1. Hardware diagnostics, Mukesh's examples are pretty good for that
2. Hardware design
Hardware design starts with a problem to solve . Depending on the hardware implementation, which could be a chip, daughter card, ASIC or FPGA, the design caries, but there are things in common.
For instance, hardware is an implementation of source code. Switches on a motherboard for instance implement the same Assembly language functions written in software. Which means you will spend time looking either at circuit boards to read the code, solder patches in the boards to test a bug fix or you will write or be given code to implement in hardware.
You will then use design applications like Autocad to virtually represent the the boards implementation of code. You then take that file and send it to a manufacturing facility and they will "print" your board for you. (or use your companies 3D printer) you will then test it out like above, look for bugs, test fixes for those and then update your design file and repeat the process.
Day in a Computer Hardware Engineer's Life:
These are some typical job duties taken from online ads for computer hardware engineer positions found on Indeed.com:
•Diagnose and troubleshoot failed rotational media and solid state storage devices.
•Analyze user needs and recommend appropriate hardware.
•Modify hardware to either enable forensic analysis of the media or to change the functionality of the hardware for other purposes.
•Participate in the design and development of electronic circuits and assemblies.
•Conduct technical exploitation and examination of high priority digital media.
•Test and peer review for technical accuracy, standards and compliance to the design.