Arduino Relay Module Control Circuit

Arduino Relay Module Control

An Arduino relay interface lets a low-current microcontroller output switch a separate load circuit. In this example, the Arduino output drives a 5 V relay module and the relay contact switches a 12 V lamp supply. Keeping the load supply separate makes the control and load roles clear, while the relay contact provides the switching boundary. A diode across a bare DC relay coil reduces the turn-off voltage spike; ready-made relay modules often include this protection already. Do not use a breadboard relay circuit for mains wiring. For larger DC loads, confirm the contact rating, wire gauge, fuse, and the need for a flyback diode across the load itself.

類型 電路圖標準 IEEE Std 315 / ANSI Y32.2引擎 schematex-circuit更新時間 2026/9/24

需求

“Draw an Arduino Uno controlling a 5 V relay module from a 5 V logic supply, with the relay switching a separate 12 V lamp load and a coil diode.”

接著試試Change the lamp to a 12 V fan.Add a pushbutton input to the Arduino.

這張圖裡有什麼

看懂背後的決策。

01Logic

Keep the Arduino on its 5 V control supply.

02Switching

Use relay contacts for the separate 12 V load.

03Protection

Suppress the relay coil voltage spike.

Use for an Arduino project that switches a low-voltage DC load through a relay.

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常見問題

Why use a relay with an Arduino?

A relay lets a low-current logic output switch a separate higher-voltage or higher-current circuit.

Does a relay module need a diode?

Bare relay coils do; many relay modules include a transistor driver and diode on the module.

Can this switch mains voltage?

Use properly rated, enclosed hardware and qualified installation for mains circuits; this example is a low-voltage load.