DC to AC to DC Efficiency (Lesson 5)

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Brett McFarland
Intended Grade Level(s):
Estimated Activity Length:
3 hours
Learning Goal(s):

1. Students will use multimeters to measure voltage and current in circuits. 2. Students will use collected data and be able to make power calculations from this data. 3. Students will also be able to calculate efficiency from their power calculations. 4. Students will be able to compare efficiencies in order to identify the circuit that is most efficient. 5. Students will be able to make circuits from a diagram and vice versa. 6. Students will know what an inverter is and what it does.

Relevant Common Core Standard(s):
Relevant NGSS PE:

This is part of the Off the Grid Unit. This lesson will continue to deal with efficiency of USB charging devices, but this time we will be using an inverter in order to create AC voltage from a battery pack, and then use a standard AC charger (what you would plug into the wall) to charge a USB device. Students will continue to use USB voltage/current meters to take readings on the charger-side of the circuit. After constructing these circuit components, students will measure the efficiency at which this inverter changes DC power back into DC power (in a DC-to-AC-to-DC conversion), and will collect the data in their journals using the self- created tables in their science journals. 

Science Kit Material(s) Used


Other Material(s) Used

All materials from lessons 3 and 4, car inverter

Thumbnail Image

Car Charger Schematic