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#### Lab Activities

Given the appropriate circuit diagrams, the students build and operate a square wave and a sine wave oscillator.

For the square wave oscillator, they are asked to:

1. measure the period of the square wave and compare it to the time constant of the RC input circuit;

2. sketch the gate-to-source voltage vs time curves for the two transistors used and explain their respective shapes;

3. sketch the gate-to-source voltage vs time graph for the first transistor and the drain-to-source voltage vs time graph for the second transistor and explain their respective shapes;

4. sketch the gate-to-source voltage vs time graph for the first transistor and the drain-to-source voltage vs time graph for the first transistor and explain their shape;

5. vary the value of the capacitors used and see what affect this has on the square wave generated; and

6. explain how the square wave generator works.

For the sine wave generator, they are asked to:

1. measure the period of the sine wave produced and compare it to the resonant period of the LC circuit in the oscillator; and

2. measure the single stage gain and the two stage gain and compare the values to the expected values;

3. measure the attenuation from the resistances in the attenuator and compare that value to the expected value;

4. measure the loop gain and compare it to the expected value; and

5. explain how the sine wave generator works.

Quantitative results tend to be within 10% of the expected values.

#### Course Level

Introductory: P4, P14, P16

#### Equipment

 Number of set-ups available: 10 Per lab station: 1 HP 54600A oscilloscope 1 oscillator 2 10:1 probes 1 frequency counter 2 BNC -> banana adaptor (female) 2 banana leads 2 alligator clips 1 60 in 1 electronics kits (student supplied)

#### Notes

 Last Update: Site contact: largent@Dartmouth.EDU