Friday 29 December 2017

Do you know?

  • Banging your head against a wall burns 150 calories an hour.
    • In the UK, it is illegal to eat mince pies on Christmas Day!
    • Pteronophobia is the fear of being tickled by feathers!
    • When hippos are upset, their sweat turns red.
    • A flock of crows is known as a murder.
    • “Facebook Addiction Disorder” is a mental disorder identified by Psychologists.
    • The average woman uses her height in lipstick every 5 years.
    • 29th May is officially “Put a Pillow on Your Fridge Day“.
    • Cherophobia is the fear of fun.
    • Human saliva has a boiling point three times that of regular water.
    • If you lift a kangaroo’s tail off the ground it can’t hop.
    • Bananas are curved because they grow towards the sun.
    • Billy goats urinate on their own heads to smell more attractive to females.
    • The person who invented the Frisbee was cremated and made into a frisbee after he died!
    • During your lifetime, you will produce enough saliva to fill two swimming pools.
    • If Pinokio says “My Nose Will Grow Now”, it would cause a paradox. Details here.
    • Polar bears can eat as many as 86 penguins in a single sitting. (If they lived in the same place)
    • King Henry VIII slept with a gigantic axe beside him.
    • Movie trailers were originally shown after the movie, which is why they were called “trailers”.
    • An eagle can kill a young deer and fly away with it.
    • Heart attacks are more likely to happen on a Monday.
    • If you consistently fart for 6 years & 9 months, enough gas is produced to create the energy of an atomic bomb!
    • in 2015, more people were killed from injuries caused by taking a selfie than by shark attacks.
    • The top six foods that make your fart are beans, corn, bell peppers, cauliflower, cabbage and milk!
    • There is a species of spider called the Hobo Spider.

    Thursday 28 December 2017

    Electric circuit symbols

    Electrical Symbols
    Symbol
    Component name
    Meaning
    Wire Symbols
    Conductor of electrical current
    Connected crossing
    Wires are not connected
    Switch Symbols and Relay Symbols
    Disconnects current when open
    Selects between two connections
    Pushbutton Switch (N.O)
    Momentary switch - normally open
    Pushbutton Switch (N.C)
    Momentary switch - normally closed
    DIP switch is used for onboard configuration
    Relay open / close connection by an electromagnet
    Close connection by jumper insertion on pins.
    Solder to close connection
    Ground Symbols
    Used for zero potential reference and electrical shock protection.
    Connected to the chassis of the circuit
     
    Resistor Symbols
    Resistor(IEEE)
    Resistor reduces the current flow.
    Resistor (IEC)
    Adjustable resistor - has 3 terminals.
    Adjustable resistor - has 2 terminals.
    Trimmer Resistor
    Preset resistor
    Thermistor
    Thermal resistor - change resistance when temperature changes
    Photoresistor / Light dependent resistor (LDR)
    Photo-resistor - change resistance with light intensity change
    Capacitor Symbols
    Capacitor is used to store electric charge. It acts as short circuit with AC and open circuit with DC.
    Adjustable capacitance
    Inductor / Coil Symbols
    Coil / solenoid that generates magnetic field
    Includes iron
     
    Power Supply Symbols
    Generates constant voltage
    Generates constant current.
    AC Voltage Source
    AC voltage source
    Electrical voltage is generated by mechanical rotation of the generator
    Generates constant voltage
    Generates constant voltage
    Generates voltage as a function of voltage or current of other circuit element.
    Generates current as a function of voltage or current of other circuit element.
    Meter Symbols
    Measures voltage. Has very high resistance. Connected in parallel.
    Measures electric current. Has near zero resistance. Connected serially.
    Measures resistance
    Measures electric power
    Lamp / Light Bulb Symbols
    Lamp / light bulb
    Generates light when current flows through
    Lamp / light bulb
    Lamp / light bulb
    Diode / LED Symbols
    Diode allows current flow in one direction only - left (anode) to right (cathode).
    Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage
    Schottky diode is a diode with low voltage drop
    Variable capacitance diode
     
    LED emits light when current flows through
    Photodiode allows current flow when exposed to light
    Transistor Symbols
    Allows current flow when high potential at base (middle)
    Allows current flow when low potential at base (middle)
    Made from 2 bipolar transistors. Has total gain of the product of each gain.
    N-channel field effect transistor
    P-channel field effect transistor
    N-channel MOSFET transistor
    P-channel MOSFET transistor
    Misc. Symbols
    Electric motor
    Change AC voltage from high to low or low to high.
    Electric bell
    Rings when activated
    Produce buzzing sound
    The fuse disconnects when current above threshold. Used to protect circuit from high currents.
    Contains several wires. Usually for data / address.
    Optocoupler isolates connection to other board
    Converts electrical signal to sound waves
    Converts sound waves to electrical signal
    Amplify input signal
    Operates with hysteresis to reduce noise.
    Converts analog signal to digital numbers
    Converts digital numbers to analog signal
    Used to generate precise frequency clock signal
    Antenna Symbols
    Transmits & receives radio waves
    Two wires simple antenna
    Logic Gates Symbols
    Outputs 1 when input is 0
    Outputs 1 when both inputs are 1.
    Outputs 0 when both inputs are 1. (NOT + AND)
    Outputs 1 when any input is 1.
    Outputs 0 when any input is 1. (NOT + OR)
    Outputs 1 when inputs are different. (Exclusive OR)
    Stores one bit of data
    Connects the output to  selected input line.
    Connects selected output to the input line.

    Do you know?

    Banging your head against a wall  burns 150 calories  an hour. In the UK, it is illegal to eat mince pies on Christmas Day! Pteron...