The Difference Between Forward Bias and Reverse Bias in Electronics
When it comes to electronic components such as diodes, transistors, and LEDs, you might have heard the terms “forward bias” and “reverse bias”. These terms describe the way that voltage is applied across a component and how it affects the flow of electric current. Here’s what you need to know about the difference between forward bias and reverse bias:
Forward Bias:
Forward bias occurs when the positive terminal of a power supply is connected to the anode of a diode, and the negative terminal is connected to the cathode. This means that the voltage across the diode is in the direction that allows current to flow through the device. In other words, the diode is “turned on” and can conduct electricity. The voltage required to forward bias a diode is called the “forward voltage” and varies depending on the type of diode.
In a transistor, forward bias is used to control the flow of current between the collector and emitter terminals. By applying a positive voltage to the base terminal of the transistor, the device can be “turned on” and allow current to flow from the collector to the emitter.
Reverse Bias:
Reverse bias occurs when the positive terminal of a power supply is connected to the cathode of a diode, and the negative terminal is connected to the anode. This means that the voltage across the diode is in the opposite direction to the direction that allows current to flow through the device. In other words, the diode is “turned off” and cannot conduct electricity. The voltage required to reverse bias a diode is called the “reverse breakdown voltage” and varies depending on the type of diode.
In a transistor, reverse bias can be used to block the flow of current between the collector and emitter terminals. By applying a negative voltage to the base terminal of the transistor, the device can be “turned off” and prevent current from flowing from the collector to the emitter.
Conclusion:
In summary, forward bias and reverse bias are two different ways of applying voltage to electronic components that affect their ability to conduct electric current. Forward bias allows current to flow through a device, while reverse bias blocks current from flowing. Understanding the difference between these two types of bias is essential for properly designing and using electronic circuits.
Table difference between forward bias and reverse bias
| Forward Bias | Reverse Bias |
|---|---|
| Current flows from the anode to the cathode. | Current does not flow or is extremely small. |
| Positive charge is applied to the anode while negative charge is applied to the cathode. | Negative charge is applied to the anode while positive charge is applied to the cathode. |
| The diode conducts electricity. | The diode does not conduct electricity. |
| The voltage drop across the diode is small. | The voltage drop across the diode is high. |
| The diode acts as a closed switch. | The diode acts as an open switch. |
| Used in circuits such as rectifiers, voltage regulators, and power supplies. | Used to protect the diode from damage due to excessive voltage. |