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A 12V relay switch is a core component in modern electrical and electronic systems, enabling safe and reliable control of high-power loads using low-voltage signals. This article will discuss the working principles, technical details, applications, and safe operation of 12V relay switches.
A 12V Relay Switch from Songle is an electromechanical switch that allows a low-power 12V DC signal to control a higher-power electrical load. When 12V is applied to the relay coil, it creates a magnetic field that moves the internal contacts, turning a connected circuit ON or OFF.
Most Songle 12V relays (such as SPDT types) can handle currents up to around 10A, making them suitable for switching AC or DC loads like lights, motors, pumps, and appliances. They are widely used in Arduino and microcontroller projects, automotive electronics, and industrial control systems because they provide electrical isolation and reliable switching.
| Pin Number | Pin Name | Function |
| Pin 1 | Coil | One side of the 12V DC control coil |
| Pin 2 | Coil | Other side of the 12V DC control coil |
| Pin 3 | COM (Common) | Common terminal that switches between NO and NC |
| Pin 4 | NC (Normally Closed) | Connected to COM when the relay is OFF |
| Pin 5 | NO (Normally Open) | Connected to COM when the relay is ON |
SPST (Single Pole Single Throw) Relay
This is the simplest type of relay, acting as a basic ON/OFF switch for one circuit. When 12V is applied to the coil, the internal contact closes (or opens), allowing current to flow. It is commonly used for simple load control such as turning lights, fans, or alarms on and off.
SPDT (Single Pole Double Throw) Relay
An SPDT relay has one common terminal that switches between a Normally Open (NO) and Normally Closed (NC) contact. When the 12V coil is energized, the contact moves from NC to NO. This type is widely used in control circuits, signal switching, and applications where two output states are needed.
DPDT (Double Pole Double Throw) Relay
A DPDT relay switches two separate circuits at the same time using one 12V coil. When energized, both sets of contacts change position together. It is often used for motor direction control, reversing polarity, and more complex automation systems.
Power Relay
Power relays are designed to handle higher currents and voltages, typically 10A or more. When the 12V coil is activated, they safely switch heavy loads such as motors, heaters, pumps, and household appliances. They are common in industrial and automotive applications.
PCB (Printed Circuit Board) Relay
PCB relays are compact relays made to be soldered directly onto a circuit board. They work the same way as other 12V relays but are optimized for embedded systems. These relays are widely used in Arduino projects, control modules, and electronic devices.
• 3V Relay
• 5V Relay
• 12V SPDT Relay
• 12V SPST Relay
• 12V Power Relay
• 1-Channel 12V Relay Module
• 4-Channel 12V Relay Module
| Parameter | Specification |
| Relay Type | Electromechanical Relay |
| Coil Voltage | 12 V DC |
| Coil Resistance | ~400 Ω |
| Coil Current | ~30 mA |
| Coil Power Consumption | ~0.36 W |
| Contact Configuration | SPDT (1 Form C) |
| Number of Pins | 5 Pins |
| Contact Capacity (AC) | 10 A @ 250 VAC |
| Contact Capacity (DC) | 10 A @ 30 VDC |
| Rated Load (AC) | 10 A @ 250 VAC |
| Rated Load (DC) | 10 A @ 30 VDC |
| Max Switching Voltage | 250 VAC / 30 VDC |
| Max Switching Current | 10 A |
| Max Switching Power | 2500 VA (AC), 300 W (DC) |
| Operate Time | ≤10 ms |
| Release Time | ≤5 ms |
| Electrical Life | ≥100,000 operations |
| Mechanical Life | ≥10,000,000 operations |
| Contact Material | Silver Alloy |
| Insulation Resistance | ≥100 MΩ (500 VDC) |
| Dielectric Strength | 1500 VAC (coil to contact) |
| Operating Temperature | −40 °C to +85 °C |
| Mounting Type | PCB Through-Hole |
| Dimensions (Approx.) | 19 × 15.5 × 15.3 mm |
• High Switching Capacity (Up to 10A) - Despite its compact size, the relay can safely switch high-current loads, making it suitable for power control applications.
• 12V DC Coil Operation - Designed to operate reliably with a 12V control signal, allowing easy integration with automotive and industrial systems.
• Compact PCB-Mount Design - Small footprint supports high-density PCB layouts while maintaining strong electrical performance.
• SPDT Contact Configuration - Provides both Normally Open (NO) and Normally Closed (NC) contacts for flexible control logic.
• Electrical Isolation Between Coil and Contacts - Protects low-voltage control circuits from high-voltage or high-current load sides.
• Certified Safety Standards (UL, cUL, TÜV) - Meets international safety and quality certifications for dependable operation.
• Sealed Relay Options Available - Sealed versions protect internal components from dust, moisture, and chemical exposure.
• Silver Alloy Contact Material - Ensures low contact resistance, stable performance, and long service life.
• Fast Switching Response - Short operate and release times support reliable and responsive control.
• High Mechanical and Electrical Life - Designed for millions of operations, suitable for continuous and repetitive switching tasks.
• Wide Operating Temperature Range - Maintains stable operation in both low and high temperature environments.
• Low Power Consumption Coil - Efficient coil design reduces energy usage and heat generation.
Catalogue
FPGA / CPLD
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