The First Telefunken Transistors
Telefunken in Germany had been producing semiconductor rectifiers for a number of years before they developed transistors for mass production. Launched in 1953, the OC601 and OC602 were alloy junction germanium pnp transistors. Telefunken also developed S (special) versions which had attached copper heatsinks. These work but are low gain. hfe=26, Vf=97mV. hfe=18, Vf=100mV.