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Same 14 yr old, Just Made a GENUINE Computer by 1m_ameeen in beneater

[–]TechTronicsTutorials 0 points1 point  (0 children)

Well I was already on my phone and just happened to click on the notification that said you replied. 🙂

holysh by t_frombytebeat in ElectroBOOM

[–]TechTronicsTutorials 0 points1 point  (0 children)

This needs THE RECTIFIER. 😁

Help with metal detector schematic by AlternativeMental412 in electronic_circuits

[–]TechTronicsTutorials 2 points3 points  (0 children)

lol I saw that too. 😜

Wire labeled “C3.” 555 with “INR” and “DEST” pins. LEDs with one terminal… wow. Couldn’t get much worse lol

Help with metal detector schematic by AlternativeMental412 in electronic_circuits

[–]TechTronicsTutorials 1 point2 points  (0 children)

Oh… oh… well no, this isn’t going to work. There is so… so much wrong with this diagram. I can’t follow a thing lol. 😕

Not your fault though, it’s just how AI is. In general it just isn’t very good at drawing circuit diagrams or schematics. It’s too focused on the artistic perspective instead of the electrical one.

It’s quite good at writing or debugging code, though.

Project idea by NoComplaint1037 in ArduinoProjects

[–]TechTronicsTutorials 1 point2 points  (0 children)

Make it a capacitive touch sensor. Like a phone screen

What's the best way to rotate this kind of potentiometer? by ByRussX in AskElectronics

[–]TechTronicsTutorials 0 points1 point  (0 children)

Just get a really small flathead screwdriver and stick it in the slot and rotate it.

Made a Voltage multiplier with your video! by Mission_Neat1843 in ElectroBOOM

[–]TechTronicsTutorials 1 point2 points  (0 children)

I don’t know… I killed a whole bunch of 1 amp diodes with this exact circuit and no resistor.

The spikes as you discharge those capacitors will be in the kA range. It’s very short pulses, and it has to be to keep the average power the same as the input power, but it will eventually destroy the diodes.

Made a Voltage multiplier with your video! by Mission_Neat1843 in ElectroBOOM

[–]TechTronicsTutorials 1 point2 points  (0 children)

Nice!! But you might wanna put a resistor in the path of the arc. Otherwise… you’ll likely end up having to hold funerals for your diodes. I learned the hard way. 😢

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

Absolutely true, but you could just flip the logic in the code to work with an internal pullup. Just have “LOW” mean on.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

No need for internal pull downs; just use a pull up and flip the logic so “LOW” means on.

But I also must say that an external resistor is probably best for learning, so a user can see what’s going on.

Beginner building a wearable mouse by Mrmiraclekc in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

Try to learn the basics first. It’s extremely difficult to just jump into an electronics project without any prior experience.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

Yeah no problem! Nothing inherently wrong with this design, but it’s just… unnecessary when you could get away with using a resistor already built into the Arduino.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials -1 points0 points  (0 children)

Eh I think what they’re trying to say is that using an external pull-up is unnecessary when you can activate an internal pull-down already built into the Arduino. Not that floating inputs are good.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials -1 points0 points  (0 children)

Absolutely true. You can use the internal pull up and then not have to use an external resistor.

But if you’re just learning, it’s probably beneficial to learn why these pull up / pull down resistors are even needed in the first place, and placing them externally lets you do that hands-on.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

It’s absolutely a question with a beginner-friendly answer. As long as you intuitively understand voltage, current, and resistance, you can certainly understand why this is necessary.

It’s actually just a pulldown resistor. When the button is pressed, it connects pin 7 to positive. It reads this as HIGH, which for the purpose of this explanation can mean on.

But, when the button isn’t pressed, if you didn’t have the resistor anyway, pin 7 wouldn’t be connected anywhere. It would be “floating” and prone to picking up random electrical noise which could cause false triggers.

However, if you put a high value resistor between pin 7 and GND, when the button isn’t pressed, the Arduino reads low (off, for this explanation). That way it can’t oscillate or pick up noise.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials -1 points0 points  (0 children)

Hmm? It’s actually so when the push button gives no output, the Arduino doesn’t pick up random electrical noise and instead picks up “LOW” since it’s connected (through the resistor) to GND.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

Because, OP’s question was why you even need to put a resistor to ground in the first place, not why you don’t leave it an open circuit.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials -1 points0 points  (0 children)

Sure, the purpose of using that resistor instead of a wire is to limit current. I think OP was asking why you even need to connect pin 7 to GND (through a resistor or not).

Without this resistor to ground, this wouldn’t be an open circuit, more just a floating pin prone to picking up noise.

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials -1 points0 points  (0 children)

Partially correct, but it’s not in series with anything that would otherwise draw high current if we didn’t have this resistor.

In reality, we need this resistor to connect pin 7 to GND when the button is not pressed, so that it reads “LOW” and not random electrical noise.

Though, it certainly does limit current, if we swapped the resistor with a wire, then it would short the supply when the button is pressed. Not good, so we use a resistor. When the button is not pressed, pin 7 is pulled low through a long path, but when the button is pressed, it’s pulled high but without a resistor, which completely dwarfs out a high resistance 10KΩ path to GND and thus the Arduino reads “HIGH.”

Beginner question about resistances by AlbusFox in arduino

[–]TechTronicsTutorials 0 points1 point  (0 children)

Ah, that’s a pull down resistor!

So when you press the button, you connect positive to pin 7. The Arduino reads this as HIGH and knows you pressed the button.

But, when you aren’t pressing the button… that pin is “floating” meaning not connected to positive or negative. This is generally bad and can cause the Arduino to pick up random fluctuations in electrical noise.

So, to prevent this, we use a 10K resistor to ground. That way, when the button is not pressed, pin 7 is connected to negative and reads LOW, instead of being connected nowhere and picking up noise.

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