5V Four-Channel Relay Module Pinout
The four-channel relay module contains four 5V relays (each capable of switching a separate electrical circuit or devices) and the associated switching and isolating components. The pinout of a four-channel relay module typically consists of multiple pins, each serving a specific purpose. Let’s take a look:
Power and Control Pins
VccThis pin provides power to the relay module. Connect it to the 5V pin on the Arduino.
GNDThis pin provides the common ground for the module.
Control Pins (IN1, IN2, IN3, IN4) These pins are the control input for relays. Sending a high or low signal to any of these pins activates or deactivates the relay associated with the pin.
Relay Output Connections
NO-Normally openThis pin represents the normally open contact of the relay. Initially, it is not connected to the common (COM) pin, but when the relay is powered on, it gets connected to the common pin.
NC-Normally Connected or CloseThis pin signifies the normally closed contact of the relay. Initially, it is connected to the common (COM) pin when the relay is inactive, but gets disconnected from the common when the relay is activated.
COM-CommonThis pin serves as the common contact for the relay. Initially, it is connected to a normally closed (NC) pin, but when the relay is activated, it gets connected to the Normally Open (NO) pin.
5V Four-Channel Relay Module Hardware Overview
A 5V four-channel relay module consists of various hardware components that work together to enable its functionality. Here’s an overview of the hardware parts found in this module:
Protection and control circuitryProtection and Control Circuitry consists of active and passive components like transistors, diodes and resistor.
- Resistor: to control the current going into base of transistors.
- Transistor: Each control pin is connected to a transistor, which acts as a switch to control the relay’s coil.
- Diodes: Diodes are used to protect the circuit from voltage spikes and back EMF (Electromotive Force) generated by the relay coils when they are switched off. These diodes, known as flyback diodes, prevent damage to the other components and ensure smooth operation.
5V RelaysThere are four relays which can be controlled by 5 V Dc which in turn can control maximum 220V AC appliances at 10 Amps current as well as 30V DC appliances at 10 Amps currents.
Power LEDThe illumination of the power LED indicates that the module’s internal power supply is active and functioning properly. It serves as a visual indicator that the module is ready to operate.
Indicator LEDsThere are usually LED indicators associated with each relay channel. These LEDs provide a visual indication of whether the relay is currently active (ON) or inactive (OFF).
Internal Circuit Diagram of 5V Four-Channel Relay Module
The input of relay board is connected to base of the PNP transistor. When this pin is HIGH the relay is de-energised. When this pin is LOW then 5V supply is shorted with the Relay supply, hence it is activated. In this circuit this PNP transistor acts as NOT GATE.
The flyback diode IN 4148 connected in parallel with coil but in reverse biased, used for protection of circuit from back EMP which is produced by relay when it is turned OFF.
When the relay activates the COM pin is connected to the NO pin. When it deactivates the COM pin is connected to NC pin.
Four-Channel Relay Module Specifications
- Supply voltage – 3.75V to 6V
- Trigger current at input pins– 5mA
- Current through coil when the relay is active – ~70mA (single), ~300mA (all four)
- Relay maximum current at output– 10A
- Relay maximum contact voltage at output– 250VAC, 30VDC
Interfacing a Four-Channel Relay Module with Push Buttons
Nowletus learn how to interface 4-Channel Relay module with push button.
In the wiring diagram below,we can see a relay board on which 4 relays are mounted along with other active and passive components.
There are four Red status LED which glows when respective relay activates. Also there is one Green coloured power LED which glows when power and ground is connected to board.
A 6V battery is used to give power to relay board. Four input pins IN1, IN2, IN3,In4 are connected to push button which are connected to ground pin of the 6V battery. The circuit of relay board is such that when ground is provided at a particular input that is when push button is pressed then corresponding relay activates and its status LED starts glowing.
NO pin which is previously open is connected to common pin as long as button is pressed, that is as long as input pin is connected to ground.
Output
Components Used
| Component Name | Quantity | Remarks |
|---|---|---|
| Push Button | 4 | Connect when button is pressed. |
| 6V Battery | 1 | To supply power to Relay Module |
| Breadboard | 1 | Half Size |
| Connective Wires | 10 | For Breadboard Connections |
Interfacing Four-Channel Relay Module with Arduino
Interfacing a 4-channel relay with an Arduino Uno is a simple and efficient way tocontrol AC/DC appliances.
We can control AC equipment which can be connected to output of relay using Arduino board which runs on 5V DC.
In this tutorial we will be controlling only DC components using the Relay.
