Science and Technology of Everyday Life
Use this as a coversheet for your lab writeup. Answer the questions on a separate sheet of paper.
Part 1A: Circuit Board Pattern Checked: _____________________
Part 1B: Circuit Board Etched Satisfactorily: _______________________
Part 1C: Basic Circuit Works Properly: _______________________
Part IV: Tuning verified: _______________________
Part V: Idea for switch installation approved: _______________________
Part VI: Final Operation and Questions: (INSTRUCTOR ONLY): _______________
- In electronics a "schematic diagram" is often used to provide a picture of a given circuit. The schematic diagram Figure 6 uses a symbol to represent each type of component. Resistors are zig-zag lines, capacitors are short parallel lines, and triangles represent amplifiers. Lines generally represent connections between components. On the back of this page (or on the next page) is a schematic of our keyboard circuit. Note that the two amplifiers are located inside the LM324 integrated circuit. The numbers on the lines coming from the amplifier symbols correspond to a particular pin on the integrated circuit. Circle the following items and label: speaker, 100 K resistors, capacitor, brass keys, photoresistor.
- Describe why pressing a key creates a sound coming from the speaker. In other words, explain how the keyboard works.
- Explain how the resistance connected to a key affects the pitch of the sound produced?
- What is the function of electrical resistors? The resistors used in this project are carbon composition resistors. From what materials are these resistors constructed? How is the electrical resistance varied?
- Describe function of electrical capacitors. What is the basic composition of a capacitor?
- Why does moving your hand over the photocell result in a variation in the output tone of the keyboard?
© 2001 John J. Krupczak, Jr.
All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of the author is prohibited.