2N5551 NPN General-Purpose Amplifier Transistor, TO-92 (5-Piece Pack)

Most everyday small-signal NPN transistors top out around 40-45V, which is plenty for low-voltage logic circuits but falls short the moment a design needs to switch or sense a signal riding on a higher-voltage rail. The 2N5551 steps up to a 160V rating while staying in the same breadboard-friendly TO-92 package, making it the practical choice for high-voltage signal switching, driving a higher-voltage relay coil's base stage, or any small-signal application where a design's working voltage exceeds what a standard-voltage transistor like the BC547 or 2N3904 could safely handle.