I want to build something for science fair. A telegraph sounds wonderful if I find out how? Can any one help or give me an idea and instructions to build something else?
2006-11-13 10:31:10 · 2 answers · asked by MyzzPinkDiamond 2 in Science & Mathematics ➔ Engineering
Did this way back in Boy Scouts....Relatively easy...just need to build 2 electromagnets and a series circuit..... I'll see if instructions are online.
http://www.terrax.org/comm/morsecode/buzzer2.aspx
http://chss3.montclair.edu/~pererat/perbuild.htm
the second one is similar to what I built
2006-11-13 10:39:33 · answer #1 · answered by The Cheminator 5 · 0⤊ 0⤋
The above links are good. I have a suggestion to improve the design in the second one http://chss3.montclair.edu/~pererat/perbuild.htm
Drive a second, long nail into the wood, next to the flapper. Bend the top of it down so it contacts the flapper from above. Cut one of the power leads, and connect one end to the nail, and the other to the flapper. You have just made the device into a simple relay. When current flows through the coil, the flapper will be pulled down. That will break the electrical connection, so it will then spring back up. The result is a buzzer.
2006-11-13 19:01:53 · answer #2 · answered by pack_rat2 3 · 0⤊ 0⤋