# Lab 3: AC and RC Circuits Lab Assignment

```2 class days
Lab 3: AC and RC Circuits
Lab Assignment
1. RC Circuit
HH 2.1. If you cannot find the capacitor specified, use the closest one available.
You must use the correct value (i.e. of the cap in your circuit) for the analysis.
2. Differentiator
HH 2.2. Do not set the function generator to 20 dB. Use an amplitude of 1 V.
3. Integrator
HH 2.3. Answer questions through “vout &lt;&lt; vin” part. Do not answer the question
in parentheses.
4. Low-pass Filter
HH 2.4. Answer all questions. Do not do the suggestion box.
5. High-pass Filter
6. Blocking Capacitor
HH 2.8. Answer all questions. What is the role of a blocking capacitor?
Source: Eyler lab 2
Part C – Capacitance of Scope
When the input of an oscilloscope is set to ac coupling, it is directed through a
series blocking capacitor to form a high-pass filter like the one shown in lab 2-5 of
Hayes and Horowitz, but with a very low cutoff frequency, typically below 20 Hz.
To find the value of this capacitor, connect a signal generator directly to your
oscilloscope, with a cable rather than a probe. Vary the frequency in the range
from about 5-100 Hz until you find the value f3dB where the response is reduced
by 3 dB when you switch the coupling from dc to ac. Given that the input
impedance of the scope is known to be 1 MW at high frequencies, calculate
based on your measurements the value CB of the internal blocking capacitor. Be
careful not to confuse radians with cycles/sec, or decibels in power units with
decibels in voltage units (see Horowitz &amp; Hill and the student manual).
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