The HFD4-I-4.5-SR is a subminiature sealed surface-mount (SMD) monostable high-load relay engineered for compact electronic systems that require reliable switching performance, low power consumption, and durable operation under moderate load conditions. Featuring a Form 2C (DPDT / 2c/o) contact configuration, it enables independent control of two circuits, making it suitable for a wide range of control, automation, and signal routing applications.
This relay operates with a 4.5VDC coil voltage and a 145 coil resistance, optimized for low-voltage electronic designs where efficiency and stable operation are important. As a monostable (non-latching) relay, it remains energized only while the coil is powered and returns to its default state when power is removed, making it ideal for fail-safe switching, momentary control functions, and automatic reset systems.
Despite its compact SMD footprint, the HFD4-I-4.5-SR supports a maximum switching current of 3A, with surge capability up to approximately 3.5A, allowing it to handle both signal-level and moderate power loads reliably. Electrical ratings include 3A at 30VDC and 1A at 125VAC, with a maximum switching voltage of 250VAC / 220VDC, providing flexibility for mixed AC and DC applications.
The sealed surface-mount construction protects the internal contacts from dust and environmental contamination while enabling automated PCB assembly. This ensures long-term reliability and makes it well-suited for high-density electronic designs and mass production environments.
Its gold flash contacts deliver low contact resistance, stable signal integrity, and extended operational life, particularly important in low-current or precision switching applications where consistent performance is critical.
Designed in accordance with IEC 60335-1 safety standards, the relay supports applications that require compliance with recognized electrical safety and reliability requirements.
Key Features
Form 2C (DPDT / 2c/o) contact configuration
Monostable (non-latching) operation
4.5VDC low-voltage coil design
SMD surface-mount sealed construction
High-load switching up to 3A
Surge capability up to ~3.5A
Low power consumption
Gold flash contacts for reliable conductivity
Compact PCB-friendly footprint
IEC 60335-1 compliance suitability
Typical Applications
Industrial control systems
Automation and relay driver modules
Embedded electronic devices
Smart metering systems
Signal routing and interface switching
Battery-powered control circuits
The HFD4-I-4.5-SR delivers a strong balance of monostable safety behavior, sealed SMD durability, and high-load switching capability, making it ideal for engineers designing compact, efficient, and reliable electronic control systems.
What's in the box
1 x HFD4-I-4.5-SR 4.5V SMD Monostable High Load DPDT Relay 3A Gold Contacts
