3V PCB Mount Sugar Cube Relay

3V PCB Mount Sugar Cube Relay is a compact, robust electromagnetic switching device designed to facilitate the control of high-power AC or DC loads using low-voltage DC signals, often sourced from microcontrollers. Commonly referred to as a “Sugar Cube” relay due to its characteristic small, rectangular size, this device provides essential electrical isolation between the control circuit (3V) and the load circuit (up to 250V AC or 30V DC). Consequently, it safeguards sensitive digital electronics from high-voltage spikes and surges. Featuring a Single Pole Double Throw (SPDT) contact configuration, the relay offers flexibility for both Normally Open (NO) and Normally Closed (NC) switching setups. Therefore, utilize this reliable relay to bridge the gap between low-power logic and heavy-duty electrical components in your automation projects.

Key Features:

• Low Coil Voltage: The relay coil operates directly at 3 V DC, making it highly compatible with battery-powered systems and microcontrollers running at 3.3 V logic levels.
• High Switching Capacity: Capable of switching currents up to 10 A at 250 V_AC or 30 V_DC, handling typical home and industrial loads.
• SPDT Contact Configuration: Features three terminals (Common, Normally Open, Normally Closed), enabling switching between two circuits using one control signal.
• High Isolation: Provides high dielectric strength between the coil and the contacts, ensuring electrical safety.
• PCB Mount Design: The through-hole pin arrangement allows for direct mounting onto printed circuit boards, ensuring a secure and permanent installation.

Technical Specifications:

• Coil Voltage (Nominal): 3 V DC
• Coil Resistance: Typically 45 Ω (±10%)
• Coil Power Consumption: ≈ 200 mW
• Max Switching Voltage: 250 V_AC / 30 V_DC
• Max Switching Current: 10 A (Resistive Load)
• Contact Form: 1 Form C (SPDT)
• Insulation Resistance: 100 MΩ minimum (at 500 V_DC)
• Electrical Life: 10⁵ Operations minimum

Mechanical Specifications:

• Package Type: PCB Mount, Enclosed “Sugar Cube” Type
• Terminal Type: Through-Hole Pins
• Mounting Orientation: Vertical
• Material: UL94-V0 plastic cover provides protection and flame resistance.

Dimensions:

• Length: ≈ 19.0 mm
• Width: ≈ 15.5 mm
• Height: ≈ 15.0 mm
• Pin Pitch (Coil): 5.0 mm
• Pin Pitch (Contacts): 5.0 mm (varies by model)

Pinout and Wiring:

• Coil Pins (Two Pins): Apply 3 V DC across these two pins to energize the coil and change the contact state. Note the polarity of the coil pins if flyback diode protection is included.
• Common Pin (COM): Connect the input power line (AC or DC) that you wish to switch.
• Normally Open Pin (NO): The circuit is open (unconnected) when the coil is de-energized. Hence, current flows through NO when you apply 3V to the coil.
• Normally Closed Pin (NC): The circuit is closed (connected to COM) when the coil is de-energized. Conversely, the circuit opens when you apply 3V to the coil.
• Wiring Tip: Always include a flyback diode (e.g., 1N4007) across the coil pins when driving the relay with a transistor or microcontroller to protect the control circuit from inductive kickback.

Datasheet Reference:

• Download HF3FA 3V Relay Datasheet (Representative Model)

Commonly Used in:

• Relay Driver Modules: Integrated into pre-built modules for easy interfacing with Arduino, ESP32, and Raspberry Pi boards.
• Smart Home Devices: Used in networked switches, smart plugs, and thermostat controls for appliance switching.
• Security Systems: Essential for operating locks, gates, and signaling devices.

Applications:

• HVAC Control: Switching heating elements, fans, and cooling compressors.
• Lighting Automation: Handling the high inrush current of AC lighting fixtures and LED drivers.
• Power Supply Control: Isolating power rails or switching between backup power sources.
• Motor Reversing: Setting up H-bridge or simple switching circuits for small DC motor directional control.

Equivalent Models:

• SRD-03VDC-SL-C: A very common and functionally equivalent model widely available from various manufacturers.
• HF3FA/003-ZS (Hongfa): Represents a popular industrial-grade version with the same 3V coil and SPDT contact rating.
• JQC-3F(T) 3V: Another series that provides an identical footprint and electrical characteristics for direct substitution.

Package Includes:

• 1 x 3V PCB Mount Sugar Cube Relay (10A SPDT)