Capacitors

What is a Capacitor?

A capacitor stores electrical energy in an electric field. It's like a temporary battery.

Real Capacitors

Here's what actual capacitors look like:

Different types of capacitors: ceramic, electrolytic, and SMD

Capacitor Types

Electrolytic Capacitors

• Polarized (positive and negative)
• Higher capacitance values
• Used in power supplies

Ceramic Capacitors

• Small, non-polarized
• Lower values (pF to μF)
• Good for high frequencies

Tantalum Capacitors

• Polarized
• Stable performance
• More expensive

Capacitor Symbols

• Unpolarized: Two parallel lines
• Polarized: One curved, one straight line

Reading Capacitor Values

Ceramic Disc Capacitors

# Marked as 104
First two digits: 10
Multiplier: 10^4 = 10,000
value = 10 * 10000  # 100,000 pF = 100 nF = 0.1 μF

Electrolytic Capacitors

Usually printed directly: "100μF 25V"

Capacitance Units

Common Uses

• Power supply filtering - smooth out voltage
• Timing circuits - RC timers
• Coupling - pass AC, block DC
• Energy storage - flash capacitors

Summary

• Capacitors store energy temporarily
• Measured in Farads (usually μF, nF, pF)
• Electrolytic = polarized, Ceramic = non-polarized

Next Lesson

In the next lesson, you'll learn about diodes and LEDs.