2007-07-06 03:28:40 · 2 answers · asked by jaedah 1 in Science & Mathematics ➔ Engineering
some components (resistors, capacitors, diodes, transistors, etc.) have wires sticking out of the component body. These wires are called leads (pronounced 'leeds'). In order to use them you must drill holes in the printed-circuit-board, put the leads through the holes and solder them to the pads (with the holes).
Surface mount parts do not have wire leads. They get soldered directly to pads on the surface of the printed circuit board. Surface mount parts have "leads" that are simply metal ends bonded to the component. Some diodes and transistors have minature metal "feet" that can be soldered to their pads.
Surface mount components may be made very very tiny, because the manufacturer doesn't have to waste space on extra wire and metallic bonding of that "thick" wire. Niether does space have to be wasted on large holes in the circuit board. Some surface mount resistors and other components are the size of individual pepper grains.
Surface mount components have made possible the minaturization of cell phones, gameboys, i-Pods, etc.
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2007-07-06 04:43:37 · answer #1 · answered by tlbs101 7 · 0⤊ 0⤋
small rectanular blob, as small a 1mm that fits neatly on the circuit board, not like the wire type with the resistor material wrapped around it
2007-07-06 10:33:12 · answer #2 · answered by zebedos 3 · 0⤊ 0⤋