Page 51 - The Basics IA by ETron Circuit Labs

until the pitch is where you want it to be. You can make a very realistic siren sound with this simple circuit. Transistor Q1 amplifies the strength of these pulses, making the sound louder.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap and press switch S1; you will hear a steadily rising tone in the speaker. When you release the switch, the tone will steadily decrease in frequency. This is the sound of the local police siren.Check Your Work HereR4R1R5Here’s What You’ll Need...RESISTORR3hole 8ahole 9ahole 8i10 Ohm ' (Brown, Black, Black, Gold) hole 20bhole 21cR66.8K & (Blue, Gray, Red, Gold) R21K $ (Brown, Black, Red, Gold) hole 24dhole 24chole 30chole 19a2.2K % (Red, Red, Red, Gold) hole 19h220 Ohm - (Red, Red, Brown, Gold)hole 28ghole 20a120K & (Brown, Red, Yellow, Gold) S1C1 103 1000uFhole 30h hole 28h a b c d e 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 a b c d e f g h i j 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 f g h i j C2hole 25hhole 24eSPEAKER0.01uFhole 20h hole 21hINTEGRATED CIRCUIT8 7 6 5 holes21e-18eIC 11234B1holes 21f - 18f SPKR 1hole 8bhole 9hREDBLACKred = hole 30e black = hole 30fQ1ec bNPN 2N3904Collector hole 9gBase hole 8gNPN TRANSISTOREmitter hole 7gSCAN HERE TO SEE MORE ONLINEWIRESW1 = 21a & 30a W2 = 25j & 30i W3 = 21i & 30j W4 = 7j & 21jW5 = 18c & 24b W6 = 9c & 21b W7 = 18g & 21d W8 = 19c & 20g49LAB 25Visit us online at www.ETronCircuit.com for more exciting projectsLab Observations