9 votes
Accepted

Powering Arduino Uno from 5V pin, what exactly is the voltage range/tolerance?

Unfortunately there is no one "clear cut" answer for all you ask. There are some hard limits, though, which you can get from the main chip's datasheet: Operating Voltage: 1.8 - 5.5V But that's ...
Majenko's user avatar
  • 105k
9 votes
Accepted

Can I use arduino's 3.3 V output directly to esp8266?

You should search for this data yourself, but since you are saying you are a newbie I'll tell you how to find this. First of all you should search for a document called "datasheet". On a datasheet ...
frarugi87's user avatar
  • 2,721
6 votes
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Correct Capacitors to use with L7805 Voltage Regulator

The answers are in the notes: Although no output capacitor is need for stability, it does improve transient response. Required if regulator is locate an appreciable distance from power supply ...
Majenko's user avatar
  • 105k
5 votes
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Is the Uno Vin pin protected by the voltage regulator?

If you look at the schematic you'll see Vin is connected to the input of the voltage regulator. Just like the barrel-jack (except for the diode). So the same input-voltage of 7-12V applies to Vin.
Gerben's user avatar
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5 votes
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Is applying 5 volts to LED dangerous?

Different color LEDs are not the same. The are made with different impurities. And some colors (blue) were really hard to figure out. So much so that the blue LED inventor was awarded the Nobel ...
st2000's user avatar
  • 7,325
4 votes
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Are the output pins on the 74HC595 shift register protected against shorting?

In this data sheet it says: When the output-enable (OE) input is high,the outputs are in the high-impedance state. However on page 3 you will notice that the *OE pin controls all outputs at the ...
st2000's user avatar
  • 7,325
3 votes
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Analog read negative voltage inbuilt protection

All the IO pins contain a pair of clamping diodes to protect against over-voltage and negative-voltage situations: As long as the current flowing through one of those diodes doesn't exceed its ...
Majenko's user avatar
  • 105k
3 votes
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Different voltage sources across Vin and DC jack

wouldnt that then send current through the Vin pin and back to the coin cell battery? Is that what would happen in this instance? Yep, that's right. shouldn't there be a design feature to prevent ...
Majenko's user avatar
  • 105k
3 votes

Is applying 5 volts to LED dangerous?

No, you cannot safely power an LED with 5V without a resistor. The resistor is absolutely 100% required. The resistor isn't put there purely on a whim, it's required to set the current based on the ...
Majenko's user avatar
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3 votes
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Power arduino from 5v rail of pc molex

The 5v of an ATX power supply will be perfectly adequate for powering an Arduino. It will already be very heavily filtered and stabilised.
Majenko's user avatar
  • 105k
2 votes

Opto Isolator question

An optoisolator is good for digital signals, but won't transfer an analog signal accurately. Instead, you could put ADCs on the different circuits and optoisolate their communication with a master ...
Dave X's user avatar
  • 2,332
2 votes
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How to use unregulated VIN voltage?

The VIN port is connected to the barrel jack. It must only be used if you are powering the board through that jack. To access the USB power just use the 5V pin - it is directly connected to the USB. ...
Majenko's user avatar
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2 votes
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Mega 2560 & smoking/burning 5v requlator, probable cause?

They are using the same SOT223 LDO as every other product. These have a very low limit of output current when run from an input voltage such as 12V. If you replace the LDO with a switching regulator,...
John Taylor's user avatar
2 votes

Correct Capacitors to use with L7805 Voltage Regulator

Could someone explain why the examples use 10uF and the data sheet specifies 0.33uF and 0.1uF? One obvious reason is that those two examples are non compliant with the datasheet. But generally ...
dannyf's user avatar
  • 2,770
2 votes
Accepted

connecting 3.3V to +3V

The 3V input on the DS1307 is for a 3V battery, usually a CR2032 or similar. The supply voltage of the DS1307 is 5V, which means that it won't work with a 3.3V Arduino without a separate supply and ...
Ignacio Vazquez-Abrams's user avatar
2 votes

Continuous voltage on IO Pins while 5V is not Connected?

For this I would recommend isolating the power from the batteries with P-channel MOSFETs and only switching them on when you want to sample the voltage. This means that there is no power consumption ...
Majenko's user avatar
  • 105k
1 vote

Connect Arduino Uno RX/TX to 3.3v NEO-M8N gps module

You can use something along the lines of this: simulate this circuit – Schematic created using CircuitLab When the 5V Rx is driven to 5V D1 protects the 3.3V Tx pin. When the 5V Rx is driven ...
Andrew's user avatar
  • 1,050
1 vote

Connect Arduino Uno RX/TX to 3.3v NEO-M8N gps module

Buy some of these, it's a simple hardware solution to your problem then. https://www.amazon.co.uk/gp/product/B0148BLZGE/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 I know you said you don't want ...
ArDweNOme's user avatar
1 vote

Powering Arduino Uno from 5V pin, what exactly is the voltage range/tolerance?

You don't say why you want this information, but there are others who are trying to do similar. (Starting with NOT destroying their Arduino) For instance, at the end of the article 10 Ways to ...
SDsolar's user avatar
  • 1,165
1 vote

Powering Arduino Uno from 5V pin, what exactly is the voltage range/tolerance?

Most decent 5V supplies (e.g. USB chargers) are within 5% of 5V. I use these all the time to power directly to the 5V pin. There has never been an issue with this. I don't use supplies outside 5% for ...
user400344's user avatar
1 vote

Powering Arduino Uno from 5V pin, what exactly is the voltage range/tolerance?

The 6.5V is too much. I have had an ATtiny chip which seems to run fine after applying 8V to it. But how can I be sure that it is okay ? There are so many parts in the chip die that can be damaged. ...
Jot's user avatar
  • 3,246
1 vote

Is my Arduino possibly broken?

If you connect 11.5V directly to the Arduino then you might have killed you Arduino, BUT you say the LED comes up when you hook up the USB lead. So take things one step at a time. Get an Arduino ...
Code Gorilla's user avatar
  • 5,637
1 vote

Is my Arduino possibly broken?

Considering that you used resistors to lower the 11.5V to an cough - cough "very normal and regulated 5V", that most certainly is the problem. The "right and cheap" way to lower such high voltage and ...
Dat Ha's user avatar
  • 2,913
1 vote

Analog read negative voltage inbuilt protection

Current through the clamping diodes shouldn't be more than 1mA according to Atmel's Zero Cross Detection Application Note (AVR182). EDIT: As Edgar Bonet pointed out you have current about (-5+0.5)/(...
KIIV's user avatar
  • 4,742
1 vote
Accepted

Hooking up the Arduino to a car's 12v

How would I hook up the arduino to the 12v system? As in, what should I do to protect the io of the arduino? First you're going to need to do some investigative work. You're going to need to beg, ...
Majenko's user avatar
  • 105k
1 vote

Can I use arduino's 3.3 V output directly to esp8266?

The specs for the Uno say that it does not provide as much current on the 3.3V line as the specs for the ESP8266 requires. You will need to provide another regulator that can supply enough current.
Ignacio Vazquez-Abrams's user avatar
1 vote

What minimal resistance should be between an input and output pin not to burn Arduino?

Looking towards the high end of recommended (vs absolute maximum) current and considering Ohm's law at a 5v difference if two outputs are trying to drive each other to opposite values, you would ...
Chris Stratton's user avatar
1 vote

Two voltage sources on the same circuit

According to the link you supply you might either receive the WS2812 or the SK6812, datasheet on Ws2812 claims you can supply up to 7V , but this is still less than 9V , the SK6812 is lacking in max ...
Hans Neve's user avatar
  • 466
1 vote
Accepted

Two voltage sources on the same circuit

First of all: 9V means that you are using a 9V "transistor" battery (like this), right? If so it won't last very long: I suggest you to use a different approach (e.g. four AA batteries in series). ...
frarugi87's user avatar
  • 2,721
1 vote

Opto Isolator question

1) using current sensors based on Hall effect: https://www.sparkfun.com/products/8882. Their sensing circuit/leads and analog parts are electrically isolated. The drawbacks are: to calculate the ...
Flanker's user avatar
  • 529

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