Page 63 - The Basics IA by ETron Circuit Labs

Pressing pushbutton switch S1 causes R5, 470k Ohms, to be put in parallel with resistor R2, thereby lowering the resistance to Pins 6 and 2.The output pulses are then sent to the transistor Q1 and amplified. This amplified signal is then sent to the speaker.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap and you should hear a tone. If you press the pushbutton switch you will hear a different tone. As you press and release the pushbutton switch, you will be able to create the sounds of the 2 tone British Siren.Check Your Work Here 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 hole 8b hole 9hHere’s What You’ll Need...R4R3R1R2 R5Q1c beRESISTORhole 8ahole 9a100 Ohm - (Brown, Black, Brown, Gold)hole 8ihole 19i220 Ohm - (Red, Red, Brown, Gold)hole 20ahole 21b1K $ (Brown, Black, Red, Gold) hole 19ahole 20b120K & (Brown, Red, Yellow, Gold) hole 20chole 24b470K & (Yellow, Violet, Yellow, Gold) NPN TRANSISTORS1Emitter hole 7ghole 26f hole 24ehole 20j hole 21hNPN 2N3904Collector hole 9gBase hole 8gC1DISC CAPACITORS 103 0.01uFREDBLACKB1red = hole 30e black = hole 30fSPEAKERINTEGRATED CIRCUITIC 18 7 6 5 holes21e-18eSPKR 1SCAN HERE TO SEE1 MORE ONLINE2 3 4holes 21f - 18fWIRESW1 = 7j & 30j W2 = 21i & 30i W3 = 20h & 26gW4 = 21c & 30b W5 = 9c & 30a W6 = 19c & 20gW7 = 21d & 18g61LAB 31Visit us online at www.ETronCircuit.com for more exciting projectsLab Observations