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Watts This All About? Or, Resistance is Futile . . . . . . NOT! The watts rating in any resistor you use is trivial to figure. Multiply volts times amps. E.G., if you use a 3-volt, 26mA Circuitron #7418 bulb with a 12-volt transformer, you need to waste 9 volts to get the volts to 3. So, since resistance is volts divided by amps, 9 volts divided by .026 amps gives you 346 ohms for the resistor (but use 440 ohms and multiply the bulb's life many fold), and for figuring watts, just multiply 9 times .026 and get .234 watts; so ¼ watt is good if you use a 346-ohm resistor, but we're using a bigger resistor that wastes more volts and .234 watts is near the ¼-watt limit, so use ½-watt resistors. If higher-watt-rated resistors are cheaper at your store, like they often are at mine, go for those, since extra watts ratings are harmless. Fresh Out of Excuses I think you can see that if you like and want signals but were letting expense or wiring confusion stand in your way, it's now time to make the leap. They're not expensive or complicated. PARTS LIST: SIG Manufacturing Co., Inc. Nylon landing gear clips, SH-522, 4 for 95¢ gives 8 signal lamp holders at 12¢ each Brass Eyelets , SH-215, 1/8" I.D., $7.75 for 100 or under 8¢ each (1/32", 1/16", 3/32" I.D. also available) Bachmann Signal Bridge, #42503 (w/6 block signals) $4.49 or under 75¢ each per signal (get from hobby stores or train shows—Bachmann quit making them; N.J.I., below, has parts if you can't find any of these dandy little signals) Teknopak T-1 LED 1/8", 2 volts, red, 5 for $1.50 or 30¢ each at electronics stores T-1 LED 1/8", 2 volts, green, 5 for $1.50 or 30¢ each at electronics stores Bob Smith Industries 1 oz cyanoacrylate, maxi-cure, extra thick, 10-25 sec. ($5.49 at hobby stores) Linrose Electronics, Inc. 29 Cain Drive, Plainview NY 11803 Bicolor LED 4301F1/5, 75-100: 99¢ each |
Above is how SIG packages items in hobby stores. |