ECET

By

Roberto Garcia

Equipment & Parts

Equipment

• Function Generator

• Oscilloscope

• 1K and 10K Resistors (12K Resistor used instead)

• 0.1 uF Capacitor

• Bread Board

• BNC T

• BNC to Alligator Cable

• BNC to BNC Cable

• Scope Probe

Experimental Procedure & Results

1. Construct the circuit shown below:

2. Using an oscilloscope test the output of the function generator to verify that it is producing a 100Hz 500mV peak to peak square wave. Adjust the offset so that the square waves negative peak is at zero volts and its positive peak is at 500 mV.

3. Connect the scope probe to the node labeled VCap and adjust the scope for good viewing.

4. Measure and record the following:

a. Minimum voltage of the waveform

b. Maximum voltage of the waveform

c. Time of positive going slope

d. Time of negative going slope

5. Using the measured slope time values calculate the time constant of the circuit.

6. Using the R and C values, calculate the time constant of the circuit. Is the measured time constant close to the theoretical time constant? Is the charge time equal to the discharge time?

7. Change R1 from 10KΩ to 1KΩ. Measure the change in charge and discharge time. What effect does this have on the circuit?

Screen Shots of simulation

Data Collected

Minimum voltage of the waveform

1v

Maximum voltage of the waveform

-1v

Time of positive going slope

4us

Time of negative going slope

-4us

Calculations

Calculations for τ

τ = RC