July 2021 StudentZone Quiz Solution

Question 1:

Would you characterize this transistor amplifier in figure 8 as being inverting or non-inverting to outputs 2+ and 2- with the base terminal of transistor M1 being considered the input? Explain your answer.

Answer 1:

By analyzing the plot for the circuit in figure 10, we can notice that the input signal (W1) reaches its maximum voltage, the output voltage on 2+ reaches its minimum value, therefore we can conclude that the amplifier has an inverting behavior.

Question 2:

Describe what happens to each of the output voltages (2+ and 2- ) as the input voltage (W1) increases or decreases.

Answer 2:

The easiest way to analyze the output/input relationship with respect to the amplitude is to simulate the circuit using LTspice software. By decreasing the input voltage amplitude, we will notice a decrease in the amplitude of the output voltage. In the example below, the input signal has amplitude reduced to 2-volts peak-to-peak.