The Difference Between Relays and Solenoids
When it comes to sourcing electronic or electromechanical components, having a clear understanding of common options and their distinct roles in operation is crucial for proper investments to be made. For many, relays and solenoids come up as a point of confusion, both devices being electrically operated switches that rely on electromagnetic principles to carry out their functions. Despite these shared features, both parts serve unique purposes as a result of their differing design, principles, and more.
In this blog, we will break down the core differences between relays and solenoids, helping buyers make more informed purchasing decisions based on their application’s requirements. As such, be sure to read on if you are interested in learning more.
What Is a Relay?
Put simply, a relay is a form of electromechanical switch that is designed to manage one or more connected circuits through a single, low-power signal. This simple capability makes relays quite versatile in use, allowing for a high level of control to be enacted over systems and devices.
Characteristics of Relays
- Input Terminals: These terminals receive the low-power control signal.
- Operating Contacts: Operating contacts are what open or close in response to received signals to control connected circuits.
- Electromagnetic Function: For basic options, an electromagnet is what activates switching for the relay.
Common Types of Relays
- Electromechanical Relays (EMR): As the most basic option, EMRs leverage physical moving parts to manage connected circuits.
- Solid-State Relays (SSR): SSRs take advantage of semiconductor elements to carry out operations with no moving parts.
Common Applications of Relays
- Automotive Systems
- Industrial Automation
- Home Appliances
- Power Distribution Panels
What Is a Solenoid?
Solenoids come in the form of coils of wire that act as an electromagnet when electrical current passes through them, serving as a basic element of larger devices. For example, one may find solenoids within switches, valves, and actuators, where they offer various functionalities through their implementation.
Characteristics of Solenoids
- Magnetic Coil: The magnetic coil is what generates a magnetic field as the solenoid is energized.
- Movable Plunger: The plunger of a solenoid moves in or out of the coil when energized to perform mechanical work.
- Spring Mechanism: This mechanism assists in returning the plunger to its resting position as voltage ceases to be supplied to the component.
- High Current Capacity: Solenoids are typically designed to handle 85 to 200 amps.
Common Applications
- Vehicle Starter Systems
- Industrial Machinery
- Electrical Winches
- Automated Doors and Locks
A Basic Comparison Between Relays and Solenoids
| Feature | Relay | Solenoid |
|---|---|---|
| Primary Function | Switch Electrical Circuits | Create Mechanical Movement |
| Form of Operation | Electrical Switching | Electromechanical Actuation |
| Current Handling | Lower (Controls High Current via Input Signals) | Higher (Can Handle 200 Amps or Higher) |
| Cost | Relatively Cheap | Potentially Higher Costs |
How to Choose Between Relays and Solenoids
Consider Your Application
Use a relay when:
- You need to control electrical circuits without mechanical motion
- Multiple circuit control from a single input is necessary
Use a solenoid when:
- You need to convert electrical signals into motion
- Physical actuation or movement is required
Determine Required Current Carrying Capacity
Solenoids tend to support higher current load levels than relays. However, this added capacity often results in a larger physical size and higher costs. Before making a concrete division on any particular part, be sure to review your system’s layout and determine if there are any sizing or accommodation restraints.
Factor in Environmental Stress and Risks
Solenoids and relays alike are at risk of exposure to various environmental conditions that may cause damage or detract from performance, with many issues stemming from exposure to:
- Moisture
- Dust
- Vibration
- Temperature Extremes
Before selecting a relay or solenoid, check the device’s Ingress Protection (IP) rating, confirm whether the component is able to withstand heat or cold conditions, and choose devices that are sealed or protected if they are to be exposed to tough environments.
Look for Duty Cycle Ratings
When considering solenoids specifically, it is important to note that they will either be rated for intermittent or continuous duty cycles.
- Intermittent Duty: With this cycle, the solenoid will exhibit short bursts of activation.
- Continuous Duty: Continuous duty solenoids will provide constant or long-term operation.
Procure Relays and Solenoids on ASAP Aviation Supplies
While relays and solenoids may seem similar at a glance, their functions, designs, and applications are quite different. By evaluating your project’s needs, especially in terms of current capacity, mechanical requirements, environmental exposure, and duty cycle, you can confidently select the right component for the job.
Here at ASAP Semiconductor, we understand how crucial it is to choose the right electronic components for your operations, so we proudly provide customers access to a wide range of top-quality products through ASAP Aviation Supplies. As you explore our curated product catalogs, you will find relays, solenoids, and other various electronics of need, all being sourced from leading manufacturers and suppliers across the globe to guarantee quality. Take all the time you need to explore, and once you are ready to begin procurement, do not hesitate to request a quote through our website to get in touch with staff.
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