What is Electrostatic Discharge Protection?

Electrostatic Discharge refers to the transfer of charge between two objects.  Electrostatic Discharge is an issue of concern particularly in electronics where sensitive components can be destroyed  by the transfer of charges.  The transfer of charges can be caused due to dielectric breakdown or physical contact.  While the spark may appear small, the voltages generated are of the order of kilovolts.

Electrostatic Discharge Protection is a key aspect of electronics design.  Electrostatic Discharge protection by measures such as the use of anti-static packaging, controlling humidity and is achieved by painting the the use of specially designed pointed features called dischargers.  This is used in Aircrafts

In Petrochemical installations, where the risk of fire is present, electrostatic discharge can result in fire.

Posted by: Electrotechnik

What are the different parts of the the electrical system in a car ?

The modern car has a sophisticated electrical system.  Electricity is used for starting the engine.  Petrol engines need a spark for ignition which is provided by the spark plug.  Power is required for lighting.  Other equipments such as the engine starter, windshield wiper, the heater and the engine fan all require power for operation.

The power for the electrical system in a car comes from the battery.  The battery in turn is charged by the alternator which is driven by the engine.  The power developed by the Alternator is AC which is rectified and stored in the battery.  

The electrical system in the car has the negative grounded.  Each equipment, thus, requires only one wire which is the positive.  The negative of the battery is grounded to the car body.  The supply reaches the equipment through the wire and returns to the battery through the car body.  

The chief components of the electric system in a car are 
  1. Alternator
  2. Battery
  3. Starter
  4. Lights
  5. Wiper Motor
  6. Wiper liquid pump motor
  7. Windscreen wiper motor
  8. Fan Motor




Posted by: Electrotechnik

Jumper Cables in cars

Jumper cables in cars are used in cars to start a car whose battery is dead.  Car batteries can get drained due to a variety of reasons such as forgetting to switch of a light, Keeping the car unused for  long periods of time, ageing of battery, etc.  

Jumper cables are used to start the engine of a car by using the battery of another car.  Once started, the car's alternator will charge the dead battery.  The jumper cables is made of copper.  It is thick with special heavy duty clamps which can withstand currents of nearly 500 amperes.  

The positive of the live battery is connected to the positive of the dead battery.  The negative of the good battery should be connected to any metal bracket or any other metallic part of  the car to be jump started.  (Do not connected the negative of the good battery to the negative of the dead battery as this may result in sparks or a battery explosion.)

Keep both cars in neutral gear.  Start the good car and let it run for a few minutes.   Now start the car with the dead battery.  

The ignition key is turned and the starter motor runs with the power from the live battery.  Once the engine is started and runs for a few minutes, disconnect the cables in the reverse sequence.  The car with the dead battery should be kept running for at least 30 minutess to charge the dead battery.  



Posted by: Electrotechnik

Shielding in Instrumentation Cables

Shielding in Instrumentation Cables is vital in order to prevent stray coupling from other circuits nearby. 

When an instrumentation cables is laid beside a power cable, there are chances of  electromagnetic coupling taking place which can induce voltages in the instrumentation cable.  This can distort the signal in the instrumentation cable.  To prevent this, instrumentation cables are provided with a shield, usually made of aluminium.  

This shield magnetically shields the wires inside it.  This eliminates the chances of stray coupling.  The shielding needs to be grounded at one end.  Grounding the shield at two ends will cause grounding loops which can cause interference.


Posted by: Electrotechnik
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