Lab 4.2.4 Series Circuits

Estimated time: 30 min.

Objectives:

> - Build series circuits and explore their basic properties.

Background:

> One of the most basic concepts in electronics is that of a continuous loop through which electrons flow, and which is called a circuit. Throughout networking there are references to ground loop circuit, circuit versus packet switching, virtual circuits, in addition to all of the real circuits formed by networking media and networking devices. One of the fundamental electrical circuits is the SERIES circuit. While most networking devices and networks are built from very complex circuits that are beyond the scope of the lessons included in this course, the process of building some series circuits will help you with some of the terminology and concepts of networking. This lab will also help increase your overall understanding of some of the most basic electrical circuit building blocks.

Tools / Preparation:

> Prior to starting the lab, the teacher or lab assistant should have several multimeters available (one for each team of students) and various items for testing voltage. Work in teams of two. The following resources will be required:

> - Fluke 12B multimeter (or equivalent)
> - Light switch
> - Wire cutters/stripper
> - Copper Wire
> - 2 light bulbs (6v) with bulb bases
> - 6-Volt lantern battery

Notes:

Step 1 - Measure the resistances of all devices and components except the battery.

> Measure the voltage of the battery. All resistances should be less than 1 Ω (Ohm), except the light bulbs. All the devices except the battery should register continuity (with the tone) indicating a short circuit, or a conducting path.

> Check the following resistance. Turn the meter off when finished or it will drain the battery.

> Item to Measure the resistance of: | Set Selector and range scale to: | Resistance reading:
> Pieces of wire to connect components |  |
> Light switch |  |
> Light bulbs |  |

Step 2 - Measure the voltage of the battery, unloaded (with nothing attached to it).

> Item to Measure the Voltage of: | Set Selector and range scale to: | Voltage reading:
> Lantern Battery: (6 V) with no load |  |

Step 3 - Build a series circuit, one device at a time (use 1 battery, 1 switch, 1 bulb and connecting wires).

> Connect the battery positive lead to one end of wire and connect the negative lead to the other wire. If the switch is turned on, the bulb should light. Disconnect one thing and see that the circuit is broken. Did the bulb go out?

Step 4 - Measure the battery voltage while the circuit is running.

> The switch should be turned on and the light bulb should be lit. What was the voltage of the battery with the light bulb on?

Step 5 - Add the second bulb in series and measure the battery voltage again.

> What was the voltage of the battery with the light bulb on?

Reflection Question:

> How do series circuits apply to networking?