roth@smoot.enet.dec.com (Lee Roth) (08/03/90)
In article <1990Aug1.081830.15979@mlb.semi.harris.com>, del@thrush.mlb.semi.harris.com (Don Lewis) writes... > >I seem to recall reading "The Boy Electrician" by the same author many >years ago. It had lots of plans for spark coils and tesla coils, told >how to use X-ray tubes :-O, etc. He also had some more recent books >on how to build things intercoms and audio amps (5 watts, wow!). >-- "The Boy Electrician" had a copyright circa 1930. Great book, but the local library has purged it in favor of newer stuff. Was the only book readily available when I was a kid that had details for building induction coils. I made a fine one with magnet wire from Allied Radio and model-T coil points I ordered from JC Whitney. It would shock the p__s out of you! The book was sufficently old that it listed the American morse code (now obsolete) rather than the newer, international code (what is in use today). Contained details on constructing radio receivers, telephones, a carbon microphone that was "sensitive enough to detect the footsteps of a fly" as well as many neato things to do with high voltage. In one experiment they hooked the homemade microphone in series with the primary of the spark coil and a battery. The instructions clearly state you are to tighten the adjusting screw on the vibrating points so that they cannot move, else a 'cruel surprise' would result (soon you'll see why!) Next, a volunteer (victim?) stood while an assistant on each side placed one hand over the volunteers' ear. A thin sheet of paper was placed between the hand and the ear. Each assistant was given a wire from the secondary of the coil to hold. The effect was supposed to be that the volunteer in the middle would hear the voice of a person speaking into the microphone. If the vibrator on the end of the coil began to work what would they hear? =:^o Sorry for the rathole in sci.chem.... Lee