Operational Amplifiers Questions

• Active filter implementation: When op-amps are used to realize standard low-pass and high-pass active filter stages in audio and instrumentation (for example, Sallen–Key or similar topologies), which amplifier configuration is most commonly employed?
• An inverting amplifier has a phase shift of 180° from input to output.
• If an input signal is applied to the inverting input of an op-amp with the noninverting input grounded, the output signal would be opposite in polarity to the input.
• If the two inputs to a differential amplifier are exactly the same, then the output is the signal multiplied by 2.
• The ideal output impedance for an operational amplifier is 0 Ω.
• Crystal oscillator circuits have a very low Q.
• Feedback is used in an open-loop operational amplifier circuit.
• An astable multivibrator has two states.
• The feedback resistor adds to the gain of an op-amp.
• It takes 4 µs for the output voltage of an op-amp to rise from –14 V to +14 V. The slew rate of this op-amp is 3.5 V/µs.
• In a common-mode input to an op-amp, both inputs are connected to the same signal source.
• An op-amp has very low open-loop gain.
• This circuit is a differentiator.
• A 555 timer can be configured as an astable multivibrator.
• Operational amplifiers (op-amps) use internal capacitive coupling between stages.
• The TO-5 operational amplifier package can have 5 pins.
• This circuit is operating in a closed-loop mode.
• The voltage-follower amplifier circuit has a fixed voltage gain of approximately 10.
• If the frequency of an astable multivibrator is 54.86 kHz then its period is 1.82 s.
• This circuit is a voltage follower.