![Page 1: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/1.jpg)
EE49Lecture
Tuesday Feb 13, 2018
![Page 2: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/2.jpg)
Photoelectric Effect
• Emission of electron when light strikes a material• Classical theory• More intense light will cause more energetic electrons• Experimentally false
• Quantum theory• Energy = h\nu• Need certain energy threshold (of min frequency) to emit electrons• Lower intensity means fewer photons means less current, not more energetic
electrons
![Page 3: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/3.jpg)
Solar Cells
• Engineered materials to produce significant useful currents• Si, other semiconductor materials, Perovskites, etc
• Costs have decreased a lot
![Page 4: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/4.jpg)
Efficiency
• Efficiencies have increased a lot • > 30% now• Near theoretic limits
![Page 5: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/5.jpg)
Explosion of growth!
![Page 6: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/6.jpg)
EE49 IOT
• Solar cells in IOT• To power electronics, microprocessors, etc• Remote sensing, device control, …• Need backup battery or capacitor, so ckt works even when dark
(for some time)
![Page 7: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/7.jpg)
I-V curves of Solar Cells
![Page 8: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/8.jpg)
Batteries
• Essential for IOT• Many options• Footprint, weight• Operating range• Cost• Voltage, power• Capacity• Lifetime• Charging characteristics• Efficiency, leakage
![Page 9: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/9.jpg)
Energy Density
![Page 10: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/10.jpg)
Battery I-V curves
![Page 11: EE 49 Lectureboser/courses/49/lectures/L09 Poo… · • Charging characteristics • Efficiency, leakage. Energy Density. Battery I-V curves . Now to the Blackboard •Ideal Voltage](https://reader034.vdocuments.us/reader034/viewer/2022050717/5e155db9a6f97d0f6f315473/html5/thumbnails/11.jpg)
Now to the Blackboard
• Ideal Voltage source model• Ideal Current source model• Real battery model• Internal resistance• Load resistance• Energy and Power• Maximum power transfer• Solar Cell Model