Note
The transistor appears in commercial catalogs and substitution guides from 1960 onward, listed as a germanium PNP type suitable for HF switching and computing, with manufacturers including Raytheon, Motorola, and Sylvania. It remained in production into the early 1960s, as evidenced by its inclusion in 1962 brochures and 1963 substitution handbooks, aligning with the era's reliance on germanium for low-power, high-frequency needs before silicon transistors dominated. Production likely tapered off by the mid-1960s, as germanium devices were phased out in favor of more stable silicon alternatives, though new old stock (NOS) units from this period are still available today.
For engineering contexts, the 2N426's timeline reflects the rapid evolution of semiconductor technology in the post-WWII era, where Raytheon's early volume leadership (over 1 million transistors by 1955) supported innovations in portable electronics and computing. Modern equivalents might include silicon PNP transistors like the 2N3906 for similar AF switching, but with improved thermal stability and lower noise. If restoring vintage equipment, verify datasheets for exact parameters, as multi-manufacturer production (e.g., Raytheon vs. Motorola) could introduce slight variations.