The transistors used in the legacy Lectron sets are made from Germanium, which is completely different from the types made of Silicon we are using nowadays.

    If you want a replacement for these Germanium (Ge) transistors, you need to check if they are PNP and also the right type.

    For example, the AC125 is a Germanium (A) and a low frequency  audio amplifier (C) type.

    Please be aware that those transistors are obsolete and the price for new old stock can be quite high.

    I don’t have my comparison chart right now but I’ll look it up when returning home from holidays.

    These are European types of transistors, so I don’t quite know the American equivalents.

    I do have a local firm which has these AC125 transistors in stock, so if you’re interested I can contact them.

    Many greetings,


    • This reply was modified 3 years, 8 months ago by Michael. Reason: Changed font and size styling for easier reading