1. Arnan Sipitakiat Dept. Compute Engineering, Chiang Mai University

2. 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

3. Transistors Using transistors as a switch

4. Using a transistor

5. Relays

6. Relay “Poles” and “Throws”

7. Driving load with a relay

8. Solid-State Relays

9. H-Bridge: A bi-directional driver

11. Relay H-Bridge

12. Transistor H-Bridge

14. H-Bridge IC / Module

16. Conclusions There are many ways to drive output devices Transistors are good for low power applications Relays are suitable for AC power applications or when low loss and high current is needed H-bridge is for bi-directional applications Choose the right tool for the job!