Lab 2: Electronics

Overview:

The purpose of this lab was to introduce me to a few basic electronic principles by testing them myself. I learned about resistance, voltage, amperage and how to test them all using a multimeter. I created a basic LED circuit using a breadboard, resistor, Arduino microcontroller, a small switch, and a few sets of wires to connect all the electronics. I also learned about a potentiometer by adding one to a circuit I created.

Procedure:

A Basic Circuit

I began the lab by ensuring we had all of our parts. The list of parts I needed for this lab can be found here.

Once I completed the inventory check, I proceeded to set up the board for the creation of a basic LED circuit. I connected the breadboard to an arduino microcontroller using wires such as in this picture:

The red wire is connected to the “5v” connection on the Arduino microcontroller. The black wire is connected to the “ground” connection.

I then connected the arduino microcontroller to a desktop using a USB cable. The Arduino served the purpose of supplying power to my basic LED circuit (from the running desktop computer). By connected the red wire to the “5v” connection, I regulated the voltage of direct current that was supplied to the LED on our circuit. An LED needs no more than 5V for this setup.

I then added a 160-ohm resistor to the circuit. This prevents the LED from being overpowered and eventually being burnt out. The resistor reduces the energy coming from the voltage regulator to a level that is safe for the LED to use. After the resistor was added, I added the final piece–the LED. I ensured that all wires were connected in the correct spots as I learned previously in the Soldering lab.

Here is a picture of the breadboard setup after everything was connected:

 I am testing the voltage of the circuit using a multimeter–notice the desired 5V. The LED lights up as expected. (Click on the image to make it bigger)

LED Circuit with a Switch

I next added a switch to the circuit. The switch allows me to turn the LED off with the press of a button. It behaves like a light-switch in my living room. There are only two possibilities for the switch: on and off. The switch is a button located next to the LED that controls the flow of electricity from the power source to the LED.

Contrary to what I wanted to happen, the light stayed on when not pressed. I describe this further in the “Problems” section of this post.

The LED light went off as soon as I pressed the switch.

LED Circuit with a Potentiometer

Whereas the switch allowed me to only turn the LED on and off, the addition of a potentiometer to the circuit allowed me to adjust the brightness of the LED.  Taken from our lab assignment, “A potentiometer is a resistor that can change its resistance. A potentiometer has three connections. The outer leads are the ends of a fixed value resistor. The center lead connects to a wiper which slides along the fixed resistor. The resistance between the center lead and either of the outside leads changes as the pot’s knob is moved.”

The LED is not lit because the potentiometer is turned all the way to the off setting.

Here the light is lit(slightly dimmed) when I turned the potentiometer.

Notes/Problems:

There were many problems I ran in to with this lab. The first problem I ran in to was that the breadboard was missing one side of connected holes. This is what it looked like:

I used duct tape to connect the extra parts to the breadboard.

The assignment was not impossible to do without the extra parts taped together. The reason I wanted to tape the parts to the breadboard (just like every other lab group had) was so that it was much easier to follow along in the lab assignment which had a breadboard with a set of connected holes on both sides like this:

Learning electronics is complicated enough! I didn’t need the added stress of organizing my components and wires differently than the lab diagrams!

Another problem that I ran in to was that when I pressed the switch, the LED turned off. When I released the switch, the LED turned on. I wanted the opposite behavior. I believe if I had simply turned the switch the other way on the breadboard the problem would have been resolved!

Aside from these problems, this lab was a great experience. I learned basic electronic principles by trying them in action. It was a great learning experience that I hope will help me in future labs.

One thought on “Lab 2: Electronics

  1. Using the breadboard layout diagrams is convenient, but you should eventually be just as comfortable following circuit schematics – because that is the standard way to document and describe electronic circuit setups.

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