Refer to FIGURE 3.1 and answer the questions that follow - NSC Electrical Technology Digital - Question 3 - 2019 - Paper 1

The internal circuit of the op-amp is divided into three main stages:

1. Input Stage: This is typically a differential amplifier that receives the input signals.
2. Intermediate Stage: Often referred to as a high-gain differential amplifier, this stage further processes the signal.
3. Output Stage: This stage drives the output signal and can take the form of a common collector or other configurations.

Negative feedback in an op-amp functioning as a linear amplifier is crucial for the following reasons:

1. Stability: It helps stabilize the gain of the amplifier by reducing the overall gain variation due to changes in temperature or power supply fluctuations.
2. Distortion Reduction: Negative feedback minimizes distortion of the output signal, ensuring that the output closely represents the input signal without significant alterations.

To calculate the output voltage ($V_{OUT}$) for the inverting amplifier configuration:

$V_{OUT} = V_{IN} \left( -\frac{R_F}{R_{IN}} \right)$

Substituting the given values:

$V_{OUT} = 2 V \left( -\frac{100 \times 10^3}{12 \times 10^3} \right)$

Calculating:

$V_{OUT} = 2 V \left( -8.33 \right) = -16.67 V$

The output waveform is not an exact replica of the input waveform due to:

• Clipping: The op-amp can enter saturation, which results in the tops and bottoms of the waveform being clipped when the output voltage reaches its limits. This occurs when the input signal exceeds the linear operating range of the amplifier.
• Phase Shift: There may be a 180-degree phase shift in the output relative to the input in an inverting configuration, leading to differences in shape and timing between the input and output waveforms.

The maximum output voltages ($V_{OUT}$) of the op-amp when powered by the given supplies are:

• Maximum Positive Output: +15 V
• Maximum Negative Output: -15 V

These voltages represent the limits to which the op-amp can output based on its power supply.

DIP stands for Dual In-line Package. This type of package features two parallel rows of pins that allow for easy insertion into circuit boards.

The NE555 timer IC can operate in three primary modes:

1. Astable Mode: The NE555 operates as an oscillator generating a continuous square wave.
2. Monostable Mode: It functions as a one-shot timer, producing a single output pulse when triggered.
3. Bistable Mode: The IC serves as a flip-flop, allowing it to maintain a stable state until a specific trigger resets it.

The typical trigger voltage of the NE555 IC when the supply voltage is +15 V is 5 V. This is the voltage level that must be reached at the trigger input to change the state of the timer.

When the trigger voltage exceeds the threshold level of 10 V, the output of the NE555 timer will switch to a low state. In this condition, the output changes from high to low, effectively changing the timer's state. If the NE555 is in monostable mode, this will trigger a timing cycle.