5.1. Inverting Amplifier

Try these first

1. 1.

   What is the role of the feedback resistor in an inverting amplifier?

   Hint

   Think about how the output affects the input signal.

2. 2.

   What is the phase relationship between input and output in an inverting amplifier?

   Hint

   Consider how the word 'inverting' describes the output.

3. 3.

   What is the formula for the gain of an inverting amplifier?

   • A_v = R_f/R_{in}
   • A_v = -R_f/R_{in}
   • A_v = R_{in}/R_f

   Hint

   Remember the negative sign indicates inversion.

4. 4.

   True or False: The output of an inverting amplifier is in the same phase as the input.

   • True
   • False

   Hint

   Think about the name 'inverting amplifier'.

5. 5.

   An engineer designs an inverting amplifier with a feedback resistor of 200kΩ and input resistor of 50kΩ. If the input voltage is 2V, what is the output voltage?

   Hint

   Calculate gain first then use it to find the output.

6. 6.

   If you want to design an inverting amplifier to invert a 5V input signal and output should be 15V, what gain would you need, and what should be the resistor values if R_{in} is 10kΩ?

   Hint

   First derive the gain then use it to find R_f.