/r/ElectricalEngineering

Photograph via snooOG

A place to ask questions, discuss topics and share projects related to Electrical Engineering.

A place to ask questions, discuss topics and share projects related to Electrical Engineering.

Rules

1.Be Respectful

Be respectful of others opinions. Intelligently explain why they are wrong, don't just say they're an "idiot".

2.No Advertising

No advertising of products, services or personal websites/blogs. Some exceptions can me made for personal websites and blogs for things such as scholarly research papers and reports.

3.Limit the Memes

A sprinkle of funny posts help keep the sub from becoming stale. However, if we see off topic, an influx and/or multiple posts (more than one a day) from a single user, they will be removed at the moderators discretion.

4.We won't do your homework

We will not do your homework for you. If you'd like help with an assignment, feel free to post the question along with your progress so far and specific questions that you have. Generic "Please solve this problem" posts will be removed.

5.No Consumer Product Tech Support Questions

No tech support questions on consumer products, unless it is truly an engineering problem. /r/gadgets is a better place for non-engineering problems.

6.No Building Electrical Posts

Posts about building electrical (residential or industrial) as well as electrical grid systems should be taken to /r/electricians.

7.No General Education Posts

Posts related to education that are not specifically EE should be taken to /r/EngineeringStudents.


If you find a post violating one of these rules please report it so the mods can review it ASAP.

Resources

Submit your favorites here!

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/r/ElectricalEngineering

221,057 Subscribers

1

Pecan Street Demand Response

Hi. Does anyone here has worked with Pecan Street Data. It is used in demand response programs and contains large scale data of user electricity demand. I can only access a limited amount of it from my university website. But i want data of at least 2 years (2015 and 2016). Can anyone help in this regard. Bundle of thanks

0 Comments
2024/06/14
09:49 UTC

1

elevator specs

Do you know any brand that offers passenger elevator car with a power supply 230 VAC of 3 phase? I just needed to know its power value/output.

thank you.

2 Comments
2024/06/14
09:21 UTC

2

Choosing my specialty for 3rd year of uni

Hello, it is time for us to choose specialties for the following 3rd and 4th year of university.

We can choose from:
Applied Electronics and Smart Systems
Microelectronics, Optoelectronics and Nanotech
Technologies and Telecommunication Systems

My question isn't really what should I choose, but more which job or field of real life each one tackles.
On a separate note, I really enjoyed the stuff about Signal Modulation (AM, FM, PM), I imagine this has to do more with telecom systems?

0 Comments
2024/06/14
07:47 UTC

1

Per unit of Time-Derivatives

Hi peeps,

im having struggle understanding the conversion of a time derivative in the per unit system. So lets say i have the equation of voltage over an inductance. So why does a conversion of L*((d*i)/(d*t)) in (1/w_b)*L_pu*((d*i_pu)/(d*t)). I dont really understand the process beuind it.

Thanks in advance for the help :)

0 Comments
2024/06/14
07:43 UTC

1

UCSB or UCI for EE Undergrad?

I already committed to ucsb for electrical engineering and recently got off the waitlist at uci. I got the same financial aid, so price wouldn’t be a factor. I like the ucsb campus vibe more but I think uci has better engineering and job opportunities? Right now I’m leaning more towards ucsb because I’m not sure if uci is even that much better.

0 Comments
2024/06/14
07:31 UTC

1

Study Partner

I finished my undergrad in Electrical Engineering in Spring 2024. Since I’m a 4+1 student, I am planning to start my masters in Fall 2024. I need to revise the following subjects from undergrad during the summer:

  • Digital Design
  • Analog Circuits
  • Electronic Materials

I am looking for study partners. Is anyone interested in joining me in these review sessions?

0 Comments
2024/06/14
06:58 UTC

2

Curious about options for jobs related to EE that I can get as a student? (E.g. if I was ME I would probably work as a cnc machinist)

0 Comments
2024/06/14
06:10 UTC

1

Advanced switching converter material?

I've got a ton of books about SMPS design and control. All the Christophe Basso books, the Erickson textbook, and a couple others. None of them go deep into the more advanced things that have been hot topics for higher transient performance like TLVR or multiphase topologies. Can anyone recommend material that covers the newer topologies?

I'm also interested in bidirectional topologies for battery applications like solar or EV.

0 Comments
2024/06/14
05:42 UTC

1

Conversion of a time-derivative in per unit system

0 Comments
2024/06/14
05:14 UTC

1

USB 3.2 Gen 1 front panel I/O wiring?

I’m looking into designing a PCB for usb ports for front panel connections on a custom computer case. Can I just wire up the matching pins, or do I need something fancy like a ground plane? I don’t know if the motherboard will handle everything and from then on everything is basically an extension cable or if I need to handle things like EMI. I do know I need the traces to have a 90 ohm impedance to prevent ground bouncing to maintain signal integrity. Anything helps, I’m new to circuitry but understand basic principles.

0 Comments
2024/06/14
03:39 UTC

1

Custom controller

Im not sure where to post this, and if this isn't the right spot can someone point me in the right direction? But anyway, I wanted to take the guts out of an Xbox one s controller, and put it in a smaller 3d printed shell, to make it more portable. And I wanted to use an old 3ds battery (8 think it's 3.7v 1500 or 1750mah) with an 18650 protection circuit, I was wondering if that would work to power the controller. Also I wanted to replace the joysticks with the ones for the switch, and for the stick clicks, those joycons short the button with gnd, and I also wanted to know if that would work.

Edit: also for the triggers I might want to move them to somewhere else on the shell, so could I solder a hall effect sensor to pins on the PCB?

0 Comments
2024/06/14
02:08 UTC

31

Completely lost

I landed my first engineering job out of college, I’ve always been told that the B.S. degree really stands for BullShit because you don’t really know anything. They weren’t lying, I feel like a total noob in this field (power conversions). I don’t know what is going on, I don’t know the terms they’re using, I don’t know how to do the tasks they gave me, I feel like I should just go do something else. I’m a full 2 weeks in and I know that “it’ll come” but man, I really feel so lost in this position. I can’t believe I’m getting paid for it lmao.

I’ve felt like this with every internship too and within 2-3 months I’m good to go but I hate the new job process. I was so comfortable at my last internship and they couldn’t offer me a spot and it blew.

Any advice from people who recently got over the “idk what is going on at all” hump?

11 Comments
2024/06/14
01:53 UTC

3

Interviewing for a PLC engineer next week. Any Tips?

Was thinking of bringing a digital multimeter and small "teaker" screw driver to show I'm ready to go. Is that a dork move?

12 Comments
2024/06/14
01:28 UTC

2

IEEE membership does not allow free access to IEEE transactions and journals in IEE Explore?

Hi guys, i m wanting to become an IEEE member but upon my inquiry with IEEE I was informed that whilst i do have access to the IEEE transactions and papers, the access is not free and i still have to pay for them, albeit at reduced prices.

In my previous job, our company has unlimited access to IEEE transactions and papers. Is there a way i can get unlimited access as well? Is this another grade of membership i am not aware of?

Any feedback please.

1 Comment
2024/06/14
00:44 UTC

32

Making circuits as compact as possible

I've been trying to make my circuits as compact as possible. I figured connections would be more stable that way, and everything would look neater.

But I think I'm not benefiting from that. In fact, it just makes it harder to change the position of the components. Also, my enclosure is still bigger than my circuits, so it's not like I need more space.

I think even in production, no one makes the circuits as compact as possible? Unless size is a feature of the product?

17 Comments
2024/06/14
00:13 UTC

5

Struggling on Chemistry class in college

As the title, the chemistry required for my EE major is really hard. Just because I don't have prior knowledge on chemistry. Even EE only needs to take only one General Chem class, unlike Materials or MechE requires a second Chem.

I know I have the passion on EE, math is my thing, physics like EMag is my thing. However, I just can't withstand on chemistry. Are there any tips for chemistry? I felt stupid because a lot of prominent EE/Physicists also have a Chemistry background.

8 Comments
2024/06/13
23:56 UTC

1

How do I wire up these rocker switches without burning down my film set?

I'm working on some set design for a short sci-fi film, and I've run into an issue.

I've bought a bunch of these illuminated rocker switches that I want to install in the control panel of our spaceship. They're not going to have any function, but I do want them to light up when they're switched on.

I've got some experience working with smaller electronics connected to arduinos, but these require a whole lot more power to light up, and I'm intimidated by the task - since I don't wanna electrocute myself or burn down our set.

Do you guys have some tips on how I can safely wire these up and what I need to power them? And what do I definitely NOT wanna do?

My workshop runs 230V since I'm in Denmark. I'm comfortable soldering, but I don't have an adjustable power supply.

I hope this is something you can help me with, and feel free to ask for any necessary extra information.

This is the rocker switch. It's got a 220K ohm resistor on the LED inside.

1 Comment
2024/06/13
23:49 UTC

1

So im building an internship project

Does anyone know of any i/o link electric motors? The whole point of the project is to use i/o link compatible components but i would like to add a motor but cannot find any i/o link electric motors?

0 Comments
2024/06/13
18:39 UTC

0

Any schlumberger or Halliburton enterprise up to at Vung tau , I am up to oil gas russia

0 Comments
2024/06/13
23:17 UTC

1

Extremely underpaid for 4+ years with chance to make a big case for large pay increase. Advice?

I started out as an intern with a company in the Midwest while getting my undergrad, and eventually got an offer for 62k as an entry level EE1, which I accepted. I knew this was alittle low but I was very happy with the work I would continuing to be doing and the people managing me. They also made an open rec. for me as they didn’t have an open position full time while I was an intern.

Upon getting promoted to EE2 in 2022 I got a 15% increase which also included my yearly merit which would have been 5% anyways (meaning I really only got a 10% for the promotion).

My last 2 yearly reviews I have exceeded expectations and I was old I was approved for an EE3 in confidence from my manager last spring but it was put on hold due to a company wide restructuring of positions and will get it in fall this year.

In 4 years time I will have went from EE1 to EE3. I think that speaks to my performance pretty well. Not to mention I was technically approved for EE3 last year. I have made lower than the 10th percentile salary range my entire career based on Glassdoor, and Salary.com. My peers who work at different companies in the same area with the same amount of experience make more than I do while they have lower job titles because I have been getting promoted a lot since I have started.

Upon my promotion in fall I plan to bring this all up and ask for a few bucks higher than median pay which is 115k with the intent to let them know I will start looking elsewhere if we cannot come to an agreement on this. My case for this is as follows….

4 years being of being paid well below the market value in my area 2 years in a row with above average yearly reviews 1.5 years of being jibbed on a promotion because of promotion freezes due to “company reorganization” Peers that I went to college with make salaries much closer to market Cost of living has substantially increased over the last 2-3 years with no consideration from my company

Any advice from anyone on this? Am I justified to ask for a 30% increase for the points I made above? I feel my case is pretty strong here. Thanks in advance!!

25 Comments
2024/06/13
22:25 UTC

1

Relay Control

Hey all,

I'm trying to switch 12V to power an automotive relay. I have a circuit that can output either +2V or connect to GND. The relay coil pulls anywhere from 150mA to 250mA.

What would be a suitable mosfet / transistor I can use to switch the relay? I would ideally like the relay to be OFF when the gate is connected to GND, and ON when the gate is at +1V. (1V switching voltage is necessary as the incoming signal will only ever be +2V MAX)

4 Comments
2024/06/13
22:21 UTC

9

Going into Renewables as a BS student who mainly focused on Computer Engineering

Hi y'all,

I'm a current BS EE senior in the US who wants to learn more about renewable energy because I've lost some amount of interest in Computer Engineering at the moment and want to explore other options to help the world. I've been looking around the internet for renewable energy because I would like to learn more about power systems, but I'm quite lost on where to even begin. Do yall know where I'd start looking in terms of internships or jobs, and what kinds of places I could look for more information in terms of reading to be done to learn more about renewables in general?

I'm also curious if the renewables space has need for embedded or FPGA engineers, as I'd like to put my skills to use in those parts of companies if possible.

3 Comments
2024/06/13
22:09 UTC

2

What kind of cable is this for?

5 Comments
2024/06/13
21:08 UTC

3

Wire sizing for high amps

How does one decide what gauge wire to use for a high current application?

My initial thought was that wire heating was the main limiting factor. To confirm/deny this, I tried to calculate temperature rise of a 1m long 4 AWG copper wire with a 2mm thick PVC insulation, running 150A. Assuming single core for convenience.

Idea was that at equilibrium, power in (P=I^2 R) would be equal to heat conducted out through the sheath (Q=Ak(Tin-Tout)/t) where Q is heat (W) instead of its usual (W/m^2 ) definition as I am accounting for the surface area available for conduction (inner cylindrical surface of sheath). Also I guess I just wanted units to be the same for my Pin=Qout equation. Assuming Tout remains at ambient temperatures, say if we have active cooling.

The idea and equations seem to make sense to me, but I get only a ~9 degree temperature rise running 150A? That sounds very low to me.

Am I missing something obvious here or is temperature rise not the biggest factor for this kind of selection? I understand for long wires the voltage drop can be an issue but I only need short wires.

16 Comments
2024/06/13
20:40 UTC

1

Can I pursue a master's degree in aerospace engineering after a Bachelor's in EE?

6 Comments
2024/06/13
20:35 UTC

2

C++ for test engineering

I recently got hired as a manufacturing test engineer and one of the preferred qualifications are to know C++. This role will be involved in new product introduction to develop and revise test plans for hardware. I only know some basic python scripting and I was wondering what kinds of C++ topics I should start to learn. If anyone has experience in this sort of role, I’d love to hear.

2 Comments
2024/06/13
19:55 UTC

1

How to be ready for EE ?

Hello, am an 17 yo HS student from belgium currently in math/science studies. Id like to get into EE in uni (or ME, but mostly EE). Id like to know what i could do to get ready in advance for my EE studies (what to learn, what to prepare etc) and what material i need (my family is financially challenged). Id also like to know if i could use remote control from a laptop from campus to use my computers specs at home, because that would save a lot of money.

2 Comments
2024/06/13
19:41 UTC

2

Quick Question: Running my heat pump off 15A, do I need 20A even though breaker not close to tripping?

I realize there are multiple aspects here, and it could be other issues with the A/C, but I think it may largely be an electrical question, and you guys are wizzes.


I'm running a 10.5k BTU heat pump in cooling mode in my RV. (Brand new Dometic Cool Cat) The circuit allows the compressor to start fine, with no brown-outs. It also starts off pretty dang cool, but, it does not STAY cool on a normal day once it gets above a certain temp. The forums say "are you running it off 20A?" and I haven't found a clue yet other than that. Well, no I'm not, but:

  • it's the ONLY thing on the circuit (not running the microwave, etc)
  • only on the other side of the garage from my sub-panel (~ 30 ft)
  • and my Kill-a-watt says it's only drawing 9-10A while the compressor is on. (which agrees with the data sheet!

**My question is: ** Wouldn't the AC (heat pump) motor trip the breaker, before it would just keep running inefficiently at 10A (if 15A is "not enough" for it to be cold on a warm day)?

If not, how can it "tell" (by "tell" I mean just having that sort of underperformance) that it's not getting enough power, even though I know via testing the circuit can handle the normal amount of current a 15A circuit holds before tripping?

My voltage drop calculations are ~1.5% (and no load measures 121V)

Thanks

10 Comments
2024/06/13
19:35 UTC

6

What does it mean when there are arrows point into from the outside of a logic gate?

I know an inverted signal is one of the inputs to these NAND gates but as title mentions, why is there a fourth input outside the gate?

3 Comments
2024/06/13
19:21 UTC

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