Quantum conductance lab

1. Before lab read the paper on quantum conductance measurements in undergraduate laboratory.

2. Develop current preamplifier based on an opamp

3. Using the developed preamplifier, measure voltage dependent current (how would you do this?) through a 10 megaohm carbon resistor. Plot your data. Use a Keithley 2400 to check the results.

4. Apply 1 V bias on the same 10 megaohm resistor: find out the peak to peak noise level using the oscilloscope.

5. Find out the bandwidth of the current preamplifier by applying a square wave bias and seeing the current response

6. Make use of capacitors to reduce the bandwidth of the preamplifier and correlate the capacitance values with the bandwidth: is the noise lower?

7. Perform the experiment as described in the paper. (it will probably be necessary to use micromanipulators: ask Ray or Masa for this)