Transistor Data Sheet [updated] -

VCE(sat)cap V sub cap C cap E open paren s a t close paren end-sub

Visual data for varying temperatures and loads. transistor data sheet

(Power Dissipation): How much heat the transistor can shed before melting. TJcap T sub cap J VCE(sat)cap V sub cap C cap E open

A common mistake: using a 2N3904 to switch a 150mA relay without base current calculation, then wondering why ( V_CE ) is 1V instead of 0.2V. transistor data sheet