What information can be determined from markings on a transistor casing?

The markings on a transistor casing provide crucial information about the device, including which leads correspond to the emitter, collector, or base. This is essential for correctly integrating the transistor into a circuit, as connecting the leads incorrectly can result in faulty operation or damage. The identification of these leads is typically indicated by the manufacturer's markings or a standardized code, allowing developers and technicians to quickly ascertain how to use the transistor.

While the markings may also include information about the manufacturer’s name or the type of transistor, the primary and most critical function of these markings pertains to designating the specific leads. Furthermore, maximum voltage ratings and other performance specifications are generally found in the transistor's datasheet rather than on the casing itself, making the identification of leads the most practical information available from the physical markings on the device.