Three identical amplifiers with each one having a voltage gain of 50,input resistance of 1KΩ & output resistance of 250, are cascaded. The open circuit voltage gain of combined amplifier is

We can use the formula for cascaded amplifiers:

[ A_{text{total}} = A_1 times A_2 times A_3 ]

Where ( A_{text{total}} ) is the total voltage gain and ( A_1 ), ( A_2 ), and ( A_3 ) are the voltage gains of the individual amplifiers.

Given that each amplifier has a voltage gain of 50, we have:

[ A_{text{total}} = 50 times 50 times 50 = 125,000 ]

To convert this to dB, we use the formula:

[ text{Gain (dB)} = 10 times log_{10}(A_{text{total}}) ]

[ text{Gain (dB)} = 10 times log_{10}(125,000) ]

[ text{Gain (dB)} approx 98.04 ]

So, the correct answer is:

C. 98dB

DB means

20log(50*50*50)=102

20log(50*50*50)=102

20 log(50*50*50) = 101.9 = 102

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