Alternating current: its electrical current which flow in all different directions at regular intervals or cycles. The current flows in power lines and the electricity travels from walls in homes. In Europe the cycles per second is 50 (frequency of 50 Hz) it’s cheap to change the voltage of the current. Direct current: its electrical current which flow in one direction.
The current which flow in a flashlight or another device which runs of batteries is direct current. Dc:Dc currents always flow in one direction and is able to flow though a conductor for example, wires and also it is able to travel through semiconductor and insulators:Ac: Ac current is current which flows in all different direction as shown in the graph sketched below: Task 1cElectric shocks happen when a person gets in contact with voltage which is high enough to become in contact with someone. The effect if has on people can be quite severe for instant if a person was to be electrocuted with a very high voltage then it could cause death as it effects the rhythm of the heart and can cause heart attacks. Electrical shocks can cause burns. If the voltage was not too high, then burns can be found just on the surface of the skin. But if a high voltage was to shock a person then it could cause internal burns.
Such as burns to the organs that can affect the heart. The burns which are caused by electric shocks can cause organ failure which results in death and if a person was to survive the healing process would be extremely long and painful. Moreover, neurological effect electric shocks also have. This is when electric shocks interfere with the nervous control mostly on heart and lungs. When electric shocks interfere with the nervous system it doesn’t in most cases leads to death but can make a person be unconscious fast.
It also, influences the chest when 50 or 60 Hz is passed through the chest. It results in ventricular fibrillation. This needs to be treated immediately as it can cause the heart muscle to beat fast and loose its normal rhyme. If too much is passed through the chest then it can immediately stop the heart from beating. The following are the most common effects of electric shocks:· A person is most likely to collapse · Muscle contractions which can lead to fractures, loss if consciousness or joint being dislocated. · Paralyze to the respiratory system and irregular heart beat or stop heart from beating completely.
Death of tissue at entry and exit points of the current. Presence of edema as the blood at the point semisolid and the muscle swell up.· Drop in blood pressure, can cause problems in the fluid and electrolyte balance can release myoglobin and it can results in kidney failure.
Fires are mostly started in mains wires (homes, buildings) or due to manufacture failure. Faulty outlets, equipment start fires and old outdated appliances. Others are started by problems in cords, receptacles and switches.
Cords that have been damaged should not be near floors, curtains and rugs as it is most likely to start off fires. And cords under rugs can cause fires which can be dangerous. Most the fires are started by people who do not follow the instructions of an electrical equipment. Extension leads can cause fire and portable heaters also start fires. The impact that fires have on humans is that it can cause severe burns which can cause the skin of the surface to bun and internal buns can be caused. This causes the body tissues to be scarred which means is dead and then the fibrous tissues is instead replaced with the dead tissue. Dc and Ac: Ac and dc both are harmful to the body but the symptoms differ according to the voltage if it is high then there is more risk than it was low voltage.
It also, effects on the amount of current, duration of flow and pathway current. It is said to be that ac current is more harmful to a human than dc because more dc currents are needed to make the same harmful effect that ac current would have. This is because more milliamps are required in DC as it is a flow of current in one direction so if a person was to get an electric shock from the hand or feet then it wouldn’t be so bad as it doesn’t cross the heart, but still the person would have a lot of internal burns which could lead to death. With AC it’s not as simple as the current flows in all directions so when a person is electrocuted with AC current then it is most likely the current has been to the heart which can stop the heart from working and lead to death. The series of contraction is dependent on the amount of frequency that is applied to the human body. Also, more milliamps are required from DC current then AC even if it is the same voltage.
uk/toolbox/electrical.htm http://www.healthguidance.org/entry/12834/1/The-Effects-of-Electric-Shock-on-the-Body.html https://en.wikipedia.org/wiki/Direct_current http://www.brighthubengineering.
com/power-plants/89792-ac-and-dc-shock-comparison/ https://www.quora.com/Which-is-more-dangerous-AC-or-DC-power Task 1d· To minimise the risk of electric shocks it’s important to reduce the voltage, portable equipment is powered by 110 voltage supply via transformer. Which are tapped on the earth so the max voltage between a live conductor and earth is restricted to 55v. Also, to minimise the risk it is essential to ensure fuses are fitted correctly. A fuse is a device which is made to protect high current. It does this by blowing up or cutting off when the current is increased the rated capacity also increases.
Fuses are made for specific equipment, so a fuse should only be used for that equipment. For example, a 3-amp fuses are used in equipment which require around 700 watts. Equipment that require more than that should not be used with a 3 amp plug as it can cause electric shocks or even fires. To avoid any electric shocks, it is important that a person reads the manufactures instructions to avoid any risk to the person itself and the equipment. To avoid any burns or shocks it is important that an extension lead is not overloaded because if it is then there is a high chance of it exploding.
When this happens, it can cause an electric shock either from the lead or from the equipment because extension leads are able to take a specific amount of current and when there is an overload it can be harmful for the person. To minimise this risk, it is important that people do not overload the lead and be careful of what electronics can be plugged in. · To avoid starting fires within the socket of an electronic device an earth wire should be used as it is the safety wire which is connected to the earth. It helps prevent fires or any AC/DC current through the external area of the plug.
It works by cutting off, when the live parts come across the earth wire then the fuse automatically blows or cuts any supply. Class 1 equipment have this earth wire. Class 2 have plugs which are double insulated and is shown by a double symbol. Class 2 equipment have no earth wires. The device of a class 2 has the basic and extra insulation.
Both can stop fires and electric shocks.