Microcontroller Output Control

Arnan SipitakiatDept. Compute Engineering, Chiang Mai

University

What’s wrong with this circuit?

A microcontroller usually supplies limited current (i.e. 25 mA). This is ok for LEDs but not enough for high current loads like a motor

TransistorsUsing transistors as a switch

Using a transistor

Relays

Relay “Poles” and “Throws”

Driving load with a relay

Solid-State Relays

H-Bridge: A bi-directional driver

Relay H-Bridge

Transistor H-Bridge

H-Bridge IC / Module

ConclusionsThere are many ways to drive output devices Transistors are good for low power

applicationsRelays are suitable for AC power applications

or when low loss and high current is neededH-bridge is for bi-directional applicationsChoose the right tool for the job!