ECE 2212

EXPERIMENT #3: Diode I-V Measurements and Use of the Semiconductor Device Parameter Analyzer

Half Wave and Full Wave Bridge Rectifiers

PURPOSE

 Use laboratory measurements to extract key diode model parameters including IS , h(N). from the I-V measurements.

 Use laboratory measurements to extract key diode model parameters including IS , h(N). from the parameter analyzer.

 Implement designs of the half wave rectifier and full wave bridge rectifier circuits and measure time domain characteristics and the transfer characteristics.

 Measure and compute ripple voltage.

 Compare individual diode results and circuit results using PSPICE simulations.

COMPONENTS

1N4001 Diodes

1KW resistors

A variety of capacitors from 0.01 mF to 100 mF.

PRELAB

Write and run PSPICE programs for each of the circuits. Use .PROBE to obtain I-V and transfer characteristics..

PROCEDURE

I-V Characteristics and Diode Model Parameter Extraction

Figure 3.1 Half-Wave Rectifier

 

Write and run a PSPICE program for the circuit of Figure 3.1 without the capacitor. Construct the circuit. Use two digital multimeters (one to measure ID and another to measure VD). Pay attention to the diode orientation. The banded side is the cathode end. Vary the supply voltage VS to adjust ID to the desired current setting, then measure VD. Take readings from 0.1 mA to 10 mA at the following intervals: 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 8, 10 ma. Now, check your voltage readings at 0.1, 1 and 10 mA using a curve-tracer measurement if the diode.. Now, consider the equation:

 

From this equation, determine and fit a straight line to your plotted I-V graph. Your equation will be in the form

y = mx + b

Use these data to modify your diode model in your PSPICE program.

Half-Wave Rectifier

Again, using Figure 3.1, input Vs as a 10 volt peak 100 Hz sinusoid. Observe and plot Vo(t) and the transfer characteristic, Vo vs Vs. Use several values of C to illustrate the ripple voltage. Also use the AC rms input on the multimeter to study the ripple voltage. Use your diode model and check your lab measurements using PSPICE.

Diode-Bridge Full-Wave Rectifier

Figure 3.2 Diode-Bridge Full-Wave Rectifier

Figure 3.3 Floating Input Circuit Adaptation

Construct the circuit shown in Figure 3.2. Input Vs as a 10 volt peak 100 Hz sinusoid. Observe and plot Vo(t) and the transfer characteristic, Vo vs Vs. Use several values of C to illustrate the ripple voltage. Also use the AC rms input on the multimeter to study the ripple voltage. Use your diode model and check your lab measurements using PSPICE. Compare your results with the half-wave rectifier circuits.

Note that to provide a floating input from the signal generator which has one side grounded , we will use a transformer as shown in Figure 3.3. Do not monitor the input of the bridge with the oscilloscope because you will automatically ground one side of the circuit. Monitor the input on the signal generator side of the circuit. (Brown and blue transformer primary winding).