surveying iii (topographic and geodetic surveys) - Modern Prepper

Figure 2-12. Cells Connected in Parallel(3) When showing from three to six lights, the hookup ordinarily used is a set of 16 cells withfour rows of four in parallel. The voltage may then be varied by using from one to four rows. Whenshowing five or more lights over a period of 6 hours or more, the set of 16 cells should be backed upwith a second set of 16 in parallel.(4) The most commonly used low-amperage bulb is rated at 0.6 ampere and 3.7 volts. This bulbis requisitioned through supply channels and requires that the amperage and voltage be marked on thebase. When it is used in a signal lamp with a 5-inch reflector, it gives good results on lines around 25miles in length. If it is necessary to have a brighter light due to a hazy atmosphere, use a 1.25-amperebulb. In ordinary cases with a small lamp and a 0.6-ampere bulb, two units of new cells, each unitcontaining three cells connected in parallel, will provide sufficient light 6 hours a day for 10 days(Figure 2-13). Although rated at 3.7 volts, these bulbs will withstand 4.5 volts. Three units of new cellsconnected in series give a voltage of about 4.5 volts, since the voltage of an ordinary cell (or of a unit oftwo or more cells connected in parallel) is about 1.5 volts. Four units of new cells would have a voltageof 6, which would burn out a bulb of this type.Figure 2-13. Series-Parallel Connection of Six Cells in Two Units of Three Cells EachEN0593 2-40