Arduino Controlled AC Dimmer Circuit

Question

I can easily switch on and off a 220V source using an electromechanical relay. But I am now looking for a much more versatile solution. Something that can not only switch the source on/off but also use them as dimmers. I had no idea how to do this so a friend of mine (from electronics background) said I could use SCR circuits to this, but he had no idea about what ICs could accomplish that. So a visit to a local store and now I have a couple of TYN612 IC which is an SCR capable of controlling upto 600v AC at 12amps.

Now, Using TYN612 how can I build a dimmer circuit, that can be controlled using arduino, which could also control on/off at 220V AC. Or any other alternative is welcome.

Answer 1

1.You can use SCR/thyristor to control a AC load .The principle used is Phase angle control. Thyristor can control only one half of A.C.If you need a full cycle control , you can either use a Triac or Two SCR connected anti-parallel. This link might be useful to know further.

2.The rms AC output depends on firing angle of the SCR.So if you want to control firing angle , you need to have a pulses of specific duty cycle to be provided to gate of scr using PWM technique from arduino digital pins. This link can help.

3.If you use two SCR connected anti-parallel, there is no need of commutation circuit.As they are automatically Commutated by Line commutation meaning during Natural AC reversal the opposite SCR switches on and present one switches off. As a thumb rule, AC to AC converters don't have commutation circuit.

• Andy aka: i think you'd do better with a triac.