အနုပညာ
အလှအပနှင့် ကျန်းမာရေး
လက်မှုအနုပညာ
ယဉ်ကျေးမှုနှင့် သမိုင်း
ဖျော်ဖြေရေး
ပတ်ဝန်းကျင်
အစားအစာနှင့် အချိုရည်
ပြောင်းပြန်အင်ဂျင်နီယာပညာ
သိပ္ပံပညာများ
အားကစား
နည်းပညာ
ဝတ်ဆင်နိုင်သောပစ္စည်းများ
Using Relays — SIK Circuit 13
Ed

ဖန်တီးသူ

Ed

17. မတ် 2026FI
၇၉
၀
၀
၀
၀

Using Relays — SIK Circuit 13

Control a relay with a transistor to switch between two LEDs. Learn about electromechanical switching, SPDT relays, Normally Open vs Normally Closed contacts, and flyback protection.

ညွှန်ကြားချက်များ

1

Parts & Introduction

A relay is an electrically-operated mechanical switch. A small current energizes a coil that physically moves a contact arm, switching a separate circuit. Relays can control high-power devices (motors, lights, appliances) from low-power Arduino signals. This experiment uses an SPDT (Single Pole Double Throw) relay to alternate between two LEDs.

Parts Needed

  • 1x Arduino Uno + USB cable
  • 1x Breadboard
  • 1x SPDT Relay
  • 1x NPN Transistor (P2N2222A)
  • 1x Diode (1N4148)
  • 2x LEDs (different colors)
  • 2x 330Ω Resistors
  • 14x Jumper Wires

Materials for this step:

SparkFun Inventors Kit - V3.2SparkFun Inventors Kit - V3.21 အစုံ
Arduino Uno R31 ခု
Breadboard1 ခု
SPDT Relay1 ခု
NPN Transistor (P2N2222A)1 ခု
Diode (1N4148)1 ခု
5mm LED1 ခု
330 Ohm Resistor330 Ohm Resistor2 ခု
Jumper WiresJumper Wires8 ခု

Tools needed:

Computer with Arduino IDE
2

Hardware Hookup

Wiring Instructions

Transistor + Relay Coil
  1. Connect transistor Base through 330Ω resistor to Arduino Digital Pin 2.
  2. Connect transistor Emitter to GND.
  3. Connect one side of the relay coil to transistor Collector.
  4. Connect other side of relay coil to 5V.
  5. Flyback Diode: Band (cathode) to 5V, anode to Collector.
Relay Contacts + LEDs
  1. Connect relay COMMON through a 330Ω resistor to 5V.
  2. Connect relay NC (Normally Closed) to LED 1 positive leg.
  3. Connect relay NO (Normally Open) to LED 2 positive leg.
  4. Connect both LED negative legs to GND.

Materials for this step:

SPDT Relay1 ခု
NPN Transistor (P2N2222A)1 ခု
Diode (1N4148)1 ခု
5mm LED1 ခု
330 Ohm Resistor330 Ohm Resistor2 ခု
Breadboard1 ခု
Jumper WiresJumper Wires8 ခု
3

Arduino Code

Open the Arduino IDE and upload the following sketch to your Arduino board.

relay.inoarduino
/*
SparkFun Inventor's Kit
Example sketch 13 — RELAYS

Use a transistor to drive a relay, alternating two LEDs.

Hardware connections:
  Transistor BASE through 330 ohm resistor to digital pin 2
  Transistor EMITTER to GND
  Relay coil: one side to COLLECTOR, other to 5V
  Flyback diode: band to 5V, anode to COLLECTOR
  Relay COMMON through 330 ohm to 5V
  Relay NC to LED 1 positive, Relay NO to LED 2 positive
  Both LED negatives to GND

This code is completely free for any use.
*/

const int relayPin = 2;
const int timeDelay = 1000;

void setup()
{
  pinMode(relayPin, OUTPUT);
}

void loop()
{
  digitalWrite(relayPin, HIGH);  // Relay on (COM connects to NO)
  delay(timeDelay);

  digitalWrite(relayPin, LOW);   // Relay off (COM connects to NC)
  delay(timeDelay);
}

Materials for this step:

Arduino Uno R31 ခု

Tools needed:

Computer with Arduino IDE
4

Test & Experiment

What You Should See

You should hear the relay clicking, and see the two LEDs alternating — one on, one off — switching every second.

Troubleshooting

  • LEDs not lighting: Check LED polarity — longer leg is positive.
  • No clicking sound: The transistor or coil circuit isn't working. Verify transistor orientation and coil connections.
  • Relay not making good contact: The SIK relay is designed for soldering, not breadboarding. Press it firmly to ensure all pins contact.
  • Confusion: Don't mix up the TMP36 temperature sensor with the transistor!

Experiments to Try

  • Replace the LEDs with a motor on the NO contact — use the relay as a motor on/off switch.
  • Use a button to control when the relay toggles.
  • Add variable delay to create morse code patterns.

ပစ္စည်းများ

9

လိုအပ်သော ကိရိယာများ

1
  • 13
    Computer with Arduino IDE
Estimated Total
$181.00

CC0 အများပိုင်

ဤအစီအစဉ်ကို CC0 အောက်တွင် ထုတ်ဝေထားသည်။ ခွင့်ပြုချက်မလိုဘဲ ကူးယူ၊ ပြင်ဆင်၊ ဖြန့်ဝေ နှင့် အသုံးပြုနိုင်သည်။

အစီအစဉ်မှတစ်ဆင့် ကုန်ပစ္စည်းများဝယ်ယူ၍ ဖန်တီးသူကို ပံ့ပိုးပါ ဖန်တီးသူ ကော်မရှင် ရောင်းချသူက သတ်မှတ်သည်၊ သို့မဟုတ် ဤအစီအစဉ်၏ ဗားရှင်းအသစ်ဖန်တီး၍ ဝင်ငွေခွဲဝေရန် သင့်အစီအစဉ်တွင် ချိတ်ဆက်မှုအဖြစ် ထည့်သွင်းပါ။

ဆွေးနွေးချက်

(0)

ဝင်ရောက် ဆွေးနွေးချက်တွင် ပါဝင်ရန်

Loading comments...