Physical Computing - AbhiAgarwal/notes GitHub Wiki

Speaker

• Converts variations in a current or voltage into sound waves
  • Magnetic Speaker
  • Crystal Speaker

Switches

• Mechanical switches permit or interrupt the flow of current.
• SPST = Single-Pole, Single-Throw switch
• SPDT = Single-Pole, Double-Throw switch
• DPST = Double-Pole, Single-Throw switch
• DPDT = Double-Poke, Double-Throw switch
• Types of switches:
  • Push-Button switch, usually a SPST,
  • Rotary,
  • Poles,
  • Mercury
  • Toggle,
  • Rocker,
  • Lever,
  • Slide,
  • Push-on/Push-off
  • Illuminated

Resistor

• The process is:

  • Incoming current -> Protective Housing -> Carbon Composition -> Wire Lead -> Outgoing current

• So the composition of the whole thing is:

  • Carbon, and there is protective housing outside to create the resistor itself, and the wires are made of lead

• Increasing carbon in a resistor decreases its resistance

  • K = Kilo = 1,000
  • M = Mega = 1,000,000

Relays

• A relay is an electromagnetic switch.

  • A current flowing through a coil in the relay decrease a magnetic field -> pulls one switch contact against or away from another

• Reed switch Relays: Enclosed glass tube housing a pair of closely spaced switch contacts is a "Reed Switch". A magnetic field will close the contacts.

Microphone

• Converts sound wave variations into corresponding vibrations in an electrical current.
  • Sound wave variations are first converted to back-and-forth movements of a flexible film or foil called a Diaphragm.
  • These movements then cause variations in an electrical current by any of following: Carbon, Dynamic, Condenser, Crystal