Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [pins]

May refer to conductive traces of an integrated circuit, exposed as metal contacts, or pins, which are large by comparison and make physical connection to other components feasible. May also refer to metal pins connected to specific traces of a printed circuit board for the purpose of connecting and disconnecting external components or peripherals in a reusable way.

489 questions
108
votes
5 answers

Why are there 3 pins on some batteries?

Lots of new batteries (for mobile devices, MP3 players, etc) have connectors with 3 pins. I would like to know what is the purpose of this and how should I use these three pins? They are usually marked as (+) plus, (-) minus, and T.
adopilot
  • 1,183
  • 2
  • 7
  • 7
64
votes
5 answers

Why do some tactile switches have 4 terminals?

I am wondering why some tactile switches have 4 terminals instead of two? For example, take a look at these switches, like the image below: (source: pranelectronics.com) What is the use of the two remaining pins? If the pins of the exact opposite…
rajat
  • 975
  • 2
  • 8
  • 17
39
votes
2 answers

Why do some pins have `~` signs next to their numbers?

I was looking at my Arduino Uno and I noticed that symbol by digital pins 11, 10, 9, 6, 5, and 3. What do these mean? Does this affect the way it works? Can I not use these pins for certain situations?
Anonymous Penguin
  • 3,750
  • 8
  • 35
  • 57
38
votes
5 answers

Can I use the analog pins on the Arduino for my project as digital?

I am new to using Arduino, and I have an Arduino Uno. For the projects I've done, I've only used the digital pins. I am building a small vehicle that uses stepper motors. I have run out of pins to control the motors for this vehicle. What are the…
bogen
  • 1,093
  • 3
  • 14
  • 27
38
votes
2 answers

What's the difference between INPUT and INPUT_PULLUP?

On newer Arduinos, one can set pinMode to one of three states: OUTPUT,INPUT, and INPUT_PULLUP. This page says: The Atmega chip on the Arduino has internal pull-up resistors (resistors that connect to power internally) that you can access. If you…
Manishearth
  • 2,882
  • 2
  • 22
  • 32
37
votes
2 answers

"Tristate a pin"

What does it mean to "tristate a pin" on a CMOS microcontroller?
J. Polfer
  • 3,780
  • 2
  • 27
  • 33
36
votes
3 answers

General "rule of thumb" for unused IC pins

This is somewhat similar to this question about NC pins. In cases where the datasheet doesn't specify what to do with unused IC pins, what is the recommendation to do with these pins? In particular I'm thinking of GPIO pins for the AT32UC3C…
helloworld922
  • 16,600
  • 10
  • 54
  • 87
33
votes
3 answers

Arduino pin spacing

How do you get around the annoying pin spacing on the Arduino? Where pin 7 and pin 8 are not standard spacing. Why is it set up like this?
mad_z
  • 5,050
  • 5
  • 45
  • 56
31
votes
6 answers

Is it really a bad idea to leave an MCU input pin floating?

I've heard that leaving a pin floating on an MCU when configured as an input (vs. the default output) is bad for the pin, and can eventually cause it to fail prematurely. Is this true? N.B. in my instance the pin is floating somewhere between 0.3V…
Thomas O
  • 31,546
  • 57
  • 182
  • 320
30
votes
4 answers

Which chemicals can be used to clean electronics?

I have access to these isopropyl alcohol ethyl alcohol vodka rum acetone And would like to know which ones should be used to clean electronics, and (out of curiosity) why some are worse choices than others?
Brian Harris
  • 409
  • 1
  • 4
  • 3
21
votes
2 answers

What's an alternate pin function on a microcontroller?

I'd like to know what "Alternative Function" refers to in the context of the IO ports of a microcontroller. I don't need to know how to activate it when connecting to a peripherial, but I'd like to know what it exactly is and why we'd need it.
user929404
  • 401
  • 2
  • 5
  • 9
21
votes
2 answers

Why does the SATA power connector have so many pins?

With only 4 cables, two of which are ground, it seems like it has way too many pins. Why is this so?
Filip Haglund
  • 311
  • 1
  • 2
  • 8
18
votes
2 answers

What are 'return' pins?

On a VGA connector, there are numerous 'ground' pins. Three of these are Red return, Green return and Blue return; But why does each color component have its own ground pin?
Chris2048
  • 415
  • 5
  • 9
17
votes
3 answers

72-pin SIMM RAM: how do ground (Vss) and supply (Vcc) voltage pins work

I have a P1004B746400 B7464 REV.A board which is a 72-pin SIMM RAM with two TI TMS418169DZ chips on it. According to 72-pin SIMM configuration, the pins #1, #39 and #72 are ground Vss and pin #10 is supply Vcc. However, those ground and supply pins…
Megidd
  • 375
  • 3
  • 10
16
votes
3 answers

I burnt a pin. Now, what do I do?

I accidently shorted pins 10 and 11 with 10 set to output HIGH and 11 set to input. The pin 11 is not working. How do I figure out what component I burned? Can the problem be fixed?
asheeshr
  • 927
  • 1
  • 10
  • 25
1
2 3
…
32 33