Hi guys, just a short article about a light dimmer switch that I opened a few days ago. I wanted a way to adjust the speed of a 220V fan and a friend of mine told me that I can use a regular and cheap light bulb dimmer for this. I told him it might not work but he was so sure about it so I had to test it and of course it didn’t work.
So I disassembled it and copied the schematic of the circuit on a piece of paper. It is so simple thus everybody should be able to build it without problems, the only thing to be aware of is that dangerous voltages are present so please be very careful when working with it. And please stop paying a lot of money for light dimmers!
So as you can see it is a very simple circuit and I think everybody can build it. Mount the BTB12 triac on a little heatsink as you can see in the pictures above. You only need 2 terminals from the 680K potentiometer and when adjusted you’ll notice that the highest brightness will be when its resistance is at minimum (zero ohms).