BZD27C68P MQG

A BZD27C68P MQG is a type of diode- a component that allow current to flow in one direction, but not the other - categorized as a single Zener diode. It has a relatively low voltage drop at forward bias, but clamps at reverse bias once a certain threshold is reached. This threshold Point, known as the Zener voltage, is typically marked on the component.

Applications

Since this component clamps the output voltage at one level, the BZD27C68P MQG is typically used to control voltage across levels or to stabilize the output of a power source. This diode also finds applications in circuit protection strategies, as it can absorb excess surges, protect against short circuits and prevent components from being damaged.

Working Principle

A standard BZD27C68P MQG is constructed from a block of highly conductive material, usually semiconductor silicon. This block is then treated with a solution of elements such as aluminum, boron and phosphorus and subjected to high-intensity treatments, such as heat and pressure, that implants these particles into the device. This effectively creates a barrier, preventing electrical flow between the anode and cathode.

Once the component has been treated, it is placed in an evacuated glass tube and treated with a conductive metal coating that makes it the anode. Current then flows from the anode to the cathode, with the resulting increase in the number of free carriers forming a current-voltage characteristic curve along the slope of the current-voltage curve.

The Curve has two breakpoints, one in the forward bias, the other in the reverse bias. In the forward bias region, the current increases with an increasing voltage, with a relatively low voltage drop. This is known as the ‘Zener Breakdown’. In the reverse bias region, however, the current remains constant and is independent of voltage. This is where the total opposite of the current-voltage curve occurs, leading to the clamping action of the Diode.

Conclusion

The BZD27C68P MQG diode is one of the most versatile single Zener diodes due to its ability to control voltage across levels, provide protection against short-circuits and protect against excess voltage surges. Its working principle involves the formation of a current-voltage characteristic curve which has two breakpoints and when supplied with a certain threshold voltage, it clamps the output voltage at one level, thus making it suitable for applications in voltage control and stabilisation.