We are usually faced with a general design of what the final product should accomplish. This is the biggest difference with the general problem solving methods that I have encountered. Contrary to problem solving for the answer, we are given or determine what the end result should be and problem solve to produce the desired specifications.
Once we know the specifications of the design, we do research and perform calculations to determine the needed components to get the results we need. Once we have the components that are believed to give the output we desire, we build a prototype of the circuit and test it. Testing includes but is not limited to varying the voltage, capacitors, and voltage frequencies. After testing we have a good idea about how all the components work together and affect each other.
After testing, we can either go back to the design and test phase or finalize a design and run tests again to verify the design before it is put into production or inserted into an existing circuit.