Physics

• An electric circuit is a closed loop path that allows electricity to flow.
• It consists of several basic components that work together to complete the circuit and allow current to flow
• The source is the component that provides the electrical energy to the circuit
• This is typically a battery or a wall outlet. The battery creates a potential difference (voltage) that pushes electrons through the circuit.
• The conductor is a material that allows electricity to flow through it easily.
• Wires made from metals like copper and aluminum are commonly used conductors in circuits. They provide a path for the electrons to flow from the source to the load.
• The load is the component that converts electrical energy into another form of energy, such as light, heat, or sound.
• Light bulbs, motors, and heaters are all examples of loads. The load determines the amount of current that will flow in the circuit.
• A control component is used to turn the circuit on and off or to change the amount of current flowing in the circuit.
• Electrical Connectors: These are physical devices that connect wires, cables, or circuit boards to transmit electrical signals or power.
• Board-to-board connectors:These connect two or more printed circuit boards (PCBs). They are often flat and ribbon-like, with many small contacts.
• Cable/wire-to-cable/wire connectors:These are used to join wires together. Examples include crimp connectors, twist-on connectors, and soldering.
• Cable/wire-to-board connectors:These connect wires to a PCB. They come in various forms, such as header pins, terminal blocks, and socket connectors.
• Electrical Power Connections: These refer to the way electrical service is delivered from the utility company to a building or residence and how it's distributed within the building itself.
• Single-phase connection:This is the most common type of connection for homes and small businesses. It uses two or three wires: a hot wire (carrying the electrical current), a neutral wire (completing the circuit), and sometimes a ground wire (for safety).
• Three-phase connection:Three-phase connections are used for industrial applications and large buildings that require more power. They use three hot wires and a neutral wire, providing a more efficient way to deliver high voltage and current.
• Multimeter:This is the most versatile tool for measuring various electrical properties.
• A typical multimeter can measure voltage (in AC or DC), resistance, and current.
• A multimeter usually has a selector switch to choose the function and range of measurement. It has probes that you touch to the circuit to make the measurement.
• oltmeter:A voltmeter is specifically designed to measure voltage (in AC or DC). It is essentially a high impedance device meaning it has very little resistance internally.
• Analog voltmeters use a needle moving across a scale to indicate voltage, while digital voltmeters display the voltage numerically on a screen.
• This ensures minimal interference with the circuit being measured. Voltmeters come in different types like analog and digital.
• Ammeter:An ammeter is used to specifically measure current flowing in a circuit. Unlike a voltmeter, an ammeter has very low resistance to minimize voltage drop across it and ensure accurate current measurement.
• Ammeters are typically connected in series with the circuit to measure the current flowing through it. Similar to voltmeters, ammeters also come in analog and digital types.
• Ohmmeter:An ohmmeter is a tool specifically designed to measure resistance of a component. It usually contains a small voltage source and measures the current flowing through the component under test.
• The resistance is then calculated based on Ohm's Law (R = V/I). Ohmmeters should not be used on live circuits as this can damage the meter or the component being measured.
• Magnets and compasses have a fascinating relationship based on the principles of magnetism and the Earth's magnetic field.
• This magnetic field is not perfectly aligned with the geographic poles, but it's close enough for compass navigation.
• A compass contains a magnetized needle free to rotate on a pivot point.
• This needle aligns itself with the Earth's magnetic field, so the north-seeking pole of the compass needle points towards the Earth's magnetic north pole.
• A magnet brought near a compass disrupts the Earth's magnetic field in its vicinity.
• The compass needle, being a magnet itself, will be attracted or repelled by the introduced magnet depending on the poles facing each other.

  • The north pole of the compass needle will be attracted to the south pole of the nearby magnet and vice versa.
  • Like poles (north-north or south-south) will repel each other.
• This disrupts the compass's ability to point towards true north and causes a deflection in its reading.
• A compass relies on the Earth's magnetic field for direction, not geographic north
• Strong magnets can interfere with a compass's accuracy by influencing its needle.
• When navigating with a compass, it's important to keep it away from magnetic objects like watches, phones, or other magnets to ensure accurate readings.
• The attraction arises due to the alignment of tiny magnetic domains within the material. These domains act like miniature magnets and can be influenced by an external magnetic field.
• Common examples of magnetic materials include iron, nickel, cobalt, some rare earth metals, and most steels.
• In non-magnetic materials, the magnetic domains are either randomly oriented or cancel each other out, resulting in no overall magnetic attraction.
• Some examples of non-magnetic materials include wood, plastic, rubber, aluminum, copper, gold, silver, and most non-ferrous materials (materials that don't contain iron).