The study of electronic designs and choice of materials, the designer must be aware of the finite resistance of transistors in the ON state which gives rise to temperature from I^2*ESR where ESR is the slope of the VI curve sometimes called Rce by Diodes Inc ( the best source of low Vce switches) or in MOSFETs called RdsON.
Keep in mind the switch should be <<5% of the load resistance for efficiency and heat issues.
The same criteria may be considered for power capacitors and inductors to limit the power loss inside with reactive currents. ESR is also related to the quality factor Q or impedance ratio at resonance.
On the voltage side dielectrics and semi's all have a breakdown limit which should be derated by at least 20% at maximum operating temperature,as well as power limits to provide a reliable fit to the application.
Learn to understand high ESR, stray capacitance and inductance is bad and how to avoid it.
You will find yourself learning much about
mechanical design from thermal challenges , climatic environment limits , mechanical vibration effects on ceramic capacitors ,crystals etc and how mechanical design affects transient E field emissions in slots , gaps, single-ended transmission lines and radiating noise cables in your understanding of improved EMI and EMC design where,shields, twisted pairs, filters,snubbers, common mode chokes and ground planes assist in noise reduction.
Most of all read application notes to understand how to interpret component specs and limitations and build of a library of experience with all types of applications.
Then when you get experience, learn what DFM, DFT means and how to perform a Design Verification Test, or DVT by starting with a good self-written design spec and test plan, so any tech can test it, to give you feedback.
I started life as an EE design military class micro-powered digital VLF navigation radios, so I had access to all the Mil-Stds on every component type of capacitor materials and the advantages and disadvantages of each type, then crystals, then resistors then what constitutes reliability derating with environmental range. It explained all.
A quick search found these NASA references, some of which may be informative and reference specs for more parts.
https://nepp.nasa.gov/files/21529/MIL-HDBK-978B_vol1.pdf