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Edison patentIn 1882, Thomas A. Edison was issued a patent for an improvement to the telephone (No. 252,442). It described a carbon microphone. Finely divided conducting material, such as carbon, between metal cups mounted on arms is attached to the mouthpiece diaphragm. As sound waves directed through the mouthpiece move the diaphragm, the arms change the pressure on the carbon button which in turn varies an electric current passing through the carbon button. Changes in the current correspond to the pitch and amplitude of the sound. One arm conducts the electrical current to the carbon button, and the the other from it.
Church Sign Chuckles
Some favorite messages spotted on church signs or billboards, submitted by Beliefnet members:
-Fire Insurance Inside
-This Church Is Prayer Conditioned
-God Answers Knee Mail
-PRAY NOW! Avoid Christmas Rush!
-Sign broken, come inside for message
-This is a ch--ch. What's missing? U R!
-Stop in the name of love and meet the Supreme
-Wal-Mart's not the only savings place
-The best position is on your knees!