Friday, February 3, 2017

Week Four

1. (Table and graph) Use the transistor by itself. The goal is to create the graph for IC (y axis) versus VBE (x axis). Connect base and collector. DO NOT EXCEED 1 V for VBE. Make sure you have the required voltage value set before applying it to the base. Transistor might get really hot. Do not TOUCH THE TRANSISTOR! Make sure to get enough data points to graph. (Suggestion: measure for VBE = 0V, 0.5V, and 1V and fill the gaps if necessary by taking extra measurements).

Ic (mA)
Vbe(mV)
0
0
0
230
0.012
520
5.6
640
10.5
725
Table1;. Ic VS Vbe

Graph1;. Ic VS Vbe
2. (Table and graph) Create the graph for IC (y axis) versus VCE (x axis). Vary VCE from 0 V to 5 V. Do this measurement for 3 different VBE values: 0V, 0.7V, and 0.8V.

VCE
VBE
IC (mA)
0 V
0 V
0
1 V
0 V
12.1
2 V
.7 V
21.6
3 V
.7 V
29.78
4 V
.8 V
35.9
5 V
.8 V
48.8

3. (Table) Apply the following bias voltages and fill out the table. How is IC and IB related? Does your data support your theory?

VBE
VCE
IC
IB
0.7 V
2 V
10.1 mA
35.9 mA
0.75 V
2 V
12.7 mA
43.4 mA
0.8 V
2 V
17.9 mA
48.8 mA



4. (Table) Explain photocell outputs with different light settings. Create a table for the light conditions and photocell resistance.

No Light
Room Light
Flash Light
30 kΩ
1.78 kΩ
30 kΩ
The resistance keeps increasing as we were making the light darker.  The highest resistance we could get was 30 kΩ and that was in total darkness
With nothing covering the photo resistor, the resistance was 1.78 kΩ.
We used the flashlight from and iPhone 7 plus, and the lowest resistance we could achieve was .37 kΩ.



5. (Table) Apply voltage (0 to 5 V with 1 V steps) to DC motor directly and measure the current using the DMM.

Voltage (V)
Current (mA)
1.08 V
25.03 mA
2.04 V
32.02 mA
3.02 V
37.1 mA
4.02 V
40.1 mA
5.11 V
46.1 mA

6. Apply 2 V to the DC motor and measure the current. Repeat this by increasing the load on the DC motor. Slightly pinching the shaft would do the trick.

With there being no pinch, the current was 32.6 mA.  With the slight pinch, the current jumped to 69 mA.  

7. (Video) Create the circuit below (same circuit from week 1). Explain the operation in detail.


(Operation is explained in the video)

8. Explain R4’s role by changing its value to a smaller and bigger resistors and observing the voltage and the current at the collector of the transistor.

The voltage won't ever change, but when a higher resistance is applied, a lower current is measured, and when a lower resistance is applied, a higher current is measured.  

9. (Video) Create your own Rube Goldberg setup.


In our Rube Goldberg set up, we used the same circuit that was created in week 1 with the photo - resistor.  We applied 10 V from outlets A and B and once the flashlight is shined on the photo - resistor, the motor drags the ping pong ball up the ramp.  

7 comments:

  1. At the time of the posting there seems to be very minimal data posted onto the blog, so it is very hard for me comment.

    Looking at your Ic vs Vbe I noticed that your voltage values are very high. I assume this is an error in the units. The data says you are supplying over 100 volts. I am sure this is just an error in the units because the graph looks correct in the way it is formed.

    ReplyDelete
    Replies
    1. Yes you are alright it must mV thank you for let us know about this mistake

      Delete
  2. At the time I am writing this comment there is only one answer, so I will comment on what you have.

    The graph looks correct, except for that little dip in the middle. I am unsure how to combat this in Excel, if I find out how I will let you know. As Alec said, it appears your units are mislabeled. To me, it looks as if they in terms of millivolts.

    ReplyDelete
    Replies
    1. Yes you are alright it must mV thank you for let us know about this mistake

      Delete
  3. I noticed that your graph does not appear to correlate to your table based off of the values that you have entered in your table for example at Vbe of 640 mV I assume you meant your table says you had 0.22 mA but your chart shows you had 6 mA give or take.

    ReplyDelete
    Replies
    1. Actually it was by mistake it should 5.6 instead of0.22
      Thank you for letting us know about this mistake

      Delete