# 4 relay expansion board, UNO R3 and MEGA2560, 5V

> 4 relay shield for Arduino UNO R3 and MEGA2560, mounts directly on the board without extra cables and keeps access to the board pins. Operating voltage 5VDC, HIGH level activation, uses pins 4-7. Each relay has NO, NC and COM terminals plus a status LED. Dimensions 69.1 x 53.3mm. Avoid contact between the relay and the USB connector on UNO R3.

- Page: https://sigmanortec.ro/en/4-relay-expansion-board-uno-r3-and-mega2560-5v
- Price: 27.75 RON
- Availability: Out of stock
- Reference: 9722 · EAN: 5944323989138
- Category: Mechatronics and IoT > Shields and Expansion Boards
- Specifications: Input Voltage: 5 V; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.
- Package (shipping data): 0.042 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 04:49 (Europe/Bucharest)

## Description

Shield with 4 relays for safe control of high power consumers from Arduino signals, mounts directly on UNO R3 or MEGA2560 without additional cables and maintains access to the board pins. Operates at 5VDC with HIGH Level activation, uses pins 4-7, includes status LEDs and NO, NC, COM terminals for quick connection.
The Shield 4 relay module, compatible with Arduino UNO and MEGA2560, is an extension board used to control high power equipment through small current and voltage signals. It is ideal for Arduino UNO and MEGA because it eliminates the need for additional cables, connecting directly to the board and still allowing access to the pins of the development board used.
The relays work at a voltage of 5V, so it is exclusively compatible with logic voltages of 5VDC.
This Shield occupies pins 4, 5, 6 and 7 of the development board, which is why they cannot be used for other purposes.
IMPORTANT! When used with the UNO R3 board, make sure that the board's contacts (relay) DO NOT TOUCH the USB plug of the development board.
The relay channels have a HIGH Level type operation, which means they require 5V to be activated.
Specifications:
Operating voltage: 5VDC
Interface: Standard Shield, compatible with Arduino
Compatibility: UNO R3 and MEGA2560
Drive: High (5V), normally open contact
Indicators: LED relay indicators on the board (red)
Special Note: Avoid short-circuiting the green terminals with the USB case when using the UNO board
Relay Terminals: Each relay has three pins: NOx (normally open), NCx (normally closed), COMx (common)
Dimensions mm: 69.1 x 53.3mm