The FX-501 is a composite PNP transistor designed for high-current switching, housing two matched transistor chips equivalent to the 2SB1205 in one package. It operates with a collector-to-emitter voltage of -20V and supports a continuous collector current of -5A, with a pulse capability of -8A. Key electrical characteristics include a DC current gain (hFE) of 140 to 400, a maximum collector-emitter saturation voltage of -500 mV at -3A, and a typical gain-bandwidth product of 350 MHz. The dual-transistor configuration facilitates high-density mounting, making it ideal for compact electronic circuits requiring high-current switching.