Conductors and Insulators

• These have a very low resistance

  Conductors
• Typical value of resistance in copper wire of 10 ft.

  0.1Ω
• It is used in the manufacture of carbon composition resistors.

  Carbon
• The resistance of the two 10 – ft lengths of copper wire conductor is

  ________.

  0.08Ω
• Most wire conductors are ________.

  Copper
• It is easier to solder for connections.

  Tinned Wire
• It is flexible, easier to handle and less likely to develop an open break

  Stranded Wire
• It is often has an insulating coating of enamel or shellac.

  Very Thin Wire
• Hookup that is bare should be enclosed in a hollow insulating sleeve called

  ___________.

  Spaghetti
• Is it used for very low resistance

  Braided conductor
• Two or more conductors in a common covering form a ________.

  Cable
• It has 25 conductors but not in pairs

  Ribbon Cable
• Constant spacing between two conductors through the entire length

  provides a _____________.

  Transmission Line
• It is generally used for the signals in cable television

  Coaxial Cable
• Two conductors are imbedded in plastic to provide constant spacing. This

  type of line is commonly used in television for connecting the antenna to

  the receiver

  Twin – Lead Wire
• It specifies an opposition to current that can include resistance, inductance and capacitance

  Impedance
• It is constant for any length because it depends on the square root of ratio

  for the inductance in the line to the capacitance between the conductors.

  Characteristic Impedance
• For ¼ inch coaxial cable, it s characteristic impedance is approximately

  _______.

  75Ω
• For twin lead wire with 3/8 inch spacing, the characteristic impedance is

  _______.

  300Ω
• It is often used for screw – type materials

  Spade Lug
• It is commonly used for shielded cables with audio equipment

  RCA – type Plug
• It is still used in some applications, but in a smaller size.

  Phone Plug
• It is universally used in cable television because of its convenience

  F Connector
• It has eight wires in a flat, plastic ribbon

  Multiple Connector
• It is a standard connector for computer equipment. It has 26 pins

  RS – 232
• Most electronic circuits are mounted on a plastic insulating board with

  printed wiring.

  Printed Circuit Board (PCB)
• These are commonly used to open or close a circuit

  Switches
• It provides an ON or OFF position for one circuit.

  Single Pole Single Throw (SPST)
• It provides an ON or OFF position for one circuit

  Single Pole Single Throw (SPST)
• It provides switching for one side of the circuit.

  Single Pole Double Throw (SPDT)
• It provides switching for both lines of either of two circuits.

  Double Pole Double Throw (DPDT)
• It has eight miniature rocker switches.

  DIP Switch
• It is an automatic switch with contacts that can be closed or opened by

  current in the relay coil

  Relay Switches
• It is used as a protection against an overload resulting from a short circuit.

  Fuse
• The metal fuse element may be made of __________.

  Aluminum, tin coated copper or nickel
• This type of fuse has a coiled construction. They are designed to open only

  on a continued overload.

  Slow – Blow Fuse
• These have a thermal element in the form of a spring

  Circuit Breaker
• It is sometimes used as a fuse in television receivers.

  Short length of bare wire
• It can be mounted between two terminal strips on the chassis

  Wire link
• A closed switch has a resistance of approximately

  • infinity
  • zero ohms
  • 1MΩ
  • none of the above

  zero ohms