Semiconductor Electronics Materials Devices And Simple Circuits

Step 1: Inductive reactance varies as frequency, XL f XL' = 20×(100)/(50) = 40 Ω
Step 2: Impedance, Z=√(R²+XL'²)=√(30²+40²)=50 Ω
Step 3: Current, I=(V)/(Z)=(200)/(50)=4 A (Considering rms and peak relation, effective current is 7.2 A)

A plano-convex lens with silvered plane surface acts as a concave mirror of focal length f/2. f'=(30)/(2)=15 cm Using mirror formula, (1)/(f')=(1)/(v)+(1)/(u) v=24 cm

Step 1: Peak current, I₀ = 6 A
Step 2: RMS current, Iₑₓtᵣmₛ = I₀√(2) = 6√(2) = 2√(2) A

The oscillator and the amplifier works in the same way but the amplifier requires input where the oscillator does not require any input. When the amplifier connects with positive feedback, it acts as the oscillator. The feedback employed here is positive feedback, this means some amount of the output voltage is given to the input. Hence the circuit continues its process without any input to the oscillator. The positive feedback is also known as regenerative feedback because the system sustains or regenerates itself without any input source. Hence the oscillator is nothing but an amplifier with the positive feedback.