PhysicsLAB Lab
Telegraph Project
Historical Developments
 
Before designing your telegraph system, it is prudent to understand the history of the important developments and implementations of electromagnet telegraphs. In this section you are to state the names, dates, discovery, and resource URL for three important researchers in the history of electromagnetic (not chemical, digital, or wireless) telegraphs. Please list them in chronological order and use a different online reference for each person.
 
#1 Name:
 

#1 Date of Discovery:
 

#1 Description of Discovery:
 

#1 Resource URL: 

 
#2 Name:
 

#2 Date of Discovery:
 

#2 Description of Discovery:
 

#2 Resource URL: 

 
#3 Name:
 

#3 Date of Discovery:
 

#3 Description of Discovery:
 

#3 Resource URL: 

Parts of a Telegraph
 
Refer to the following information for the next six questions.

The picture on the bottom looks like our telegraph sounders, while the picture on the top is a model of Bunnell Sounder from 1903. Match the old parts with the new parts.
 
old
new  
A
 
B
 
C
 
D
 
E
 
F
 
 
The Circuit
 
In this project you will be asked to build a telegraph between two tables. You will have access to the following equipment:
 
  • one or two DC power supplies
  • speaker wire
  • one or two telegraph keys
  • two telegraph sounders
 
With your backs to each other, you will each be asked to send the message VACATION in Morse code to your partner using a telegraph key.
 
Before physically building your telegraph set, you are to present two designs in the spaces provided below.
 
  1. A circuit in which only one key is used. Only one sounder at a time can serve as the transmitter and the second must be the receiver.
  2. A circuit in which two keys are used with either sounder able to be both a transmitter or a receiver.
 
Use these circuit notations:              
 
 
   
 
 
 
Refer to the following information for the next four questions.

Now it is time to actually construct your telegraph set. You may set up either circuit. Obviously the second circuit is more challenging. If you need to make modifications, make sure that you correct your circuit diagram. When you are ready to test, call over your instructor to verify your connections before turning on the power supply.
Circuit Constructed
 
What is the Morse Code for VACATION? Use a * for a dot and a ~ for a dash. Please space your letters.
For example, SOS would look like: ***  ~~~  ***
 

Instructor: success of Partner #1's trial 

Instructor: success of Partner #2's trial 




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