Ece 203 electrical circuit (12)

ECE 203 – CIRCUIT THEORY LABORATORY MANUAL – 3 – LINEAR RESISTIVE CIRCUITS

Materials: • • •

4 x 2.2 kΩ resistor 10 kΩ resistor 100 Ω resistor

Experimental Work: 1)

Construct the circuit on figure1. Here AC voltage source Vin(t) is a 12Vpp, 2KHz sinusoidal wave, which you will apply using function/waveform generator. The DC voltage source is supplying 9V to the circuits. You will apply DC voltage using DC voltage source.

a. Attach the oscilloscope channel 1 probes as shown in the figure1 to measure the output voltage V0(t). Plot the waveform.

b.

Using “measure� menu of oscilloscope, find and record the Vmax and Vmin.

Propose a method to find the DC offset of V0(t) using Vmax and Vmin (i.e. write DC offset in terms of Vmax and Vmin). Write DC offset voltage of V0(t), show your work and explain your reasoning.

c. Now try to find the DC offset voltage using coupling from the channel 1 soft menu, cursors and Vmax point of the V0(t) (Hint: changing the coupling, try to see how much the signal is shifted). Explain your reasoning.

2) Construct the circuit on figure2. AC voltage source Vin(t) is a sinusoidal wave of 10 kHz and 5Vpp.

Figure 2

a. Try to display V1(t) only by using single channel probes of the oscilloscope. Plot the waveform. Observe whether the amplitude of the signal is the same as you found in preliminary. Draw the probe connection and comment on the waveform.

b. Propose a method for observing V1(t) and V0(t) simultaneously using both probes (CH1,CH2 together) and “Math� menu of the oscilloscope. Plot the observed waveforms, draw the probe connections and comment on your method.

c. Now increase the frequency of Vin(t) to 10 MHz and measure the V0(t) using CH1 probes.

Is it the same as in part b or changed? Plot the waveform and comment. (Hint: refer to preliminary.)

3) Construct the circuit on figure3. Vin(t) is a square wave of 3Vpp and 2KHz frequency.

Figure 3

a. First connect 10kâ„Ś as R1. Observe and plot the waveform of V0(t).

b. Now change R1 to 100ℌ. Observe and plot the waveform of V0(t). Comment on it’s differences with the waveform on part a. (Hint: refer to preliminary)

4) Set your function generator to produce a sinusoidal wave of 10Vpp amplitude, 0V DC offset and 500Hz frequency. Measure and record the RMS voltage of the signal using your multimeter (i.e. set your multimeter on AC voltage measurement and connect both ends into function generator). Is the value you observed close to the theoretical result? Explain.

5) Change the signal waveform into ramp (triangular) and square respectively. Do not alter the amplitude and frequency. For both cases measure and record the RMS voltages. Calculate also theoretical RMS values for both waveforms. Are they the same with measured values?