Gather two different metals, such as copper and zinc
Gather an electrolyte, such as lemon juice, vinegar, or saltwater
Insert the two metals into the electrolyte without letting them touch
Connect a wire from one metal to the other through an external circuit
Use the setup to produce a small electric current
Repeat the cell arrangement in series to increase voltage
Enclose the components in a safe container if needed
Test the output with a multimeter or small device