Through-hole technology based transistorsThrough-hole technology based resistors
Through-hole technology is a way to mount electronic components to printed circuit boards (PCB).
It involves the use of leads on the components that are inserted into holes drilled in the PCBs and soldered to pads on the opposite side either by manual assembly (handiwork) or by the use of automated insertion mount machines.
↑Electronic Packaging:Solder Mounting Technlogies in K.H. Buschow et al (ed), Encyclopedia of Materials:Science and Technology, Elsevier, 2001 ISBN0-08-043152-6, pages 2708-2709
↑Horowitz, Paul; Hill, Winfield (1989). The art of electronics (2nded.). Cambridge [u.a.]: Cambridge Univ. Press. ISBN978-0-52137-095-0.