Tested Overhead Proiection Series Comp~ledby HUBERT N. ALYEA
Princeton Un~versily
I n this issue TOPS present two exciting new items: (1) all inexpensive (33k) lensless projector and (2) Uni-cell, a multi-purpose device for most TOPS experiments. These items should prove invaluable to introduce the beginner to the TOPS technique, and encourage him to progress to the better basic TOPS dcvires and Daylight l'rojector alrrady descrihrd.
A LENSLESS PROJECTOR
s t a ~ a s l i t s :or USB tracing paper, war paper, or Stancor D-6456 a t 6.3 v. 6 a m p a n d 82-omdlc I high-intensity low-voltage (sutumohiie) bulb tmnsluoent plastic for a screen. Glue t h e stop at can be used directly ss a ~rojeotor, "focusing" power automobile lighl bulb No. 1138. the srppro~riatellosition on the s t w e . heinp sellieved hy covering the bulb with a l u m "am foil irarine a >/*in, ol,ening. ~h~ Conshuction. Assemble ar shown in Fipere. C u t Alternate inputa: 220 volt se r i t h rectifier in slits Vrin. deep in the base-box t o hold the shown in the Figure. o ~ e r a t e son local 110/220 %o, primary of the transformer: or replace transa t r h n a f ~ ~deiiverine , ~ , ~ ~ 6 v ao to a 3 2 - ~ ~ ~ d k . screen. A cardboard box holding the Uni-=ell and former hy 220 t o 6 volt trhnsformer, or a Variae. all accessories e m slip into this base-box o ~ e n i n l ~ power boll,. I f luoai current fails. which ooeltrs Or use a 12-volt IhUli,. &V for storage. The hack of the electriosl box is all too frerll,entlgi n developing countries, =torape hnt,tery ill the lamp for 10 h r screwed on for easy removsl. In the electrical Horirontalizer. A 1,urizonthi staxe, s h o r n in the liefore r e q ~ i r i n r iecltarelnp. A minor feature box, the three posts of tlie S P D T awiteh rilouid i n c i d e s a reotifier t o deliver 3 r do for eleetrioal he wired sr foliors. (a) The oenttal poat to one dc outlet pluv and t o the wire of the ism^. (b) exzxriments. I n outer post of the S P D T awiteh to an inmnt Materials. m ~ w o o dboa8 from pieces 16 X 8 X ~1.g. ( c ) The third "oat of the SI'DT switch thiuueh the hrae holder t o one wire of the seoon'/.-in.. 8 X 6 X '/--in. stare, twu 8 X 2 X l/d-in. dary of t h e transformer. Finally a r i r e from lire wood aides, an 8 X 11, X l/--in. stoo. Eleclriral bor i a m ~sass (grounded line) t o the foilowing three f r o m 8 X 21/, x li-in. tom t w o 8 x PI/4-in.X l / r paints: (1) to the other wire of the seoondary of in, sides, and thrpe 2,/, X 2 X '/.-in. wood blocks for ends and inner cuartition hoidine lhnw iousine. the transformer. (z) through the rectifier t o lile F u ~ h o l d ~ Littelfuse r. 34201 finger-knob type for other of the do outlet posts, and (3)to the other of the de input posts. Bore a ring of lhoies in tile 8 AG. 5-amp faxe. Silicon redilier, medium ourrent (&I0 amp) 200 PIY. Lafayette 81-267. back of the lamp housing for ventilation. and Four bindina porla, live-way. Newark 35Fi48. cover the front of the lamp bulh with s thin . 70662. Edmund aluminum plate, or foil, with a >/,-in. hole in the Tirmslnrenr projection B C I B ~ ~NO. Srientifie Cu., &. Barrington. N. J. Douhle pull, center ~ r e s a e d directly against the lamp bulb. double throw (SI'DT) s u 4 c h . Tensor I$ghMount the ~ r o j e e t i o n acreen on two vertical \,ox. The parts ran he ,,naere,red for fitoraee. stripe of 8 x Va x l / ~ ~ - i n piastic . stuok into the intemity lamp. .Model 5975, or tmnaformer,
THE TOPS UNICELL Msaerinls: Clear plerialas, t w o 5 X st/, X '/sin. i d . Iliael piexidas, one 5 X I",$ X ,/*-in. l m e ; six 31/< x V/Bx '/#-in, dividers. C u t istter fro,,, a/=in. stock if availsl>le, othenvise irom '/,-in, stook. with saw-oat sanded srnlaie and amoothed.
one end of a :
