How do you calculate voltage gain for cascade amplifier?

Answer 1

The same way you would with a two-stage transistor. If you know how to calculate the bandwidth for a one or two stage, then you can just as easily solve a three stage circuit. Using the formula for your f(-3dB), for each stage, you simply add another time coefficient tau. One stage has one tau, two stages has two taus, and four million stages has four million taus. Obviously, it's a little more complicated with three stages because you have a input and output resistance on your second stage, and the calculations can get a little sticky if you have a complex third or first stage, but it's all the same. Just crunch the numbers.

Answer 2

In three-transister cascaded amplifier gain can be be calculated simply by multiplying the three individual gains of every amplifier.But one should take care that for first and second transister R-OUT is taken in consideration with R-INPUT of second and third transitor respectively and R-INPUT resistance can be neglected if it is very high as in the case of common-emitter. Simlarly R-INPUT of second and third should be taken into consideration with R-OUTPUT of first and second transistor respectively.

Answer 3

For cascaded amplifiers you just multiply the two voltage gains together (or add the decibels).