From home automation to industrial control, the 5V relay module is one of the most popular modules for switching power systems. So we decided to write an article about it, explaining how it works and some of its popular applications.
What is a 5V Relay Module?
Before we can understand how a 5V relay module works, we need to know what it is. The 5 volt relay module is a type of relay module that requires a 5V DC input to operate. But that’s not all there’s to it. Here’s more, including the specifications
5V Relay Module Description
A 5V relay module is a single or multi-channel relay module that works with a low-level trigger voltage of 5V DC. The input voltage can be from any microcontroller or logic chip that outputs a digital signal.
Like most other relays, the 5V relay module is an electrically operated, electromagnetic switch that can be used to turn on or turn off a circuit. It consists of two parts: the relay itself and the control module.
- The relay contains the coil that creates the magnetic field, the armature that move to complete or disconnect a circuit, and contacts that open and close to operate the load switch.
- The relay control module is the interface or part of the relay module that the user interacts with. It contains the input terminals for connecting to the microcontroller, as well as the output terminals for connecting to the load.
- The control module also contains LED indicators for power and status and other devices such as protection diode, transistor, resistor, and other semiconductor devices necessary for its operation.
5V Relay Module Specifications
The 5V relay module specifications are normally written on the top side. These include the input voltage/current, load current/voltage, and operating or release times. The specifications vary depending on the manufacturer. In general, they would look something like this:
- Normal voltage: 5V DC
- Normal current: 70mA
- Maximum load current: 10A/250V AC, 10A/30V DC
- Maximum switch voltage: 250V AC, 30V DC
- Operate time: ≤ 10ms
- Release time: ≤ 5ms
5V Relay Module Circuit
The 5V relay modules are made up of connection points or pins, and several major components, such as diodes, transistors, resistors, and the relay itself. These make up the circuit that controls the relay. The 5V relay module circuit is further explained below.
5V Relay Module Pinout
The 5V relay module pinout is composed of connections on the input side where it receives the trigger signal, and the output side where it controls the load.
The input side, as shown in the above relay module circuit diagram, has 3 or 4 connections: These are listed and explained below.
- VCC – this is the power connection. It supplies 5V DC to the module and is normally connected to the positive terminal of the power supply.
- GND – this is the ground connection. It connects to the negative terminal of the power supply.
- IN1, IN2 – these are the inputs where the trigger signal is applied. IN1 is for a single-channel relay module, while IN2 is for a dual-channel relay module. The IN (Input) pin is connected to the output of the microcontroller, sensor, or logic device.
The relay module output side has three connections:
- NO (Normally Open) – this is the load connection when the relay is ON. When the relay is off, the NO maintains an open connection with the COM.
- COM (Common) – The relay module connection labeled “COM” is the common connection for both the NO and NC (Normally Closed) pins.
- NC (Normally Closed) – this is the load connection. It connects to the COM terminal by default, or when the relay is OFF.
5V Relay Module Parts
Now, let’s take a look at the main components of a 5V relay module. They include
- The LED – this is an indicator or status LED that lights up when the relay is ON.
- The transistor – the transistor amplifies the trigger signal so that it can activate the relay.
- The diode – a flyback diode is used to protect the 5V relay module circuit from flyback voltage spikes when the relay coil de-energizes.
- The resistor – the resistor limits the current flowing through the relay module circuit.
- The relay – this is the main switching component of the module and usually either an NC (Normally Closed) or NO (Normally Open) type.
5V Relay Module Working
The 5V relay module requires a 5V signal delivered from a microcontroller or sensor to trigger the switch. Its working is also very simple. When the input pin is HIGH, the relay turns on, and when the input is LOW it turns off. Below is the 5V relay module working principle.
- The relay is activated by a low-level trigger signal applied to its IN1 or IN2 pin. When the trigger signal is applied, the transistor turns ON and amplifies the signal.
- This triggers the relay to turn ON and connect the load to either the NO or NC pin. The LED will light up to indicate that the relay is ON.
- When the trigger signal is removed, the transistor turns OFF and the relay turns OFF. The load is then disconnected from the NO or NC pin. The LED will turn OFF to indicate that the relay is OFF.
The 5V relay module can be used to control a load such as a lighting system, motor, or solenoid. It can also be used to switch AC or DC voltages. The maximum voltage and current that the 5V relay module can control is dependent on the specifications of the relay.
5V Relay Module for Arduino
The 5V relay module can be easily interfaced with an Arduino. The above diagram shows how to connect a single-channel relay module with Arduino microcontrollers, a popular project among hobbyists. The 5V relay module Arduino wiring is very simple:
You only need to connect the VCC and GND pins of the relay module to the 5V and GND pins of the Arduino, connect the IN1 pin of the relay module to a digital output pin of the Arduino, and connect the load to the NO and COM pins of the relay module.
- When the digital output pin is set to HIGH, the module turns ON and activates the relay. This will turn ON the load connected to the NO and COM pins of the relay module.
- When the digital output pin is set to LOW, the circuit OFF and deactivates the relay, turning OFF the load.
The 5V relay module can also be easily interfaced with a Raspberry Pi. When used with a Raspberry Pi, 5V relay module can be used to control a load such as an LED system, motor, or solenoid.
5V Relay Module Price
The 5V relay module price varies greatly, and is dependent on the specific configuration of the module. A single-channel 5V relay module can cost as little as $2 and a double relay module can cost as much as $3.
Because it finds wide use in electronics projects, the 5V relay module is a very popular module among hobbyists. It is also widely used by professionals in home, industrial and commercial power systems and equipment. Common applications include:
- Home automation
- Light control
- Motor control
- Solenoid control
- Valve control
- Process control
- Alarm systems
- Access control systems
- Surveillance systems
- DIY projects
The 5V relay module is a very handy tool for switching electric loads and power systems. What’s more, you can interface with an array of microcontrollers, including Arduino or Raspberry Pi, as well as other logic devices. The 5V relay module can also be used to switch AC or DC voltages. Just be sure to check the specifications of the relay to ensure that it can handle the voltage and current of your load.