Showmen's Trade Review (Oct-Dec 1944)

October 7. 1944 SHOWMEN'S TRADE REVIEW 43 Reports Widespread Interest in New Lens lesser amount of current to flow in the circuit. If we cut out all of the resistance the lamp will light to full brilliancy and if we cut all of the resistance "in" we will have the lamp at onehalf brilliancy. This is the method employed to vary the amount of light that we have in our projection arcs (in the old days) and also the method of controlling the speed of electric fans and motors. This is a very inefficient method because our resistance will absorb power, which is a waste. There are more efficient methods and we will come to them later. Now let us go back to problem number two. Here we will notice that 100 volts is connected to each lamp, and knowing the resistance of each lamp to be 200 ohms we can soon find out that 0.5 amperes is flowing through each lamp. We will then have 50 watts in each lamp. Since there are 0.5 amps for one lamp and 0.5 amps for the second lamp and all of this current is coming from the line, then the line is supplying one ampere to the circuit. This circuit is termed a "Parallel" circuit. Therefore the several currents of a parallel circuit add to each other in order to determine the total current of the circuit. Also we can say that across each branch of a parallel circuit the voltage is the same as the line voltage. And we can also say that the current through each branch of a parallel circuit is in proportion to the resistance of that particular branch of the circuit. We know that there was a total of one ampere flowing in circuit number two. Since this is so, what is the total resistance of the circuit in problem number two? Well let us treat it as a circuit similar to circuit number one. The total voltage is 100; the total current is one, then the total resistance must be 100/1 or 100 ohms. So now we find that as we increase the number of lamps in a parallel circuit, the current increases and the resistance decreases. We will note that the resistances of each lamp are equal so we may now say that whenever equal resistances are connected in parallel with each other the total resistance of the combination may be determined by dividing the resistance of one by the number of resistances making up the combination. In the next article we will further consider the resistance problems. Wayne Theatre to Seat 1500 Walter D. Shafer, owner of the Wayne Theatre, Wayne, Mich., near Detroit, is planning a new 1500-seat house in the former town to be known as the Shafer Annex. As soon as materials are available construction will be undertaken by the Johnson Construction Co., of Birmingham, Mich. Cost will be $100,000 for building and $50,000 for equipment. Of cinder block interior and face brick exterior, ample parking space will be provided in the rear. Shafer also owns the Shafer Garden Theatre, in Garden City, Mich. Marion, Ky., House Reopened The Kentucky Theatre, Marion, Ky., owned and operated by William E. Horsefield, which was badly damaged by fire about four months ago, was reopened Oct. 1. Completely renovated and redecorated, the house has a brandnew appearance throughout. Two Theatres to Cost $750,000 Building permits issued by the State of New York during July and August included approval of the construction of two Manhattan theatres *o cost $750,000. The New Orthoscope auxiliary lenses recently introduced by National Theatre Supply, and claimed by its sponsors to be "the greatest development in projection optics in half a century," have won rapid and enthusiastic acceptance by hundreds of theatre owners, according to J. W. Servies of National's Sales Promotion Department. "At the present time," Air. Servies said, "we are averaging 25 orders per week in each of our 28 branch offices from coast to coast. If sales continue at the present rate, we anticipate that within a year, one out of every five theatres will be equipped w^ith these new lenses and that thereby millions of theatre patrons will enjoy better projection." The Orthoscope lenses are a development by the H & H Optical Co., Hollywood, and consist of a positive lens placed, in most cases, 1% inches from the film, and a negative lens placed 6 inches from the film. The principle involved is that the negative lens magnifies the carbon crater seven to fourteen times its normal size (depending on the type of lamp in use and other contributing conditions) and the positive lens collimates the light on the film at the aperture plate, enlarging the film image to cover the rear combination of the objective lens. In most cases the over-all light is increased as much as 61 per cent by the Orthoscope Lenses according to tests by the manufacturer. Back to the Best! 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