advertisement

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. Answer all questions. 2. Differentiator HH 2.2. Do not set the function generator to 20 dB. Use an amplitude of 1 V. Answer all questions. 3. Integrator HH 2.3. Answer questions through “vout << 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 HH 2.5. Answer all questions. 6. Blocking Capacitor HH 2.8. Answer all questions. What is the role of a blocking capacitor? 7. Effects of instruments on your readings 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 & Hill and the student manual).