7.1 Name TWO characteristics of an ideal op amp - NSC Electrical Technology Electronics - Question 7 - 2016 - Paper 1

Bandwidth refers to the range of frequencies over which an amplifier can operate effectively without losing gain or distorting the output signal. It is defined as the difference between the upper and lower frequency limits in which the amplifier maintains an acceptable level of performance.

Positive feedback occurs when the output signal of an amplifier is fed back to the input in such a way that it enhances the output. This is typically achieved when the feedback signal is in phase with the input signal, resulting in a greater amplification and potentially driving the circuit to saturation.

The circuit symbol for an op-amp consists of a triangle shape with two inputs labeled (+) for non-inverting and (-) for inverting. The output is represented as a line extending from the point of the triangle. Additionally, the symbol includes power supply terminals, which are often indicated as +V and -V at the top and bottom of the triangle, respectively.

The input waveform, represented by a sine wave, should be drawn alongside the output waveform. The output waveform will mirror the input for the non-inverting configuration, indicating amplification (e.g., V_out = A * V_in). It is important to clearly label the two waveforms as 'Input' and 'Output'.

The op-amp configuration can be identified as a non-inverting amplifier, as the input signal is given at the non-inverting terminal.

For the input and output signals, the input should be a sine wave, while the output will also be a sine wave but amplified. Both waveforms should share the same y-axis to easily compare them, and labels 'Input' and 'Output' should be included.

The voltage gain (A_V) can be calculated using the formula: $A_V = 1 + \frac{R_f}{R_{in}}$ Given that R_f = 45 kΩ and R_{in} = 15 kΩ, substituting these values results in: $A_V = 1 + \frac{45000}{15000} = 4$ Thus, the voltage gain is 4.

To find the output voltage (V_out), we use the gain calculated earlier: $V_{out} = A_V \times V_{in}$ Substituting the values: $V_{out} = 4 \times 2.5 V = 10 V$ Therefore, the output voltage is 10 V.

1. Tone Generator: Astable multivibrators can be used to create audio tones.

2. Clock Pulse Generator: They are frequently employed in digital circuits to provide timing pulses.

The input waveform is a square wave signal transitioning between +V and -V levels. When drawn below, the output waveform will reflect the input signal but delayed or altered based on the circuit characteristics.

The RC phase-shift oscillator uses positive feedback, which is necessary for sustaining oscillations.

One application of the RC phase-shift oscillator is as a tone generator, often used in musical and sound applications.

The oscillation frequency (f) can be calculated using: $f = \frac{1}{2\pi\sqrt{6}RC}$ Where R = 15 Ω and C = 150 nF. Substituting these values gives: $f \approx 43.31 Hz$

One application of the integrator circuit is in analog signal processing, where it is used to integrate signals over time.

The input waveform should be a square wave, while the output will be a triangle wave, demonstrating the integration effect. Ensure both waveforms are labeled correctly.