In a detector, output circuit consists of `R = 10kOmega and C = 100 p F.` Calculate the frequency of carrier signal it can detect.

Options

A. `gt gt 1MHz`
B. `0.1 kHz`
C. `gt gt 1GHz`
D. `10^(3) Hz`

Answer

A

Explanation

Here `R = 10 kOmega = 10^(4) Omega`
`C = 100 pF = 10^(-10) F`
Time constant of the circuit
`tau = RC = 10^(4) xx 10^(-10) = 10^(-6) s`
For demodualation, `(1)/(f_(c)) lt lt RC`
or `f_(c) gt gt (1)/(RC)`
or `f_(c) gt gt (1)/(10^(-6)) = 10^(6) Hz`
Therefore, frequency of carrier singnal must be much greater than `1 MHz`.