Through-hole technology
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![Through-hole devices mounted on the circuit board of a mid-1980s home computer. Axial-lead devices are at upper left, while blue radial-lead capacitors are at upper right](/Images/godic/202502/03/MOS6581_chtaube0612291638.jpg")
![Axial- (top) and radial- (bottom) leaded electrolytic capacitors](/Images/godic/202502/03/Capacitors_electrolytic1638.jpg")
![A box of drill bits used for making holes in printed circuit boards. While tungsten-carbide bits are very hard, they eventually wear out or break. Making holes is a considerable part of the cost of a through-hole printed circuit board.](/Images/godic/202502/03/Box_of_02in_pcb_bits1638.jpg")
Through-hole technology, also spelled "thru-hole", refers to the mounting scheme used for electronic components that involves the use of leads on the components that are inserted into holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side either by manual assembly (hand placement) or by the use of automated insertion mount machines.