Page 49 - The Basics IA by ETron Circuit Labs

transistor which drives a speaker. R1, R2, R5, and C1 control the frequency of the pulses coming from Pin 3 of the 555 Timer IC. When you adjust the potentiometer R5 you change the frequency of the tone that the speaker will put out. Q1 amplifies the loudness of the audio signal.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap. You should hear a tone from the speaker. You should be able to adjust the frequency of the tone by adjusting the potentiometer R5.Check Your Work HereHere’s What You’ll Need...RESISTORR4R3R1R2hole 8ahole 9b10 Ohm ' (Brown, Black, Black, Gold) hole 8ihole 19h220 Ohm - (Red, Red, Brown, Gold)hole 20ahole 21a6.8K & (Blue, Gray, Red, Gold) hole 20dhole 26d6.8K & (Blue, Gray, Red, Gold) DISC CAPACITORSC1104c b0.1uFhole 20h hole 21hNPN 2N3904Collector hole 9g 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 Q1eNPN TRANSISTORIC 1INTEGRATED CIRCUITPOTENTIOMETER R5Base hole 8gEmitter hole 7g8 7 6 5 holes21e-18e1234holes 21f - 18fSPEAKERSPKR 1hole 8b hole 9hBLACKSCAN HERE TO SEE MORE ONLINEW1 = 21c & 30b W2 = 9a & 30c W3 = 7j & 30jW4 = 21j & 30i W5 = 21d & 18g W6 = 19d & 20ghole 19a hole 26cnot usedB1WIRESREDred = hole 30e black = hole 30h47LAB 24Visit us online at www.ETronCircuit.com for more exciting projectsLab Observations