Challenge your understanding of operational amplifier concepts, including ideal characteristics, basic configurations, and practical applications. This quiz is designed to reinforce key fundamentals and clarify common misconceptions about op-amp circuits for electronics learners and enthusiasts.
What is the ideal open-loop voltage gain of an operational amplifier, assuming perfect conditions?
Explanation: The ideal open-loop voltage gain of an operational amplifier is infinite, meaning any input voltage difference produces an unlimited output (in theory). One and ten thousand are common values for real, non-ideal op-amps, but do not apply to the ideal case. Zero would mean the amplifier has no amplification ability, which is not the function of an op-amp.
If an ideal operational amplifier is configured as a voltage follower, what condition is established between its inverting and non-inverting inputs?
Explanation: In an ideal voltage follower, the op-amp maintains a 'virtual short' between its inverting and non-inverting inputs, keeping them at the same voltage without actual current flow. 'Virtual ground' refers to configurations like inverting amplifiers, not voltage followers. 'Open circuit' and 'high resistance' are incorrect as the op-amp feedback ensures the inputs are at the same potential.
In an inverting amplifier circuit with a 10 kΩ input resistor and a 100 kΩ feedback resistor, what is the closed-loop voltage gain?
Explanation: The closed-loop gain of an inverting amplifier is given by -Rf/Rin, where Rf is the feedback resistor and Rin is the input resistor. Substituting 100 kΩ and 10 kΩ gives a gain of -10. +10 is the correct magnitude but wrong sign, +0.1 uses improper resistor placement, and -100 incorrectly swaps the resistor values.
Which statement best describes the input bias current in a practical operational amplifier?
Explanation: Input bias current in real op-amps is typically very small due to high input impedance but not exactly zero. Infinite input current is incorrect as it would damage the device. Bias current is not always negative; it depends on current direction and op-amp design. In an ideal op-amp, it would be zero, but not in practical models.
Which application is a standard use for a summing amplifier built with operational amplifiers?
Explanation: Summing amplifiers are commonly used to combine multiple analog signals, such as mixing channels in audio systems. Generating clock pulses is unrelated because it involves timing circuits, not summing voltages. Voltage regulation typically requires a different circuit, and while current can be summed, the phrase 'current amplification only' does not accurately describe the primary application.