Wiring PV Cells in Series and Parallel

In this section, you will practice wiring photovoltaic (PV) cells. You will begin by determining the power rating of LEDs. Next, you will design and construct electrical series and parallel circuits using photovoltaic (PV) cells. Finally, you will learn how to provide a PV-based power source for a LED-based safety light system. LEDs are devices that give off light using very little electrical current. Typically, they require a DC voltage supply of 2 to 3 volts and cannot tolerate current larger than 20 mA. The operating voltage and current of LEDs vary slightly, depending on the manufacturer and the brightness of the LEDs. The PV cells used in this module have an output voltage of about 0.5 volts. You will learn the techniques to connect multiple PV cells to provide sufficient voltage and current for your LED-based safety light system.

Materials
goggles
4 small solar cells (at least 0.5 volts output each)
60 cm of thin electrical wire (use with alligator clips unless meter leads have alligator clips on their ends)
1 DC ammeter (to measure electric current in amps) / volt meter (to measure electric voltage in volts), or separate volt meter and ammeter
1 light source (desk lamp, flashlight or sunlight)

Develop Your Understanding
1. How do you increase the output voltage of your PV circuits?

a. By parallel connecting several PV cells
b. By series connecting several PV cells