Speakers and Microphones -- A speaker is an electromagnet next to a paper diaphram that vibrates with an audio signal at audio frequencies to translate the electrical signal to air vibrations. While there are several different kinds of microphones, the simplest one just uses vibrations from the air to move a tiny metal peice against an electromagnet to induce an audio signal into the windings.
Stepper Motors and Servos
Primary and Secondary Windings on an Iron core
Impeadance or Voltage and Turns Ratios
Laminated Steel Plates cut down on eddie currents
Transformers fail due to Vibration
The Ignition Coil in a car is a transformer to convert the 12 volts from the battery up to a much higher voltage for the spark plugs. Here is the circuit (courtesy wikipedia) from the French Citroën 2CV wasted spark ignition system. The ignition switch closes the circuit to the coil along with the points. So whenever inside the distributor the points come around to their little cam, the circuit is all the way closed and current flows through the (12 v) primary windings of the coil and in the secondary windings a much higher voltage is induced. Note that this works, even though it is only direct current because it is periodically happening at a frequency proportional to the rotation of the points cam.
The condensor is a capacitor which reduces the electrical noise made by the points.
If I've made any mistakes, please Call me or email Kila or you can call us directly at (707) 413-6435. Here is my main website.