DIODA
Based on the characteristics and limitations in its application, the diode is classified into three groups, the standard diode (diode for public use), high speed diodes and Schottky diodes.
a. Diodes standard
Standard diode is a type of diode that is used for general corporate purposes. These diodes are used in low-speed applications, such as rectifiers and converters with input frequencies up to 1 kHz. These diodes have a current rating of 1 to thousands of amperes and a voltage of 50 V to 5 kV.
b. High speed diodes
Diodes of this type have the ability penyaklaran with speeds higher than standard diode. Therefore, the common usage applied to DC-chopper circuit (DC-DC) and an inverter (DC-AC) where the speed aspect is a very important factor. Diode type has a smaller current rating of 1 A to hundreds of amperes, with from 50 V to 3 kV.
c. Schottky Diodes
Schottky diodes built reverse the PN connection so it is suitable for applications with a DC power supply high current and low voltage. Rating voltage limited to 100 V with a current of 1-300 A. However, these diodes are also suitable for low current power supply for increased efficiency.
2.6 Application diodes
Diodes applied to many current hand over power suply circuit or AC to DC converter. Each type varies depending on the maximum current and voltage breakdwon her.
Application diodes are widely used in vehicles for Rectification currents as on the charging system. As the function is as a rectifier diode current from alternating current into direct current that can be used to charge the battery and supply the current demand on the vehicle.
Another function of this diode on the vehicle are as anti shock voltage. An example application is given on the type of relay diode in order to prevent reverse flow in the circuit. Reverse flow power can be derived from the induction of the magnetic field generated by the coil relay. Electric induction is usually higher voltage than the source voltage. To prevent damage from the induced voltage is then the relay circuit coupled diode circuit.
2.7 Application of Rectifier Diodes In Series
Since a PN diode connection of electrical current can flow only in one direction, then the diode can be used as a rectifier to convert the alternating current (AC) into direct current (DC). There are two types of rectifier that we studied, the half-wave rectifier and full wave rectifier.
a. Half-wave rectifier
The simplest rectifier circuit is the half-wave rectifier, consisting of a diode mounted on the secondary side of the transformer and diserikan with a load R, as shown half-wave rectifier. Direct voltage required by the load, such as lamps, relays, bateray, etc.. Transformers convert alternating voltage to a voltage suitable for the particular rectified.
Figure 2.6. Half-wave rectifier circuit
Source: analysis of 2009
Secondary side voltage transformer, an input voltage for half-wave rectifier circuit. Input voltage is in the form of alternating voltage sinusoid. In one period, the positive and negative polarity change in turn. We're just reviewing one wave period only, namely half the period of positive and negative half-periods. In half the period of positive, forward bias diode given (the anode (A) associated with positive polarity and the cathode (K) associated with negative polarity), so the diode current will flow through the load R. To be considered purely resistive load R, the output voltage or the ends of the load equal to the input voltage. Therefore, the shape teganga equal to half the output voltage waveform.
In half the period of the next negative, given the bias backward diodes (anode (A) associated with negative polarity and the cathode (K) associated with positive polarity), so it will not drain diode current through the load R. This resulted in the output voltage between the ends of the load is equal to zero, and is described in a horizontal straight line as shown below.
Output voltage waveforms at half-wave rectifier circuit shown in the figure below. Because the output voltage is only in the direction of the positive half of the wave period of the input voltage, the rectifier is called half-wave rectifier.
b. Full wave rectifier
In order to drain current in a full wave so that the output voltage is more easily flattened and can produce a constant value, we use a full wave rectifier. Full-wave rectifier can be used four diodes are connected as a Wheatstone bridge, also called a bridge rectifier, the circuit as shown below.
Always only a pair of bridge rectifier diode current flows through the load R, is a pair of diodes are not. In this circuit, the diode pair is D1 with D4, and D2 to D3. (In a simple pair diodes diodes shown by the direction parallel arrows).
In the positive half period, the couple diodes D2 and D3 dipanjar forward, while pairs diodes D1 and D4 dipanjar retreat. Electric current will flow from the input voltage through a pair of diodes D2 and D3, and the load R with direction from a to b. So, in this period, the output voltage equal to the input voltage.
In the negative half period, the couple diodes D4 and D1 were advanced dipanjar pair diodes D2 and D3 dipanjar retreat. Electric current will flow from the input voltage through a pair of diodes D1 and D4 and load R, in the same direction from A to B, as shown. Can we say that the input voltage is negative be positive at the output. Furthermore, the input voltage waveform and the output voltage is shown in the figure below.
Therefore the rectifier bridge output voltage wave direction for a period of input voltage given to him, then the bridge rectifier is also called a full wave rectifier.
c. Principles of Alignment Full Wave Rectifier
Direct voltage generated by a half-wave rectifier and bridge rectifier (full wave) has a fairly large ripple (uneven voltage waveform). Such direct voltage is not eligible to be given to electronic components contained in the radio, television and computers, which require more direct voltage level. Simply put direct voltage can be leveled by placing a large capacity electrolytic capacitor, parallel with the load R, as in the picture series leveling system below.
Smoothing capacitor circuit system are called grading capacitors or capacitor storage (reservoir circuit). When the voltage at the load ends up on the time between A and B, the capacitor C is loaded in such a way that the upper plate positive polarity. Shortly after the rectifier output voltage between B and C is reduced, the capacity C dispose of their electrical charge through the load R. as a result, the voltage at the ends of the load never reaches zero, but follow the trajectory of thick lines. It appears that the ripple voltage waveform becomes smaller and direct voltage produced at the ends of the load is a little more flat.
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