What is SMPS?

Key Components Of a Switch-Mode Power Supply

What is a Contactor?

A contactor is a switch in an electrical power circuit, similar to relays, which is designed to handle high currents. They are very important in electrical systems, and they are safe & efficient in switching high-power devices. They are mostly used for controlling electric motors, lighting systems, heating equipment, and other heavy-duty electrical devices. 

Contactors are controlled by an electromagnetic coil when they are energized, closing the circuit and allowing current to flow to the connected load. Contactors are used as an important part of motor starters, HVAC systems, lighting controls, and various automated electrical networks.

Contactor Symbol, and Representation

Contactor symbol is made of a rectangle with coil designation (e.g., “K”) and associated contact symbols.

The contactor coil is usually represented by a rectangle with terminal numbers (e.g., A1 and A2) indicating coil connections.

Contact Representation - Contacts are shown separately from the coil using lines and symbols normally open (NO) contacts are shown as two parallel lines, and normally closed (NC) contacts as one straight and one angled line.

Components of Contactors

Components of contactors ensure the safe and efficient operation under high electrical loads.

1. Electromagnetic Coil

This is the main component in the contactor, which is responsible for generating the magnetic field required to operate the switch. When voltage is applied to the coil terminals A1 & A2, it generates a magnetic force that pulls in the armature, closes the main contact,s and completes the circuit.

2. Armature

Armature is a movable iron core that gets attracted to the coil’s magnetic field. It is made up of silver alloy. The movement of the armature causes the main contacts, and these contacts are typically designed to handle high current loads.

3. Auxiliary Contacts

These contacts are used for signaling, interlocking, or control functions. They can be normally open (NO) or normally closed (NC) and are often used in control circuits.

4. Enclosure and Arc Chutes

Enclosure provides insulation and mechanical protection, and arch chutes help to extinguish electrical arcs which formed when the contacts open under load.

Types of Contactors

Based on the design, operating mechanism, and application, contactors are classified as electromagnetic, manual, magnetic, AC, and DC contactors.

1. Electromagnetic Contactors

Electromagnetic contactors operate using an electromagnetic coil which, when energized, pulls the movable armature into close the contacts and allows the current to flow through the circuit. They are used for remote and automatic switching of high-power loads, such as motors and heavy machinery.

 Manual Contactors

Manual contactors require human intervention to operate. The push button is required in these types of devices to open or close the circuit. Mostly manual contactors are used in remote operation, and they are valued for their straightforward operation.

Magnetic Contactors

They use a magnetic field to operate the switching mechanism. They are mainly used for frequent switching mechanisms and are widely used in motor control centres, HVAC systems, and industrial automation. They offer various features like overload protection, arc suppression, and durability, which makes them suitable for continuous duty applications.

AC Contactors

They are designed for controlling alternating current circuits. AC contactors have components that are optimized for the nature of AC power, such as arc chutes and laminated cores to reduce humming and heat. They are commonly used in lighting, heating, and motor control applications.

DC Contactors

DC contactors are used to switch direct current circuits. They are used to handle the constant voltage and higher arc energy associated with DC power. These contactors include specialized arc suppression techniques and are often used in battery-powered systems, electric vehicles, and solar applications.

Functions of Contactors

• Contactors are used to turn high-power electrical devices ON and OFF remotely or automatically. 

• For managing the function like starting, stopping, and reversing, contactors are used in motor starters.

• Contactors isolate the control circuit from the high-voltage power circuit, which ensures user and system safety.

• Contactors enable the remote control from a distance using control signals, ideal for automation.

• Contactors are often integrated with overload relays to disconnect power during fault or overload conditions.

• Contactors are used in large commercial setups to manage lighting circuits and heating elements efficiently.

Contactors Working Principles

• Contactors' working principle is based on electromagnetic switching, which allows for to control high-power electrical circuits using a low-voltage control signal.

• When an electrical current flows through the contactor’s coil, it generates a magnetic field that pulls a movable iron armature toward the coil.

• This movement causes the main contacts to close, completing the circuit and allowing current to flow to the connected electrical load, such as a motor or lighting system.

• When the coil is de-energized, the magnetic field collapses, and a spring mechanism pushes the armature back to its original position. This action opens the contacts and interrupts the current flow, effectively turning off the load.

• Contactors usually feature normally open (NO) main contacts, which means the circuit remains open until the coil is energized.

• To enhance safety and performance, contactors may also include arc suppression mechanisms, such as arc chutes, to safely extinguish electrical arcs formed when contacts open under load. Additionally, auxiliary contacts are often integrated for signaling or interlocking purposes in control systems.

Contactor Wiring Diagram

A contactor wiring diagram is a schematic representation showing how a contactor is connected within an electrical circuit to control a load such as a motor or lighting system.

It includes components like contactor coil (A1 and A2 terminals), main contacts (L1, L2, L3 to T1, T2, T3), overload relay, auxiliary contacts, and power source.

Wiring diagrams typically separate the power circuit (handling high current to the load) from the control circuit (managing the contactor's coil).

The coil is connected to a control switch or push button, often in series with protection devices like fuses or circuit breakers.

A basic contactor diagram includes a start button (NO) and a stop button (NC) connected in series to control the coil energization.

An overload relay is usually wired in series with the contactor to protect motors from overheating and current surges.

Auxiliary contacts are shown in the diagram to provide latching or interlocking functions, enhancing control and automation.

For motor control, the diagram shows three-phase input (L1, L2, L3) connected to the contactor’s top terminals, and output to the motor from T1, T2, T3.

Proper neutral (N) and ground (PE) connections are indicated for safe and reliable operation.

Difference Between Contactors and Relays

Applications of Contactors

• Contactors are used extensively to start, stop, and reverse electric motors in industrial machinery and automation systems.

• They are employed to control large lighting circuits in commercial buildings, stadiums, and street lighting systems.

• Integral in heating, ventilation, and air conditioning systems for switching compressors, fans, and pumps.

• Contactors are used to manage the distribution and switching of power in electrical panels and substations.

• Essential in automated production lines, PLC systems, and control panels for remote and sequenced operations.

• Contactors are applied in power factor correction units to switch capacitor banks on and off automatically.

• Contactors are utilized to control water pumps, irrigation systems, and sewage treatment equipment.

Frequently Asked Questions

1.What is the most common reason for contactor failure?

The most common reason for contactor failure is contact wear due to frequent switching and electrical arcing.

2. What happens when a contactor fails?

When a contactor fails, it can result in equipment not starting, stopping unexpectedly, or continuous operation due to stuck or burned contacts.

 3. What is the function of AC contactor?

The function of an AC contactor is to switch and control the flow of AC electrical power to loads such as motors, lighting, and heating systems.

 4.Are contactors AC or DC?

Contactors are available in both AC and DC versions, depending on the application and coil voltage requirements.

 5. Does a contactor reduce voltage?

No, a contactor does not reduce voltage; it simply switches electrical power on or off in a circuit.

 6. How do you test if a contactor is bad?

You can test if a contactor is bad by checking coil voltage and measuring continuity across the contacts using a multimeter.

 7. Can a contactor work without a coil?

No, a contactor cannot work without a coil, as the coil is essential for creating the magnetic field that closes the contacts.

In the ever-evolving landscape of communication technologies, the integration of MQTT (Message Queuing Telemetry Transport) protocol with 4G modules has become an important aspect in IOT. In this article we will discuss how the MQTT protocol works in 4G modules, we will understand what MQTT protocol is, its use cases. And much more.

What is MQTT?

MQTT is a standards-based messaging protocol, or set of rules, used for machine-to-machine communication. Smart sensors, wearables, and other Internet of Things (IoT) devices typically have to transmit and receive data over a resource-constrained network with limited bandwidth. These IoT devices use MQTT for data transmission, as it is easy to implement and can communicate IoT data efficiently. MQTT supports messaging between devices to the cloud and the cloud to the device.

The MQTT Protocol Consists of Four Main Components

Client: A device or application that connects to the MQTT broker to either publish or subscribe to topics.

Broker: A server that receives and distributes messages between publishers and subscribers. The broker is responsible for authenticating clients, enforcing access control, and managing subscriptions and message delivery.

Topics: A named channel that a publisher uses to send messages to subscribers. Topics are hierarchical and use a forward-slash (/) as a delimiter to create a tree-like structure.

QoS (Quality of Service): MQTT provides three levels of QoS to ensure message delivery reliability. QoS 0 delivers messages at most once, QoS 1 delivers messages at least once, and QoS 2 delivers messages exactly once.

The basic flow of MQTT communication is as follows:

• The client connects to the broker using a TCP/IP connection and authenticates itself.

• The client subscribes to one or more topics by sending a SUBSCRIBE message to the broker.

• The publisher sends a message to the broker, which stores the message and forwards it to all subscribers that have subscribed to the corresponding topic.

• The broker sends the message to the subscribers based on their QoS level.

• The subscribers receive the message and acknowledge receipt to the broker based on their QoS level.

• The publisher and subscribers can disconnect from the broker by sending a DISCONNECT message.

Why is the MQTT protocol significant?

The MQTT protocol has attained the status of a standard in IoT data transmission because of the following advantages:

Lightweight and Efficient Implementing: 

MQTT on IoT devices demands minimal resources, making it suitable for deployment even on small microcontrollers. A case in point is a basic MQTT control message that can consist of as little as two data bytes. Additionally, MQTT message headers are designed to be compact, enabling optimization of network bandwidth.

Scalable:

The implementation of MQTT involves a modest amount of code that consumes minimal power during operations. The protocol is equipped with inherent features that facilitate communication with a vast number of IoT devices. Consequently, deploying the MQTT protocol allows seamless connection with millions of such devices.

Reliable: 

Numerous IoT devices operate in environments characterized by unreliable cellular networks with low bandwidth and high latency. MQTT incorporates features that mitigate the time taken by IoT devices to reconnect with the cloud. Moreover, it defines three distinct quality-of-service levels— at most once (0), at least once (1), and exactly once (2)—to ensure reliability in various IoT use cases.

Secure:

 MQTT streamlines the process for developers to encrypt messages and authenticate devices and users, leveraging contemporary authentication protocols like OAuth, TLS1.3, Customer Managed Certificates, and more.

Well-supported:

 Languages such as Python offer robust support for the implementation of the MQTT protocol, enabling developers to swiftly incorporate it into diverse applications with minimal coding effort.

How to Establish MQTT Connection with SIM7672 4G Module

SIM7672 MQTT AT Commands

The SIM7672 GSM Modem comes with a pre-installed MQTT AT commands stack. These AT commands help us to establish connections with an MQTT broker and publish messages. Additionally, we can subscribe to MQTT topics, facilitating the reception of messages from other MQTT clients. Refer to the table below, which illustrates the utilization of diverse AT commands related to MQTT.

You can use microcontroller for eg. ESP32, Arduino or which has UART pins to connect with SIM7672 4G module, to fully automate the AT sequence and run the system seamlessly.

You can refer below image for interfacing microcontroller with SIM7672 module:

Applications of MQTT Integrated with 4G Modules

Smart Cities

In the realm of smart cities, MQTT over 4G enables efficient communication between various sensors, devices, and infrastructure components.

Industrial IoT

In industries, the combination facilitates real-time monitoring and control, ensuring seamless operations and quick response to potential issues.

Home Automation

In smart homes, MQTT over 4G allows devices to communicate seamlessly, providing homeowners with centralized control over various appliances and systems.

Conclusion

MQTT's simplicity and efficiency make it an ideal choice for many IoT and M2M communication scenarios, where low power consumption, small code footprint, and low network bandwidth are essential.

If you want to establish MQTT communication Protocol in your project then SIM7672 4G module is the best in overall performance. If you're ready to elevate your projects with the seamless synergy of MQTT and SIM7672, and many other electronic components, visit the best electronic components online store- Campus Component today.

OLED (Organic light emitting diodes) are a type of display technology that is rapidly gaining popularity in a variety of applications including embedded systems, IOT, smart wearables, smartphones. OLED displays offer many advantages over  LCD displays. OLED has revolutionized the way we interact with screens on various devices. In this blog, we'll discuss OLED displays, their advantages, and applications.

What is OLED?

The acronym ‘OLED’ stands for Organic Light-Emitting Diode. OLED is a technology that uses LEDs in which the light is produced by organic molecules. OLED displays are made by placing a series of thin organic films between two conductors. When an electrical current is applied, a bright light is emitted. 

OLEDs make use of emissive displays, allowing each pixel to be individually controlled and emit its light, in contrast to LCDs that work on a backlighting unit. This feature of OLED displays results in excellent image quality, vivid colors, rapid motion response, and high contrast. Another advantage of the uncomplicated design of OLEDs, this makes it easy to produce flexible and transparent displays.

Advantages of OLED Displays

• Flexible and Thin: OLED displays can be made to be flexible and thin, which makes them ideal for applications such as wearables and curved and small displays.

• Faster Response Times: OLED pixels have faster response times than LCD pixels, reducing motion blur in fast-paced scenes, which is especially beneficial for gaming and sports enthusiasts.

• Wider Viewing Angles: OLED displays maintain their picture quality at wider viewing angles, ensuring a consistent visual experience for viewers from various positions.

• Improved Image Quality: OLED displays offer superior contrast, brightness, and viewing angles compared to LCD displays. This is because OLED displays emit their own light, rather than relying on a backlight.

• Thinner and Lighter: OLED displays are significantly thinner and lighter than LCD displays. This is because OLED displays do not require a backlight or polarizer, which are two of the major components of LCD displays.

• Lower Power Consumption: OLED displays consume significantly less power than LCD displays. This is because OLED displays only emit light when they are being activated, which means that they can be turned off when they are not being used.

Applications of OLED Displays

• Consumer Electronics: OLED displays are commonly used in smartphones, tablets, laptops, and smartwatches, enhancing the user experience with vibrant colors and sharp images.

• Television and Monitors: High definition televisions and monitors use OLED technology to deliver superior picture quality, captivating viewers with lifelike images.

• Automotive: OLED displays are increasingly finding their way into the automotive industry, dashboards, infotainment systems, and rear lights, providing both aesthetic appeal and functionality.

• Lighting: OLEDs are also used in lighting solutions, offering soft, diffused lighting that can be taken use into various designs and shapes.

Lets See Some Features of Available OLED Displays from Campus Component

1. 0.96 inch OLED Display -AR-826-D

0.96 inch OLED display Features:-

• Display Type: OLED

• Dot Matrix: 128x64

• Dot Size: 0.154mm * 0.154mm

• Dot Pitch: 0.17 * 0.17 mm

• Aperture Rate : 78%

• Active Area : 21.744 * 10.864mm

• Driver IC: SSD1306

2. 2.8" DWIN Smart Capacitive Touch Screen Display DMG32240C028_03WTC- LC-2849-D

The DMG32240C028 2.8" Smart Capacitive Touchscreen Display can easily be interfaced with microcontrollers & controller boards like Arduino Uno, Arduino Nano, Arduino Mega, ESP8266, ESP32, PIC Microcontrollers, 8051 family of microcontrollers, etc.

2.8” Smart Capacitive Touch screen Display DMG32240C028_03WTC Features:-

• Size: 2.8"

• Touch Type: Capacitive

• Resolution: 320x240

• Grade: Commercial

• Color: 262K Colors; 18 Bit

• Dimensions: 85.2 mm (W) x 55.6 mm (H) x 11.65 mm (T)

• Backlight: LED

• Brightness: 200 nit

• Operating Voltage: 5 Volts

• Operating Current: 40ma to 105ma

• Working Temperature: -20 to 70°C

3. OLED 0.91 Inches 128X32-LC-585-D

OLED 0.91 inches 128*32 – LC – 585 – D Features:-

• 0.91inch small form factor

• 128x32 high resolution

• I2C interface, requires only two signal pins

• Driver: 1306

• Interface: I2C

• Display color: White

• Resolution: 128x32

• Viewing angle: >160°

• Operating voltage: 3.3V / 5V

Conclusion

OLED display is a promising new display technology that offers a number of advantages over traditional LCD displays. As OLED technology continues to develop and more applications come in, it's become easier for developers to rely on an OLED display because of features offered at lower price.

If you are building an IOT device and looking for OLED display from brands such as Sinda, Nextion, Abilton to incorporate in your project then reach out to us at Campus Component today!

In the rapid development of Embedded systems and IoT (Internet of Things), the ESP8266 series of Wi-Fi modules has become popular for its ease of use and affordability. Recently Espressif launched its successor, i.e., the ESP8685 Wi-Fi module, which is a powerful upgrade to revolutionize the world of connected devices. In this blog post, we'll discuss in depth details of the ESP8685, exploring its features, advantages, and its potential impact on the IoT.

What is ESP8685?

ESP8685 is an ultra-low-power and highly-integrated MCU-based SoC solution that supports 2.4 GHz Wi-Fi and Bluetooth® Low Energy (Bluetooth LE). It is a powerful and versatile chip that can be used in a wide variety of applications, including smart home devices, industrial automation, and wearables and all types of IoT application. The block diagram of ESP8685 is shown below.

Pin Layout of ESP8685:

Below diagram shows the Pin Definition of ESP8685

It comes with Ultra Low Power SoC with RISC-V Single-Core CPU Supporting IEEE 802.11b/g/n (2.4 GHz WiFi) and Bluetooth® 5 (LE) 2MB(ESP8685H2) or 4MB(ESP8685H4) flash in the 4×4mm QFN package.

Refer ESP8685 datasheet for more details on Architecture.

Let’s See the Features of ESP8685:

WIFI

1) ESP8685 has IEEE 802.11b/g/n-compliant WiFi.

2) It Supports 20MHz, 40MHz bandwidth in the 2.4 GHz band.

3) 1T1R mode with data rate up to 150 Mbps 

4) Wi-Fi Multimedia (WMM).

CPU and Memory

 1) 32-bit RISC-V single-core processor, up to 160MHz..

 2) Core Mark® score:–1 core at160 MHz, 407.22 Core Mark, 2.55 Core Mark/MHz.

 3) 384KB ROM.

 4) 400KB SRAM (16KB for cache).

 5) 8KB SRAM in RTC.

 6) Access to flash accelerated by cache 

 7) Supports flash In-Circuit Programming (ICP).

Advanced Peripheral Interfaces

1) 15 × programmable GPIOs 

2) Digital interfaces:

– 3× SPI (SPI0 and SPI1 are used to connect the SiP flash. Only SPI2 is available).

– 2×UART

– 1×I2C

– 1×I2S

– Remote control peripheral, with 2 transmit channels and 2 receive channels

– LED PWM controller, with up to 6 channels

– Full-speed USB Serial/JTAG controller

– General DMA controller (GDMA), with 3 transmit channels and 3 receive channels

– 1×TWAI®controller compatible with ISO 11898-1(CAN Specification 2.0) 

3) Analog interfaces:

–2×12-bit SAR ADCs, up to 6 channels

–1× temperature sensor

4) Timers:

–2×54-bit general-purpose timers

–3×watchdog timers

–1×52-bit system timer

Low Power Management

•Power Management Unit with four power modes.

Security

1) Secure boot 

2) Flash encryption 

3) 4096-bit OTP, up to 1792 bits for use 

4) Cryptographic hardware acceleration:

–AES-128/256 (FIPSPUB197) 

5) Permission Control 

6) SHA Accelerator (FIPSPUB180-4) 

7) RSA Accelerator 

8) Random Number Generator (RNG) 

9) HMAC 

10) Digital signature

Applications of ESP8685

• Smart Home

– Light control

– Smart button

– Smart plug

– Indoor positioning.

• Industrial Automation

– Industrial robot

– Mesh network

– Human machine interface (HMI)

– Industrial field bus.

• Health Care

– Health monitor

– Baby monitor.

• Consumer Electronics

– Smart watch and bracelet

– Over-the-top (OTT) devices

– Wi-Fi speaker

– Logger toys and proximity sensing toys.

• Smart Agriculture

– Smart greenhouse

– Smart irrigation

– Agriculture robot.

• Retail and Catering

– POS machines

– Service robot.

• Audio Device

– Internet music players

– Live streaming devices

– Internet radio players.

• Generic Low-power IoT Sensor Hubs 

• Generic Low-power IoT Data Loggers

Conclusion

ESP8685 combines advanced features, low power consumption, and affordability. Its robust connectivity, powerful processing, offer developers endless possibilities for creating innovative smart applications. If you are looking for a Wi-Fi and Bluetooth LE-enabled chip with ultra-low power consumption from Espressif, ESP8685 Wifi Module is a great option to consider.