Question
Consider an amplifier circuit using a transistdf. The output power is several times greater than the input power. Where does the extra power come from?
✓
Answer
The amplifier takes this energy from the power supply. Amplifiers take the energy from the power supply and control the output to match with the input signal but with greater amplitude.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Two sources of sound $S_1$ and $S_2$ vibrate at same frequency and are in phase figure. The intensity of sound detected at a point P as shown in the figure is $I_0.$
→- If 0 equals $45^\circ,$ what will be the intensity of sound detected at this point if one of the sources is switched off?
- What will be the answer of the previous part if =$ 60^\circ?$
The torque on a current loop is zero if the angle between the positive normal and the magnetic field is either $\theta=0^\circ$ or $\theta=180^\circ$ In which of the two orientations, the equilibrium is stable?
→The mass of cyclist together with the bike is 90kg. Calculate the increase in kinetic energy if the speed increases from 6.0km/h to 12km/h.
State Bohr’s quantization condition of angular momentum. Calculate the shortest wavelength of the Bracket series and state to which part of the electromagnetic spectrum does it belong.
Three particles of mass m each are placed at the three corners of an equilateral triangle of side a. Find the work which should be done on this system to increase the sides of the triangle to 2a.
A capacitor of capacitance C is given a charge Q. At t = 0, it is connected to an ideal battery of emf $\in$ through a resistance R. Find the charge on the capacitor at time t.
→The volume charge density in the space between two conocentric spheres of radii $a$ and $b$ is $\rho=\frac{A}{r}$, where $A$ is a constant and $r$ is the distance. There is a point charge $Q$ at the centre of the sphere. Find the value of A such that there is a uniform electric field in the space between the spheres.
→Area of cross-section of a wire is $1.0 \times 10^{-7} m^2$ and the number of free electrons per cubic metre in the wire is $2 \times 10^{28}$ per $m ^3$. A current of 3.2 A is flowing in the wire. Find (i) current density in the wire (ii) drift velocity of free electrons.
→On a cold winter night you are asked to sit on a chair. Would you like to choose a metal chair or a wooden chair? Both are kept in the same lawn and are at the same temperature.
Define threshold frequency. How does it relate with the work function of the metal?