Question 1

What is the purpose of the switch shown in this schematic diagram?



 

Question 2

How is an electrical switch constructed? What goes on inside the switch that actually “makes” or “breaks” a path for electric current?

 

Question 3

What difference will it make if the switch is located in either of these two alternate locations in the circuit?





 

Question 4

Does this switch (in the closed state) have a low resistance or a high resistance between its terminals?



 

Question 5

How might you use a meter (or a conductivity/continuity tester) to determine whether this electrical switch is in the open or closed state?



 

Question 6

Identify the following types of switches, according to the number of “poles” and “throws” each switch has:



 

Question 7

Identify the following types of switches, according to their style of actuation (how each switch is physically operated):



 

Question 8

What type of switch is represented by this schematic symbol?



 

Question 9

What type of switch is represented by this schematic symbol?



 

Question 10

What positions do the switches have to be in for the light bulb to receive power?



 

Question 11

Electric motors of the permanent magnet design are very simple to reverse: just switch the polarity of the DC power to the motor, and it will spin the other direction:



Complete this schematic diagram, showing how a DPDT switch may be placed in this circuit to reverse the motor’s direction of rotation without the need to disconnect and re-connect wires:



 

Question 12

What will the light bulb do when the switch is open, and when the switch is closed?



 

Question 13

Examine this schematic diagram:



Now, without moving the following components, show how they may be connected together with wires to form the same circuit depicted in the schematic diagram above:



 

Question 14

What does the normal status of an electrical switch refer to? Specifically, what is the difference between a normally-open switch and a normally-closed switch?

 

Question 15

Identify the “normal” status of each switch, whether it is normally-open (N.O.) or normally-closed (N.C.):



Based on the symbols shown, describe what physical condition results in the switch contacts being open, and what condition results in the switch contacts being closed, for each switch.

 

Question 16

Identify the “normal” status of each switch, whether it is normally-open (N.O.) or normally-closed (N.C.):



Based on the symbols shown, describe what physical condition results in the switch contacts being open, and what condition results in the switch contacts being closed, for each switch.

 

Question 17

Identify the “normal” status of each switch, whether it is normally-open (N.O.) or normally-closed (N.C.):



Based on the symbols shown, describe what physical condition results in the switch contacts being open, and what condition results in the switch contacts being closed, for each switch.

 

Question 18

Find one or two real switches and bring them with you to class for discussion. Identify as much information as you can about your switches prior to discussion:

• Number of poles
• Number of throws
• Voltage rating of contacts
• Current rating of contacts
• Contact status for various actuator positions
• Type (toggle, pushbutton)

 


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