The first transistor radio was released, and 150,000 units were sold. It was the Regency TR-1, made by the Regency Division of IDEA (Industrial Development Engineering Associates) in Indianapolis, Indiana. It cost $49.95. It used four Texas Instruments NPN transistors mounted on a printed circuit board. A few months later, in 1955, Sony released the transistorized TR-55, but its focus was almost exclusively on the Japanese domestic market. True international success came with the more advanced TR-63 model in 1957.
