After highschool, you should learn subjects like Microprocessors, Digital Circuits, Integrated Circuits, Semiconductor Characteristics, Analog Circuits, Firmware, Assembly Language. Also please learn about instrumentation to learn about measuring instruments like Oscilloscopes and other digital instruments.
I would also strongly support learning Industrial Electronics courses as well.
Hope this helps
With technology in today's world you can research answers to any topic that you don't understand. The most important thing about becoming an electronic engineer is first and foremost is to be prepared for the time it will take to become one. You must have good communication skills, and be willing to persevere with patience to studying in a bachelors program in engineering, and get experience working as a protégé position for a couple of years before becoming a license engineer. The time will be worth it as far as financial security with salaries starting out at $72,000 per annual. More importantly, you must have some aptitude of understanding advanced electrical systems, communications, navigation systems, and power generation equipment after graduating. This is important because you will become skilled in building designs and prototypes related to engineering in specialized working environments. In closing, I would recommend networking with other engineers for more information based on their experiences.
Source: Suxia, X. I. (2007). Electronic Circuit Simulation Designing Based on Computer Simulation Software Platform. Electronic Engineer, 12.
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