Static electricity is the buildup of an electric charge resting on a surface. This buildup may zap a component and cause damage. This is known as electrostatic discharge (ESD). ESD can be destructive to the electronics in a computer system.
Static electricity can build up on you as they walk across a carpeted floor. When you touch another person, you both receive a shock. If the discharge causes pain or makes a noise, the charge was probably above 10,000 volts.
At least 3,000 volts of static electricity must build up before a person can feel ESD, but less than 30 volts of static electricity can damage a computer component.
Preventing ESD Damage
Keep all components in antistatic bags until you are ready to install them.
Use grounded mats on workbenches.
Use grounded floor mats in work areas.
Use antistatic wrist straps when working on computers.
Climate affects computer equipment in a variety of ways:
If the environment temperature is too high, equipment can overheat.
If the humidity level is too low, the chance of ESD increases.
If the humidity level is too high, equipment can suffer from moisture damage.
Teaching Strategy: ESD is one of the potential dangers to computer equipment and data. Climate impacts probability of ESD. Devices that can protect the equipment from ESD damage include; antistatic mats, antistatic bags, and antistatic wrist straps.
Antistatic bags are somewhat electrically conductive, to eliminate differences in potential across the circuit boards stored in them. They are typically colored to indicate this.
If the conditions are conducive, consider letting a student demonstrate static electricity.
Tuesday, September 23, 2008
Power Supplies-For IT Essentials Students
The power supply converts alternating-current (AC) power coming from a wall outlet into direct-current (DC) power, which is a lower voltage. DC power is required for all of the components inside the computer.
Most connectors today are keyed connectors. Keyed connectors are designed to be inserted in only one direction. Each part of the connector has a colored wire with a different voltage running through it. Different connectors are used to connect specific components and various locations on the motherboard:
Molex connector is a keyed connector used to connect to an optical drive or a hard drive.
Berg connector is a keyed connector used to connect to a floppy drive. A Berg connector is smaller than a Molex connector.
A 20-pin or 24-pin slotted connector is used to connect to the motherboard. The 24-pin slotted connector has two rows of 12-pins each, and the 20-pin slotted connector has two rows of 10-pins each.
A 4-pin to 8-pin auxiliary power connector has two rows of two to four pins and supplies power to all areas of the motherboard. The 4-pin to 8-pin auxiliary power connector is the same shape as the main power connector, but smaller.
Older standard power supplies used two connectors called P8 and P9 to connect to the motherboard. P8 and P9 were unkeyed connectors. They could be installed backwards, potentially damaging the motherboard or power supply. The installation required that the connectors were lined up with the black wires together in the middle.
NOTE: If you have a difficult time inserting a connector, try a different way, or check to make sure there are no bent pins or foreign objects in the way. Remember, if it seems difficult to plug in any cable or other part, there is something wrong. Cables, connectors, and components are designed to fit together snugly. Never force any connector or component. Take your time and make sure that you are handling the hardware correctly.
Most connectors today are keyed connectors. Keyed connectors are designed to be inserted in only one direction. Each part of the connector has a colored wire with a different voltage running through it. Different connectors are used to connect specific components and various locations on the motherboard:
Molex connector is a keyed connector used to connect to an optical drive or a hard drive.
Berg connector is a keyed connector used to connect to a floppy drive. A Berg connector is smaller than a Molex connector.
A 20-pin or 24-pin slotted connector is used to connect to the motherboard. The 24-pin slotted connector has two rows of 12-pins each, and the 20-pin slotted connector has two rows of 10-pins each.
A 4-pin to 8-pin auxiliary power connector has two rows of two to four pins and supplies power to all areas of the motherboard. The 4-pin to 8-pin auxiliary power connector is the same shape as the main power connector, but smaller.
Older standard power supplies used two connectors called P8 and P9 to connect to the motherboard. P8 and P9 were unkeyed connectors. They could be installed backwards, potentially damaging the motherboard or power supply. The installation required that the connectors were lined up with the black wires together in the middle.
NOTE: If you have a difficult time inserting a connector, try a different way, or check to make sure there are no bent pins or foreign objects in the way. Remember, if it seems difficult to plug in any cable or other part, there is something wrong. Cables, connectors, and components are designed to fit together snugly. Never force any connector or component. Take your time and make sure that you are handling the hardware correctly.
Computer Cases-For IT Essentials Students
A computer case contains the framework to support the internal components of a computer while providing an enclosure for added protection. Computer cases are typically made of plastic, steel, and aluminum and are available in a variety of styles.
The size and layout of a case is called a form factor. There are many types of cases, but the basic form factors for computer cases include desktop and tower. Desktop cases may be slimline or full-sized, and tower cases may be mini or full-sized.
Computer cases are referred to in a number of ways:
Computer chassis
Cabinet
Tower
Box
Housing
In addition to providing protection and support, cases also provide an environment designed to keep the internal components cool. Case fans are used to move air through the computer case. As the air passes warm components, it absorbs heat and then exits the case. This process keeps the components of the computer from overheating.
The size and layout of a case is called a form factor. There are many types of cases, but the basic form factors for computer cases include desktop and tower. Desktop cases may be slimline or full-sized, and tower cases may be mini or full-sized.
Computer cases are referred to in a number of ways:
Computer chassis
Cabinet
Tower
Box
Housing
In addition to providing protection and support, cases also provide an environment designed to keep the internal components cool. Case fans are used to move air through the computer case. As the air passes warm components, it absorbs heat and then exits the case. This process keeps the components of the computer from overheating.
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