Day 2: 5V power supply (cont.), using breadboards and multimeter

01/09/2013
                          Today's Topic: 5V Power Supply, and Intro. to Breadboard and Multimeter.

       Continuing with the assignment left from last night, I had finally completed repairing the wire loop, and constructing the 5V power supply.

This was the completed loop constructed by connecting 6 black and brown wires with heat shrinks covering the joints.

Here was the completed 5V power supply converted from a recycled cell phone charger.

The following is the procedure of making the power supply:

1. Cut off the plug end (not the AC adaptor end!!) of the wire.
2. Seperate the joint wires by slicing between the wires. Strip off the end of both wires (don't need to be too long, one wire shall be striped a little more than the other wire).
3. Indentify the polarity of the wires and paint come color to identify them. Solder them to a double head joint pins. (1 wire per pin).
4. Insulate the wires using 2 layers of heat shrink. (apply 1 heat shrink to prvent contact between wires, and the other prevent contact from outside. 

This is the a completed view of the pin end of the 5V power supply. Notice that the copper wire is fully covered by the heat shrink.
 
Now, let test the power supply!
How did we test it?  Connect it to a breadboard! If a functional LED lit up in a correctly completed circuit, congratulation! You now have a functional 5V power supply.

Knowing how the plug holes on the breadboard were connected, 3 parallel circuits were built using 100 ohm, 1k ohm, and 10k ohm resisters while each was connected to a LED light. The LED light (yellow) connected to a 100 ohm resister gave off the most intense light because it conducted the strongest current. The LED light (red)connected to a 10k ohm resister gave off the least intense light since it conducted the weakest current.

 

The Last task for the day was measuring resistance, and voltage of different electronic components with the multimeter.

Using the multimeter to measure the resistance of different resistors and to compare with their reported values according to the color codes.

 

Using the multimeter to measure the voltage supplied by a given power source.

Using the multimeter to measure the voltage of different batteries in connection with a 64ohm resistor and determine their service hours base on the reading.

Finally, we overloaded a 100ohm resistor circuit with around 17 volt of power supply.The result was...

Fume comming out of the resistor, smell of burning electronic, and...

a mostly burnt resistor!

 

The lession learned from tonight, power off (or unplug) the circuit immidiately upon smelling burning electronic or seeing fume (or smoke) comming out of the circuit.