Electronic Components: Types, Functions, and Uses

Electronic Components

• Fixed Resistors:
  • Limit the amount of current flowing through a circuit.
  • Protect certain components.
• Potentiometer: Provides variable resistance. They regulate the amount of current that passes through the circuit.
• Variable Resistance with Temperature:
  • NTC (Negative Temperature Coefficient): If the temperature increases, the resistance decreases.
  • PTC (Positive Temperature Coefficient): If the temperature increases, the resistance increases.
• Variable Resistance with Light (LDR):
  • Decreases its resistance value when the amount of light it receives increases.
  • If the resistance decreases, the current intensity increases.
• Capacitor: Stores electrical charge for later use.
  • Its capacity is the ratio of electric charge stored to the voltage at which it is subjected.
  • Unit: Farad (F)
  • C = q / V
  • Types:
    • Normal
    • Electrolytic
  • The loading and unloading time t = 5 * R * C
• Semiconductors - Diodes:
  • Materials that can conduct electricity if they receive external power.
  • Two types: P (Anode) and N (Cathode)
  • If directly polarized, it becomes a conductor; otherwise, the current does not flow.
• LED (Light Emitting Diode):
  • Emits light.
  • If directly polarized, it becomes a conductor; otherwise, the current does not flow.
  • The voltage required for conduction is about 2V, and the current flowing through an LED is typically 20mA.
• Transistor:
  • Types: NPN and PNP
  • Transistor as a Switch: For a transistor to operate as an open or closed switch, it is necessary to control whether current flows between the collector and emitter. In both cases, resistance is inserted to limit the amount of current through the base and the collector.
    • Open Switch: If the resistance is too large, no current passes.
    • Closed Switch: If the resistance decreases, the intensity increases, and current flows.
  • Transistor as a Temperature-Dependent Switch:
    • At ambient temperature, the current through the transistor base is zero, and the transistor is in cutoff; therefore, it does not conduct current, and the bulb does not shine (open switch).
    • As the temperature increases in the NTC, its resistance decreases, increasing the current flow (closed switch).
  • Function of the Potentiometer: If the potentiometer's resistance is close to 0, current will flow through it. But if the potentiometer resistance is very high, the current will take the other path.
  • Transistor as an Amplifier (Water Detector): Used to detect when a tank is full. A transistor amplifies the intensity of the current, allowing a small current to be detected when probes are placed in water.