More Resistors Activity 6.2.3a © 2011 Project Lead The Way, Inc.Magic of Electrons.

More ResistorsActivity 6.2.3a

© 2011 Project Lead The Way, Inc.Magic of Electrons

Variable Resistors

Potentiometers

Variable Resistors

A resistor whose value can be varied mechanically between its minimum and maximum values

Schematic SymbolFor

Potentiometers

Potentiometer Lab

On your activity sheet, draw a schematic diagram using a 3 volt DC source that will power two LEDs in parallel, and includes a fixed resistor on only ONE of those LEDs.

Build the circuit as shown so that you can easily insert various resistors.

Schematic SymbolFor

Potentiometers

Potentiometer Lab

• Identify the color bands on the supplied resistors and calculate the resistor amounts.

• Rank your resistors 1 through 5, with #1 the resistor having the smallest amount of resistance, and #5 with the greatest amount of resistance.

• Follow the rest of the instructions on your activity sheet, answering the questions as work through the lab.

Finish this statement:

The __________resistance, the

brighter the light.

Variable Resistors

Thermistors

TEMPERATURE SENSITIVE resistors. INCREASING the temperature DECREASES the resistance. 

Schematic SymbolFor

Thermistors

Thermistor Lab

On your activity page, draw a schematic diagram of a series circuit powered by 3 DC volts that contains an LED and a thermistor.

Follow the instructions in your activity worksheet to complete this lab. Be sure to answer all questions completely, and to get your instructor’s signature verifying your finished circuit.

Variable Resistors

A light-sensitive device in which the internal resistance changes with a change in light intensity

Photoresistors

Schematic SymbolsFor

Photoresistors

Either symbol can be used

Variable Resistors

Photoresistors

PhotoresistorsOn your activity page, draw a schematic diagram of a series circuit that uses 3 DC volts that will power an LED and is controlled by a photocell.

• Following the instructions found on your activity sheet, build the circuit that you designed (you may want to space the photocell far from the LED).

• Cover and then use the lamp to adjust the amount of light reaching the photocell.

• Be sure to answer all the questions as you complete the activity.

Image Resources

Microsoft, Inc. (2009). Clip Art. Retrieved January 13, 2009, from http://office.microsoft.com/en-us/clipart/default.aspx