Semester 1: Amplifiers

Question 1

What are the general functions of amplifiers?

Answer 1

Signal Filtering; Mathematical Operations (+, -, integrate and differentiate); Signal Amplification.

Question 2

What is the Pin-map for an OP-Amp?

Answer 2

Unused: 8, Offsets: 1, 5, Inverting Input: 2, Non-Inverting Input: 3, Power (-): 4, Power (+): 7, Output: 6.

Question 3

What are the Circuit Simplification assumptions behind analyzing OP-Amps?

Answer 3

1) The impedance / resistance across the input ports is infinite.
2) The gain / voltage across the input ports is 0.
3) The impedance / resistance of the output port is 0, so the current from the output is determined by the resistance of connected components (Ohm’s Law).

Question 4

What is the equation for Voltage Gain for an Inverting OP-Amp?

Answer 4

Vout = - (Rf / Rin) Vin

Question 5

What is the equation for Voltage Gain for a Non-Inverting OP-Amp?

Answer 5

Vout = (1 + R2/R1) Vin

Question 6

What is the equation for Voltage Gain for a Difference OP-Amp?

Answer 6

Vout = (V2 - V1)(Rf / Rin)

Question 7

What is a Buffer Circuit? How is it constructed?

Answer 7

Prevents current and power leakage between 2 connected circuits but allows voltage to be ‘shared’ / compared between them. Consists of a Non-Inverting OP-Amp with infinite input resistance (R1) and 0 output resistance (R2).