EEE 334 Exam 2025 Latest Update with complete
solutions.
What does an offset nulling terminal do?
It allows for the application of a potentiometer to an opamp. The pot's resistance value can be
adjusted with a knob, allowing it to dull the V0s (offset voltage supplied by a cheap opamp) so
that the opamps output voltage across the "short" is 0.
How can you block offset voltage from an opamp without using an offset nulling terminal?
Use a capacitively coupled inverting amp - A capacitor is placed in series with the input signal,
effectively acting as a high-pass filter. It blocks the DC portion of the input signal from reaching
the amplifier's inverting terminal, preserving the amplifier's DC biasing conditions.
What is the input bias current of opamps?
the DC current which must be supplied to the op-amp inputs for proper operation. So when we
say opamps have zero current flowing inward that is not necessarily true although ideally this
current is zero
What is input offset current of opamps?
the difference between bias current at both terminals
How do you reduce input bias current of opamps?
Add a resistor between the non-inverting input and ground (at point 2 you add R3)
What is offset voltage of an opamp?
,the small, unwanted DC input voltage that must be applied across its input terminals to force the
output to zero volts. With offset voltage, the output of the op amp (difference between Vn and
Vp) will not be 0V.
What is impedance?
Impedance is the combined effect of resistance (from resistors) and reactance (from inductors
and capacitors) that impedes the flow of electrical current.
What is op amp input impedance ideally?
Input impedance is the opposition to current entering the input terminals, ideally infinite to
prevent loading (or stealing energy / current from) the signal source. The input impedance is
what the signal source (e.g., a sensor or another amplifier) "sees" when it connects to the op
amp's input.
What is op amp output impedance ideally?
Output impedance is the opposition to current leaving the output terminals, ideally zero so the op
amp can drive any load without voltage drop. The output impedance is what the load (e.g., a
speaker or another circuit) "sees" when it is connected to the op amp's output.
If there is infinite input impedance in an op amp, what does that mean?
There is no current flowing into the op amp
What is the differential input of an amp?
the differential input is the voltage difference between the two inputs (V+ and V-), which is the
desired signal to be amplified
, What is common-mode input?
The common-mode input is the average voltage present on both inputs, effectively the voltage
shared by both inputs and often a source of unwanted noise or interference
What is differential gain?
Differential gain (Ad) is the ratio of the amplifier's output to the difference between its two input
signals. A well-designed differential amplifier has a high differential gain (infinite)
What is common mode gain?
while common-mode gain (Acm) is the ratio of the output to the average (or common) voltage
applied to both inputs. Ideally want a low common-mode gain (0) to effectively reject unwanted
common-mode noise.
Purpose of inverting closed loop configuration of an op amp
An inverting op-amp configuration provides negative voltage gain, meaning the output signal is
180 degrees out of phase with the input signal.
What is the weighted summer closed loop amp configuration?
an inverting operational amplifier configuration that sums input voltages, each scaled by a
different weight determined by the ratio of the feedback resistor to the respective input resistor
What is the non-inverting op-amp configuration?
uses an operational amplifier with negative feedback and has the input signal applied to the non-
inverting (+) terminal, resulting in an output signal that is in phase with the input, meaning it
amplifies the signal without inverting its polarity
solutions.
What does an offset nulling terminal do?
It allows for the application of a potentiometer to an opamp. The pot's resistance value can be
adjusted with a knob, allowing it to dull the V0s (offset voltage supplied by a cheap opamp) so
that the opamps output voltage across the "short" is 0.
How can you block offset voltage from an opamp without using an offset nulling terminal?
Use a capacitively coupled inverting amp - A capacitor is placed in series with the input signal,
effectively acting as a high-pass filter. It blocks the DC portion of the input signal from reaching
the amplifier's inverting terminal, preserving the amplifier's DC biasing conditions.
What is the input bias current of opamps?
the DC current which must be supplied to the op-amp inputs for proper operation. So when we
say opamps have zero current flowing inward that is not necessarily true although ideally this
current is zero
What is input offset current of opamps?
the difference between bias current at both terminals
How do you reduce input bias current of opamps?
Add a resistor between the non-inverting input and ground (at point 2 you add R3)
What is offset voltage of an opamp?
,the small, unwanted DC input voltage that must be applied across its input terminals to force the
output to zero volts. With offset voltage, the output of the op amp (difference between Vn and
Vp) will not be 0V.
What is impedance?
Impedance is the combined effect of resistance (from resistors) and reactance (from inductors
and capacitors) that impedes the flow of electrical current.
What is op amp input impedance ideally?
Input impedance is the opposition to current entering the input terminals, ideally infinite to
prevent loading (or stealing energy / current from) the signal source. The input impedance is
what the signal source (e.g., a sensor or another amplifier) "sees" when it connects to the op
amp's input.
What is op amp output impedance ideally?
Output impedance is the opposition to current leaving the output terminals, ideally zero so the op
amp can drive any load without voltage drop. The output impedance is what the load (e.g., a
speaker or another circuit) "sees" when it is connected to the op amp's output.
If there is infinite input impedance in an op amp, what does that mean?
There is no current flowing into the op amp
What is the differential input of an amp?
the differential input is the voltage difference between the two inputs (V+ and V-), which is the
desired signal to be amplified
, What is common-mode input?
The common-mode input is the average voltage present on both inputs, effectively the voltage
shared by both inputs and often a source of unwanted noise or interference
What is differential gain?
Differential gain (Ad) is the ratio of the amplifier's output to the difference between its two input
signals. A well-designed differential amplifier has a high differential gain (infinite)
What is common mode gain?
while common-mode gain (Acm) is the ratio of the output to the average (or common) voltage
applied to both inputs. Ideally want a low common-mode gain (0) to effectively reject unwanted
common-mode noise.
Purpose of inverting closed loop configuration of an op amp
An inverting op-amp configuration provides negative voltage gain, meaning the output signal is
180 degrees out of phase with the input signal.
What is the weighted summer closed loop amp configuration?
an inverting operational amplifier configuration that sums input voltages, each scaled by a
different weight determined by the ratio of the feedback resistor to the respective input resistor
What is the non-inverting op-amp configuration?
uses an operational amplifier with negative feedback and has the input signal applied to the non-
inverting (+) terminal, resulting in an output signal that is in phase with the input, meaning it
amplifies the signal without inverting its polarity
