It simply means:

You slowly increase the voltage, and watch what the current does.Then you draw a graph of current (I) on one side, and voltage (V) on the other.

This graph tells you a lot about the behavior of that component.

🧠 Think of it Like This:

• Voltage is like a push.

• Current is like how fast the electrons are flowing.

If you push harder, does more current flow?Yes — but it depends on the thing you're pushing the current through.That’s what the I–V graph shows.

🧪 Let’s See Different Kinds of I–V Characteristics:

1. Ohmic Resistor (like a normal wire or resistor)

This follows Ohm’s Law:

I=VRI = \frac{V}{R}I=RV​

• The graph is a straight line.

• If you double the voltage, the current also doubles.

• This is called linear behavior.

👉 Such materials are called Ohmic conductors.

2. Non-Ohmic Components (like diodes, filament bulbs, etc.)

These do not follow Ohm’s Law perfectly.

• Filament bulb: As voltage increases, the wire heats up, so resistance increases.The graph curves — current doesn't increase evenly.

• Diode: It lets current flow only in one direction.The graph looks like a sharp curve in one direction, and flat in the other.

👉 These are called non-ohmic devices because resistance changes with voltage.

📈 What Does the I–V Graph Tell Us?

• Slope of the graph = related to resistance(steeper slope = less resistance, flat slope = high resistance)

• Straight line = constant resistance

• Curved line = changing resistance

You can look at the graph and immediately know:

• Is this component obeying Ohm’s Law?

• Does it behave differently at high or low voltages?

• Is it working like a switch (diode), heater (bulb), or something else?

💡 Why It Matters in Real Circuits:

• Engineers design circuits using these graphs.

• To control current, avoid overheating, or create logic for computers.

• To know how a device responds when voltage is applied.

🔍 Summary:

• Current–Voltage characteristics show how current changes with applied voltage.

• For ohmic devices (resistors), the graph is a straight line.

• For non-ohmic devices (bulbs, diodes), the graph is curved or weird-shaped.

• It helps us understand and control how electronic parts behave.