This week we will continue with the 555 timer and the oscilloscope
Using the microphone circuit and a tuning fork you can produce a sound and a electronic picture of the sound. Be sure and explore how the picture changes as the sound changes. Determine which sounds look like the picture below (sine wave). Tuning forks produce this type of sound.
A handout shows how to drive a speaker with the oscillator. What you do is drive the base of a transistor (shown below) with the output from the oscillator. In this case the transistor is acting as an amplifier. It takes the output of the 555 timer that is small and makes it bigger. The signal is then sufficient to drive a speaker. Be sure you know how to change the frequency of oscillation and what effect that has on the sound.
There are a number of objects that have regular vibrations. Tuning forks, strings, and drum heads vibrate and pass those vibrations to the air. Sounds that we hear are based on these vibrations. Most sounds are a combination of many superimposed simple oscillations. The resulting pattern looks very complicated. With our michrophones and oscilliscopes we can observe these complex patterns. We will also find that those vibrations that have the simple form that is shown in the first figure sound to us like a single note.Therefore if we can produce an electrical oscillation and use that oscillation to drive the diaphram of a speaker back and forth we will here a sound that we will recognize as a note.
In order to receive a grade of A you must successfully complete the lab portion of the course, read prelab material, and pass the lab quiz. In order to pass you must get 75% of the questions correct.
In order to receive a grade of B you must successfully complete the lab portion of the course. The quiz is optional. For fun feel free to try the quiz.
You are not allowed to consult with other students while taking the quiz. You will be given a limited time period to complete the quiz. You may refer to any written material.
You may take the quiz at any time during the week but only once.
The quiz will be available starting on the day you cover the material and ending one week later.
If you have troubles please discuss the difficulties with DRG.
You are not allowed to consult with other students while taking the quiz. The quiz will be available at least from lab until following lab. You will be given 30 minutes to complete the quiz and you may refer to any written material.