Normally Open 20 mm Reed Switch

The ZFAST-A Normally Open 20 mm Reed Switch is a compact, high-reliability magnetic switch designed for non-contact sensing applications. Operated by an external magnetic field, this reed switch closes its contacts when a magnet is present and returns to an open state when the magnetic field is removed.

Unlike traditional glass reed switches, this model is encapsulated in a durable housing, making it more robust and suitable for PCB mounting in environments where mechanical protection and longevity are required. Its sealed construction ensures stable performance, low contact resistance, and long operational life.

With support for relatively high switching voltages and low power consumption, the ZFAST-A reed switch is ideal for industrial sensing, security systems, automation projects, and embedded electronics.

Key Features

• Normally Open (N/O) magnetic reed switch

• Durable encapsulated design (more robust than glass reeds)

• Non-contact switching operation

• Low contact resistance and fast response

• Easy PCB mounting

• Long electrical and mechanical life

Technical Specifications

• Model: SZFAST-A

• Contact form: 1A – Normally Open (N/O)

• Contact material: Ruthenium (Ru)

• Contact load: 10 W

• Maximum switching voltage: 200 VDC / 140 VAC

• Maximum switching current: 0.5 A

• Maximum contact resistance: 100 mΩ

• Breakdown voltage: 250 V

• Contact capacity: 0.25 pF

• Insulation resistance: 10¹² Ω

• Resonant frequency: 9 kHz

• Operating temperature range: -55 °C to +100 °C

• Dimensions: 20 × 16.1 × 3.8 mm

• Weight: 1 g

Typical Applications

• Door and window sensors

• Alarm and security systems

• Position and proximity sensing

• Industrial automation

• Embedded electronics and PCB designs

• Arduino, ESP32, and microcontroller projects

The ZFAST-A 20 mm Normally Open Reed Switch offers a reliable and space-efficient solution for magnetic sensing applications where durability, accuracy, and electrical performance are critical.