Mains Dimmers And how (not) to work with mains voltage Tim Clark - - PowerPoint PPT Presentation

Introduction Background Approach Waveform Slicing Finally

Mains Dimmers

And how (not) to work with mains voltage Tim Clark (eclipse) October 17, 2014

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

DMX

Previous talk on DMX Now I’ve made the other end A mains dimmer

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

Background Approach

BIG potentiometer (used to work that way) Instead we slice the waveform TRIAC work for this

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

TRIAC

TRIACs are (essentially) 2 back to back thyristors Turns on when triggered Turns off only when supply hits 0v (ish)

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

Waveform Slicing

Mains hits 0v 100 times a seconds (twice a cycle) Detect the 0 cross and time as far as you need

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

Waveform Slicing

V1 sine 50 Hz XFMR1 D5 1N4001 C1 100 µF D3 1N4001 D4 1N4001 D1 1N4001 D2 1N4001 U1 7805 R1 10 kΩ TRI1 TRI2 LAMP1 100 Ω F1 D6 R2 330 Ω F2

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

The Internet

Slides Available at http://sucs.org/~eclipse

Tim Clark (eclipse) Mains Dimmers

Introduction Background Approach Waveform Slicing Finally

Questions?

Any Questions?

Tim Clark (eclipse) Mains Dimmers