EE 2212

PROBLEM SET 5

S. G. Burns

Due: Friday, 5 March 2021

NOTE 1: I strongly encourage studying the photonic concepts and devices from the (Photonics PowerPoint). Problems associated with Text Section 3.18 are quite limited but the optoelectronics area is of rapidly growing importance. You can expect Quiz 5 to cover topics in the Text Section 3.18 and the Photonics PPT slides PhotonicsSupplementTextSection3.18.ppt LED operation and LED lighting is important!

NOTE 2: Recall, what is left of Spring Recess is Monday and Tuesday, 8 and 9 March. I never like to have work assigned or a quiz after an academic break. A “break” is designed for a bit of relaxation.

Problem 1 Tuned Circuit Design Using A VARICAP

(a) Refer to the capacitance curves for the Motorola 1N4002 1N400XCap.JPG . The input tuning circuit of a standard analog FM radio is given below. Specify, that is design for, a voltage, capacitance required to tune the circuit to the center frequency of KUMD-FM which operates at 103.3 MHz. (By the way-Did you know that KUMD is probably going to be sold to WDSE-Local PBS Station). Under Minnesota Board of Regents consideration. Sketching and labeling a representative resonance curve is required to support your calculations.

(b) Repeat if you use the Motorola MMBV109LT1 MV209. Refer to the EE 2212 WEB pages Hyperdiode1.JPG and HyperDiode2.JPG.

Problem 2 A ten watt power diode with a V_J = 0.8 volts has a thermal resistance of θ_JC = 4^°C/watt. The maximum junction temperature is 175°C operating at an ambient temperature of T_A=40°C. A heat sink with 6°C/watt of thermal resistance from the sink to ambient is used but must be electrically isolated from the diode case with a thin mica washer having a thermal resistance of 2°C/watt. See the figure for an idea as to the heat flow path. What is the maximum value of I_D and illustrate using a sketch of the derating curve.

Problem 3 (Excerpted from an old quiz) Assume V_J = 0.7 volts.

(a) Using the derating curve from the 1N4001 shown below, compute the total thermal resistance, q.

(b) Recommend a maximum operating current and power if this power diode were located under the hood of your car where the temperature approaches 212°F = 100°C.

Problem 4 Solar Panel Analysis (Adapted from an old quiz). Refer to topics covered in the

PhotonicsSupplementTextSection3.18.ppt . This commercial solar panel has an area of 1.6 m². The I-V curves are shown below. Estimate/compute values for the quantities indicated. Illustrate your answers on the vendor I-V curves.

(a) _____________Reasonable accepted value for the solar constant above the Earth’s atmosphere.

(b) _____________Reasonable accepted value for the solar constant at the surface of the Earth.

(c) At the Earth’s surface, the solar spectrum peaks in the (IR, Red, Green-Yellow, Blue, UV).

(d) ______ Open Circuit Voltage, V_OC.

(e) ______Short Circuit Current, I_SC

(f) _______Estimate of maximum Power Output corresponding to your answer in Part (b) above and illustrate, on the graph, how you obtained this value.

(g) ________________ Panel Conversion Efficiency, %, using your results from Part (f) above.

Panel Area = 1.6 m²

All of these cartoons are relevant my pre-COVID life at UMD.

(1) I have my own K-Cup coffee pot to avoid issues.

(2) I have a slide rule collection and even know how to use them. Amaze your parents and grandparents-Stop in to my office when face-to-face resiumes post-COVID if you want a short course on how to use a slide rule. Free lessons! In their day, prior to the early 70s, slide rules were a great tool to learn about log₁₀ theory and applications. I have a few displayed in my office. My HP 35 scientific calculator I purchased as a poor graduate student was $400 when UW tuition was $112.50/semester. Lots of Ramen noodles for a couple of months but I had to have it!

(3) The iPAD and Macbook are so friendly and the graphics are great. WINDOWS 10 very buggy.

(4) For those of you who are aware of the current UMD budget issues, the Dilbert cartoon says it all. ENJOY!

Recall the WOM (Write-Only-Memory) Signetics Data Sheet from the attachment to Experiment 4. Fun-loving (sort of depends on you define fun) Signetics engineers may have taken a clue from some engineers at EIMAC or the other way around. EIMAC manufactures high power and specialty vacuum tubes used in high power transmitters and RF generators and related. This is a data sheet for the “PHANTASATRON”. EIMAC is now a subsidiary of Communications and Power Industries. Even though small vacuum tubes are no longer made in the U.S., some manufacturers in Russia and Brazil cater to the high end audiophile market. We will talk about vacuum tube audio amplifiers towards the end of the semester. Larger, high power transmitting tubes and speciality vacuum tubes are manufactured by EIMAC and others. Enjoy!