ECE 1100: Introduction to Electrical and Computer Engineering David R. Jackson Professor, ECE Dept. Spring 2008 Notes 8 Class Project

To build and successfully demonstrate a crystal radio. Note: We will be discussing the theory behind it in class.

Schematic Antenna Ground Inductor Variable Capacitor Diode (1N34A) High-Impedance Earphone

Rules It should be a team project: team size either 2 or 3. The project must be demonstrated to the instructor. To get credit, it must work (the instructor must be able to hear at least one radio station.) The project must be finished and demonstrated by 4:00 p.m. on Thursday, May 8. (Our last class day is Tuesday, April 29. Exam 3 is on Thursday, May 8, from 5-6 p.m.) Each team must turn in a piece of paper with the name of all team members, and a statement certifying that all team members participated in the project. This statement must be signed by all team members.

Instructions The kit can be ordered from Ramsey Electronics (CS-2) for $9.95. Go to (then search for “crystal radio”). The kit can be ordered from Elenco Electronics (MX- 901C) for $ Go to (then go to “Toy Division” and then “Radio Kits”). Step 1: order a crystal radio kit: Note: your kit does not have to be one of these – but it must be a crystal radio kit. You might be able to also find it locally.

Project Ramsey Electronics CS-2 This is what the kit would look like if it is assembled using the included base – but you will not be using this for the project. You will be using a breadboard.

Instructions The radio must be assembled on a breadboard. Your team should borrow a breadboard from the ECE shop (S386-D). Your team should also borrow a ground wire from the shop. Step 2: Assemble the crystal radio

Breadboard All of the holes in a column are connected together. The columns are not connected across the gaps All of the holes in these top and bottom rows are connected together (but each row is isolated from the other rows and the columns).

Ordering Advice If you order your kit online, order it early! Sometimes there are delays in getting the kits shipped. Your team is responsible for building and demonstrating the project by the deadline.

Ownership Your team may keep the kit if it wishes. However, the breadboard and the ground wire should be returned to the ECE shop.