Form#: 22 Allowed materials include calculator (without wireless capability), pencil or pen. Honor Statement: On my honor, I promise that I have not received any outside assistance on this exam (I didn’t look at another student’s paper, I didn’t view any unauthorized written materials, I didn’t talk or listen to another student, . . .).
also fill in CWID, name and course (121) . . . don’t forget to black in bubbles you must show your work on problems that require calculations to receive credit Problem 1 What type of relay is shown? a. b. c. d. e. f.
SPST DPST SPDT DPDT ABC ABC one coil
Problem 2 Which is true of a 3-way valve? a. Allows 3 separate water sources to be turned on or off independently b. Allows a single source to be diverted down any one of three outlets c.
Allows a single source to be diverted to three outlets at the same time
d. Allows a single source to be diverted to either of two outlets e. Allows a single source to be diverted to two outlets at the same time
Problem 3 In the fishtank system, what is the purpose of the relays? a. Use a small current to control the flow of a larger current b. Use a 5V system to control a 12V device c.
Use a large current to control the flow of a smaller current
d. Use a 12V system to control a 5V device e. Work magic f.
Frustrate students
g. a and b h. c and d
Problem 4 Which leg of a transistor is designed to receive a small current in order to control larger current flow between the other two legs?
a. b. c. d. e. f. g. h. i.
Collector Base Emitter Microcontroller Receiver Jackleg Pant leg Last leg Lego
Problem 5 What is the purpose of a flyback diode? a. To act as a cooling system so that an electromagnetic device does not overheat b. To generate power to operate a circuit without being plugged into the wall c.
To dissipate energy constantly during operation of an electromagnetic device
d. To dissipate energy immediately after an electromagnetic device is switched off e. To provide a “short circuit” so that power never enters an electromagnetic device
Problem 6 For the electrical symbol shown, which configuration will result in current flow?
a. Positive on the right, negative on the left b. Positive on the left, negative on the right c.
Depends on other factors
d. a and b e. None of the above
Problem 7 Assuming the power busses (two left-hand columns) of the breadboard are properly energized with 5V, which of the following circuits is correctly wired according to the circuit diagram?
A C
B
D
Problem 8 What does UCL stand for? a. Upper Calibration Level b. Upper Conductivity Limit c.
Upper Control Line
d. Upper Calibration Line e. Upper Control Limit f.
Upper Conductivity Level
Problem 9 In the electrochemical reaction of the conductivity sensor, which of the following receives an electron from the cathode?
a. b. c. d. e. f. g. h.
Na+ OHH2 H+ H2O Cl2 Cle-
Problem 10 What TWO steps does this piece of code do just after adding DI water? 1. 2. 3. 4.
Records the current time Checks if salinity is too low Checks if deadtime is past Pauses ½ second
a. b. c. d. e.
void loop() { check_sensor();
// function to measure conductivity
t_since = millis() - t_last; if(t_since>deadtime) { if(analogS>UCL) { add_DI(); // function that adds DI water t_last=millis(); }
