PASCO EM-8656 AC_DC ELECTRONICS LABORATORY - Manual (Page 45)

41
012-05892A AC/DC Electronics Laboratory
®
➂ Click the “Smart Cursor” button ( ). The cursor changes to a cross-hair when you move the
cursor into the display area of the Graph.
• The Y-coordinate of the cursor/cross-hair is shown next to the vertical axis.
• The X-coordinate of the cursor/cross-hair is shown next to the horizontal axis.
➃ Move the cursor to the point on the plot where the voltage begins to rise. Record the time that is
shown in the area below the horizontal axis.
➄ Move the “Smart Cursor” to the point where the voltage is approximately 2.00 Volts. Record the
new time that is shown in the area below the horizontal axis.
➅ Find the difference between the two times and record it as the time to “half-max”, or t
1/2
.
Data
Beginning time = _________ s
Time to 2.00 V = _________ s
Time to half-max (t
1/2
) = __________ s
➀ Use t
1
2
= τ
ln2 = 0.693 RC to calculate the capacitance (C) of the capacitor.
Capacitance = _________ Farad
➁ If a capacitance meter is available, use it to measure the capacitance of the capacitor. Using the
Percent Difference method, compare the measured value to the experimental value. (Remember,
the stated value of a capacitor may vary by as much as ±20% from the actual measured value.) If
a capacitance meter is not available, use the Percent Difference method and compare the stated
value (e.g., 330
µ
F) to the experimental value.