A(n) chip converts sound waves from a voice into a digital signal.

The correct answer for the question above is the Analog-to-digital converter chip. 
ADCs transform information from analog to digital form. They receive analog input, perform calculations on the analog signal, and then digitally encode the output in a format that computerized systems can process. 

The modern-day generator works on the principle of electromagnetic induction discovered by michael faraday in 1831-32. faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field.