CD-to-Cassette Adapter Lab
The CD-to-cassette adapter project involves making a device to allow a personal "walkman" type CD player to be used in an automobile cassette tape player. Figure 4 shows a completed device. The idea for this project was inspired by the modulated coil demonstration reported by Rathjen1. The CD output from each channel is used to drive an electromagnet mounted inside an empty tape cassette. When installed in the tape player, the varying magnetic field from the electromagnet induces a current in the tape heads. This project is a compelling demonstration of electromagnetic induction and affords an opportunity to discuss digital to analog conversion in the CD player.
The electromagnets in the device are created from two "jumbo" paper clips. Each clip is surrounded by 200 turns of 28 gage magnet wire. These electromagnets are then connected to the left and right channels from a standard 3-mm headphone jack. Although the impedance is low, the magnets can be driven from the headphone output of a personal compact disc player.
1.) D., Rathjen, Modulated Coil, The Physics Teacher, Vol 36, October (1998) 416.