In which year did Hewlett-Packard develop their first product?

In which year did Hewlett-Packard develop their first product?

• 1958
• 1988
• 1978
• 1938

EXPLANATION

HP invents first product

Drawing on Bill’s study of negative feedback, Bill and Dave produce HP's first product, the resistance-capacitance audio oscillator, used to test sound equipment. They name it the HP Model 200A. 

1938 HP invents first product