The request
“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.”
Then tryChange the lamp to a 12 V fan.Add a pushbutton input to the Arduino.
What is in this drawing
Read the decisions behind it.
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.
More like this
Other examples in this family.
FAQ
Common questions
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.