Relays, which may regulate one electrical circuit by opening or closing contacts in another, are essential components in many electronic and electrical systems. The market is dominated by two types of relays: standard and power. So, how are they different, and where does each excel?
A relay is an automated electrical switching device that works on electromagnetic principles. It can control high power circuits by means of low power electrical signals (such as current or voltage), thus achieving switching control of signals such as current and voltage. Relays are commonly used in areas such as automated control, protection and alarm systems.
A power relay isolates the control circuit from the load circuit, allowing a low-voltage signal to switch high-power currents. When energized, the electromagnet attracts an armature, changing the contact positions—normally open (NO) contacts close to complete the load circuit, while normally closed (NC) contacts open to interrupt it.
Designed for high-current switching, power relays reliably control motors, heaters, and other heavy loads. They often include protective features such as arc suppression, overload protection, and time-delay functions to ensure safe and stable operation.
A regular relay operates on electromagnetic principles, where current flowing through the coil generates a magnetic field that attracts an armature, mechanically switching the contacts. These contacts consist of normally open (NO) and normally closed (NC) types—when energized, the NO contact closes while the NC opens, and when de-energized, a spring returns the armature, reversing the contact positions.
Designed for low-power control, regular relays typically operate at 12V or 24V DC with current ratings of a few amps, making them ideal for household appliances and small equipment. Unlike power relays, they lack advanced features like overload protection or time delay, serving primarily as simple electrical switches for basic circuit control.
Power relays are usually used to control high-power, high-current circuits, carrying currents of tens of amperes to hundreds of amperes, and voltages ranging from a few hundred volts to several thousand volts. Power relays need complex materials and designs to handle high currents safely.
In contrast, conventional relays operate in low-power circuits. They typically carry a few to tens of amperes and work at lower voltages, such as 12V, 24V, 48V, or 110V. Their contact design and materials are relatively simple and suitable for control of smaller loads.
Power relays are required to handle higher currents and voltages, the contact structure of power relays is more robust and often equipped with arc suppression systems (e.g., arc interrupter chambers, carbide plating, etc.) to prevent arc damage to the relay contacts during switching. The contacts of power relays can withstand high current loads for long periods of time without damage.
Regular relays have relatively simple contacts and are designed for small-current switching, so they do not require special arc extinguishing protection. The contacts of Regular relays are susceptible to wear or corrosion during prolonged periods of high load and have a shorter life span.
Power Relays Power relays have a relatively small signal on the control side, usually a low current (e.g. 10-50mA) DC current or AC voltage, but the load side of the relay is capable of switching high voltage and high current electrical loads. Power relays typically rely on electromagnets or solid-state control circuits to actuate the switching action of the contacts.
Regular relays also have relatively small control currents, but because they control small load currents, they usually do not require special protective measures. The difference in current between the signal on the control side and the signal on the load side is small.
Power relays are usually larger in size and more complex in design and structure, requiring greater resistance to heat, vibration and electromagnetic interference. Because their operating environment usually requires high stability and reliability, the structure and material selection are more delicate than Regular relays.
Regular relays are smaller and simpler in structure, and are suitable for control circuits with relatively light loads. Regular relays are often compact in design and can be used in equipment with less space.
Power relays handle higher currents and often run in tough conditions, like high temperatures, humidity, or vibrations. So, they must meet stricter reliability standards. Power relays typically have a longer life span and are able to withstand extended workloads.
Regular relays have a relatively low durability and may have a shortened life span, especially under prolonged high load or high frequency operation. They are suitable for low-frequency switching operations, for milder environments, and have a shorter life span, making them suitable for simple switching control of low-power circuits.
Power relays are more costly due to the high design and material requirements, especially when they are required to carry very high currents, and the manufacturing process and selection of materials are very stringent.
Regular relays are lower cost and are suitable for simple circuit control and signal switching. They are usually price-sensitive products and are therefore widely used in electronic products.
Power relays are widely used in power equipment, mainly for current control, load protection and automation control in power systems. They are used for protection and switching operations in high-voltage substations, power distribution systems, and power transmission networks.
Power relays are widely used in industrial heating equipment control, motor control, conveyor belts, automated production lines, etc. They are used for the control and protection of high power loads in production line equipment, power tools, large machinery and equipment. Power relays are used to control high current loads, such as electric heating furnace, electric water heater, to ensure the efficient operation of equipment. Power relays are used to control high current loads, such as electric heating furnace, electric water heater, to ensure the efficient operation of the equipment.
Power relays also play an important role in the new energy industry, such as solar and wind power generation, as well as in charging stations for electric vehicles. They are used for current control, system protection and high-performance power dispatch.
In high-voltage equipment such as high-voltage switchgear and circuit breakers, for example, power relays can be used to switch circuits automatically or to fulfil protection functions.
Regular relays are widely used in home appliances, such as for circuit protection, timing control and automatic switching of home appliances such as air conditioners, refrigerators and washing machines. They achieve the switching operation of home appliances through simple switching control.
In communication and control systems, ordinary relays are commonly used for signal switching and current protection in low-power circuits. For example, signal routing and equipment protection in automation control systems are indispensable for Regular relays.
Regular relays are also widely used in electronic products for circuit protection and signal switching. They can be used to protect electronic equipment from overloads or short circuits and ensure the normal operation of the system.
In the control of in-vehicle equipment, they are used in the low-power control system of automobiles, such as power windows, power seats, lights, in-car audio, seat heating and other functions.
In car lighting systems, regular relays control the switches for headlights, brake lights, and turn signals. They are used in various applications.
Regular relays are used in many home appliances. They protect circuits, control timers, and switch automatically in air conditioners, refrigerators, and washing machines.They achieve the switching operation of home appliances through simple switching control.
In communication and control systems, regular relays are commonly employed for signal switching and current protection in low-power circuits. For example, signal routing and equipment protection in automation control systems are critical for regular relays.
Power relays can be used in low-power equipment. But, their high load capacity and cost often make them unsuitable. Regular relays are more appropriate for low-power equipment.
Regular relays cannot replace power relays. They can't handle high current loads. Using them may damage the relay or the system.
To improve relays' efficiency and lifespan, choose the right type. Regularly inspect and maintain them. Avoid overloading and ensure a suitable environment.
Therefore, choosing a relay depending on the needs of an application is very important: when there are heavy power loads and poor working environments, a power relay should be used in order to keep equipment running safely and steadily; in applications using low-power equipment and of relatively simple functionalities, Regular relays can be a better and more economic option. During buying, one should consider the load current, working environment, cost budgeting, and other factors to ensure that the most suitable type of relay is selected.
