THR: Through hole technology for the reflow oven
Electrical and electronic components come in a wide variety of sizes and mounting technologies. The classic is the through hole technology (THT). Its modern counterpart is the surface-mounting technology (SMT).
Unfortunately, these two technologies, which are combined in almost every electronic device, require different soldering methods. A dilemma? Yes and no.
At the beginning of the 20th century, there were no printed circuit boards. All components available at that time were wired freely by hand. It was not until around 1920 that the first prototypes were created: stamped conductor tracks riveted to hard paper and held together with sheet metal springs.
In 1943, the Viennese engineer Paul Eisler was granted a patent for a printed circuit board. With moderate success for quite a long time. Manual wiring remained the standard for a good decade.
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