Questions tagged [voltage-protection]

Use this tag when referring to circuit or component for voltage protection.

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Does NodeMCU have some protection against wrong connections that could kill a computer USB?

I know some computer USB could handle some bad connection (by blocking the port, which need to reboot the computer). But I wonder if a NodeMCU 8266 offers some protection.
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1answer
34 views

Different voltage sources across Vin and DC jack

So I understand that the USB VBUS circuitry turns off provided there is a high enough vin voltage using the PFET and comparator. I can see that the DC jack is connected to the Vin pin via a diode. ...
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1answer
853 views

Electric meter pulse counting using LLC

I am trying to create an electric meter reading setup for Arduino, and I have been searching for it and almost every posts available is using LDR sensor. http://www.reuk.co.uk/wordpress/solar/...
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1answer
147 views

Why is there a third connection to the host in this 3 wire current output sensor diagram?

I've got a 3 wire 4-20mA current output sensor, externally powered by 12V, which I want to read from an Arduino Uno (5V). The sensor connection diagram is below, but I don't understand why it says to ...
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2answers
81 views

Grounding for arduino, measuring phase controllled 240V

I would like to measure a phase controlled 240Vac waveform as a digital PWM input for an arduino. The signal would look something like this: My intent was to use a zener clipping circuit to limit the ...
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2answers
2k views

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

I'd like to connect an M8N gps module to an Arduino Uno. From what I understand the Arduino pins 0-RX/1-TX work on 5V the M8N RX/TX work on 3.3v the sensor-TX sending to the Arduino-RX should work (...
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1answer
2k views

Are the output pins on the 74HC595 shift register protected against shorting?

In the following schematic you can see that Q1 and Q4 both are connected to a Arduino's Digital Input Pin. So if Q1 is high and Q4 is low, would there be current flowing from Q1 through Q4 (and ...
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2answers
2k views

Correct Capacitors to use with L7805 Voltage Regulator

I am making my own arduino. I am in the process of hooking up power to the Atmega328. In both these articles they use the L7805 voltage regulator with two 10uF capacitors. https://www.arduino.cc/en/...
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4answers
4k views

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

I want to bypass the onboard regulator and use the 5V pin to feed arduino with external, regulated source. Everybody just keeps saying regulated 5V, but how precise does the regulation need to be ...
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1answer
568 views

Mega 2560 & smoking/burning 5v requlator, probable cause?

Problem: board seriously fried. Desired outcome: measures to take in future. Background: This project has been running for about a week on the 2560, and previously for a few weeks on an UNO clone. ...
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2answers
734 views

Is my Arduino possibly broken?

We work in groups on a project at school. We had to build an electric scheme with an Arduino to make a small car moving. We got the parts from our school, except the Arduino (we had to buy it ...
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1answer
49 views

Gnd pins at the power pin strip VS Gnd pin at the IO pin strip

I noticed there are two Gnd pins at the lower pin strip, and another on the upper strip. Is there a difference in their purpose?
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2answers
741 views

Analog read negative voltage inbuilt protection

I'm trying to read a -10 to +10V analog signal on my Arduino Mega (2560). I've been using a voltage divider to obtain a -5V to +5V signal (with two 10kOhm resistors), which used to work just fine. I'...
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4answers
840 views

Is applying 5 volts to LED dangerous?

The Arduino Uno manual (from the kit) instructs to connect a resistor to GND when lighting an LED on the breadboard with the 5V (socket?). The red, green, and yellow LEDs don't light up so brightly... ...
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1answer
109 views

connecting 3.3V to +3V

Well, I hope this question won' t be buried to the dark depths of this forum as my previous q' s:) But I suppose it won' t this time cause it's pretty short without this introduction part... I have ...
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1answer
536 views

Power arduino from 5v rail of pc molex

I'm building a small device using arduino that should be connected to my pc via a usb header to exchange data with the PC. What I'd like to achieve is that arduino turns on when the pc is on, whereas ...
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1answer
639 views

Hooking up the Arduino to a car's 12v

I am planning an uno based tachometer for my truck, which doesn't have a tachometer. With nothing in place for me to get a reliable signal, I started looking at other sources to read the rpm from the ...
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1answer
638 views

connect arduino to battery with 12V motor

I am looking at this(instructable with circuit picture) tutorial for making a self-balancing robot. However, I am confused about how the battery connects to the arduino. I know the 12 V must go to ...
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3answers
5k views

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

I just bought esp8266 and ftdi usb driver, I want to power the esp8266 with Arduino's 3.3 V output, is that possible? I saw some tutorial on youtube in that they are suggesting us to use 3.3v ...
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1answer
785 views

How to use voltage divider between ESP8266 (3.3v) and IR proximity sensor (5V)?

I am a software developer and I don't know much about circuits so I need help. I have an ESP8266 (esp-12) 3.3V and I'm planning to use it with an IR proximity sensor (runs between 4.5-5V). I have 2 ...
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2answers
495 views

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

So, I'd like to put a button between input and output pins to read when button is pressed. What minimal resistance should I add to the scheme not to burn Arduino when the button is pressed? Does this ...
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1answer
453 views

How to use unregulated VIN voltage?

I have recently bought an Arduino Mega, and I am powering it with a USB charging port, 5V at 1A. I need to use the 1A with a transistor, since the Arduino itself can only supply a maximum of 20mA ...
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2answers
605 views

Two voltage sources on the same circuit

I am looking to power a Trinket Pro 5V microcontroller using a 9V voltage source. I have logic running on this controller to gather the data from an accelerometer (powered off of the 5V pin on the ...
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2answers
51 views

Opto Isolator question

I'm building a CANBUS network based on an arduino to go into an offroad racing truck. The vehicle has two separate battery systems, and I would like to monitor the voltage while still electrically ...
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2answers
1k views

Is the Uno Vin pin protected by the voltage regulator?

I guess it's all in the title. When using Vin as input, does it go through voltage regulator, or must I feed it precisely 5V?
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2answers
648 views

The 3.3 volts of the USB To TTL

I'm using ESP with USB to serial converter (D-SUN) is it possible to use the 3.3 volts of the USB instead of the Arduino Uno?
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1answer
881 views

Will 12.6v really damage my arduino?

I'm using a 12v fan and 12v LED modules in my project, so I need about 400mA by their combined specs. I have a 12.6v dc regulated power source that can give ~700mA I wish to use, and since it has a ...
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2answers
2k views

Reading a photoresistor

I have a wire with a 0-5v current. I want to detect if the current is there or not (HIGH/LOW.) I'm using an optocoupler to avoid putting too much current into my micro, as it is only a 3.3V micro. I'...
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4answers
3k views

Best way to protect a digital output?

I am looking for a way to protect my Arduino's digital outputs from unwanted, outside voltages. My project uses about 20 different outputs, each connected to a wire (run) that can range from 20 to 100 ...
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1answer
10k views

best way to protect a digital or analog input from 12volts

At work, I have connected an Arduino to a security key (which has a 12v power supply) in order to give us a more versatile door lock. Unfortunately, people keep removing the key pad, disconnecting ...