Today was spent further investigating why the buzzer didn't sound for any potentials higher than 3.55 V. Our first step involved rearranging the circuit on our breadboard so that we could utilize more of the available space, making debugging easier as we would be able to look at individual sections of our circuit rather than attempting to fix something hidden amongst a tangle of wires. We also changed the op-amp that we are using (from the LM741CH to the LM741CN). Using the buzzer alone in the output circuit from the timer at this point still doesn't work. However, two significant observations/achievements were made today:

1) Given that this circuit is designed to detect the presence of water between two leads, we decided to determine if we could introduce a pair of leads between the voltage source and inverting terminal on the op-amp to see if the circuit still works as intended. This was successful.

2) The voltage from the output pin on the timer across the buzzer is the same voltage as the input. As we have been working on it, we've consistently found that the buzzer operates when the voltage across the entire circuit has been 3.55 V. Thus, we decided to add a set of in-series diodes before the timer so as to drop the voltage across the timer to 3.55 V by the time current reaches it. After some trial and error, we found that sixteen 1N4148 diodes were enough to produce a sufficient voltage drop (we plan on using a 9 V battery as our power source, so this was determined by running 9 V into the breadboard using the NI Elvis application on the laptop).

As a result of these two changes, along with the further observations, troubleshooting, and modifications, the buzzer produces an audible, consistent noise without the need for external "persuasion" (pushing leads and intermediate circuit elements around to produce the expected result of noise).

Because of this, our next step is to solder the circuit elements and lead connections to PC board and attempt to replicate the results that we have observed to date.