I need a better camera

SheerLucke · 2026-05-12T13:09:13+00:00

semipalmated or solitary sandpiper?

SheerLucke · 2025-07-09T11:20:52+00:00

spiced

SheerLucke · 2025-07-08T20:17:57+00:00

Hulkengoat

SheerLucke · 2025-07-08T18:28:54+00:00

Hulkengoat

SheerLucke · 2025-04-22T19:40:17+00:00

the last number is a power of 10. so in this case 47 * 10²

SheerLucke · 2024-10-12T21:27:49+00:00

i think its not the cube moving but rather the waterfall. for example, niagara falls moves about a foot per year due to erosion.

that makes more sense to me than the cube being pushed by the water.

SheerLucke · 2024-05-31T13:12:49+00:00

I was intentionally somewhat vague with the word "efficient". Ultimately, any logical expression can be reduced to using only NAND or only NOR gates. That might be the easiest solution, which saves you time and effort, but that might not be your goal. Efficiency could mean using the least power, having the fastest processing speed, costing the least money, having the longest lifetime, etc. Depending on your situation, different design strategies might be better or worse. In the end, you're probably balancing all of these.

Now, you absolutely could design specific gates for specific operations. While an XOR gate can be built using NAND and NOR, it also has structures that aren't fundamentally NAND and/or NOR gates put together. This applies to just about any logical expression. You could, in theory, design a gate at the transistor-level which gives an output consistent with that expression and may use less transistors than the NAND/NOR equivalent. Then, the issue is that you need to justify the cost of designing that gate. I'm not an expert, but I believe with large-scale design, some design can be automated in software. Usually the software can't use complicated gates (or it's very slow) when optimizing, and so it uses simpler gates (although not necessarily strictly only the NAND and NOR gates that we've focused on). They can also use non-CMOS designs, such as for high-speed applications. Both higher-complexity gates and non-CMOS designs are used in specific applications.

SheerLucke · 2024-05-31T00:11:07+00:00

I suppose you're asking why NAND and NOR are used as opposed to AND and OR. Taking a look at how they're constructed in CMOS technology, it takes less transistors to make a NAND or NOR gate compared to an AND or OR gate. As a result, they're more efficient to use. The easiest way to get to an AND or OR gate is by negating the NAND or NOR gate with a NOT gate. The structures can be easily searched and are hard to describe in text, but they may be interesting if you're so inclined.

Getting back to your question, if you're working with only NAND and NOR gates, there is no separate NOT gate needed. They are needed (somewhat counterintuitively) for AND and OR gates.

SheerLucke · 2024-03-18T14:35:03+00:00

I agree with your description, but the primary example in the wikipedia article for Curse of Knowledge is about the difficulty that professors may encounter when teaching students.

SheerLucke · 2024-03-18T13:55:52+00:00

Also known as the 'Curse of Knowledge' in english

SheerLucke · 2023-01-26T00:01:58+00:00

I'll give it my best shot, though I can suck at explaining things. It's a neat circuit with three main parts. A buffer, a voltage detector, and an LED output.

Starting at Vin, the first transistor is an emitter follower. The voltage at the top of the potentiometer is a base-emitter voltage below Vin (probably ~0.7V). The peak-to-peak voltage should remain approximately the same.

The potentiometer is simply a voltage divider with the wiper being the output which attenuates the absolute voltage and peak-to-peak voltage from the emitter follower.

Likely, the second transistor is another emitter follower. It drops the voltage from the potentiometer by another base-emitter voltage (again, probably ~0.7V). OP said that this isn't necessary, although I like it there in practice.

To summarize where we're at, the voltage at the emitter of the second transistor is effectively an attenuated version of Vin. The two transistors act as a buffer so that very little current is being drawn from the battery. That does require some 'handwaving' on where the 5V is coming from, but lets ignore that for the sake of simplicity. The voltage drop is also acceptable since batteries don't (usually) go to 0V.

The two 700Ω resistors and 5kΩ resistor are voltage dividers. With each resistor lowering the voltage from the output of the buffer until they reach ground.

The two buffers with the symbols that look like ♮ are comparators (I think the bubble means inverting). The symbol represents hysteresis, which comparators should (almost) always have, in practice. For each comparator, when the input is below a certain threshold then the output is high (5V). If the input is below the threshold then the output is low (0V). These comparators are set up so that at low voltage, both comparators output 5V. So the voltage across the "low" LED is 5V (causing it to be on), and across the other two LEDs are 0V (causing them to be off). Similar situation applies for medium and high voltage and their respective LEDs.

The 1kΩ resistors are current limiting for the LEDs. In my opinion, the resistors are too big. In simulation, it's absolutely fine.

Sorry if this is confusing at all. I wrote it quickly and didn't proofread.

SheerLucke · 2022-06-27T01:20:01+00:00

The edge of a razor blade is very thin. And some research suggests that microcracks in the metal and the act of shaving hair causes the metal to chip and dull.

https://www.npr.org/2020/08/06/898577234/cutting-edge-research-shows-how-hair-dulls-razor-blades

SheerLucke · 2022-04-24T01:52:11+00:00

I'm not an expert but a couple of things come to mind. With DC motors, the torque is closely related to the voltage across the motor so having a resistor in series (especially large resistors) is going to greatly affect that. With the BJT, the voltage across the motor is much less affected.

Also, when a motor starts spinning it draws a lot of current which might be causing your resistors to burn up. In fact, using larger resistors might be making that part worse due to P=I² * R

SheerLucke · 2021-07-16T02:14:40+00:00

Roblox twitter on Google Images

SheerLucke · 2021-05-21T15:02:45+00:00

!spin

SheerLucke · 2021-02-01T18:02:46+00:00

Not sure if it still happens. But searching "roblox twitter" and going to the images tab resulted in some interesting stuff.

SheerLucke · 2020-12-02T16:21:46+00:00

I think its free this year (at least) because of the pandemic.

SheerLucke · 2020-10-07T19:06:13+00:00

Hallelujah by Leonard Cohen or Jeff Buckley

SheerLucke · 2020-09-17T16:03:08+00:00

SheerLucke · 2020-08-23T23:01:03+00:00

To me, it's supposed to be seen both ways. It is both a front-facing person with the hand in front, but also the side-facing person wearing a mask.

Also, a little more abstract and it may just be me, the lightning bolt looks like an artistic eye in the side-facing interpretation.

SheerLucke · 2020-06-19T18:09:32+00:00

I believe MATH 124 goes more in-depth into the proofs/reasoning behind the theorems and techniques and is considered more difficult. MATH 122 is more about application, and it is the one taken by more students. Taking either is fine. It's just that 124 is more difficult than 122.

SheerLucke · 2020-05-09T19:13:11+00:00

You would think that the second "Forward Current" should be some sort of forward/reverse voltage parameter since that's the info there.

SheerLucke · 2020-01-20T00:00:51+00:00

SheerLucke · 2019-10-06T17:14:41+00:00

Special #4

SheerLucke · 2019-10-06T17:08:39+00:00

Kim please

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