Frequency response of a r-c coupled amplifier, Electrical Engineering

Assignment Help:

Q. Write a short note on the frequency response of a R-C coupled amplifier.

At low frequencies (<50Hz), the reactance of coupling capacitor Cc is quite high and hence very small part of signal will pass from one stage ot the next stage. Moreover, Ce cannot shunt the emitter resistance Re effectively because of its large reactance at low frequencies. These two factors cause a falling of voltage gain at low frequencies.

At high frequencies (>20KHz), the reactance of Cc is very small and it behaves as a short circuit. This increases the loading effect of next stage serves to reduce the voltage gain. Moreover, at high frequency, capacitive reactance of base-emitter junction is low which increases the base current. This reduces the current amplification factor b. Due to these reasons, the voltage gain drops off at high frequency.

At mid-frequencies (50Hz to 20KHz), the voltage gain of the amplifier is constant. The effect of coupling capacitor in this frequency range is such so as to maintain a uniform voltage gain. Thus, as the frequency increases in this range, reactance of Cc decreases which tends to increase the gain. However, at the same time, lower reactance means higher loading of first stage and hence lower gain. These factors almost cancel each other, resulting in a uniform gain at mid frequency.


Related Discussions:- Frequency response of a r-c coupled amplifier

Evaluate phase difference between voltage and current, Evaluate Phase diffe...

Evaluate Phase difference between voltage and current: An inductive coil of reactance 15.7 Ω and resistance 32 Ω is connected in series with a capacitor of reactance 79.5 Ω. T

The potential difference at the battery terminals, Ten 1.5V cells in series...

Ten 1.5V cells in series, each cells having an internal resistance of 0.3Ω, are connected series to a load of 25Ω. Determine : i.The current flowing the circuit

Evaluate the magnitude of the wave impedance, Questions: (a) Suppose a ...

Questions: (a) Suppose a 100 kHz switching power supply. (i) Evaluate the magnitude of the wave impedance of the radiated field of a very short wire in the switching power s

Conductometry experiment, why conductance is not zero at end pont? reply as...

why conductance is not zero at end pont? reply as soon as possible.

Define multiplexing, 1 Explain the advantages and disadvantages of optical ...

1 Explain the advantages and disadvantages of optical fiber versus copper Medium of communication 2 Define multiplexing. Explain TDM 3 Describe the protocol architecture and

Find the per-unit voltage regulation, Q. A single-phase, 3-kVA, 220:110-V, ...

Q. A single-phase, 3-kVA, 220:110-V, 60-Hz transformer has a high-voltage winding resistance of 0.3 , a low-voltage winding resistance of 0.06 , a leakage reactance of 0.8  on i

Waveguides, Why are waveguides not used at low frequencies?

Why are waveguides not used at low frequencies?

Defective metering and meter reading errors, Defective Metering and Meter R...

Defective Metering and Meter Reading Errors Defective Metering Tampered, slow running, stalled, damaged meters are a cause of huge losses to the utility. The electromecha

Explain the effect of magnetic field on superconductors, Explain supercondu...

Explain superconductivity and explain the effect of magnetic field on superconductors. Various metals become superconducting below a temperature that is the characteristic of t

Electronics, #What are the types of Negative Feedback Amplifier?

#What are the types of Negative Feedback Amplifier?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd