Precis About V-I Characteristics

The voltage or current characteristics of an electrical component or device are called V-I characteristics. Using a V-I graph, you may learn about a component’s resistance and deconstruct it. A component’s functional area may also be found here. An electric circuit can be better understood by studying a component’s properties. An electronic component’s voltage-ampere characteristics describe its response to varying input voltages. Simply put, it’s a voltage-current graph obtained by applying a voltage across an electronic component and measuring the current flowing through it. Because voltage is more straightforward to manage than current, the x-axis of V-I characteristics depicts voltage and the y-axis represents current. 

Varieties of V-I Characteristics

Characteristics of the Linear VI System

Constant resistance may be found in a linear voltage or current curve because of its constant slope. The resistance of carbon resistors and metals is consistent because they follow Ohm’s law. A straight line travelling through the origin defines the V-I curve. Only a small portion of an electrical component will show linear behaviour. In its operational range, a diode, for example, exhibits a linear behaviour.

Characteristics of the Non-linear VI

When the resistance of a circuit component fluctuates in response to changes in voltage or current, it has a non-linear characteristic. For example, the resistance of a diode varies depending on the voltage applied to it. The limited operational zone, on the other hand, has a linear property. Depletion type transistor shows that diodes can function at their maximum forward and reverse voltage without breaking down or exploding.

The SCR’s V-I Characteristics

It is a three-terminal semiconductor switching device used as a controlled switch for rectification, regulation and inversion of power flow. SCR stands for the Silicon Controlled Rectifier (SCR). Anode-cathode voltage V and anode current I, at constant gate current, make up the V-I characteristic curve of an SCR.

V-I: The PN Junction Diode’s Properties

Pn junctions and semiconductor diodes have voltage-ampere (voltage or current) characteristics, which describe the relationship between the voltage across the junction and current flow. Typically, voltage is measured on the x-axis and current on the y-axis. However, this may be reversed.

Zero Bias

No external voltage is delivered to the pn junction in the zero bias state; hence the circuit is entirely open at K. As a result, the junction’s potential barrier prevents current flow. This means that at V=0 V, the current in the circuit will be zero.

The p-type of the pn junction is linked to the positive terminal of the external voltage, while the n-type is connected to the negative terminal. A smaller potential barrier is created as a consequence of this. The potential barrier is essentially reduced at a specific forward voltage, such as 0.7 V for Si and 0.3 V for Ge. After that, as the forward voltage rises, the current also rises. As a result, a curve OB with a forward bias, as illustrated in the depletion type transistor.

Forward Bias

The non-linearity of the curve and the gradual rise in current in area OA may be seen in the forward characteristics because the potential barrier is overcome by applying an external voltage to the pn junction at this area. However, when the external voltage surpasses the potential barrier voltage, the potential barrier is removed and the pn junction functions as an ordinary conductor. In the Pn junction, as the external voltage increases, the current increases rapidly and linearly.

Reverse Bias

When the external voltage is reversed, the p-type and n-type are linked to the external voltage’s negative and positive terminals. This raises the risk of a collision at the intersection. Consequently, the junction resistance is relatively high and as a result, the circuit is effectively dead.

However, just a few pico amperes of current travel across the enhancement type transistor. Because of the minority carriers in the junction, reverse saturation current (IS) is generated. We already know that p-type materials have fewer free electrons and n-type materials have fewer holes. Minority carriers refer to these unoccupied electrons and holes in a p-type or n-type semiconductor. The pn junction’s reverse bias works as a forward bias for the junction’s minority carriers, causing a modest reverse current to flow.

An increase in reverse voltage may raise the minority carriers’ kinetic energy to the point where they knock electrons out of semiconductor atoms. The connection may break down at this point. There is a rapid rise in reverse current and a sudden decrease in barrier resistance in this case. This has the potential to damage the connection irreversibly. Due to its independence from any other factors, voltage is generally shown on the graph’s x-axis.

Conclusion

The voltage or current characteristics of an electrical problem or device are referred to as V-I characteristics. The v-i graph provides valuable information about the resistance and breaks down a digital part of the equation. It also serves as an element’s working space. We can figure out where and how to employ an object in an electric circuit by reading its characteristics. Electronic factors are characterised by their voltage-ampere characteristics when applied to varying voltages. When a voltage is applied across an electronic component, it is distant from the graph that shows the relationship between voltage and current when modern is being measured.