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ATT Comp Test| Answered 100% Correctly
What is electrical Shock? A sensation and muscular spasm when electric current passes through the body. What is a GFCI? Ground Fault Circuit Interrupter (automatically shut's off electrical flow in the event of an overload) TS Transformers Open: T doesn't generate output V Short: could be partial which would then change number of coils so Ep would change or Es What is voltage Potential of electric energy; pressure of electrons pushing away from each other. Current is defined as __________________________. a flow of electric charge What are some factors affecting shock? Amount of current, path of current, amount of body resistance, and length of time current flows in body What is not a primary factor in severity of an electric shock? The general health of the victim. Ways to prevent shock?
Isolate, insulate & ground What is the minimum AC current required to cause severe muscle contractions? 12 mA How much more DC is required to freeze the body than AC? 5 times more What types of burns are there? Electrical burns, arc burns, and thermal contact burns Electrical burns are what? Electrical current flowing through tissue or bones Arc burns are what? Electrical current flowing through tissue or bones Thermal contact burns are what? When skin comes in contact with hot surfaces of overheated electrical conductors Factors of electrical accidents Unsafe equipment, unsafe environment, and unsafe work practices What should you do first if someone has been shocked? Remove the victim from the source. What type of protection is worn when use of a tool produces sparks and debris? Safety goggles. What category includes electrical fires?
voltage drop The difference in voltage across an electrical device that has current flowing through it. Applied voltage Sum of all voltage drops in the circuit. Faults in series are: Open, Short, Changed value What are the four basic TS steps? A)Analyze circuit B)Check Setup C)Calculate/measure values D)Check Results What fault provides no resistance to current flow? A short. What fault causes resistance to increase or decrease? A changed value. What fault causes current to stop? An open. In a series parallel open, current ___________ in parallel and series, while the voltage drop ____________ due to an ______________ in total resistance.
decreases; increases; increase TS procedures should be __________ and ____________. logical; systematic An open wire will measure ___________ resistance. maximum Current is measured in an open circuit when the leads are placed in what way? Across the open. Shorts have a voltage drop of ____. zero What three characteristics needed for sine wave? Frequency, period, wavelength. Wavelength is what? The actual distance between the beginning and end of a cycle. What is induction? The generation of AC current by passing a conductor through a magnetic field. How many cycles per second is a frequency of 100 Hz?
To induce a current, three things are needed: A conductor, a magnetic field, and relative motion Peak value is:
basic unit is Henry (H, big so usually mH), ability of conductor to induce(generate) V when cut by mag F. What factors determine the amount of inductance? Number of turns of wire, distance between windings, cross sectional area of core, and permeability of core. What is a capacitor made of? Two parallel plates separated by a dielectric. What are the types of capacitors? Non polarized, electrolytic, and variable. What is capacitance? The ability of a conductor to store energy in the form of electrically separated charges. What factors affect capacitance? Plate size, distance between plates, and dielectric material. What occurs when positive current hits a capacitor plate? It builds up a positive charge. Transistors Control a large current with a small current. Emitter
Heavily doped so it emits larger # of current carriers inside semi conductive material. Base Very thin and lightly doped, allows most current carriers to pass between emitter to collector. Collector Moderately doped, largest area, dissipates heat. Receives most current carriers. What two types of signals applied to transistors? Input and bias. An open in the primary of a transformer won't do what? Produce current in the secondary. An open in the secondary of a transformer prevents an output voltage in _____ _________ ________________. the open secondary A partial short in the primary of the transformer will _____________ secondary voltage. Increase A complete short in the secondary transformer will ____________ secondary voltage. eliminate
Maintains output voltage. Power supply protection Prevents damage to power supply if load shorts. Which two parts of a power supply are optional? Regulator and protection. There are three types of rectifiers. What are they? Half wave, full wave, bridge. Describe a half wave rectifier. 1 diode. Looks like a filter. What is the output frequency of a half wave rectifier? Same as input. How many diodes does a full wave rectifier have? Two. Why is full wave more efficient than half wave? It uses the entire input. What is the output frequency of both a full wave and bridge rectifier? Twice the input frequency (180° out of phase). How many diodes does a bridge rectifier have? Four. Which internal IC can produce signals that show three different volt levels?
Short between pins other than VCC and ground TS relays and switches, sealed component and 2 types just replace entire component, faulted mag coils and contacts relays and swithces contacts TS, NO NC coned or cratered (burned and pitted) burnishing tool, prevents out when E and prevents out when de E. Electrical TS common faults open or short, LED will not illuminate if open or shorted Procedure for electrical TS is cot op normal? measure Vout observe LEDs Setup okay? check inputs okay Calc/measure check results (repair fault and check again) What are three steps for repairing digital systems? Fault detection, isolation, and correction. An IC's internal malfunctions make its operation _______________. unpredictable What are the three most common IC faults? Opens, shorts, and faulty power supply units.
A step-down transformer _____________ output voltage in the secondary. decreases A step-up transformer ___________ output voltage in the secondary. increases
