1. comments

See exam_old_example.pdf, page 8.

There are too many unknowns for the amount of constraints (equations) given. How do you decide?

The above is (only) 9 pages of discussion and strategy that you won’t find any where else.[1] It requires you to vaguely recall STAT240, Ohm’s law, and pay attention to the effect of changing your “arbitrary” value on other parameters in the circuit.

Really, a spreadsheet is a supertool for this sort of what-if-ing. Set up all your equations, change the independent (decision) variable, and see what happens to all the computed valued.

Why we force everyone you learn some programming

Matlab or another scripting language also makes this easy, just change a number and run the script again.

The super power, is to then wrap that script into a function whose:

  • inputs are the decision variables

  • output(s) are the performance calculations

and then make a series of plots where you sweep various inputs (x-axis) and show the resulting calculations (y-axis).

2. Operational amplifier problems

2.1. DC (low-frequency) gain

Draw circuit for a non-inverting amplifier with a gain of +4 V/V. Use only E12-series resistor values.

Amplifier with a low-frequency gain of −12 V/V. Input resistance between 10 kΩ and 50 kΩ.

What is the -3 dB frequency of a circuit using an NE5532A op amp configured for a low-frequency gain of 15 V/V.

1. In my experience, this is how a deep expert will think about things. They just don’t write it down in this way. This comes out in how they talk about their design decisions. Intuition is difficult to codify into language.