Welcome to /r/ElectricalEngineering!

Hi y'all, I'm a first year EE student and I'm really excited and passionate about it especially because I just found a big lot of EE equipment for free on facebook marketplace that I've been learning all about. I've learned most of the circuit analysis stuff from practical electronics for inventors, all about circuits, khan academy, etc. but the issue is that I've been trying to learn EE on my own from textbooks and forums/datasheets online but asking questions to chatGPT once I'm confused only gets me so far, as I'm starting to get into stuff that's a little niche and tough to understand when it comes to designing and working on this project I have. I've been learning and doing some notes for a few weeks not but I'm not in any EE classes yet nor do I know any students learning or professors teaching EE at my college so I feel like I may be easily misunderstanding basic concepts that other people already know about.

I've been trying to make a variable voltage switch mode power supply from (kinda) scratch with a 19.5v 10.26a laptop DC power supply using a switching buck converter and some rotary encoders as knobs for current limit and voltage from 0-15V and 0-3A without using any dedicated gate driver, buck converter, or other specialized ICs (because I don't have them) but I've been having trouble finalizing the design as I might be going in a different direction than what I should be doing to learn.

I'm not sure whether learning theory and application analytically by taking notes on each configuration and usage of op amps, transistors, etc. for things like error amplifiers and filters by going through textbooks page by page is worth it (as I was doing for a while, but has the downside of me not learning everything about how real vs. non-ideal electronic components work) or if I should be going trial and error as I see problems in my circuit design, then learning through the rabbit holes those take me (which I have been doing and has been seeing progress but takes a lot of time and patience for a small amount of progression) or if there's some other way to learn that I haven't considered yet.

The reason I wanna do this project in particular is because I don't have a power supply to test components yet, and once I have one I could attach a circuit to it to make a waveform generator, but as of now I've had to just go from my multimeter and datasheets to try and discern specs and limitations. I also like the challenge of it and I don't wanna cheat with a gate driver IC or anything because I think it would be valuable for me to learn conceptually what every part of the power supply does and what things to consider in real circuit design.

My main questions are:

1. Is this project even plausible? I see a lot of power supply projects online that only use linear regulators but I feel like that's not applicable in my case because of the large amount of power dissipated by the regulator so I want to make a switch-mode buck converter for it.

2. I've been considering whether a synchronous buck would be worth the extra effort with the extra MOSFET for CCM and better power transfer vs. an asynchronous buck, because driving just one P-channel MOSFET at 100kHZ with 13v level-shifted gate voltage from a 3.3v PWM output has brought up a whole load of challenges like trying to learn how a bootstrap circuit works and how I can use it without an optocoupler, so how I would synchronize the dead time correctly with the low-side MOSFET might be a pain compared to just using a Schottky Diode.

3. Trying to figure out how to implement a variable current limiter circuit and/or overcurrent protection in with the variable voltage has been a pain, thus I wonder exactly how a commercial variable voltage variable current bench power supply works to vary both of those and I haven't got many good results online for schematics or anything.

4. I've neglected simulating my circuit designs because my components are a little older and I can't find most of them on the LTspice libraries, so it doesn't seem worth it to sacrifice accuracy at the risk of extra wasted time messing around with things, but is there some other way? A lot of people on forums online use simulations and I wonder if it would be worth it and if I can upload obsolete components onto the library somehow.

5. I'm sure this is simply a theory ignorance question, but I'm completely lost on how engineers online come up with filter capacitor values and types for input, output, and between components and signals, it just seems like they choose an arbitrary capacitance. Similarly to this when a voltage divider is chosen, the resistor ratio is always the same but resistances can change quite a bit, so choosing between say 1ohm and 5ohm vs 1kohm and 5kohm I feel like should be a more difficult choice than it seems to be, because I never see any resistances for voltage dividers other than between around 1k and 10k ohms and I wonder if this has to do with it being a sweet spot of current diversion, or some reason that I'm neglecting.

Thanks :D

Hello, I’m 25 years old, I played college football and earned a degree in general studies. The last three years I have been an intern high school teacher and football coach in Kansas. I do not want to get a teaching degree, and I am looking to change my career path. I’m interested in becoming an electrician, but not sure where to start.

I know a lot of companies have apprenticeship opportunities in this field, but not sure what option is best suited for me. I know the three big areas are residential, commercial, or lineman, but not really sure what these have to offer.

I’m really looking for an opportunity to grow and have the opportunity to earn my journeyman‘s license. To be honest, not really sure what that will take or what that does for you, just have read that’s what most electricians strive for.

Any help would be awesome, I also know union versus non-union is a big debate as well. Thanks.

Hey! I’m looking to get into EE but I really want a 9-5 schedule. My big girl jobs have all been 6am with one project being a temp 7am situation. I’m tired of waking up at 4-5am for work and really want to be able to wake at a normal human time of 7-8 for work.

I just keep getting a bunch of answers around weekly hours and not actual start times, so can I find a 9-5 pretty easy? I thought it was normal but every job I’ve had has been before 7am unless it was restaurant/retail.

I’m considering getting a bachelors in electrical engineering, I am already familiar with a lot of the basic concepts from small projects and poking my nose into things from a young age.

However I was having a hard time finding information about what a career path looks like a while down the road 40-50 to retirement. Will you start to specialize in a specific regiment like RF or communications? Do salaries naturally go up? Will companies pay more for your larger experience, or do most switch into project management or supervisory jobs instead?

Thanks.

https://preview.redd.it/5kxeam5a7b5e1.png?width=877&format=png&auto=webp&s=422e290b2e94842c1022e2b798fd084d10ca2fd4

Assuming the light intensity received by the LDR is reliably constant (I was assigned blue), how do I make it so that the green LED only turns on when that certain light is detected? Do I really just need to play around with the potentiometer? How, then, do I make it so it's just an instant switch and not gradual like my current setup does now?

I'm a college student and for the life of me I can't understand how to find these values in a DC RLC circuit.

iL(0-) , iL(0), iL(infinity) vL(0-), vL(0),vL (infinity)

iC(0-), iC(0), iC(infinity) vC(0-),vC(0),vC(infinity)

So, I'm interested in pursuing a career in the electrical engineering field and I'm wondering: what are some things you guys wish you knew before college/you're first EE job? (like knowledge, experiences, challenges, rewards, etc.)

A more specific question, how much/what type of math do you see commonly used? I don't suck at math but I'm no math-wiz either, I'd rather be prepared than behind tho

Thank youuu

So far, the only job offer I have is for an “Industrial Controls Programmer” position. I don’t really want to go into programming, but for the people who have, how do you like it?

View Poll

I wanted to do a project on the said topic.I was wondering how i could estimate the required torque for different inclination scenarios given it is just a prototype and uses BLDC motors

https://preview.redd.it/4zdfwt0gja5e1.jpg?width=1920&format=pjpg&auto=webp&s=4b8f87d593935078cd810bf3e01eac77df277529

I’m doing some work that requires me to have a really solid understanding of the electrodynamics of 3-phase BLDC motors.

My question is around the Torque-Speed curve is a Wye wound motor . My understanding is that there are a few linked motor constants (Ke, Kv, Kt) that are very useful for defining a motor.

My assumptions/understanding:

Ke is the Back-EMF the motor coils produce per unit rotational speed of the permanent magnet array

Kv is the speed a motor attains per unit Voltage applied across it’s coils (assuming the applied electric field is perfectly sinusoidal and in-phase with the rotational speed of the permanent magnet rotor, and also ignoring friction)

Kt is the moment produced by the motor per unit current that passes through its coils (I know this is dimensionally equivalent to Ke, but the realistic Kt must depend on friction and drag, right?)

So does this mean, that if I have Ke, and the coil/phase resistance, that if I ignore friction, I can construct a torque-speed curve for a frictionless motor? And every point on the curve is defined by the resultant voltage -> current in the system after the difference in Voltage due to BEMF is accounted for?

I.e, if I spin a wye-wound BLDC at a known speed, and measure the peak V between any phase and the neutral point, I should be able to get the Ke, and then if I measure the resistance across two phases, divide by two, I should get the phase resistance, calculate the phase Ke, and that should be numerically equivalent to the phase Kt.

So with just this information, (Kt, and phase R) can I predict the expected speed and torque relationship at a given applied Voltage?

This seems a bit simplistic to me, and I’m worried I’m missing something here?

Extremely new to PCB design and robotics but please bear with me

Im trying to make a PCB for a 6DOF arm that takes in the encoder and limit switch values (using separate motor controllers) and I originally wanted to use an SPI bus, but realized that one of the encoder only has SSI.

Is there a way to convert SSI into SPI? I was planning on making a breakout board and using the STM NUCLEO-F042K6 because I need to convert everything into CAN. Or would it be easier to just use SSI, if that’s the case the NUCLEO only has SPI so I would have to figure out a different approach

Any advice would be greatly appreciated!

Encoders: Broadcom AEAT-6012-A06 RLS Orbis BRD01

I recently asked about using body heat to power a small device or charge a battery so when it depletes, it does not need to be plugged in and I got a good number of answers that made me understand more so thank you for that.

i recognize using body heat is quite inefficient and maybe could not give enough power so I went down a semi rabbit hole and am learning about RF harvesting to power the same small devices from ambient RF signals. I saw a video of someone trying this and he got like 1V from I think 7 hours of letting it run. I also seen the e-peas AEM chips that can help with energy management from solar, thermal or RF sources.

so my question is could one use a combo of the three ambient signals to continuously charge a battery for a data sensor or even smart watch? Could the three together be enough? I’ve seen that there’s a company doing this pending patent called tahkine technologies. I wanted to hear opinions from more experienced people tho as I am still a college student and just thought of this randomly.

Thank you. Also will appreciate any nudges or pointers of where to learn more or research it

Has anybody else been running into issues with AdvancedPCB recently? I recommended them to my colleague and they apparently dropped the ball on her project, a simple board fab and assembly that is now several weeks late. They have been unresponsive to my requests for updates and an explanation. Also, the last few times I tried to use freeDFM i never received a response. That seems strange for an automated system... It's possible we are being ignored because of the size of the project or the low cost of the project, but I'm really surprised at how this has been handled by APCT.

(Newb)

I'm having issues with a small Li-Ion device (a flashlight). The light is a tube containing the battery, with a threaded end that receives a small round board with a switch on it, subsequently receiving a threaded cap that sandwiches the board into the tube under compression. The cap is torqued hard into place, and loctite is used to prevent it from backing out.

The problem: The power briefly drops out at random times when it sustains impact forces. The power drop lasts fractions of a second, like switch bounce. It seems to get worse over weeks/months until it becomes unusable. I'm having a very difficult time diagnosing the problem because when I remove the parts, I can't find any issues; visually or with a meter. When I reinstall the board, the issue appears resolved, temporarily, before ultimately reverting to a bad state.

Could this be some kind of oxidation layer building up between the aluminum and the pads on the board? (The pads are tinned, not gold). If so, would dielectric grease or conductive grease fix the problem? The only other thing I can think of is that the switch itself has a limited life and is failing, but that doesn't explain the un/re-install fix, so I'm inclined to think that the switch is fine.

I'm looking for knowledge. What do I need to know in order to make sure the connectivity in the chassis is reliable? I'm also considering nickel plating on the aluminum and gold pads on the board...

Thanks.

How do you find the frequency in your home ?

The reason I am asking here is in my country we do not have electrical engineering as in general electrical engineering. I have to specialize in something and this happens to be the closest to my interests. Also ignore the fact that it is 5 years that's the norm in my country for engineering.

I recently transitioned into an ECE masters from a CS undergrad. I had this notion from friends and others that RF is a niche field, and that though theres usually few position openings, there’s even fewer engineers that specialize in rf.

However, perusing the subreddit (and applying a bit for some internships), it seems that rf being in demand isn’t exactly true. Or is it?

What kind of competition as well as career track can I expect as someone starting completely fresh in EE with an interest in rf based in US? It seems the line between an electrical engineer and an “electrician” (more or less) is a really slippery slope, and any warnings, advice, or realistic 2-cents on how this industry is right now is greatly appreciated.

Sidenote: part of the rf interest is done in self preservation. I am under the impression if I work in power electronics there’s a slim but higher than rf chance that I may work in some power substation and get electrocuted with a few thousand volts. Are there any other practical decisions of certain parts of EE that isn’t really written on paper but kind of life altering

First of all, I think this question does not violate the rules, but if it does, delete away!

So, we've moved into our newly built house. There are 2 heat pumps that provide heating/cooling. Recently I found that when I plug my (old) PC 5.1 speakers, the subwoofer starts buzzing whenever any of the pumps starts working - if any of the fans is spinning, the subwoofer is buzzing.

It's an older speaker setup, Creative Gigaworks from like 15 years ago. The buzzing comes on when the main switch on the subwoofer is turned on - even if the satellites are disconnected. Also the buzzing sound is not audible through the satellites at all, it all comes from the subwoofer.

Here is a short history of what I've tried and any results:

- The speakers did have an issue (with some of the capacitors) years back, it turned out it was common for this model, and it has been fixed.

- The buzzing sound is very similar to what you would hear when there's a grounding issue - I've had this checked, everything is properly grounded.

- I've also tried this speaker set in other places where I know there are no grounding issues (no buzz from the same speakers), and also tried different speaker sets here (the same buzz).

- I have a neighbor who REALLY knows about electricity and stuff, and he said that there's a bunch of issues with the electricity supply in our particular area - uneven voltage that could actually damage appliances (this is EU, so we use 220-230V), also there are frequent short interruptions almost daily, and also this area is right now getting more and more populated, after being uninteresting agricultural countryside forever - there's a lot of construction going on everywhere.

- I've tried the same speakers in the electricity-informed neighbor's house, same thing. HIS speakers are much much MUCH more expensive than mine, and his whole sound system is absurdly awesome, and while completely inaudible at listening volumes, the same buzzing is still there. (so yes, option 1 - better speakers, I get that)

- Same guy actually started building a filter of some sort for me that could theoretically help with this buzz, not done yet, but probably soon.

So, any ideas or pointers or whatever?

While I can afford new speakers, I'd love to keep those if possible, they sound great. Also, while I know new and expensive stuff usually works better, those speakers, even if old now, weren't really cheap or low quality, and newer stuff still buzzes here. Also actually buying and returning stuff isn't that easy, so I don't feel like buying and trying a bunch of speakers.

I don't expect the filter idea idea to work well, if at all, and I don't expect the electricity company to change anything in their network until absolutely forced to do so.

Could/would it work if I get some sort of cheap UPS and connect the speakers to it? There's no buzz with battery powered speakers (tried and tested), so would the UPS work like that? It is continuously powered from the grid, but then supplies battery electricity to the speakers?

If you've read this far, you already know that I don't understand jack about shit when it comes to electricity, so please dumb it down as much as possible.

Telecommunications degree over here; in College I worked mostly with Multisim and Proteus; and actually and working as presales for Fiber equipment and RF applications.
I really liked the Circuit design doing my major; but I know that Proteus/Multisim does not look very professional to show to my clients; I am looking to get into another design software to make electrical solutions to problems; so I get to look another software as Eagle, but I found that are or too expensive or too complicated to work.
Recently I am looking the new steam game/simulator as Crumbs, and even some people in this sub are using it; so I was thinking in paying it and using in a professional level; but I don`t know how the software behave more that putting some resistors and less to make low level projects; they have a good integration to controllers as PIC or Arduino? how is the file export? or it have some tools to export as plains?
I would look into your comments and suggestion about this move I am making here.

Hello Community,

I’m struggling to understand how these circuits work. Specifically, I’m having trouble figuring out how to determine I1​, I2​, and Uq​. My main issue is this: if I simplify the circuit (for example, combining R2​ and R3 in series to get R23​), I’m unsure what happens to the currents. I2​ flows through R2​, and I1I flows through R1​, but when I simplify the circuit (as shown in the second picture), what happens to the current? Does the total current become I=I1+I2I, or is something else happening? I would really appreciate your help in understanding this issue, as I need to figure out how to reach the solution to this problem.

1/2

2/2

In a simple opamp integrator circuit, why is there an offset in the output? Is it because the capacitor might have some initial charge stored inside of it? Or is it something else that I'm missing?

The way I understand it is that all the keyboard buttons are attached to the inputs of logic gates, and when a button is pressed the logic gate is turned on and it sends a signal to the led in the screen which makes it light up in the form of a letter or symbol corresponding to the keyboard button that was pressed.

Hello guys,

I switched to EE from SE in third year because I realised I did not like doing coding all the time although I do like it I want to work with hardware too.

I am not good at math and I am also physically weak so this is my only option for being able to provide for myself as I cannot handle physical labour and do not have the funds to be able to switch to another course so I’ll be going hungry if I fail.

I did pass normal engineering mathematics barely as I was doing SE before but it was 50 something percent as my mark and so I now that I switched I need to somehow revise everything and do advanced engineering mathematics too on top. Is there anything you guys can tell me to help so I can pass this and be able to provide for myself with a job, like any resources online or anything you guys did to get good at the maths, I also need to learn the basic hardware components again as well.

Thanks.