Why are NPN types usually scarcer and more expensive?
According to R. G. Keen, the physical characteristics of germanium made it much easier at the time to manufacture PNP devices rather than NPN. The demand for non-leaky, temperature-stable NPN devices of consistent gains was one of the factors that drove germanium out of the picture in favor of silicon. The result is that, today, there are large, fairly dependable supplies of old-stock PNP germanium on which I can draw. I have secured some stock of U.S. and European NPN types, and I will make these available as I am able to get testing and auditing done. • Do you offer any of the Western European types (NKT275, AC12x, OCxx, etc.)? I have a few OCxx types, and we offer matched pairs of some. If you do go looking for European numbers, buyer beware! The old-stock devices have become very expensive, and fakes are common. AFAIK, devices marked NKT275 are all re-labeled. They may or may not be decent quality–that depends on what raw stock the seller started with–but they are almost surely n
