1. Lecture L Mid-term in ~2 weeks. Covers all materials we covered up that date (lectures and labs) You can bring one page (letter format), handwritten on one side to the mid-term exam. Optional exam review and Q&A session on Thursday Oct. 18, 1-1:50pm in G125. Keep thinking about your final projects! (Proposal due in 4 weeks) Check out the guidelines and a list of previous projects on the course web page.

2. MOSFET: Current is conducted on the surface of the semiconductor. Surface-contamination is an issue (causes current noise.) JFET: Current is conducted in the (high quality) bulk of the semiconductor  lower noise

3. Our Trusty LF356: Inputs are JFETs (low noise, high impedance), but most gain is provided by BJTs. Inputs are JFETs gain is provided by BJTs

5. M1 What is the transconductance g fs for the JFET in the saturated region (V DS > 4V) for V GS biased at 0V? A) 1 mS B) 2 mS C) 5 mS D) 10 mS E) 15 mS

6. M2 What is I DSS for this JFET? A) 3 mA B) 5 mA C) 7.5 mA D) 10.5 mA E) 12 mA

8. What is V out for a common source amplifier? M3 A)V DD - R D I D B)V in - R D I D C)V DD - g fs R D I D D)V in - g fs R D I D E)other

10. M4 A) 0 V B) 4 V C) 5 V D) 6 V E) 10 V What is V out with the gate grounded? IDID V DS V GS = 0V V GS = -0.2V V GS = -0.6V V GS = -1.5V 4mA 3mA 2mA 1mA 5V

11. M5 What is the magnitude of the gain with V GS biased at 0V? A) 0 B) 0.5 C) 1 D) 5 E) 10 IDID V DS V GS = 0V V GS = -0.2V V GS = -0.6V V GS = -1.5V 4mA 3mA 2mA 1mA 5V

13. M6 What is the approximate output impedance of the common source amp? A) 10  B) 500  C) 1000  D) 2000  E) 10 12 

14. M7 V out of the amplifier is initially 6V. Next, I put a 1000  resistor to ground on the output. What is V out now? (Assume g fs is unchanged by this.) A) 1 V B) 3 V C) 6 V D) 10 V E) 12 V

15. M8 What is the input impedance of the circuit at DC? A) 10  B) 500  C) 1000  D) 2000  E) 10 12 