How is power calculated in Class A amplifier?
Calculation of Class A Amplifier Collector Efficiency:
- RL’ = n2 RL As we know, DC power input and AC power output is given as,
- η max = (Pac / Pdc ) * 100. Substitute the value of DC power input and AC power output in the above equation, we get,
- η max = 50%
What is the efficiency of a class A power amplifier?
50%
In theory, a class A amp can achieve 50% efficiency with inductive output coupling or 25% with capacitive coupling.
How is amp power calculated?
Power = Voltage squared divided by Resistance. With a constant sine wave input, you measure 10 volts AC on the speaker output of the amplifier. Since you know the resistance (5 ohms) and the voltage (10 volts), you can calculate the power: Power = (10 times 10) divided by 5 = 100/5 = 20 watts.
What is class power amplifier?
A Class A power amplifier is one in which the output current flows for the entire cycle of the AC input supply. Hence the complete signal present at the input is amplified at the output. It is so selected that the current flows for the entire ac input cycle. The below figure explains the selection of operating point.
How does a Class A power amplifier work?
Class A power amplifier circuit. They form a voltage divider network which supplies the base of the transistor with a voltage 0.7V higher than the “negative maximum amplitude swing” of the input signal. This is the reason behind the transistor being ON irrespective of the input signal amplitude.
What are the different types of power amplifiers?
Therefore the size of the collector region of power transistors must be large. There are 3 types power amplifiers based on the manner in which a transistor is operated: class A, class B and class C — we won’t discuss whats called the class AB, we will just mention in passing what they are.
What is the maximum efficiency of a Class A power amplifier?
From the above figure its is clear that the Q-point is placed exactly at the center of the DC load line and the transistor conducts for every point in the input waveform. The theoretical maximum efficiency of a Class A power amplifier is 50%.
Which is better class A or transformer coupled power amplifier?
The efficiency of a class A power amplifier is nearly than 30% whereas it has got improved to 50% by using the transformer coupled class A power amplifier. The advantages of transformer coupled class A power amplifier are as follows. No loss of signal power in the base or collector resistors.