Thanks, I'm glad I asked. I appreciate the concern. Don't worry, I always ask before doing anything I'm unsure of. But for my information, please explain why I can't use the TVS diode. Isn't it's job to cut off power if voltage gets too high, and reactivate when voltage is within range? I figured it would only 'activate' when the voltage is between 6.8v and 0 volts. I wasn't going to directly connect the mains to the arduino lol PS. Just want to reiterate that I only want an explanation on why it won't work. Doesn't mean I'll go and do it anyway I just want to know what the TVS diode can and can't be used for, and maybe a small explanation and recommendations on how I can get the arduino to detect 0 volt crossovers on the AC line
a diode (or any 2-terminal device, for that matter) cannot be used as a switch.
If you simply want to detect zero crossings, use ...
A rectifier is a "switch" in the same way as a check-valve is a "faucet" (AmEnglish) or "tap" (BrEnglish). It doesn't equate IMHO.To my way of thinking, a rectifier or a check-valve are passive and uncontrollable.To my way of thinking, a transistor or SCR or Triac, or relay or toggle or pushbutton, etc. is an active SWITCH and "controllable" by a "3rd party".
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC) which flows in only one direction. The process is known as rectification. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury arc valves, solid state diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches......http://en.wikipedia.org/wiki/Rectifier
Jack,I'm trying to send signals through the main line while the voltage is 0. Just wanted to experiment if it would work. I wanted to use the led to see if I can get as far as detecting the 0 crossovers I read somewhere online that the voltage on a regular line will be about 0 for 1 millisecond. Figured that if I used a fast enough baud rate, I could get a few characters through.