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93 Cards in this Set
- Front
- Back
Alternating Current |
Current that continually changes in value and periodically reverse its direction. |
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Wave Forms |
Graphical representation of how voltage and current changes in amplitude and direction over a period of time. |
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Sine Wave |
The most common type of AC wave form. |
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Cycle |
The complete representation of a sine wave throughout 360 degrees. |
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Peak Voltage |
The absolute voltage value from the zero volt axis to the peak of either alternation (90 degrees for positive peak, 270 for negative peak). |
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Peak-to-Peak Voltage |
This is the absolute voltage value from the negative peak to the positive peak. |
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Root-mean-square Voltage |
The most common aspect of AC voltage. -This value is calculated using the root-mean-square of a sine wave. -This voltage value identifies an equivalent DC voltage. |
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Three voltage aspects of AC |
Peak voltage, peak-to-peak voltage, and root-mean-square voltage. |
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Frequency |
Frequency is defined as the number of 360-degree sine waves per second. Also known as simply cycles per second |
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Frequency calculation |
F= 1/t T=1/f |
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Common Frequency ranges within 15 Hz to 10 Hz |
Audio: 15-20 Hz Radio: 20kHz - 300kHz Microwave: 1 GHz - 300 GHz Optics: 300 GHz-10 to 17th GHZ X-rays: 10 to 17th GHz - 10 to 23rd GHz |
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Wavelength |
The physical length of one cycles or the distance the electromagnetic wave travels over the time of one cycle. Electromagnetic wave travels at the constant velocity of 300 million meters per second. |
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In-phase |
Three requirements that must exist for sine wave to be considered in-phase. Same frequency Reach their peaks Pass through zero axis at the same time |
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Out-of-Phase |
If any of the three requirements for the sine waves are not met, they are considered out-of-phase. This can cause problems in telecommunications. |
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Matter |
All matter is made of interconnecting atoms. Atoms have a nucleus containing protons, neutrons and at least one orbiting electron. |
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Coulombs Law of Charges |
It is the positive charge of the proton that keeps the electron from leaving the atom. -Like charges repel -Opposite charges attract |
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Shells
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Electrons orbit the nucleus of an atom in what are referred to as shells. |
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Valence Electrons |
The electrons in the outermost orbit. -most easily removed because farthest from proton -have weakest attraction |
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Movement of electrons from atom to atom
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This is known as electron flow, current flow, or electric flow. |
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Conductor |
Is a material whose atomic structure is such that the valence shell contains less than half the number of electrons for that particular shell. -Conductors facilitate current flow. |
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Insulator |
Is any material whose atomic structure is such that the valence shell has more than half the required electrons for that particular shell. -Insulators inhibit current flow. |
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Direct Current (DC) |
Current which flows in one direction. |
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Symbol for current flow |
Symbol is I -Current flow is measured in amperes. |
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Frequency of standard American household |
Frequency of 60 Hz |
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Three requirements for current flow |
Voltage source, conductor, and continuity |
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Voltage |
Voltage is the electrical energy causing electrons to move from one atom to another. Voltage exists where there is a difference in potential or when one side of an electrical component is more positive than another. |
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Resistance |
Opposition to current flow. -Measured in Ohms. -Symbol =R |
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Resistor |
Designed to oppose current flow. |
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Power |
The ability to do work over a given period of time. -Also defined as the rate of work. -Measures in watts. -Symbol =P. |
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Ohm's Law |
Applies to all electronics. -The current is directly proportional to voltage (voltage increase, current increase) -The current is inversely proportional to resistance (resistance increase, then current decreases). |
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Fixed resistor |
Permanently introduce a specific amount of resistance into an electronic circuit. |
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Load device |
Anything that uses current to produce work such as a resistor, light bulb, or computer. |
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I |
Current I=E/R |
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E |
Voltage E=(I)(R) |
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R |
Resistance R=E/I |
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P |
Power equals current multiplied by voltage. P=(I)(E) |
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Total Resistance |
Rt=R1+R2+R3 The sum of all resistor values in the series circuit. |
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Total Current |
It=Ir1=Ir2=Ir3 Total current is the same at each point in the series circuit. Ir1 refers to the current dropped by resistor #1. |
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Ea=Er1+Er2+Er3 |
Kirchhoff's Voltage law which paraphrased means the applied voltage equals the sum of all voltage drops in a series circuit. Er1 refers to the voltage measured across resistor #1. |
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Four basic properties of series circuits. |
(EIRP) E-Voltage I-Current R-Resistance P-Power |
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Series circuit |
CurrenIn a series circuit current is common and voltage is divided. |
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Parallel DC Circuit Calculations |
Current is not common in parallel. Voltage is common in parallel. |
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Parallel DC Circuit calculations |
1. Total resistance equal the reciprocal of the sum of 1 divided by each resistor value in the circuit. 2. Kirchhoff's Current Law provides the formula for current, which shows total current (It) equals the sum of all branch currents in all circuits. 3. Voltages in the circuit are always equal to and directly proportional to the applied voltage. |
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Series-Parallel DC Circuit Calculations |
Is simply a group of parallel resistors connecting in a series with other resistors. |
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Series-Parallel DC Circuit Calculations |
Step 1. Findthe RE (equivalent resistance) of the parallel branches then draw anequivalent series circuit. In Figure 1-24, R2 and R3 arethe parallel branches. By using the formula for solving parallel circuits, wecan get an RE of 6 kΩ. |
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Series-Parallel DC Circuit Calculations
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Step 2. Add REto the series resistance (R1) to get Rt [MJG1] = R1 + RE = 2 kW + 6kW= 8 kW
Step 3.Calculate It using Ohm’s Law: I = E/R = It = = 3 mA Step 4. Calculatethe voltage drop across the series resistor and equivalent resistor RE: ER1 = It ´ R1= 3 mA ´2 kW= 6V ERE = It ´ RE= 3 mA ´6 kW= 18V The sum of the two voltage drops equals the appliedvoltage (Kirchhoff's voltage law): Ea = ER1 +ERE = 6V + 18V = 24V Step 5. Calculatebranch current using ERE for the parallel branches: and IR2 = = 1 mA IR3 = = 2 mA Total current equals the sum of the branch currents(Kirchhoff’s current law): It = IR2 + IR3 = 1 mA+ 2 mA = 3 mA Step 6. Calculate power dissipation PR1 =IT ´ER1, PR2 = IR2 ´ ER2, and PR3= IR3 ´ ER3. Total power dissipated equals the sumof the power dissipated by each resistor. Pt = It´Ea = 3 mA ´ 24V = 72 mW [MJG1]Aversion #6 |
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Series-Parallel Circuit troubleshooting |
Shorted resistor: All current will be diverted through the short and all current with flow through R3. Open resistor: If any parallel resistor opens, the branch will not have continuity. |
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Electrostatic Discharge |
Is the transfer of charge between bodies at different electrical potentials. Electrostatic discharge can charge the electrical characteristics of a semiconductor device, degrading or detroying it. Electrostatic discharge may also upset the normal operation of an electronic system, causing equipment malfunction or failure. |
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Static Electricity |
An electrical charge caused by an imbalance of electrons on the surface of a material. -This imbalance of electrons produces an electric field that can be measured and can nifluence other objects at a distance by transferring energy. -Electrostatic can be costly and dangerous in the technological age. |
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Cost of ESD (Electro static discharge) |
Cost money, loss of production time, repair, rework, shipping, labor, and overhead. -Charged surfaces can attract and hold contaminants. |
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How to reduce ESD |
1. Handle all ESDS items at an approved static control station. 2. Transport and store all ESDS items in static shielding and non-charge generating packages or containers. |
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Motherboard |
The main circuit board is a desktop computer and provides all the interconnections for all necessary parts and associated protocols. |
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ATX |
The form factor replacement for the older AT and baby AT form factors. Created in 1995, rotated orientation of motherboard by 90 degrees. |
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Micro ATX |
Smaller variant of ATX, compatible with most ATX cases, however has fewer expansion slots. |
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BTX |
Has single thermal module both cooling the processor and creating stream of air to cool other components. Designed for optimal air flow through case. |
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Central Processing Unit |
The main component in a computer that interprets computer program instructions and processes data. -Made up of arithmetic logic unit, control unit, and registers. |
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Pin Grid Array vs. Land Grid Array |
Mishandling or misalignment can bend pins, while land grid contact pins avoid this issue. |
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Arithmetic Logic Unit |
Is a digital circuit that calculates an arithmetic operation and logic operations between two numbers. |
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Control Unit |
Part of the CPU that directs its operation. |
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Registers |
A small amount of very fast computing memory used to speed the execution of computer programs by providing quick access to commonly used values. |
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CPU Heatsinks |
Keeps CPU from getting too hot, a term for a component or assembly that transfers and dissipates heat generated within a solid material. |
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System clock |
Provides the timing source/reference for all devices to work, typically a quartz crystal that oscillates at a fixed frequency. |
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Types of Buses |
Serial Bus: one single path for data signal flow Parallel Bus: Multiple paths for data signals. |
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Bus Functions |
Address Bus Data Bus Control Bus |
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Address Bus |
An address is defined as a label, symbol, or other set of characterised used to designate a location or register where information is stored. |
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Voltage is common in |
A parallel series |
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Shorts in series circuit |
no resistance, max current |
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Open in series circuit |
no current, no connectivity |
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Form Factor |
The size and shape of the motherboard |
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Types of CPUS |
PGA and CGA |
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Static ram is |
More expensive because is is smaller and has more memory per chip |
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Volatile |
All memory erases after computer turns off |
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Non-volatile |
Memory stays after PC turns off |
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Device Drivers |
Software component of hardware devices, can be updated or rolled back to previous versions. |
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Sound card |
Goes into any PCI or open expansion slot. |
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NIC |
Operates at layer one, the physical layer, providing physical access to networking medium And layer 2, the data layer providing low-level addressing system through the MAC address. |
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Laser printing 7 steps |
Processing Conditioning Exposing Developing Transferring Fusing Cleaning (purple cows eat dirty trailmix from cars) |
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Parts of the Platter |
Magnetic platter, read-write heads, arm, and motor. |
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Data Storage/Retrieval |
Retrieved from tracks and sectors. |
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Interrupt requests |
Signals that cause the hardware to transfer program control to the CPU. |
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Data Storage/Retrieval |
Data is stored on each platter in a series of known, standard locations called tracks, sectors and clusters. |
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Flash Drive |
Works the same as EPROM |
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Power Supply |
A power supply (PSU)converts 110/120 or 220/240 V AC current to usable, low voltage DC power
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Color Coding |
Black is ground Orange 3.3 Red 5 Yellow 12 |
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Power Supplied: P1 |
P1 powers motherboard has 20-24 connectors 4 pin molex power older hard drives 15 pin SATA power new SATA hard drives and other devices |
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About ATX |
PSUs have form factors that correspond to ATX motherboard |
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Conductors/Facilitators |
Conductors facilitate current flow Insulators inhibit current flow |
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Series Circuit |
Current is common, voltage is divided. |
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Sanitizing |
Removes classified information |
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When is sanitizing complete? |
6 passes |
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UPS Conversion |
Converts AC to DC then to AC |
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AFI 32-1062 |
Provides operating, maintaining, and accounting for all electrical power. |
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Trouble Shooting Process |
I E T E V D I eat truffles every valentines day |