William Eitel and Jack McCullough were two young engineers that started their company, called EIMAC, in San Francisco in the mid-30s.

Means of controlling the amount of current and volts for use featured a breakthrough when Lee de Forest invented the "audion" in 1906. This audion led to the development of the triode tube necessary for further use of the radio wave concepts. Many credit de Forest with being the inventor of the radio. In 1912, de Forest transmitted the first wireless voice message to a receiver a few miles away. Later that year, San Jose began the world's first radio broadcasts. During this time, he worked at a research lab in Palo Alto and lived in San Carlos for many years as his inventions turned to Hollywood concepts of developing the Photofilm process which made the movies talk.

In a small garage on Green Street in San Francisco during the 1920s, Philo Farnsworth developed the iconoscope (an image dissector) that became the most single important invention in the evolution of television.

Charles Litton built his own ham radio set at the age of 10 and later went to Stanford to help perfect the vacuum tube. In 1931, Litton opened his own business in Redwood City. He later moved to San Carlos as Litton Engineering Laboratories and began original work on laser technology. His business later became a part of ITT system.

Tomlinson Moseley, at the age of 19 in 1921, formed his own company, the Dalmo Corporation, in San Francisco. As Dalmo Victor the company began making electronic components and moved to Belmont where it became the town's largest employer. By the 1970s it became absorbed into Bell Aerospace-Textron conglomerate.

In 1946 Ampex, in San Carlos, made news by perfecting a magnetic tape recording process with founder Alexander Poniataoff and former Delmo employee, Harold Lindsey. A year later it was sold to the American Broadcasting Company thus enabling the network to pre-record its programs. In 1977, Ampex, now headquartered in Redwood City and employing 10,000 people worldwide, merged with the billion dollar Signal Companies conglomerate of Los Angeles.

William Eitel and Jack McCullough were two young engineers that started their company, called EIMAC, in San Francisco in the mid-30s. They moved to San Bruno in 1934 and rented a previous butcher shop and began perfecting their process of producing vacuum tubes. After working out how to keep the tubes from cracking, the Government in 1939 awarded contracts to EIMAC to produce them. With orders for thousands of tubes, Eitel and McCullough expanded throughout the community and hired every available person to keep WWII supplied for our military. After the war television tubes were produced until they moved their operation to the Bel-Carlos Industrial Park in San Carlos. In 1948, two brothers, Russell and Siguard Varian formed Varian Associates in San Carlos. They had invented the Klystron Tube- a key element in radar and microwave technology (in 1937). In1953, Varian moved to Palo Alto's Sanford Industrial Park in Santa Clara County. In 1965, EIMAC was absorbed by Varian.

Lennart Erickson and Kurt Appert began specializing in communications equipment in San Francisco in the 1930s. Barely out of their teens, they took extension courses, trade school courses and with their practical experience they began capturing a widening market on the West Coast. In 1947 they moved to San Carlos. Due to the demand for their equipment, Lenkurt as the company was now called, allowed General Telephone and Electronics to buy Lenkurt and reorganized as GTE Lenkurt.

All of these electronic companies in San Mateo County contributed the rise of its industry and as time went on, inventions and patients of these companies became the foundation of an even larger economic boost in the world