This lab was completed in two weeks.
Lab VIII:refers to the first week, which encompassed a continuation of lab vii (can be seen as an edit on lab vii) and part I of the transistor lab.
Lab IX: refers to part 2 of transistor lab, which was completed in the second week.
( i.) Transistors as Diodes
To verify that the transistor behaves like two diodes in series, the lab asked to measure it with a multimeter and verify it had certain resistances. However, this verification was not done using the power supply of the Heathkit. A better way to verify that the transistor behaves like two diodes is by arming a full wave rectification circuit with it and use an alternate power supply (i.e. function generator) and to make sure that the transistor doesn’t fry.
Image I: Function Generator
Image II: Full wave rectification circuit using transistor
According to the lab manual, the BC resistance should be lower than the BE, which means I probably committed an error while wiring or measuring.
Image III: Transistors as switches
Image three demonstrates a huuuge misunderstanding on my part. I thought that the 30V was the ONLY power supply on the Heathkit for some reason. So I thought “ok, start out at the power supply, connect to the +5V, so it also has power….”. I’m guessing this is why the green leds started flashing.
Anyway, the voltage measurements:
270ohm resistor ~4.87V
8.2kohm resistor ~3.72V
Image IV : Transistors as switches, extra 10kOhm resistor
Image V: A circuit we weren’t supposed to arm
After I had found out I was arming the wrong circuit, I thought I would just continue with the lab using this circuit and connecting the DAQ card to the LED. However, the fact that the +5V was a power supply on its own was still misunderstood by me and I committed the same error as in Part I-ii. The Heathkit began to smoke, and Anthony checked if I had broken the Heathkit by wiring the LED by itself. It appeared to be working.
Image VI: The majority of the circuit (left), wiring the LED separately to check if the Heathkit was still working (right)
I decided to abandon this circuit completely as well as abandon the Heathkit. Skylar suggested to use the protoboard and the DAQ card as the power supply. This worked out really nicely, since the DAQ card provides +5V, has two grounds and wiring is a little smoother on the protoboard.
Image VII: Right circuit using protoboard and DAQ card
Image VIII: DAQ card terminals
Image IX: DAQ card terminals
Image X: Front Panel
Image XI: Back Panel
The gist of the VI was to act as the switch of the circuit. Notice how one of the switches is on in image X? This means that the LED in image VII was on, which is really neat. PhD. Koch explained that the “binary representation” and the “decimal representation” both represent the same value. It seems pretty obvious reading it now on the front panel, but since I’m not familiar with binary numbers, it wasn’t obvious at first. The board number is the number acquired from the DAQ card via instacal testing, and PortNum was the number of the portal on the DAQ card, which was 33 aka FIRSTPORTB aka PortB1.
Problems and Solutions
1. DAQ card testing: while testing it via instacal I tested the analog, not digital. This was wrong because we’re using the VI to control the LED, which is digital. So, I retested the digital and plugged the wires into the digital side.
Since the forked folder from Part I was altered for Part II, we couldn’t just refork it.
To do this, I referenced Brian’s notebook (we were supposed to have done this in lab 6/7) : https://docs.google.com/leaf?id=1KiwETxAfA4R6QhfnDnX5KomGLqjkRfuhXpLPC3nt5xs&sort=name&layout=list&pid=0BzJAt7upwcA4ZGI3NTQ2ZmQtMDk1Yy00MzQ5LWFjNDItZWFmNzAxNmQ4OWIw&cindex=5
However I ran into some problems.
PhD. Koch explained that I had to re-adjust the remote from upstream to origin. Also, not to include https when commanding git remote add upstream git: copyandpastethelinkoftherepositorybutwithoutthehttps