Modules
1-Channel Relay Module
৳95
Switches one mains or DC load from a single microcontroller pin, with an opto-isolated input and a status LED.
The opto-coupler keeps the switched side electrically separate from the microcontroller, which is what makes it safe to drive a high-voltage load from a 5V logic pin. Screw terminals bring out normally-open, normally-closed and common contacts.
What you can build
- Switching a lamp, fan or pump from a timer or a sensor
- Home automation controlled over WiFi from an ESP32
- Fail-safe circuits using the normally-closed contact
Not sure it will work? Test your circuit free in Tekko Sim — on your phone, in Bangla or English.
| Category | Modules |
| Model no. | 1CH 5V |
| Availability | In stock |
| In stock | 10 pcs |
| Delivery | Cash on Delivery, nationwide Bangladesh |
| Channels | 1 |
| Coil Voltage | 5V DC |
| Trigger | one digital pin, active LOW on most boards |
| Isolation | opto-coupler on the input side |
| Contact Rating | up to 10A at 250V AC or 10A at 30V DC, as printed on the relay |
| Contacts | normally-open, normally-closed and common screw terminals |
| Coil Current | roughly 70 mA when energised |
Questions about the 1-Channel Relay Module
Can this relay switch 220V mains?
The relay is rated for it, but the module has no enclosure and mains wiring is genuinely dangerous. If you are not confident working at 220V, switch a low-voltage load instead or have an electrician wire the mains side.
Why does the relay switch on when my Arduino pin is LOW?
Most of these boards are active LOW, so the relay energises when the input is pulled to ground. Use digitalWrite(pin, LOW) to turn it on. Set the pin HIGH before you set it as an output, otherwise the relay clicks on for a moment at every boot.
Does it need its own power supply?
The coil draws around 70 mA, which is more than a single Arduino pin can source but is usually fine from the board's 5V rail for one channel.
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