2n4910.pdf datasheet:

INCHANGE Semiconductor isc Product Specification isc Silicon NPN Power Transistor 2N4910 DESCRIPTION Collector-Emitter Sustaining Voltage- : VCEO(SUS)= 40V(Min) Low Collector Saturatioin Voltage- : VCE(sat)= 0.6V(Max.)@ IC= 1A Wide Area of Safe Operation APPLICATIONS Designed for driver circuits, switching and amplifier applications. ABSOLUTE MAXIMUM RATINGS(Ta=25) SYMBOL PARAMETER VALUE UNIT V Collector-Base Voltage 40 V CBO V Collector-Emitter Voltage 40 V CEOV Emitter-Base Voltage 5 V EBOI Collector Current-Continuous 1 A CI Collector Current-Peak 4 A CMIB Collector Current-Continuous 1 A Collector Power Dissipation P 25 W C@ T =25 CT Junction Temperature 200 JTstg Storage Temperature Range -65~200 THERMAL CHARACTERISTICS SYMBOL PARAMETER MAX UNIT Rth j-c Thermal Resistance,Junction to Case