An AC-DC converter is a device that can turn an AC power supply into a DC power supply by forcing the current to flow one direction with a diode and reading a low frequency from the high frequency produced by the carrier.

As shown above in figure 1 the voltage supplied across point a and c is sinusoidal. When the diode D is inserted between the voltage source (AC) and the resistor R the current is only allowed to flow in the positive direction. Between point b and c the wave form is only positive because both the negative current and voltage have stopped by the diode. This positive only waveform is called a half-wave rectified voltage.

An alternative to finding a more precise DC voltage is to use a capacitor as a filter. The Capacitor is inserted in figure 3 parallel to the load resistor so that it can absorb the voltage as it changes throughout the circuit. The capacitor works as a battery within the circuit and absorbs the voltage provided by the voltage source. As the voltage reaches its max the capacitor contains the same voltage and then begins to discharge through the parallel load resistor. This occurs until the voltage reaches its maximum value again because of the sinusoidal function of the voltage. This fluctuation of voltage is called the ripple voltage (Vrip) and can be calculated by equation 2 below. The minimum and maximum can be found in when obtaining a wave form similar to that of figure 3. The ripple factor is the percentage of ratio between the between the ripple voltage and DC voltage. This ripple factor can define the quality of the power supply through the circuit and can be found by equation 3 below. A larger capacitance results in a smaller ripple factor and a better power supply.

The capacitor draws more current then the load resistor because there is a protective resistor directly after the diode which can be seen in figure 3. A disadvantage to the setup if this circuit is that the maximum voltage is reduced because of the protective resistor.

1. A circuit with a full wave rectifier can be designed similar to that of figure 1 as long as the circuit includes a voltage source, diode, and resistor.
2. The time constant of the filter is equal to the RC instead of the rc because the load resistor (R) maintains the the voltage because it is in the same loop of the capacitor. This happens because the capacitor replicates the voltage provided by the voltage source.

Conclusion

After analyzing the data and the oscilloscope the theory can be confirmed about how a power supply interacts with a diode, resistors, and a capacitor. The equations provided analyze that data for the Vrip, Vdc, and ripple factor.