1. DESIGNING
Selection of transistor: Use high frequency transistor BF195, NPN transistor.
L =10μH and VCE=0.5Vcc VRE=VE=0.1Vcc VRC=VC=.4VCC
Applying KVL for the output loop
VCC = ICRC+VCE+IE RE = IC RC + VCE +VE There for
There for
Let Vcc=12V, β=60 and IC=1mA
Applying KVL for the output loop
VCC = ICRC+VCE+IERE = ICRC+VCE+VE there for 4.7k
= 1.2 k
Let IR1 21IB and IR2 = 20 IB
i.e
Design of feedback network :
Selection of capacitors : All capacitor values may be taken 1μF
Required frequency of oscillation f= 1000KHz
Let L =10μH
Effective capacitor Ce=2.5nF
There for C= 5nF
Result
Amplitude and frequency of sine wave from Colpitts Oscillator =…….....V, ............Hz.