Questions tagged [resistor]

Passive electronic component which reduces current flow in a circuit, dissipating power as heat.

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1answer
612 views

4-20 milliamp to volts to pressure maths

I am measuring pressure in bars from OsiSense™ XMLP pressure sensor (4-20 milliamp) on a arduino uno. When the machine im measuring pressure on is switched off the reading is 0v as expected. When the ...
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1answer
122 views

Powering arduino sensors - what resistor should I use?

Recently I have asked a question, why my sensors do not work on external power supply (link). I have found out, that I was limiting the current too much with the resistors. I have tried using two ...
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1answer
13k views

Reading 4 to 20ma pressure sensor using uno

I have a OsiSense™ XMLP pressure sensor that I want to read from my Arduino uno. This is the circuit I am looking at building for measure 4 to 20 milliamp. I've read online to find out how to build ...
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1answer
1k views

In a circuit with a switch and a pull-down resistor, why does the high impedance of the input not discourage current from flowing into pin?

I'm a beginner to Arduino and circuits. I've spent the last couple hours hung up on the concept of how current flows through switches and pull-down resistors, having read every thread and watched ...
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1answer
3k views

Using Capacitive Sensing Library with a 74HC4067 multiplexer

I'm trying to use the Capacitive Sensing Library by Paul Badger in conjunction with one or more 74HC4067 multiplexers to achieve a lot of capacitive touch inputs. I came across this youtube video ...
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2answers
9k views

Purpose of this resistor in Arduino Nano schematic

I was looking at the Arduino Nano's schematic and noticed a resistor that seems to be pointless (RP2C on this picture). Also there is numbers 6 and 3 on it, does it mean that resistor is connected to ...
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1answer
396 views

How do I pull up D1-D6 using 10k ohm resistors?

I'm using push buttons to control CR servos (button1=turn CW; button2=turn CCW). How do I pull up D1-D6 and what does that do exactly? I can't find a tutorial that explains it well enough how to use ...
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2answers
5k views

8Ω speaker, what resistor values to use?

I want to connect 2 speakers of 8 ohm to 2 (different) pins of the Arduino. However, for this example one speaker is enough. I came across a lot of circuits without or with a single resistor which on ...
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3answers
5k views

How to select which resistor is required for my curcuit to reduce voltage

I am trying to connect arduino and esp8266 as like this I know arduino runs at 5V and RX of ESP8266 should not have voltage more than 3.5V. If you see my diagram there voltage is large than need on ...
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1answer
1k views

Understanding schematics: resistors attached to Attiny85 pins V-USB

I'm currently trying to create my own Attiny85 usb thumb(to mimic an joystick). I understand that I have to limit the voltage on the attiny's pins that are connected to the D+/- pins from the usb. In ...
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1answer
197 views

Resistors/capacitor used in connecting 23LC1024 SRAM 1 Mbit

Yesterday I received by 23LC1024 SRAM with 1 Mbit memory. I tried to search for some libraries and ways how to connect it. So I searched around on internet first for the connections and saw some ...
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3answers
11k views

What difference makes resistance of thermistors?

Following this thermistor tutorial i used 1k thermistors (and resistors) instead of 100k as in video. What difference does it make? What about 10k thermistors? Is it good idea to use 1k/10k/100k ...
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5answers
12k views

Stop Led's from blinking

My code: // Pin 13 has a LED connected on most Arduino boards. // give it a name: int led = 13; const int buttonPin = 2; // the setup routine runs once when you press reset: void setup() { // ...
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2answers
1k views

Newbie Arduino DC motor problem

So I am new to Arduino and new to electronics in general. I've looked up a few tutorials and they all have a simple early tutorial that turns on a DC motor and turns it off again. Something like this: ...
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1answer
44 views

Arduino Starter Kit - firmly wiring longer parts

I am getting started with project 01 on the Arduino starter kit. I'm facing an issue when wiring parts with long ends e.g. led & resistor. To make the simple circuit with led, resistor & ...
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1answer
135 views

What is micro C in a circuit diagram?

This is probably a simple question but I am a beginner with these things. What does the micro C part of the circuit diagram mean? The diagram is from the datasheet of the tssp77038 IR receiver. Does ...
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1answer
932 views

Getting the DS18B20 detected and temperature read

I'm quite new with the electronics part of Arduino, but I thought that this was the basic way to get the DS18B20 temperature device hooked up. However, I can't detect it in my program using OneWire ...
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0answers
495 views

How to use Honeywell NBP Series Sensor with Arduino

I am trying to use a HONEYWELL NBPDANN100PAUNV Pressure Sensor. I found an example here http://www.circuitstoday.com/interfacing-pressure-sensor-arduino As this example says as instrumentation ...
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3answers
361 views

Unexpected Delay Between For Loops

I made some arduino code for leds that blink down a row and then back again, but when the program is run, there is an approximately 2 second delay in between the first for loop and the second. This is ...
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1answer
1k views

Formula for current through shift register

Hi I am programmer that just started learning electronics and Arduino. I built this simple circuit on Autodesk Circuits earlier. Originally I used 220 ohm resistors. Then when I ran the simulation ...
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1answer
74 views

Switch between ntc resistor sensors time based for other device

We have a heating system that uses an ntc resistor to measure water temperature. I would like to replace that ntc resistor by a fixed one (low enough to disable heating) temporary on a 5 minute ...
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3answers
1k views

Multiple I2C BREAKOUTS with pull-up resistors doesn't work [UPDATE]

[UPDATE] Now it works fine but the as soon as I add the GY-521 module (hardware not software), it starts sending me crapy info Project uses: Arduino Pro Mini as brain FTDI as a programmer GY-521 ...
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1answer
171 views

Self made microphone burns Arduino

I'm very new to electrical engineering and I'm trying to read microphone input with Arduino Nano. I've made a separate microphone module (based on this example) and plugged it into Arduino like this: ...
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3answers
228 views

Why have resistor at end of circuit cycle if GND dissipates final energy?

The first challenge on the Arduino Uno manual is to make a closed circuit with a button and LED. The voltage is provided by the 5V pin (non IO), connected by wire to (+) on the bus (breadboard). The ...
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1answer
188 views

digitalPin giving lower voltage than Vcc

I am using an ATTINY88 for a project that requires to turn on an LED. Right now I am using pin PA1(ADC7/PCINT25). I noted, however, that when the pin is ON, I get about half the voltage that is ...
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1answer
61 views

How to encode resistance change (reed) for Arduino?

I have a water counter which switches reed on each 10 liters of water. I would like to count these values with Arduino. I wrote a program which counts changes from analog input and connected counter ...
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2answers
923 views

Use LDR with 220 ohm resistor

I have read many tutorials on LDR(Light dependent resistor) with Arduino which includes a 10 kilo ohm resistor but can i use it with 220 ohm resistor or even without resistor.
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3answers
140 views

How can I understand the circuit diagram for Arduino Starter Kit Project 4?

I have acquired the arduino starter kit project book, and the explanations seem at times confusing and difficult to understand. Concerning the above circuit diagram, the book states (I am ...
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1answer
45 views

How to 'label' module using electric techniques

I am in a project where it makes set of 'modules(set of separate circuits that will work as a sensor when connected to the board' that would be connected to Arduino Mega. Currently, I'm planning to ...
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1answer
190 views

Photoresistor Switch

How would I use a photoresistor like a switch. My issue is it is always bleeding out a little bit of power and always on. Is there a way to connect it to a digital pin and when a resistance of xxx is ...
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3answers
4k views

What is the minimum wattage of resistors for breadboarding with Arduino Uno?

I'd like to buy new resistors for breadboarding with my Arduino Uno. There are 0.25W, 0.4W, 0.6W, 1W, 2W, 3W, 5W, 10W resistors in the shop. What is the most suitable for this operation?
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1answer
143 views

Diode lights generate false interruptions

I have spent quite a considerable time debugging my code that was triggering false interruptions. I have found out that the source of the error were the diode lights (on the picture). I would like to ...
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1answer
632 views

Driving multiple LED arrays with shift registers

The project I'm building requires multiple LED arrays. I'm going to wire these LEDs in parallel and then connect the arrays to individual pins on a shift register. In addition to the LEDs running in ...
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3answers
2k views

does INPUT_PULLUP uses power?

When using a digital pin as input, one has the option of using the internal arduino resistor, which is connected to VCC; that is setting the digital pin as INPUT_PULLUP, and then the pin reads HIGH. ...
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2answers
13k views

10k ohm Potentiometer vs 10k ohm Resistor on LCD Display

I'm trying to use a LCD Display with my Arduino, but I don't have a potentiometer and all of the guides I find always require one, usually a 10k ohm potentiometer. The point is that I'm not very good ...
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1answer
828 views

what is the importance of the resistors that connect to push buttons ? can i replace them by wires?

Please, iam a junior in arduino and i want to know what is the importance of the resistors that connect to push buttons? can i replace them by wires? thanks in advance.
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2answers
7k views

Can I supply the board's 3.3V directly to the AREF pin?

Short dumb question: can I connect the 3.3V pin and the analog reference pin (AREF) directly? I've heard mentions of a 32K internal resistor but I'm not willing to risk a short circuit without ...
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1answer
121 views

Use of Resistor in PinWheel Exercise

I'm working on project 9 of the Arduino starter kit - the motorized pinwheel. Here is the schematic: (if img not showing: https://goo.gl/tqZmKD) My question is, why is the 10k resistor needed after ...
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2answers
4k views

Why all blink tutorials use 330 ohm resistor

When I do the led calculation I found 150 ohm resistor is enough for 3mm red led. If so why all arduino tutorials, like this one, are suggesting 330 ohm resistor? I assume V = 5 Volt, diode forward ...
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2answers
590 views

How to interface DS1801 digital resistor with Arduino DUE SPI interface? What clock rate so use?

I am trying to program a digital resistor and set it's wiper resistance. The general circuit looks a little like this where "pot" represents the Maxim DS1801 digital resistor and DUE is, of-course the ...
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1answer
476 views

Lighting 5 leds...the last one lit is always dim

I have a simple project with a close deadline. I am trying to light up 5 LEDs as part of the project. The first 4 light up in sequence fine, and if I light up just the last one it lights up fine, but ...
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2answers
303 views

Source power with 2 V and LED with forward voltage of 2 V

I have a source power with 2 V and 100mA. I have an LED that has a forward voltage of 2 V and a max current of 20mA. Should I use a resistor to reduce the current? I see many formulas in the internet ...
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1answer
133 views

How much current and voltage has my resistor + LED

I have a very simple circuit: 5v -> LED (5mm, forward voltage of 2 V and max. current of 20mA) -> 1k ohm resistor -> GND. I want to know how much current is flowing in my circuit. I am using this ...
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1answer
316 views

how to calculate correct resistor value to use with LEDs Potentiometer and other devices?

I have been following http://arduino.cc/en/Tutorial/Fade to fade and LED. But I don't know why they are using a 220 Ohm resistor. According to Ohms law if LED is of 2.2 V and it runs on 0.025Amps and ...
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2answers
182 views

Which side should I connect the resistor on?

I understand that when connecting an LED and a resistor in series; the resistor can be placed on any side of the LED as the current will remain same in a series connection. Please correct me if I'm ...
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2answers
104 views

What does the datasheet information for a switch mean?

I'm clueless when it comes to the information on datasheets for switches. When I see a datasheet for LEDs or servos, I'm used to seeing a fairly straightforward call out for the required volts and ...
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2answers
2k views

Performance of internal vs external resistors

Is there any significant performance trade-off between buttons wired with the internal vs external pull-up/down resistors? I see a lot of tutorials demonstrating the use of external resistors when ...
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4answers
2k views

Importance of resistor

I'm new to Arduino and also new to electronics. I'm following the tutorial here. I'm not understanding the importance of the resistor in this schematic diagram. Can someone please help me on this?
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2answers
4k views

Can two LEDs attached to different pins share their resistor?

I'm designing an Arduino style board with built-in LEDs for several of the pins. To simplify assembly of the board and save on components, I was wondering whether it would be safe for those LEDs to ...
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1answer
4k views

Sensors and leds. This need resistors? and how?

I have a project with leds and sensors, this is my first project in Arduino and I want to know if it need resistors and how and where? I use 16-Bit I/O Expander MCP23017 for leds and multiplexer ...