FIGURE 4.1 below shows an operational amplifier - NSC Electrical Technology Digital - Question 4 - 2021 - Paper 1

The output voltage waveform should mirror the input signal, maintaining the same phase. It should show an amplified version of the input waveform without any distortion. The waveform will have the same frequency as the input but will be larger in amplitude.

Operational amplifiers are called differential voltage amplifiers because they amplify the voltage difference between two input terminals. The output voltage is proportional to the difference in voltage applied to the inverting (-) and non-inverting (+) terminals, thereby effectively amplifying only the voltage differences.

1. Gain Control: Negative feedback allows for control over the gain of the amplifier, stabilizing the output across varying input signals.

2. Reduced Distortion: Negative feedback reduces distortion in the output signal, resulting in a more accurate amplification of the input.

The RS flip-flop stores the information it last received until new information is provided through two stable states, effectively memorizing the input signal.

The typical operating voltage range for the 555 IC is from +5 V to +15 V or +18 V.

The three 5 kΩ resistors divide the supply voltage into three equal values, which are used by the two comparators to set the thresholds for timing operation.

1. Astable Mode: Where the 555 operates as a free-running timer, continuously generating a square wave output.

2. Monostable Mode: Where the 555 acts as a one-shot pulse generator, producing a single output pulse in response to an input trigger.

The threshold pin monitors the voltage, and when a specified level (2/3 Vcc) is exceeded, it triggers the IC to switch states, thereby controlling the timing mechanism.

In FIGURE 4.3, the 741 op-amp amplifies the difference between the two inputs. If both inputs are equal, the output will be zero volts as the op-amp cannot provide any amplification from a zero differential voltage.