Page 89 - The Basics IA by ETron Circuit Labs

IC Electronic OrganTheory:This project uses the 555 Timer IC as an Astable Multivibrator. As you change the voltage across Pins 6 and 7 you change the frequency of the output pulses at Pin 3.These tones can be made louder by feeding them to a transistor and amplifying them. Compare this circuit to Lab 31 for a sample was to connect the output of Pin 3 to a transistor.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap and touch one of the Tone Probe wires to a resistor lead, from R4 to R11. As you touch each one you will hear a different tone. Use both hands, one Tone Probe in each hand, and you can play your favorite tune. Note: The 10 Ohm resistor will get hot while running this project.The pitch or frequency of each tone is different depending on the value of the resistor.Potentiometer Used as a Voltage DividerTheory:In this electronic circuit consisting of 2 LEDs, 2 100 Ohm resistors (to keep the LEDs from burning out from too much current when the potentiometer is adjusted to zero ohms), a 9-volt battery, and a potentiometer. The electrons flow from the battery through the potentiometer, through the resistors, through the LEDs, and back to the battery. Potentiometers can be used to divide voltages in many types of electronic circuits and devices. For example, they are used in radios and televisions to control voltages of many circuits.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap and observe the two LEDs. This circuit causes the Brightness of the LEDs to very according to the position of the potentiometer. Turn the potentiometer fully clockwise and LED 1 should become brighter than LED 2. Turn the potentiometer fully counter-clockwise and LED 2 should become brighter than LED 1.SCAN HERE TO SEE MORE ONLINE87BUILD 4Visit us online at www.ETronCircuit.com for more exciting projects