Identify transistor type from color band/dot markings
Small transistors (especially Japanese types) use color dots/bands to indicate type number. The three bands give a 3-digit number that maps to the transistor type. For example: Red-Red-Yellow (2-2-4) = 2N224. Common prefixes: 2N (JEDEC), BC (European), 2SA/2SB/2SC/2SD (Japanese).
Transistor Color Code is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.