Signals and controls
Capacitors
Reduce brief supply disturbances or smooth changing signals.
What it does
A capacitor stores charge. Small ceramic bypass capacitors provide a short local path for fast supply-current changes; larger capacitors help with slower changes.
Connections and compatibility
Put a 100 nF ceramic capacitor close to an IC’s supply and ground pins. Electrolytic parts have polarity and a maximum voltage rating.
Choosing one
A few 100 nF ceramic parts and appropriately rated electrolytics are useful. Follow the actual module’s recommendation for bulk capacitance.
Common mistakes
A capacitor cannot make an undersized supply adequate. Reversed electrolytics can fail; never guess their polarity.
Use it in a tutorial
- Shift registers — Use a 74HC595 to drive eight low-current indicators with three controller pins.
- Using an RFID module — Read an RC522 tag identifier with correct voltage translation, and understand why a UID is not a secure key.