HF3FF-012-1HS

Overview

HF3FF-012-1HS 12V DC PCB Power Relay with Single Pole Single Throw Normally Open (SPST-NO) configuration. A compact and reliable relay from Hong Fa (HF) series, widely used in power control, home appliances, industrial automation, HVAC systems, and embedded electronics projects.

Specifications

Parameter	Value
Model	HF3FF-012-1HS
Coil Voltage	12V DC
Contact Configuration	SPST-NO (Normally Open)
Contact Rating AC	10A / 250VAC
Contact Rating DC	10A / 30VDC
Coil Resistance	~400Ω
Coil Power	~360mW
Insulation Resistance	≥100MΩ
Dielectric Strength	1000VAC (coil to contact)
Package	PCB Through-hole
Dimensions	19 x 15.5 x 15.5mm
Operating Temperature	-40°C to +85°C
Mechanical Life	≥10,000,000 operations
Electrical Life	≥100,000 operations

Features

• 12V DC coil — compatible with 12V power systems
• SPST-NO contact — Normally Open, closes when energized
• 10A switching capacity — handles motors, pumps, heaters, lights
• Compact PCB mount — easy integration on custom PCBs
• High insulation — safe for AC load switching
• Long mechanical life — reliable for industrial use
• Compatible with ULN2003, 2N2222, BC547 driver circuits

Wiring

Pin	Description
Coil+	Connect to 12V via transistor or relay driver
Coil−	Connect to GND
NO	Normally Open — load connects here
COM	Common terminal — power source connects here

Driver Circuit

• Transistor: NPN (2N2222, BC547, or S8050)
• Base: 1kΩ resistor → GPIO pin (3.3V or 5V)
• Collector: Relay coil positive pin
• Emitter: GND
• Flyback diode: 1N4007 across coil pins (cathode to Coil+)

Applications

• Home appliance control (fans, lights, pumps)
• HVAC and thermostat systems
• Industrial machine control
• Smart home automation
• Motor ON/OFF switching
• Arduino / ESP32 / STM32 relay control
• Solar charge controller switching
• Battery management systems