The NMOS is preferred because it can handle much higher voltages and negative currents, whereas the NPN BJT is limited to low-voltage, positive-current applications.

The NPN BJT is voltage controlled (requires , while the NMOS is current controlled (requires ), making the NMOS more efficient.

Both are equal in terms of power, but NMOS is cheaper to manufacture and so is the better choice to support maintenance and repairability.

The NMOS is easier to manufacture, but the NPN is a more efficient switch because its “on” state power consumption is typically zero.

The NMOS’ “on” state power consumption is only due to . The NPN’s “on”state power includes , making it less efficient.

The NMOS has a lower “on” state power consumption, primarily because it is a voltage-controlled device. Its insulated gate draws negligible current at DC, whereas theNPN BJT is a current-controlled device, that requires a continuous base current () to stay “on”, which consumes power.

is the minimum gate-to-source voltage () that allows current to flow. If then the device is in cut-off. Otherwise, if , the device is in the saturation region. If both and , then the device is in the linear region.

is the minimum gate-to-source voltage () that allows current to flow. If then the device is in cut-off. Otherwise, if , the device is in the saturation region. If both and , then the device is in the linear region.

is the minimum gate-to-source voltage () that allows current to flow. If then the device is in cut-off. Otherwise, if , the device is in the linear region. If both and , then the device is in the saturation region.

is the minimum gate-to-source voltage () that allows current to flow. If then the device is in cut-off. Otherwise, if , the device is in the linear region. If both and , then the device is in the saturation region.

is the drain-to-source voltage () at which the transistor enters saturation, causing the drain current () to become independent of .

is the minimum gate-to-source voltage () required to form an inversion channel. If then the transistor is in the cut-off region. If then the transistor is in the saturation region.

Add a capacitor in parallel with the input to dampen high frequency oscillations.

Use an op-amp with a higher open-loop gain to make switching faster

Add hysteresis (positive feedback) to create a deadband around the switching threshold so small perturbations cannot cause multiple crossings.

Use an op-amp with a lower open-loop gain so that low amplitude noise doesn’t get amplified above the switching threshold

Use a bandpass filter to filter out the high frequency noise.

Increase the amplitude of the input signal using a second op-amp in a non-inverting amplifier configuration.

Since op-amps are active components, sometimes their internal circuitry can store extra energy and output voltage that exceeds the supply rails when configured with feedback.

An ideal op-amp can amplify voltages according to the gain, regardless of the input voltages. 

Thermal noise caused the op-amp to behave non-ideally. This is more likely than the others, as we always set up things perfectly.

The DSO software had a bug. Power-cycling the DSO will fix this problem, as test and measurement equipment in our labs is cheap and unreliable.

Measurement error, probe compensation, and supply voltage tolerances.

The ground of the DSO probe and the ground of the op-amp circuit are not connected. The student who built this circuit is good at building circuits.

Both circuits have the same undamped resonant frequency (). However, for the series circuit, damping is controlled by , while for the parallel circuit, it is controlled by .

Both circuits can be underdamped, overdamped, or critically damped. The series circuit’s transient behaviour is controlled by current, and its damping coefficient is inversely proportional to R. The parallel circuit’s transient behaviour is controlled by voltage, and its damping coefficient is directly proportional to R.

As both circuits are second order circuits, there is no difference in their behaviour fundamentally, and we can treat them in exactly the same way. Also, I don’t believe in inductors, and so they can’t hurt me.

Both circuits have the same undamped resonant frequency (), and the same damping coefficient (). Therefore, their transient responses will be identical.

Both circuits have the same undamped resonant frequency (), and can exhibit all three damping behaviours (underdamped, overdamped, or critically damped). However, their damping coefficients are different. For series, , and for parallel, .

Both circuits can be underdamped, overdamped, or critically damped. In the series circuit, increasing R increases the damping (making it less oscillatory). In the parallel circuit, increasing R also increases the damping.

In both circuits, will spike. In the RC circuit, this is because cannot change instantly, and in the RL circuit, this is because cannot change instantly.

In the RC circuit, both and will spike. In the RL circuit, both and will spike. This is likely due to parasitic capacitance and stray resistance in the oscilloscope probe wires causing unexpected effects on the circuit.

In the RC circuit, will spike, and in the RL circuit, will spike. This phenomenon is only seen in practice and is not observed in simulation.

In the RC circuit, will spike, and in the RL circuit, will spike. This is because must be continuous, and must be continuous, forcing the other component in each circuit to absorb the instantaneous input change (via KVL).

In the RC circuit, will spike, and in the RL circuit, will spike. This is because capacitors resist instantaneous changes in current, and inductors resist instantaneous changes in voltage.

In the RC circuit, will spike, and in the RL circuit, the inductor current () will spike. These spikes are due to the instantaneous change in the input, and theory predicts they will be infinite in magnitude.