RC Circuit Lab

Names: ______________________________________________________________

Background

1.  Reactance (X) is defined as the resistance or opposition to alternating current as a

     result of inductance or capacitance.

     X_C = 1/2pfC where

    f = frequency in hertz, and C = capacitance in farads

2. Impedance (Z) is defined as the total opposition to an alternating current in a circuit

    having resistance and reactance.

    Z = (R² + X_C²)^1/2 for capacitive reactance   or Z = (R² + X_L²)^1/2   for inductive reactance

    X_C is capacitive reactance, X_L is inductive reactance

3.  Ohm's Law for AC Circuits

     Same as before (V = IR) except use Z for R.Z represents the total resistive force

     opposing the current.      E = I Z

The Lab

1.  Use a breadboard to connect the following circuit.

     a.  The power supply is AC as covered below.

     b.  Place a 0.47 µF capacitor (E_C1)in series with a 4700 W resistor as shown

2. Connect the AC voltmeter across the capacitor (remember to push the AC/DC

    selector in to select AC).

3.  Connect the signal generator to the breadboard (red to red, black to black).

4.  Set the voltage to 9 volts and set the frequency to the first position indicated in the

     table below.

5.    Record the voltage reading in the column labeled E_C1 above.

6.    Set the frequency dial on the signal generator to the next position and record the

       voltage readings in the table.

7.    Repeat for the remainder of the frequencies.

8.   Turn off the equipment.

9.    Replace the 0.47 µF capacitor with the 47 µF capacitor.

10.  Repeat the above readings for the frequencies listed.

11.  What conclusions can you draw from this experiment. Be specific.

       Place response on separate sheet.

Tektronix CFG250 Function Generator

1.   Power button: Push to turn on or off

2.   Power on light

3.   Function buttons - set to sine wave (push button on far right)

4.   Range buttons - set to frequency range desired

5.   Frequency control - set to frequency desired

6.   Amplitude - Depending on position of Volts Out button, determines signal level - set

      to mid range.

7.   Volts out range button. Set to range desired - we will be using 9 volts, so should be in

     10. DC Offset. Pull this control out to activate The control sets teh DC leval and polarity of

     the signal at the Main output. When the control is pressed in, the signal is centered at zero V

     dc. out position.

14. Main output connector - insert red and black prongs into the breadboard input receptacles.

Remainder of buttons - do not use