800 mA PNP with built-in bias network
The Toshiba RN2427TE85LF is a PNP pre-biased transistor rated for 800 mA continuous collector current and 50 V collector-emitter breakdown. The 2.2 kOhm base resistor and 10 kOhm emitter-base resistor form a complete bias network inside the S-Mini SOT-23-3 package — no external resistors needed on the base leg.
What the ratings mean on the bench
800 mA collector current and 200 mW max power mean this part drives small relays, solenoids, or indicator loads without a heatsink. The 200 MHz transition frequency is well above the switching speed of most relay coils or DC loads — the transistor stays in saturation during the on-time, not in the linear region where dissipation climbs. Vce saturation is 250 mV max at 50 mA collector current with 1 mA base drive — the on-state voltage drop is low enough that a 5 V logic rail driving the base through the internal 2.2 kOhm resistor will saturate the output cleanly. DC current gain minimum of 90 at 100 mA and 1 Vce means the transistor has enough beta to stay saturated with modest base current from a microcontroller GPIO pin.