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).
|Figure 2.1 Vce Vs Ic|
3. (Table) Apply the following bias voltages and fill out the table. How is IC and IB related? Does your data support your theory?
4. (Table) Explain photocell outputs with different light settings. Create a table for the light conditions and photocell resistance.
|Table 4.1 Shows the value of resistance that we got from the different amounts of light we allowed to hit the photocell. With more light the resistor gives less resistance.|
5. (Table) Apply voltage (0 to 5 V with 1 V steps) to DC motor directly and measure the current using the DMM.
|Table 5.1 the table shows the different current given on the motor with different voltage source.|
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.
|Table 6.1 shows the current acting on the DC motor with a constant voltage but different load on the motor.|
7. (Video) Create the circuit below (same circuit from week 1). Explain the operation in detail.
The video explains the operation of the circuit.
we used a 1k photocell which is used to control the voltage at the base and when we cover the photocell the resistance will increase causing the motor to stop and when we shine on the photocell, its resistence will decrease causing the motor to move faster.
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.
R4's role is to manage the amount of current that travels to the collector then to the motor from the second voltage source. By increasing the resistance of R4 the motor does not receive enough current to operate, and by lowering the resistance the motor out put increases.
9. (Video) Create your own Rube Goldberg setup.
Video shows our Rube Goldberg Project
In Our Rube Goldberg Setup, we used a strain to pull pieces of Dominos. We reduced the voltage so the motor will not move fast and when we used the iPhone flashlight on the photocell, the dc motor rotates and pull the dominos.