Unit c electrical principals & technologies notes(controlling the flow)
- 2. Insulators & Conductors Insulators: Electricity does not easily flow through this material Conductors: Electricity easily flows through this material. Why does this happen?
- 3. Insulators & Conductors Insulators have electrons that are very closely bonded to their nucleus. Because the electrons are closely bonded they do not transfer very easily and so they don’t move a charge very well. Conductors have electrons that are loosely bonded to their nucleus. Because of this they quickly and easily transfer electricity.
- 4. Insulators & Conductors “Superconductors” They are perfect conductors - they have no resistance to electron flow.
- 5. Insulators & Conductors SUPERCONDUCTORS ARE USED FOR: Transport vehicles such as trains can be made to "float" on strong superconducting magnets, virtually eliminating friction between the train and its tracks. Japan has done much work in this area. Magnetic Resonance Imaging (MRI) use superconductors to produce images more quickly. Superconductors are used in generators and in the storage and transmission of electricity.
- 6. Resistors Engineers need to know how well different materials conduct electricity so they can design both safe and effective devices. In some applications a conductor is called a resistor. A resistor allows electrons to flow through it but provides resistance to it. This means it is harder for electrons to flow through the device. Resistance is measured in Ohms.
- 7. Resistors So why do we need resistors? A light Bulb is a resistor. So is an electric heater. And a lie detector.
- 8. Resistors The volume control on a stereo is a special kind of resistor called a variable resistor or rheostat. An additional example of a rheostat is a light dimmer. Variable Resistor or Rheostat: Resistor that can change the amount of resistance provided