Polynomial

I'm struggling to articulate it. The exact context is that someone is having trouble with a company's delivery process, and I want to send them this video which is a funny story about a company's disastrous attempt at fridge delivery. The word I'm looking for describes the experience of watching something like that and feeling better because it's a humorous reflection of your own situation. Not schadenfreude, but the same kind of dark humour.

@JourneymanGeek at least one, possibly even two!

sigh I really wish I could've been at Securi-Tay this week.

ohai

has been too long.

I was prompted back here by TidalWave :3

Hide it in some innocuous filename, include it from index.php

Yeah, exactly.

Unsure. There's no /helper/data/functions.php in that package.

The admission of having config stuff exposed on the site makes me think it's perhaps not an 0day, and instead just mass exploitation of bad configs.

Could be.

I poked the Laravel folks on Twitter, just in case.

but could be a new Laravel vuln

my first guess is mass scanning for exposed config files, given what the second linked question mentioned.

Both within an hour of each other, both Laravel, both mentioning index.php being modified, both mentioning SEO.

So this is intriguing.

although now I'm reading through and can't really see where I'd split it up. it's all kinda interconnected.

@schroeder Hmm, sure I guess? I don't usually like putting section titles in answers though.

@schroeder yeah I just stopped replying, they're clearly having a moment.

@schroeder lmao

I do want to get hold of some discrete MOSFETs with body terminals exposed though, just to have a play with them and see how they work with varying voltages/currents at the body terminal.

my guess would be that you can actually do this, but if there's a positive potential difference between the body pin and the source pin then you'd have a flow of current across the body diode, so you'd need a resistor in there. if you negatively biased the body pin I guess that wouldn't happen, but then your threshold voltage would get all wonky.

@TannerSwett I'm a bit hazy on the details too, but I think the switching behaviour is technically based on V_gb but since we attach the body to the source pretty much every time we tend to talk about V_gs

I'm gonna duck out of the conversation now, but consider it a lesson learned for next time.

@NicoCano Nobody's telling you the answer because you haven't provided any information about the design requirements. The reason you're struggling is due to a gap in your knowledge. We'd would've been perfectly happy to explain why your design won't work, and what a better approach would be to achieve the goals given a set of design requirements, in order to help you bridge that knowledge gap. But instead of engaging in good faith, you were rude.

@NicoCano In which case you are trying to run before you can walk. I'd advise that you study electronics further before attempting to jump in with something like this. I'd also ask that you be respectful to others on here - your last reply to Hoagie was both incorrect and rude.

It's impossible to advise further without at least knowing your source voltage range, AC source frequency, the amount of power you want to dissipate, what level of precision you require in the power dissipation setpoint, and any other design parameters.

This is not a trivial thing to design. You absolutely can't just use an RC low pass filter to turn PWM into an adjustable DC voltage in this context. Trying to slam the MOSFETs on and off at max \$I_d\$ is going to be an EMI hellscape. You have to be careful with MOSFET FBSOAs, and probably need planar MOSFETs that are designed for linear operation. You need a control feedback loop and a low inductance layout to ensure stable operation and avoid shoot-through. You need to properly characterise the \$Q_g\$ vs. \$I_d\$ and \$V_{ds}\$ transfer functions as part of that.

also makes it more obvious which pads are intended to be bridged vs. which ones are just DNP'd.

if you use the same pad-to-pad clearance that your PCB manufacturer normally allows, but with the pointed shape, it makes it far easier to manually bridge with solder than if you just use two square pads.

@MattS a good trick to use is to make a pair of pads that look like this: [> >]

and yeah, no, definitely not wire jumpers. I don't think I've used a wire jumper on a PCB in, like, 10 years haha

fwiw I do actually think your use-case is legit, and even combines with what I said in my answer regarding thermals, it's just probably the last option I'd pick.

:)

@MattS With the jumper you wouldn't remove the parts. The PCBA would fit all the resistors on every board, and you'd just short the necessary jumper pads with a solder blob to configure the specific value you need. No soldering components at all. And if your shunt resistances work out to be even multiples (e.g. 0.2/0.1/0.05Ω) you can fit the same maximum shunt resistance value (e.g. 0.2Ω) multiple times and bridge 1/2/4 jumpers to put them in parallel to get the final value required, which means instead of buying N of each value, you buy 2N or 4N of one value, which works out cheaper.

Fair. It's not a bad idea, per se, but I wouldn't consider it to be my first choice. Bit of a niche case.

I'd probably just go with a jumper in that case. Could even parallel several resistors of the same value for BOM reduction, too, if your different input voltages match up, which pushes you into lower price-per-unit brackets. The TH option is certainly valid, but I would question whether it's optimal or really justified.

Not sure about point 1. Your PCBA can certainly handle design variants / conditional BOMs with SMDs, just the same as with TH. Or just place all three parts and add a jumper. The TH part seems more costly and labour intensive, and uses more board space.

@DavidMolony Might be worth contacting JOB Group to see if they can supply you with some samples, and offer some advice regarding higher current applications (their off-the-shelf parts seem to top out at 16A). I almost wonder if their thermo bulb link could be repurposed as a high-current disconnect.

It sounds like you essentially want a DC AFDD. As mentioned by others, this is an active area of research, for example: ieeexplore.ieee.org/document/9209997

@MarcusMüller Ah, yes, right you are. I was mixing the terms up in my head. Sorry for the noise.

@MarcusMüller For sure, but you can't assume that the frequencies of concern are always directly matched to the clock rate. My bet would be that the rise and fall times on the USB transceiver are a little faster than the bare minimum needed to meet the timing requirements, hence the upward shift in frequency.

@MarcusMüller The bandwidth of the signal is determined by the rise/fall time, not the clock rate. You can have a 100kHz clock signal driven by a modern small-die CMOS part and it'll happily radiate in the 300MHz+ range on every transition due to the Tr/Tf being short.

If you put a trace inside the soldermask expansion around a pad there'll be copper exposed very close to the pad. So it's quite possible that you've got a lot of shorts on this board.

I'm not super familiar with KiCAD but yeah I'm pretty sure that's what the line is depicting, assuming it's the same as what I would normally see in Altium.

That via under the IC also seems highly suspect to me. If I'm reading it right, that via connects the SET pin to the sense resistor and LED+. If the solder from the ground pad has infiltrated into that via (e.g. if it wasn't fully masked off) it would be shorting SET to GND.

Out of curiosity, did you run DRC? Could be the low-res rasterisation but it looks like some of those traces are infiltrating into the soldermask expansion on pads with different nets.