The 220V to 5V Power Module is a compact AC-to-DC converter that takes standard household wall voltage and steps it down safely to a steady 5 volts. This module is commonly used inside custom enclosures to power microcontrollers like Arduino, small relay boards, and low-power IoT devices directly from mains electricity.

The 1/4W Resistor 180 Ohm is a standard passive electronic component designed to limit electrical current flow in a circuit. It handles up to a quarter watt of power. This resistor is commonly used in LED lighting circuits, signal conditioning, and general prototyping to protect sensitive components from receiving too much voltage.

The 1/4W Resistor 20k Ohm is a standard through-hole component that offers twenty thousand ohms of electrical resistance to restrict current. It is rated for a quarter watt. This resistor is commonly used in analog signal processing, voltage divider networks, and biasing transistor circuits in various electronic projects.

The 1/4W Resistor 3.9k Ohm is a reliable passive electronic part used to control current and set specific voltage levels in a circuit. It handles up to a quarter watt. This resistor is commonly used in pull-up or pull-down configurations for microcontroller pins, audio equipment, and general hobbyist circuit building.