Overview

Test Case

Compute the Fourier series coefficients of the output voltages for three configurations of the following circuit: first with no capacity, as shown in Problem Sketch 1 in Figure 513: Diode Rectified Circuit Problem Sketch; second, with a capacitor C(2) of value 1 x 10^-6 Farads, as shown in Problem Sketch 2; and third with a capacitor C(3) of value 10 x 10^-6 Farads, as shown in Problem Sketch 2. In all three cases, the circuit is driven with a 60 Hz, 125 V AC power source and contains a 2500 resistor and an ideal diode as indicated.

Figure 513: Diode Rectified Circuit Problem Sketch

Material Properties	Loading
R1 = 2500 Ohm C1 = 1 x 10-6 F C2 = 10 x 10-6 F	V

Analysis Assumptions and Modeling Notes

The diode is modeled with CIRCU125 elements, configured to behave as an ideal diode with zero forward resistance, infinite backward resistance, and a zero forward voltage threshold. The voltage source, resistor, and capacitor are modeled with CIRCU124 elements, the three different behaviors being achieved with different KEYOPT settings.

For each of the three circuits, Mechanical APDL is used to calculate the Fourier series coefficients, , , and in the following equation:

where is the period.

Calculatuon of the coefficients for the two circuits with the capacitor is significantly more involved than the first case without the capacitor.

Results Comparison

Figure 514: Low Voltage Waveform with No Capacitance

Figure 515: Output Potential for No Capacitor Circuit

Figure 516: V_load with Capacitance 1 x 10^-6

Figure 517: Output Potential with Capacitance 1 x 10^-6

Figure 518: Output Potential with Capacitance 10 x 10^-6