Quote Originally Posted by westom View Post
When does a dimmer switch using triacs create highest heat? When at the half dimmed position. How much heat? Depends on how it is designed. Semiconductors are routinely used to switch power - even hundreds of thousands of volt transmission lines. AC is converted to DC from Washington to California, all lines incoming to Quebec, and the connection from NJ to Long Island. Then more semiconductors convert that DC back to AC - without excessive heat. But again, semiconductors are problematic when one does not implement additional design concepts. Hundreds of megawatts controlled and delivered by semiconductors that do not overheat.

When does a computer's power supply (that is constantly switching) create greatest heat? Typically when operating at half power. Heating is minimized at full power - when semiconductors are selected and properly designed to perform switching.

Denials only exist because you could not make semiconductors and snubber circuits work. Others have used those well proven solutions successfully. Which one is best for the OP? He must first provide necessary information. Otherwise only solutions based in speculation (ie a protector) will exist.
I don't think you understand. "When does a dimmer switch using triacs create highest heat? When at the half dimmed position." This is not true. In a half dimmed position on a solid state dimmer is is only passing current half the time and therefore generating half the heat. During the ac cycle the voltage goes from 0 to 120V and back to zero in a half cycle. Triac based control waits for zero crossing and then delays and then triggers in that half cycle and stays on until back to zero volts. The longer the delay the less power. If you wait half the cycle then you are not passing any current and not sinking any current during that half phase therefor not generating any heat.

"semiconductors are problematic when one does not implement additional design concepts" This is true.

"When does a computer's power supply (that is constantly switching) create greatest heat? Typically when operating at half power." This is wildly false. They do have better efficiency at certain loadings (usually more than half loaded) but they definitely do not create more heat at half power. This is also why many switching power supplies do not turn on the fan until load goes up. You are confusing linear power supplies with switching power supplies.

"Denials only exist because you could not make semiconductors and snubber circuits work." I certainly have proven to make semiconductors work just fine with 10+ years of building and designing thermostats which have snubbers built in. I also had snubbers working in my relay experiments but in order to see much improvement it required a large cap and due to size restrictions was not the best option. There is a difference between successful and not practical for a circuit.

And with that I have thermostats to build.