# Electronics written problems

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Revision as of 15:04, 16 October 2018 by Steven Wasserman (Talk | contribs)

This is Part 2 of Assignment 6.

## Ideal elements

- Draw the symbol for one of the two terminal, ideal elements. Label the terminals and indicate the direction of current flow. Show the constitutive equation for the element you chose.

## Conservation laws

- Find the voltage at each node and the current through each element in these circuits consisting of resistors and ideal sources.

## Equivalent circuits

- Create a simplified version of each circuit. The simplified circuit should contain one source and one resistor. The I-V curve of the port should be the same as the original circuit.

## Measuring voltage

A circuit model for a neuron in culture connected to a patch clamp apparatus consists of a time-varying voltage source in series with an output impedance of 10^{11} &Omega. There is an oscilloscope next to the neuron with an *input impedance* of 10^{6} &Omega. A circuit model for the oscilloscope is a 10^{6} &Omega resistor to ground. A new UROP in the lab attempts to measure the electrical spikes produced by the neuron (called *action potentials*) using the oscilloscope. The oscilloscope has a noise floor of 10^{-3} V.

- What is the magnitude of the action potential signal after the student connects the oscilloscope?
- Does the student succeed? Why or why not?
- What is the
*signal to noise power ratio*? - How many times does the student curse during the measurement attempt?
- What is the minimum input impedance that a measurement device must have in order to make a high-fidelity measurement of an action potential.

## Bode plots

- Draw a Bode plot for each of the circuits: