Lecture Notes on Input and Output Devices

Flashcards summarizing the key input and output devices discussed in the lecture, including LDRs, thermistors, microphones, LEDs, buzzers, and relays.

Light-Dependent Resistor (LDR)

A device whose resistance decreases when exposed to sunlight and increases in darkness. Its resistance varies from approximately 10 MΩ in darkness to about 100Ω in bright sunlight.

Thermistor

A device whose resistance varies with temperature. A thermistor with a negative temperature coefficient decreases in resistance as temperature increases.

Microphone

A device that converts sound waves into electrical signals.

Light-Emitting Diode (LED)

A device that emits light when a current flows through it in one direction. It begins to conduct when the anode is about 1.8V more positive than the cathode.

Buzzer

A device that produces a sound when connected to a solid-state sound-producing circuit. It consists of an electromechanical or piezoelectric device.

Relay

A device that consists of a coil and switch contacts. The switch contacts are controlled by an electromagnet; when the electromagnet is energized, the relay becomes 'closed' (NC).