Farnsworth was born August 19, 1906, the eldest of five children of Lewis Edwin Farnsworth and Serena Amanda Bastian, a Latter-day Saint couple living in a small log cabin built by Lewis's father near Beaver, Utah. In 1918, the family moved to a relative's ranch near Rigby, Idaho, where his father supplemented his farming income by hauling freight with his horse-drawn wagon. Philo was excited to find that his new home was wired for electricity, with a Delco generator providing power for lighting and farm machinery. He was a quick student in mechanical and electrical technology, repairing the troublesome generator. He found a burned-out electric motor among some items discarded by the previous tenants and rewound the armature; he converted his mother's hand-powered washing machine into an electric-powered one. He developed an early interest in electronics after his first telephone conversation with a distant relative, and he discovered a large cache of technology magazines in the attic of their new home. He won $25 in a pulp-magazine contest for inventing a magnetized car lock. Farnsworth was a member of The Church of Jesus Christ of Latter-day Saints.