A modulated coil can be used to transmit signal from one device to another wirelessly. The original modulated coil experiment played sound/music from a radio through a cassette player without connecting the two physically. Here we will do the same experiment but with an iPod rather than a radio. Keeping up with the times, you can say!!!
Materials Required
- 1 medium sized Iron nut with bolt
- Thin insulated copper wire
- Audio cable with alligator clips at one end and headphone jack at the other
- iPod
- Cassette player with speakers
- Adhesive tape
- Knife or sandpaper, depending on type of insulation on the wire
Experimental Setup
- Leave some 3-5 cm of copper wire on one end and wind it around the nut. Ensure that you have minimum 20 turns clockwise or anticlockwise.
- Leave another 3-5 cm of wire at the other end. Scrape the insulation at both ends using knife (plastic insulation) or sandpaper (enamel insulation).
- Tighten the bolt at the bottom. If you don’t have the bolt, skip this step.
- Stick adhesive tape over the coiled wire firmly. You have your modulated coil ready.
- Connect the alligator clips of the audio cable to the two ends of the coil.
- Insert the audio cable jack into iPod and play any music.
- Play the cassette player without any cassette/tape and keep the door of cassette chamber open.
- Place the coil near the head of cassette player. You can hear clear iPod music from speakers of cassette player.
Explaining the Experiment
You first need to know how the cassette player works. The cassette player head detects variations in magnetic field of the audio tape and streams it to the speaker as electric signal. The speaker outputs this signal as audio.
When we play music in the iPod, electrical signal flows through audio cable to the modulated coil. As electricity flows through the coil, it starts acting as an electromagnet. Depending on variations in the music being played, strength of the electric current also varies. This varies the magnetic field around the modulated coil. This variation in magnetic field is picked up by the cassette player and played as audio.
Related Posts:
Principles of Electromagnetism
