Switching Circuits

Question 1

The abbreviation for normally closed switches is what?

Answer 1

NC or N/C

Question 2

The terms normally open or normally closed signify what?

Answer 2

The position taken by the device when no force is acting upon it.

Question 3

What does it mean if a switch or contact is momentary?

Answer 3

It signifies that the device changes state only when acted upon by an outside force.

Question 4

What does it mean if a switch or contact is maintained?

Answer 4

It signifies that the device changes state when acted upon by an outside force and remains in that state when the force is removed.

Question 5

What is a switch pole?

Answer 5

The number of separate circuits that a switch controls.

Question 6

A single-pole switch controls two circuits, true or false?

Answer 6

False, it only controls one circuit.

Question 7

How many circuits does a double-pole switch control?

Answer 7

Two circuits.

Question 8

The number of ‘throws’ in a switch contact determines what?

Answer 8

It determines how many different switching positions a switch can be in.

Question 9

A simple light switch is an example of a single break type device or a double break contact device?

Answer 9

A single break type device.

Question 10

What are single break and double break contacts?

Answer 10

Single break and double break contacts refer to the number of circuit breaking contacts a device has.

Question 11

One way to classify switches is by the connections they make. What two factors determine what types of connections a switch makes?

Answer 11

The polls and the throws.

Question 12

The two most common types of throws are:

Answer 12

Single-throw and double-throw.

Question 13

What is a single-throw switch?

Answer 13

A single-throw switch is a simple on/off switch that connects or disconnects two terminals.

Question 14

What is a double-throw switch?

Answer 14

A double throw switch connects an input terminal to one of two output terminals.

Question 15

How many terminals does a double-throw switch have?

What are they called?

Answer 15

3.

• The common terminal
• A
• B

Question 16

Winch controls and engine starters are examples of which type of switch?

Answer 16

A momentary switch.

Question 17

A double-pole double-throw (DPDT) switch has how many terminals?

Answer 17

6.

• 2 for the inputs
• 2 for the A outputs
• 2 for the B outputs

Question 18

The abbreviation for normally open switches is what?

Answer 18

NO or N/O

Question 19

What is a schematic diagram or drawing?

Answer 19

A schematic diagram or drawing shows the logical sequence of operation of the circuit without regard to the physical location of the circuit components.

Question 20

Schematic diagrams are also referred to as ___ diagrams or ___ diagrams?

Answer 20

Elementary diagrams or ladder diagrams.

Question 21

The two vertical lines on a schematic diagram represent what?

Answer 21

The power source.

Question 22

What are ‘rungs’ in a schematic diagram?

Answer 22

Horizontal conductors

Question 23

What is a wiring diagram?

Answer 23

A wiring diagram is a graphic representation of a circuit showing the electrical interconnection of circuit components and their relative physical location.

Question 24

In most circuits you work with, the white wire is the grounded conductor and is properly called the ___ ___.

Answer 24

Identified conductor

Question 25

What is the common name given to the two wires that connect three-way or four-way switches together?

Answer 25

Travellers

Question 26

Which conductor should be connected to the brass screw of lampholder in a switched circuit?

Answer 26

The switch leg (coloured)

Question 27

Which conductor should be connected to the silver screw on a duplex receptacle?

Answer 27

The identified conductor (white)

Question 28

A standard door chime unit consists of which three components?

Answer 28

• two solenoids (electromagnetic coils)
• two spring-suspended plungers that slide back and forth within the solenoids when the solenoid is energized and
• two chime plates