Relay Sourcing Guide: Types & Applications

Relays switch power and signals reliably. This guide covers types and sourcing.

By Vigny (深圳市华芯购电子有限公司) · Published 2026-09-27 · Data verified 2026-09-29 · Sources: manufacturer datasheets & HuaXinGou stock verification

Relay Types

Electromagnetic relays (coil-driven, mechanical contacts), solid-state relays (SSR, semiconductor switching), latching relays (pulse set/reset) and reed relays.

Key Parameters

Coil voltage (5/12/24V), contact rating (current/voltage), contact form (SPST/SPDT/DPDT), coil power, life cycles and isolation.

Applications

Home appliances, industrial control, HVAC, automotive (with proper coil suppression), and power metering.

Sourcing

Relays from Omron, Panasonic, TE, Finder and domestic (Hongfa, Song Chuan) have broad availability. HuaXinGou quotes with contact form and coil specs.

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Frequently Asked Questions

What is the difference between relay and SSR?

Relay uses mechanical contacts (audible click, lower cost, higher current); SSR uses semiconductors (silent, longer life, needs heatsink).

What is contact form SPDT?

Single Pole Double Throw — one common contact switching between two terminals.

How do I protect the relay driver?

Add a flyback diode across the coil to suppress back-EMF.

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