Question

2. An amplifier with a power gain of 80 dB is using a dual power supply voltage of ±10 V. a. Calculate the voltage gain of the amplifier. b. Sketch the transfer characteristics curve of the amplifier. c. Determine the peak to peak value of the largest input signal that can be amplified without clipping. d. Determine the peak to peak value of the largest output signal that the amplifier can produce without clipping. e. Determine the DC offset of the output signal found in part d.

Answer 1

The voltage gain of the amplifier is 10,000. The transfer characteristics curve is a linear graph with a slope of 10,000 passing through the origin. The largest input signal that can be amplified without clipping is a peak-to-peak voltage of 20 V, and the largest output signal without clipping is a peak-to-peak voltage of 200,000 V. The DC offset of the output signal is 10 V.

Step-by-step explanation:

a. To calculate the voltage gain of the amplifier, we need to convert the power gain from dB to a ratio. The ratio is calculated using the formula:

Voltage Gain (in dB) = 20 log10(Voltage Gain Ratio)

So, to calculate the voltage gain, we solve for the Voltage Gain Ratio:

80 dB = 20 log10(Voltage Gain Ratio)

Voltage Gain Ratio = 10^(80/20)

Voltage Gain Ratio = 10^4

Voltage Gain Ratio = 10,000

Voltage Gain = 10,000

The DC offset of the output signal found in part d can be determined by calculating half of the peak-to-peak voltage. So, the DC offset is 20 V / 2 = 10 V.

Answer 2

The voltage gain of an 80 dB power gain amplifier is 10,000. The input and output peak to peak voltages without clipping are 2 mV and 20 V, respectively, and the DC offset is 0 V.

Step-by-step explanation:

Amplifier Voltage Gain and Transfer Characteristics
The power gain of an amplifier in decibels (dB) is related to the voltage gain through the following equation, which derives from the power gain formula in dB:

Power Gain (dB) = 10 × log10(Voltage Gain)^2

To calculate the voltage gain (Av), we can rearrange the equation:

Voltage Gain (Av) = 10^(Power Gain (dB) / 20)

For a power gain of 80 dB, the voltage gain can be calculated as:

Voltage Gain (Av) = 10^(80 / 20) = 10^4

Therefore, the voltage gain of the amplifier is 10,000.

The transfer characteristics curve of an amplifier is a plot of the output voltage versus input voltage. Since the power supply limits the output voltage to ±10 V, we would see a linear increase in output voltage with input voltage until the point of saturation, beyond which the output cannot increase and hence 'clips'.

To determine the peak to peak value of the largest input signal (Vin(pp)) that can be amplified without clipping, calculate the maximum output voltage (Vout(max)) and divide by the voltage gain (Av).

Vin(pp) = Vout(max) / Voltage Gain (Av)

Given that Vout(max) is the power supply voltage, 10V in this case, the result is:

Vin(pp) = ±10 V / 10,000 = ±0.001 V or 2 mV peak-to-peak

The largest peak to peak output voltage is twice the power supply voltage, so:

Vout(pp) = ±10 V × 2 = ±20 V peak to peak

Lastly, the DC offset of the output signal is typically the average value of the output waveform; for an amplifier output with no DC bias, this would be 0 V.