Relays and optocouplers

Relay module: this relay board supports high and low level trigger and can be controlled by any 5V digital output of the microcontroller Parameter

Weewooday 15 Pieces 5V Relay Module 1- Channel Relay Control Boards with Optocoupler Isolation High and Low Level Trigger Expansion Board

Buy 1 channel 5V 10A Relay Control Board Module with

Diitao 2PCS 4 Channel DC 12V Relay Module with Optocoupler

What is the difference between a relay and an optocoupler? - Quora

Is optocoupler necessary with relays when using them with a

Relays, Optocouplers, & signal conditioners - Relays and

Make a Relay Modul With Optocoupler : 5 Steps - Instructables

Review of my Optocoupler as Relay Board circuit - General

☛ STRONG DRIVING ABILITY -- Adopt patch photocoupler isolation, strong driving ability, stable performance. Trigger current is 5mA. ☛ HUMANIZATION

Relay Module with Optocoupler 1 Channel High Low Level Trigger Relay Module Board AC 250V/10A DC 30V/10A (5V)