The frequency of alternating current (AC) plays a big role in how its circuits work. This is very different from direct current (DC).

AC changes in strength and direction over time. We can think of it like a wave that goes up and down. This change happens according to how fast the current cycles, which we measure in Hertz (Hz). Because of these changes, we see effects like capacitive and inductive reactance in AC circuits.

Here’s a simple formula for understanding impedance, which is a measure of how much the circuit resists the flow of electricity in AC:

$Z = \sqrt{R^2 + (X_L - X_C)^2}$

In this formula:

• $Z$ is the impedance,
• $R$ is resistance,
• $X_L$ is inductive reactance, and
• $X_C$ is capacitive reactance.

What’s important to remember is that impedance changes with frequency. As the frequency goes up, inductive reactance ($X_L = 2\pi f L$) increases, and capacitive reactance ($X_C = \frac{1}{2\pi f C}$) decreases.

On the other hand, DC circuits have a steady voltage and current. This makes them easier to analyze because there’s no reactance. So, DC circuits mainly deal with resistance and follow Ohm’s Law ($V = IR$) to calculate voltage, current, and resistance.

The uses of AC and DC are also quite different. AC is commonly used for power distribution. This is because it can easily be changed to higher voltages, which is great for sending electricity over long distances without losing much energy.

DC is used in electronic devices, batteries, and systems that need a consistent voltage, like digital circuits.

In short, the frequency of AC introduces some complicated effects like reactance and changing impedance. This makes AC circuits quite different from the stable and simple nature of DC circuits.