I disassembled a printed circuit board from an old device, removing its components to be able to use in my projects. However, all transistors on that board were unmarked. How can I know what they are?
The simplest way is to try to separate the NPN transistors from the PNP and eventually from some FET. For this you can use the multimeter as explained in our article "how to identify transistors". Once you know what type they are, set aside for use. By the size you can have an idea if they are of power or general use. Separate and use experimentally on less critical projects.
