: electronics / beginners

author: Dmeads
author_rank: Regular Contributor
timestamp: February 26, 2019, 07:52:28 pm
content: Hello! hope everyone's week is going well!I am trying to build boost converters to step up 5v to 20v to power an operational amplifier, and I have two questions.1.) the boost converter I built can only step up the voltage effectively when the load is above 80kohms, so I was wondering if anyone knows the supply impedence of an op amp? can you find this on the data sheet? I found input impedence but I want to know the supply impedence because if it is low, then my boost converter wont be able to power the op amp.2.) if the supply impedence on an op amp is low (<80kohms), then how could I re-design my boost converter to still provide the stepped up 20V to smaller loads?I have attached an LT spice simulation, but when i actually built the circuit I used an IRFZ34 N channel MOSFET instead of the FDS4410 in the simulation, but the build still worked fine. I used a 555 timer from TI to drive the mosfet which switched at about 500kHz but I can adjust it using a trimmer.thanks!

author: David Hess
author_rank: Super Contributor
timestamp: February 27, 2019, 01:21:54 am
content: Operational amplifiers do not have a supply impedance in any useful way. What they do have is a quiescent current which is continuously drawn between the positive and negative supply inputs which depends on supply voltage, temperature, and sometimes other things like common mode voltage and saturation condition. Further, the load on the output of the operational amplifier also contributes to the positive and negative supply currents depending on if the output is sourcing or sinking current.So in practice what you can do it look up or measure the operational amplifier's supply current at 20 volts, add the maximum load current, and decide whether your boost converter can provide it.Depending on how your boost converter is configured, it may be a good idea to add like a 24 volt zener diode across the supply to protect the operational amplifier from an over-voltage condition.

author: unitedatoms
author_rank: Frequent Contributor
timestamp: February 27, 2019, 01:44:28 am
content: You can choose PWM ratio to have as high voltage as you need. Try 2.5us/3us ratio, it will double the voltage comparing to 1.8us/3us ratio.It looks like the voltage ratio is more defined by PWM ratio than the impedance. However for accuracy, less dependency on load impedance and to lower output impedance of supply, practical circuits of DC-DC converters include feedbacks, references, etc.

author: Dmeads
author_rank: Regular Contributor
timestamp: February 27, 2019, 01:54:49 am
content: Awesome thanks peeps!
Boost converter circuit using MC34063 IC, what ground? - Page 1
Forum section: electronics / beginners

author: newtekuser
author_rank: Frequent Contributor
timestamp: October 29, 2023, 03:47:32 am
content: Hi All,I have picked up a MC34063 buck/boost converter, finished wiring almost everything up except the pins from the IC that go to ground, namely pin 4 and the gnd lead coming from C2 from pin 3. I do not know where they should goIs GND in this case the negative Vin- ?https://theorycircuit.com/boost-converter-circuit-using-mc34063-ic/Long story short, my Vin is +5v which is powering up my PIC and peripherals and I'd like to boost voltage so I can create a separate circuit to drive a 12V stepper motor.

author: schmitt trigger
author_rank: Super Contributor
timestamp: October 29, 2023, 04:16:45 am
content: It goes to Vin(-). Which is also common to Vout(-).Question for you; how much current do you intend to draw from the +12v supply?

author: Dan123456
author_rank: Regular Contributor
timestamp: October 29, 2023, 04:36:00 am
content: At a guess, I would say yes. Use the 5V-I usually assume that the Vcc/Vin and Ground of an IC should usually be linked (i.e. so pins 6 and 4 should be connected to the same source) unless the data sheet gives me a good reason to think otherwiseThat said, I’m still a noob using a rule of thumb that I have picked up along the way so could be wrongWill definitely be keeping an eye out for answers from more knowledgeable people as have a few of these IC’s too!One thing I did notice though, the inductor you are using is significantly smaller than the example in the data sheet (33uH vs 170uH). Not sure if you have done the calcs on that and is lower due to the lower output voltage but figured I’d mention it just in case

author: newtekuser
author_rank: Frequent Contributor
timestamp: October 29, 2023, 06:06:50 am
content: Quote from: Dan123456 on October 29, 2023, 04:36:00 amThe stepper motor I have draws 400mA and I do not intend to power anything else from the 12v coming from the boost convertor.

author: newtekuser
author_rank: Frequent Contributor
timestamp: October 29, 2023, 06:11:35 am
content: Quote from: Dan123456 on October 29, 2023, 04:36:00 amIndeed. The schematic from the article shows values for a 10v output. I do have the right R1 and R2 values to generate close to 12v but do not have an inductor larger than 33uH. Thanks for reminding me I need a bigger one
Boost Converter Duty Cycle and Constant Current Mode - Page 1
Forum section: electronics / beginners

author: bayjelly
author_rank: Regular Contributor
timestamp: May 19, 2019, 07:18:04 pm
content: Hello,I'm trying to verify my intuition about how boost converters work:Is it true that if I boost to at least twice the voltage (ignoring the diode drop for simplification), then if I want to stay in continuous current mode, I need a duty cycle of at least 50% (which would be the break even point, not really boosting)?My reasoning: When the switch is on (i.e. the inductor having a path to ground), the inductor has the input voltage across, defining the upward slope of the current. But with the switch in the off position, the voltage across the inductor is at least as high in magnitude (but reversed) as the input voltage, meaning the current's downward slope will be at least as steep. So if the total current difference during a cycle is not to be negative, we have to spend at least as much time in the upward slope as in the downward slope (to break even).So, for example with boost converters converting from 5V to 20V, I will always see duty cycles somewhere over 50%, no matter the load. Does that make sense?

author: bayjelly
author_rank: Regular Contributor
timestamp: May 19, 2019, 08:04:47 pm
content: Quote from: blueskull on May 19, 2019, 07:50:20 pmI misstated this part, actually. As per the title and earlier paragraph, I meant boost converters under the restriction to always keep them in continuous current mode, but overall my intuition seems confirmed. Thanks a lot for the thorough explanation!Now, I experimented a little with a self-made boost converter using an inductor that is tool small for the given load and voltage ratio, and have no trouble keeping my desired output voltage with closed loop controlling, using duty cycles way below 50%. Obviously, it's operating in DCM (and that's what I ultimately wanted to confirm), but now I'm wondering under what circumstances I need to care about DCM's disadvantages? If I'm happy with the lower efficiency and don't see too much ripple, is there anything else? EMI? (This is only a hobby project.)
Boost converter TLV61070A, can it handle input voltage on the output? - Page 1
Forum section: electronics / beginners

author: pasimasi2
author_rank: Newbie
timestamp: August 07, 2023, 08:21:16 am
content: I have used TLV61070A boost converter to increase li-ion voltage to a stable value of 5.5V. It works great but it consumes a bit too much, when I leave the EN-pin high all time. And if turning it off, the voltage to the output is cut off completely and my microcontroller cannot turn it back on anymore.So I had an idea: I could connect the input voltage directly to the output, and the microcontroller would be powered all times, even when the boost converter not active. and the microcontroller can then turn on the boost converter when needed to support the other circuitry and to give stable voltage for its own operation.here is the fuctional diagram of the tlv61070a. Is it ok to connect the input voltage to the output even when the IC is switching, does it affect the operation?EDIT: I realized it probably would not work since the boost converter would try to increase similarly the voltage of the input of the battery, which is probably not possible.How about if I add a separate diode for this input -> output connection, so that the current can only go that way, this should take care of this issue.

author: CountChocula
author_rank: Unknown
timestamp: August 07, 2023, 01:43:26 pm
content: Why not connect the µC directly to the battery? There is no need for it to share the output of the boost converter if it doesn't need it to run.

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 07, 2023, 01:50:08 pm
content: ^^This^^Sometimes the best solution is the simplest solution.If you still require to proceed with your suggestion, use a Schottky diode from input to the output. This will also help to have your output capacitors precharged for a faster turn on.

author: pasimasi2
author_rank: Newbie
timestamp: August 07, 2023, 05:42:23 pm
content: Thank you, the reason I cannot connect directly is the maximum voltage of 3.6V allowed for the uC.I need 5.5V for controlling MOSFETs efficiently and between the output of the boost converter and uCI have an LDO linear regulator 3.3V connected to the output of the boost converter providing safe voltage level for the uC.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 08, 2023, 08:59:05 am
content: RTFM?"When the input voltage is higher than the setting output voltage, the output voltage is higher than the targetregulation voltage. When the output voltage is 101% of the setting target voltage, the TLV61070A stopsswitching and fully turns on the high-side PMOS FET. The device works in pass-through mode."
Boost converter vs. Voltage regulator - Page 1
Forum section: electronics / beginners

author: retroplace
author_rank: Newbie
timestamp: February 23, 2021, 04:52:18 pm
content: Hello there,I am a total noob but want to learn more about electronics. My first little project: My KIM-1 (single board computer from 1976) needs 5 V and 12 Volt. I drags around .8 amps on the 5 V and about 0.2 Amps on the 12 V as far as I see.Now: I would like to create a little circuit that takes the 5 V from a USB charger (2 A) and feeds …… the five volts needed – this already works, well, nothing to do here, really… the 12 V (for the cassette interface)Now I saw there are those boost converters that cost close to nothing. And first I wanted to re-build one of those. But then I saw the specs of simple voltage regulators and now I am confused: Isn't a voltage regulator (12 V, 2 A) *exactly* what I want? So, instead of building a boost converter, I could just use ONE single part and be happy for the rest of my live?If that *is* the case: Why would someone use a boost converter instead to get from 5 to 12 V? Is it a question of efficiency?Any wisdom is highly appreciated.BTW – as we are at it: Can you recommend a great Beginner's Guide to electronics (maybe even with a focus on small PCB projects? I am a the "practical" type of learner. The more hands-on examples, the better. Again, any recommendation would be highly appreciated.Great to be here, btw. I have watched Dave's channel for years.Best,Armin

author: andybrandi
author_rank: Contributor
timestamp: February 23, 2021, 05:43:22 pm
content: The 12V regulator you saw presumably was a so-calledlinearvoltage regulator - those take a higher (DC) input voltage to produce a regulated, lower (DC) output voltage by simply "dropping" the excess voltage as heat. You could, for instance, use a 12V linear regulator to turn a 15V unregulated supply into a regulated 12V supply, but not the other way around, and even less so when starting from 5 volts.Turning a DC voltage into a higher DC voltage is a little more complicated. Boost converters usually use inductors and switching components to generate a higher (boosted) voltage.
boost converter with current limiter - Page 1
Forum section: electronics / beginners

author: mechorican
author_rank: Newbie
timestamp: November 19, 2023, 12:00:55 pm
content: Hi,I'm looking for a boost converter with the following specifications:Vin: 24VVout 40V - 42Vadjustable output current limit(200mA - 250mA)Can somebody help me with a suggestion? Thank you very much.

author: Zero999
author_rank: Super Contributor
timestamp: November 19, 2023, 02:03:42 pm
content: What's it for?The current limit won't work if the output voltage falls below the input voltage, because the output is always connected to the input, via a forward biased diode and inductor.https://en.wikipedia.org/wiki/Boost_converter?useskin=vectorIf it's for over-current protection, a fuse is the only way.If it's to power LEDs, then the forward voltage must always be greater than the maximum input voltage.Use a different topology, (flyback transformer, SEPIC, buck-boost etc.) for current limiting, at output voltages lower, than the input voltage.

author: Konkedout
author_rank: Frequent Contributor
timestamp: November 20, 2023, 12:05:19 am
content: The boost converter can limit current at the boosted voltage, but by itself it cannot limit current once Vout falls below Vin. There are a number of ways to do that but it takes added hardware such as another series FET which "open circuits" when the current limit is exceeded.I think there are some ICs out there which offer that functionality....look at Tea Eye.
Boost feedback resistor - Page 1
Forum section: electronics / beginners

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: May 21, 2019, 07:36:53 am
content: How much current do the feedback voltage divider resistors need to conduct to allow this boost IC to work properly?Seems only ~50nA max is required.https://datasheet.lcsc.com/szlcsc/XI-AN-Aerosemi-Tech-MT3608_C84817.pdf

author: pwlps
author_rank: Frequent Contributor
timestamp: May 21, 2019, 10:34:46 am
content: Typically it is recommended to have a divider current at least 100 times larger than the feedback input leakage current.You might look at §8.2.2.2 inhttps://www.ti.com/lit/ds/symlink/tps61372.pdf

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: May 21, 2019, 12:00:42 pm
content: Datasheet only listsSW Leakagenothing about input leakage current.

author: pwlps
author_rank: Frequent Contributor
timestamp: May 21, 2019, 12:34:38 pm
content: Quote from: LaserTazerPhaser on May 21, 2019, 12:00:42 pmI wanted to say input bias current which is probably the right terminology here. But in some docs it was called input leakage current. Anyway there is only one "input current" going into the FB pin, whatever they call it.

author: David Hess
author_rank: Super Contributor
timestamp: May 21, 2019, 09:57:54 pm
content: The feedback voltage could be as far off as +/-0.012 volts so the feedback parallel resistance should not be any higher than the worst case voltage error of 0.012 volts divided by the worst case input bias current of 50 nanoamps or 240 kilohms to double the error.In practice, it will be much lower than this and typically the AC impedance at the feedback pin needs to be low anyway to prevent capacitive coupling into it from preventing proper operation.
Boost LED Driver for short impulses - Page 1
Forum section: electronics / beginners

author: Sp4
author_rank: Contributor
timestamp: September 02, 2020, 03:04:48 am
content: Hi AllI have a need to build a device, producing short (10-200 msec) impulses of UVC LED, powered from 5V power bank or 18650 rechargeable battery. I see some good topics around, but can't really find how they would behave with short pulses. Will I be able to achieve the stable timing or I will be better of with just regular dc/dc boost and the transistor key?I am planning to use this LED: XBT-3535-UV-A130-CC275-01 (Current - DC Forward (If) (Max) = 800mA, Voltage - Forward (Vf) (Typ) = 6.5V). I am going to drive it with 700mA. The timing circuit will be defined by ATMega328 which will have some display and timing selection.To make it work from 18650 or USB Power bank, I need to pick the driver, but don't really have an experience with Boost LED drivers, so need some help with it.Thanks in advance.
boost range on garage door opener receiver - Page 1
Forum section: electronics / beginners

author: richard295
author_rank: Newbie
timestamp: January 10, 2015, 02:05:32 am
content: garage door remote operates on 310mhz. Stanley secure code Antenna from garage door opener control is a small 9" wire hanging down. probably 22 gauge or lessHow can I boost the range of this opener. Do I add some kind of antenna or extend the wire? Anything I can use?

author: steve_w
author_rank: Regular Contributor
timestamp: January 10, 2015, 02:09:32 am
content: Richard,Without a lot more detail it not possible to give an answer, but its probably not worth the effort unless you are after a learning experience or you really love playing with stuff.regardsSteve W

author: Psi
author_rank: Super Contributor
timestamp: January 10, 2015, 03:01:56 am
content: Make a 310mhz yagi, connect it to the control box instead of the wire and point it towards the door.This will reduce range in all the directions you don't need and boost range it in the direction that you want.

author: zapta
author_rank: Super Contributor
timestamp: January 10, 2015, 05:55:28 am
content: Quote from: richard295 on January 10, 2015, 02:05:32 amThat's what I did, added long wire. Don't know what the frequency of mine.

author: SeanB
author_rank: Super Contributor
timestamp: January 10, 2015, 06:48:28 am
content: The wire is designed to be a rough quarter wave antenna. Better results are obtainable using a short coax cable to extend it ( solder core to the antenna point and shield to the board ground plane next to there) to a better antenna. A dipole at the end using the same length as the original connected to shield and centre will improve things, or you can get an antenna for those receivers that improves things.Just note though that too much signal is no good, as the receiver is a superhet design, and too much signal will stop it working. Best is to just move the receiver out of the motor unit and mount it near the door on a non metallic wall. It likely is a single black box with 3 wires connecting it.
Boost Up Converter Dropping voltage? - Page 1
Forum section: electronics / beginners

author: SirAlucard
author_rank: Regular Contributor
timestamp: May 23, 2018, 11:14:44 pm
content: Hey guys. So today I got in my 3in1 DC/DC Boost/Protection/Charger board to install into my DSO150.Specifically this one.I'm having an issue however that it seems to drop the 9v step up to about 5v briefly causing my DSO150 to restart. Now besides a possible bad battery, which is completely plausible. Is there anything else I can take a look at or can test?

author: JS
author_rank: Frequent Contributor
timestamp: May 23, 2018, 11:30:39 pm
content: Can you test how much juice is your thing sinking?High peak current might explain the issue, other option is just to add some capacitance at the output and test again to see if it solves the problem.JS

author: SirAlucard
author_rank: Regular Contributor
timestamp: May 24, 2018, 04:45:31 am
content: Yea I was thinking of adding a cap on the output, or maybe on the battery? I'm going to have to figure out how much power the DSO150 is drawing, however it shouldn't draw more than 250mA and this board is good for 400mA. However I'll end up checking tomorrow to see if that may be it.