Experiment 6: Very Simple Switching

Chapter Experiment 6: Very Simple Switching

Make Electronics Book Learning by Discovery
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Make Electronics Book Learning by Discovery

  • Switching Basics and More43Experiment 6: Very Simple SwitchingCeramic capacitors, assorted. Make sure you get at least one rated at 0.0047 μF (which can also be written as 47 nF). See Figure 2-15.ResistorsIf you bought only a minimal selection for experiments 1 through 5, now’s the time to buy a larger assortment, so that you won’t be stuck needing the one value that you don’t have. 1/4-watt minimum.LoudspeakerAny 8Ω, 1-inch miniature loudspeaker such as part 273-092 from RadioShack. See Figure 2-16.Experiment 6: Very Simple SwitchingYou will need:• AA batteries. Quantity: 4.• Battery carrier for 4 AA batteries. Quantity: 1.• LED. Quantity: 1.• Toggle switches, SPDT. Quantity: 2. See Figure 2-12.• 220Ω or similar value resistor, 1/4-watt minimum. Quantity: 1.• Alligator clips. Quantity: 8.• Wire or patch cords. See Figure 2-10, shown previously.• Wire cutters and wire strippers if you don’t use patch cords. See Figure 2-4, shown previously.I 28,n Experiment 3, you illuminated an LED by attaching a battery, and switched it off by removing the battery. For greater convenience our circuits should have proper switches to control power, and while I’m dealing with the general topic of switches, I’m going to explore all the varieties, using a circuit to sug-gest some possibilities. Assemble the parts as shown in Figures 2-17 and 2-18. The long lead on the LED must connect with the resistor, because that is the more positive side of the circuit. You’ll notice that you have to include a couple lengths of wire. I suggest green wire to remind you that these sections are not connected directly to positive or to negative power. But you can use any color you like. You can also substi-tute patch cords, if you have them. However, learning to strip insulation from pieces of wire is a necessary skill, so let’s deal with that now.Figure 2-15. Ceramic capacitors mostly look like this, although many of them are round or bead-shaped instead of square. The packaging shape is unimportant to us.Figure 2-16. This miniature loudspeaker, just over 1 inch in diameter, is useful for verifying audio output direct from transis-tor circuits.