Current, resistor LED

• Electricity works by showing how electrons move randomly between atoms in a copper wire

  
• In a circuit with a battery, electrons flow from the negative terminal to the positive terminal

  
• Everything is made up of atoms with moving electrons
• In some materials, electrons in the outermost shell are loosely bound and can transfer to other atoms, making them conductors like metals
• Metals, such as copper wires, are the best conductors of electricity
• When a wire is connected to a battery, the voltage forces the electrons to move in the circuit
• Electron flow is opposite to current flow (positive charge flow)
• Conventional current flow is the flow of charges in the circuit that powers up devices like lighting up a bulb or charging a cellphone
• Electric current (I) is the flow of charges or the number of charges flowing at a point per unit time
• A light-emitting diode (LED) is a semiconductor device that emits light when an electric current passes through it
• A multimeter is a device used to measure electrical properties such as voltage, current, and resistance
• LEDs require a forward current of 10-30mA and a forward voltage of 1.2-3.6V
• Most LEDs burn out if connected to a 9V battery without a resistor, as the resistor limits the current flowing through the LED
• To calculate the resistance needed to limit current to an LED, subtract the LED's voltage drop from the source voltage and divide by the desired current
• In a circuit with a 400Ω resistor connected to a 12V source, the current flowing through the resistor can be calculated using Ohm's Law
• For a 5V battery connected to light up an LED with 2V voltage drop and 14mA current, the resistance needed can be calculated using Ohm's Law
• When the potential difference across the diode exceeds its forward voltage (0.6V), the diode will not allow any more current to flow.
• A voltage drop occurs across the diode when it conducts.
• The maximum power that can be dissipated is determined by the size of the resistor used.
• The current through the diode is limited by the resistance.
• If the power rating of the resistor is exceeded, it may overheat or melt.
• Resistors are available in different sizes and colors, indicating their tolerance and wattage ratings.
• If the resistor value is too low, the LED may burn out due to excessive heat generated.
• The value of the resistor depends on the desired current level and the characteristics of the diode.
• Series circuits require all components to share the same pathway, while parallel circuits split into multiple paths.
• To prevent this, a series resistor is added to limit the current.
• If the current through the diode is too high, it may burn out or damage other components in the circuit.
• To prevent this, a series resistor must be added to limit the current flowing into the diode.