Calculate the time constant of the circuit shown in Figure 1.
Adjust the signal generator for a voltage source to obtain a unipolar square wave with a peak-to-peak value (Vpp) of 10V. The square wave half period is T/2 = 5Ï„. Calculate its frequency as f1. Adjust the signal generator frequency to f1.
Build the RC circuit in your Preliminary Work.
Observe the input signal and voltage across the capacitor and record them.
Verify your results using the oscilloscope cursor mode in order to identify the voltage across the capacitor at Ï„, 5Ï„, and 6Ï„.
A. Preliminary Analysis of the circuit in Fig.1 for a square wave voltage source with the waveform shown in Fig.2. Assume that the initial voltage on the capacitor is zero and determine the voltage on the capacitor (Vc) for t=t, 5t, and 6t. Adjust the frequency for T/2 = 5t. (R = 2.2kΩ, C = 1F)
MM R
+
Vst
Vc(t)
Figure 1. RC Circuit with a square wave source
B. Proteus
Set up the circuit in Proteus. Observe the input signal and voltage across the capacitor and record them. Use graph mode, analogue graph, or oscilloscope - You can search with RC transient analysis with Proteus.
C. Procedure: If we apply a continuous square wave voltage waveform (Use Signal Generator as a source in Proteus) to the RC circuit whose pulse width matches exactly that of the 5 time constant (5T) of the circuit, then the voltage waveform across the capacitor would look something like this: Vs Square Wave Indu
0 Vc
5T
10T
15T
Time (t)
0.63Vc
0.37Vc