Ch2 - Morse code

• it is the combinination of dot and dash like binary code in computer.
• the more dash and dot, the more ability to defined the character, which the number is the power of 2(2^{number of dash and dot}). It is just like binanry number. Ch3 - Braille
• it's the sophisticated algorithm that use 6 dot emboss on the paper to reproduce the writing system.
  • It also uses the precedence(or shift code) for number, capital indicator(or escape code) to make this system a lot versatiles.

Ch4 - Anatomy of a flashlight

• V=IR
• The high conduction element are those that have only one outer electron such as Cu, Ag, Au.
• the wider diameter the more easier for electron to transfer = less resistant
• Transferring electrons lose some energy as heat, the more resistance, the more heat produced.

Ch5 - Communicating around the corner

• We can use the earth as an unlimited electron supply(absorb or provide), it's called "connect to earth or ground".
• The longer the wire the higher resistance.

Ch6 - Logic with Switches

• AND == Series connection in the electric circuit
• OR == Parallel connection in the electric circuit

Ch7 Telegraph and relay

• Telegraph is the first device in human history that use electricity and electromagnetic to transfer data.
• Relay can repeat the telegraph with new electricity source so that the data signal is renewed.

Ch8 Relay and gate

• Relays can be connected together either in series form or parallel form, and they will work like Logic gate in circuits. However, they are connected in the metal bar part, not the electromagnetic part. For the electromagnetic parts, they are connected with outer switches.
  • Series form = AND
  • Parallel form = OR
  • connected the going out wire with upper plate = Inverter
• There is 6 types of relay: buffer, inverter, and, or, nand, nor