Diode and Its Application
I. Diode and Diode Application
1. Diodes
2. Rectification
3. Power supply filter
4. Applications of diodes ← Signal rectifier ← Diode gate ← Diode clamps ← Limiter
Diodes
Some elements are linear (resistors, capacitors, inductors), which means that doubling the applied signal (let us say a voltage) produces a doubling of the response (let us say a current). They are also passive – they do not have built-in source of power. They are two-terminal devices, (which is self-explanatory). Diode is also two-terminal, passive but non-linear a device. Figure 1 shows the diode.
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|[pic] | |
|Fig.1. Diode. |Fig.2. Diode voltage-current curve, U-I curve. |
In Fig. 2 there is U-I (voltage-current) curve (characteristic). The diode arrow, anode terminal, shows the direction of forward current flow. If the diode is in a circuit in which a current of 10mA=10*10-3A is flowing from anode to cathode, then the anode is approximately 0.5 volt more positive than cathode. We call it the forward voltage drop. The reverse current is measured in nanoampers and 1nA=1*10-9A. It is so small in comparison to mA, that can be neglected until we reach the reverse breakdown voltage. Typically it is approximately 75V and normally we never subject a diode to voltage large enough to cause reverse breakdown. Similarly, the forward voltage drop, which is about 0.5 or 0.8 V, is of little concern. For these reasons we treat the diode as a good approximation of an ideal one-way
1. Diodes
2. Rectification
3. Power supply filter
4. Applications of diodes ← Signal rectifier ← Diode gate ← Diode clamps ← Limiter
Diodes
Some elements are linear (resistors, capacitors, inductors), which means that doubling the applied signal (let us say a voltage) produces a doubling of the response (let us say a current). They are also passive – they do not have built-in source of power. They are two-terminal devices, (which is self-explanatory). Diode is also two-terminal, passive but non-linear a device. Figure 1 shows the diode.
| |[pic] |
| | |
|[pic] | |
|Fig.1. Diode. |Fig.2. Diode voltage-current curve, U-I curve. |
In Fig. 2 there is U-I (voltage-current) curve (characteristic). The diode arrow, anode terminal, shows the direction of forward current flow. If the diode is in a circuit in which a current of 10mA=10*10-3A is flowing from anode to cathode, then the anode is approximately 0.5 volt more positive than cathode. We call it the forward voltage drop. The reverse current is measured in nanoampers and 1nA=1*10-9A. It is so small in comparison to mA, that can be neglected until we reach the reverse breakdown voltage. Typically it is approximately 75V and normally we never subject a diode to voltage large enough to cause reverse breakdown. Similarly, the forward voltage drop, which is about 0.5 or 0.8 V, is of little concern. For these reasons we treat the diode as a good approximation of an ideal one-way