Electronic Circuit Design Lab Experiments

Analyse the working of Clapp Oscillator.

Sep 24 2023

Aim

Analyse the working of Clapp Oscillator....

Apparatus Required:

Breadboard, Workstation, Function Generator, Trainer Kit, Patch cords, DC Power supply

The instrument comprises of the following built in parts:

Fixed Output DC Regulated Power Supply of +12 VDC.
Circuit consists of transistor (CL100) & biasing resistances Combination
Inductor(L =2. 5 MH) is placed the front panel

Tank circuit consists of three capacitors & one inductor

Theory:

Fo = 1/2 (LC) ^1/2

1/C = 1/C1 + 1/C2 + 1/C3

Circuit diagram:

Procedure:

CRO

Connect external +12V DC supply & Ground to the + 12VDC & Ground (GND) Sockets of the module with the help of patchcords.
Connect the CRO probes across output sockets of the module.
Switch ON the instrument as well as CRO & observe the output wave shape on CRO and note down the frequency of oscillation from CRO or from Frequency Counter.

fo = 1/2 (LC)^1/2

1/C = 1/C1+ 1/C2 +1/C3

Calculation:

C1 = 1µF

C2 = 0.01µF

C3 = 0.033µF

Then

C = 7.6 nf

L = 2.5 mH

Calculated frequency = 36.51 kHz

Results:Result has been verified by observing waveform at different Phase Shift

Viva Questions:

Q.-1. How Clapp Oscillator if different from Colpitt's Oscillator?

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Q.-2. Why it is called as Clapp Oscillator?

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Q.-3. How Barkhausen Criterion satisfies in Clapp Oscillator?

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