Hi, i send arduino input low and high to transistor, but when input is low relays remain in NC status.
Code is blink code with pin 13 , and schemas is under....
Please help me
pinMode(13, OUTPUT);
Always show us a good schematic of your proposed circuit.
Show us good images of your ‘actual’ wiring.
Give links to components.
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There are two things that will cause always closed. The coil is powered or the contacts welded. Turn off the power and measure between the contacts, they should be open, if not the relay is bad. What are you trying to switch with it and post a link to your load.
Its look like the coil is always powered.
If i put 330 ohm in R1 the coil is never powered.
The rele is ok, i try to energize it separtely.
Maybe the breadboard is broken?
Hi,
Please post your code.
What pin do you have coded as output?
If you remove the orange jumper does the relay open?
Can you please post pictures of the other side of the board with the relay on it?
Thanks.. Tom... 
Assume the red in on pin 13. Code work well.
I've connected fast to take a photo.
The problem, if rhere is a problem is on components o in the bredboard zone.
Can you have see something wrong in that area?
Sorry, what do you mean?
Tom...
Jumper in the photo is in bad position but only for th photo. If i remove orange jumper the relay is open.
The rest of connection is ok?
Maybe i can solder all to test without breadboard?
You have a base resistor of only 10 ohms so you probably burned out the transistor. That's why it's always on.
Get a new transistor and use a base resistor of 1K ohms
But you thought it was 100Ω .
That's a common mistake to make.
The colour code on the resistor is brown, black, black.
Brown = 1, Black = 0, so it looks like 1 0 0 , which you have read as 100Ω.
But that last 0 is actually a multiplier - you multiply the first two digits by 10^0 (=1), or you add zero zeros after the first two digits.
For 100Ω, the colour code is brown, black, brown.
1 0 1 means 10 plus 1 more zero which equals 100.
That's why I always check my resistors with a DMM... besides the fact that my color vision is defective 
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I try to replace my transistor, put 1k resisto in base and test.
Also my color vision is defective 
I'll update you as soon as possible. Thank you all
[image]
This is my code
/*
Blink
Turns an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
the correct LED pin independent of which board is used.
If you want to know what pin the on-board LED is connected to on your Arduino
model, check the Technical Specs of your board at:
https://www.arduino.cc/en/Main/Products
modified 8 May 2014
by Scott Fitzgerald
modified 2 Sep 2016
by Arturo Guadalupi
modified 8 Sep 2016
by Colby Newman
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink
*/
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
pinMode(8, OUTPUT);
pinMode(13, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
digitalWrite(8, HIGH);
digitalWrite(13, HIGH);
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
digitalWrite(8, LOW);
digitalWrite(13, LOW);
delay(1000); // wait for a second
}
It's work!! It's burned the transistor for the low R1. Thanks
1 Like
Glad it worked!
Now have fun.
There is only one thing worse than a photo of a circuit and that’s a photo with the wires in the wrong place
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