Please enable JavaScript.

Coggle requires JavaScript to display documents.

ELECTRITICITY - Coggle Diagram

- - - - Resistors in series cause more resistance to the current. Combined resistance equals the sum of all resistances. Also called:  Efficient resistance  Total resistance
      - RT = R1 + R2 + R3 + … Rn
    - - The combined resistance is smaller than the smallest resistor.
    - - Steps to follow when solving mixed circuit A real circuit is usually a mix of series and parallel in one circuit  Divide the circuits to small parts.  Start with parts that do not affect other parts.  Simply the circuits as you go.
- - - - Batteries
        
        Transform Chemical energy to electrical energy
      - Solar cell
        
        Transform Solar energy to electrical energy
      - Dynamo / Generator
        
        Transform Kinetic energy to electrical energy
    - - Different charges - attract Same charges - repel
      - Electrostatics
        
        Produced by - friction . Detected by - electroscope .
    - - Current
        
        1) What is the definition of electric current? Electric current (I) – the rate of flow of charge (electrons). The amount of charge passing any point in a circuit in a period of time.
        
        2) What is the unit to measure electric current? Unit: [A] Ampere
        
        3) Who discovered current? Andre-Marie Ampere
        
        4) Which device do we use to measure current? Current is measured by ammeter (Ampere meter)
      - Voltage
        
        1) What is the definition of electric voltage? Voltage (V) – A potential difference between two points. We need energy to move the electrons between the atoms.
        
        2) What is the unit of voltage? Unit: [V] Volt
        
        3) Who discovered voltage? Alessandro Giuseppe Antonio Anastasio Volta
        
        4) Which device do we use to measure voltage? Voltage is measured by voltmete
      - Resistance
        
        Electrical resistance is like friction in a wire. It opposes the flow of charges in a circuit. Same as friction, it causes heating effect. The symbol of resistance is R . Unit: [Ω] - Ohm
        
        Superconductor - allow the charges to flow easily. Resistor - resist the flow of charges. Insulator - does not allow charges to flow through it.
        
        1) What is electrical resistance? Resistance opposes the flow of charges in a circuit.
        
        2) What is the unit of resistance? Unit: [Ω] Ohm
        
        4) What are the effects caused by electrical resistance? (What does resistance cause?) Resistance reduces the amount of charge that can flow in a conductor and cause heat.
        
        3) Who discovered resistance? George Simon Ohm
- - - - Capacitor
        
        Capacitor can store an electrical charge for a period of time. The larger the capacitance the more charge it can store.
        
        Applications of capacitors  Smoothing AC voltages into steady DC voltages.  Filtering electrical noises.  Timing applications.  Short term electrical memory.
      - Resistor
        
        Limit the level of currents that passes through it in order for other components to work properly
        
        The value of the resistor is marked on it by a color code .
        
        Resistors that work with high currents are physically bigger
      - Variable Resistor
        
        Resistor with changing resistance
      - Diode
        
        If connected the wrong way  no current flows.
        
        Need more than 0.7 Volts across a diode to "turn on" allowing current to flow.
        
        The diode has a very high resistance in one direction . The current can only flow in the other direction .
        
        Store an electrical charge for a period of time
      - LDR
        
        LDR (Light Dependent Resistor)
        
        LDR used to detect light levels. Their resistance changes according to light. In low light , LDR has high resistance. In bright light , LDR has low resistance
      - LED
        
        LED – Light Emitting Diode
        
        Works the same as diode , has light when current passes through it. Gives off light and are often used for indicator lights in electrical equipment such as computers and electric devices. Consume very small current (energy efficient).
      - Transistor
        
        Transistors have three leads: emitter, collector, base. The base controls the transistor. Transistor works as an electronic switch or an amplifier (increase current).
      - Ammeter
        
        Measure current (connected in series)
      - Thermistor
        
        Thermistors are used as temperature sensors , for example, in fire alarms. Their resistance changes according to temperature. At low temperatures , thermistors have high resistance. At high temperatures , thermistors have low resistance.
      - IC
        
        Integrated Circuits (IC)  microchip
        
        These are tiny circuits attached to a piece of silicon or chip in a plastic package. The circuits inside the package contain hundreds of tiny resistor, diodes, transistors etc. They are arranged in different configurations for specific purposes.
- - - - Ammeter is always connected in series Ammeter has very low resistance which doesn’t affect the current.
      - In series circuit the voltage of the batteries is the sum of all voltages VT = V1 + V2 + V3
      - The current is the same in every point of a series circuit. IT = I1 = I2 = I3
    - - The components are connected in branches. Voltmeter is always connected in parallel . Voltmeter has very high resistance which doesn’t affect the circuit because current can’t pass through it.
      - In parallel circuit, the voltage of the batteries is the same in every branch.
      - The current in the circuit is the sum of currents from all the branches. IT = I1 + I2 + I3