Assertion (A): The harmonic distortion of an amplifier increases at higher power levels,
Reason (R): For high quality audio amplifiers, the maximum THD is 0.7% at the desired listening level.
A common-emitter amplifier, with a self-bias circuit to bias the transistor in the active mode, -is an example of a class ____ amplifier.
The O-point of class-A amplifier is located in active region i.e. at the mid-point of dc load line as shown below.
The advantages of class B as compared with class A operation are
1. efficiency is higher.
2. possible to obtain greater power output.
3. less distortion and noise interference.
4. negligible power loss at no input signal. Of these the statements:
Compared to class A operation, class B operation has
Hence, statements 1,2 and 4 are correct.
Assertion (A): In a system where the power supply is limited, such as those operating from solar cells or a battery, the output power is usually delivered through a push-pull class B transistor circuit.
Reason (R): It is possible to obtain greater power output, higher efficiency and negligible power loss at no signal with the help of a push- pull class B transistor circuit.
For a given transistor, the thermal resistance is 8 °C/W and the ambient temperature TA is 27°C. if the transistor dissipates 3 W of power, the junction temperature Tj will be
We know that,
Crossover distortion refers to the distortion caused due to
In a class B amplifier, VCE(min) = 2 V and supply voltage Vcc = 15 V. The collector circuit efficiency is approximately
Collector circuit efficiency is
The maximum theoretical efficiency of a class A amplifier can be
For a transistor, Tj = 160°C, TA = 40°C and θJ-A = 80°C/W. What is the power that the transistor can safely dissipate in free air?
The power dissipated by the transistor is
ln a class A amplifier, VCE(max) = 15 VCE(min) = 1 V. The overall efficiency for series fed load and transformer coupled load are respectively
For series-fed load, overall efficiency,
For transformer-coupled load, overall efficiency,