Download Electrical Engineering Fundamentals: Comprehensive Q&A for Exams and more Exams Workplace Safety in PDF only on Docsity!
ATT Comp Test (FC) | QUESTIONS WITH CORRECT
VERIFIED SOLUTIONS 100% GUARANTEED PASS
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? - ✔✔Class C. Switches have resistance when closed, and resistance when open. - ✔✔minimum, maximum Type of switches - ✔✔Toggle, slide, rotary, and push button. Single or double pole and throw. Fuses and circuit breakers are both protection devices, however, while fuses are not , circuit breakers are. - ✔✔reusable Are capacitors circuit protection devices? - ✔✔No. A fuse will typically blow in about one second, while a could take 1-30 seconds. - ✔✔Fast acting; slow blow What happens to the current path if the wire in a fuse melts? - ✔✔It stops.
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? - ✔✔100. To induce a current, three things are needed: - ✔✔A conductor, a magnetic field, and relative motion Peak value is: - ✔✔The voltage or current value of a waveform at its maximum positive or negative points. How effective is AC vs DC? - ✔✔AC is only 70.7% as effective as DC. What is peak-to-peak voltage? - ✔✔Voltage of a sine wave measured from the most negative to the most positive point. What is the formula for finding a period of a wavelength? - ✔✔T = 1/f What is the period of a 100 Hz sine wave? - ✔✔0. Formula for a wavelength? - ✔✔(300 X 10^6)/f
What quantity cannot be measured directly or derived from oscilloscope? - ✔✔Resistance A/an is a component that has the ability to concentrate a magnetic field. - ✔✔inductor What are the three types of inductors? - ✔✔Air core, iron core, and variable. Inductance - ✔✔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.
Power supply rectifier - ✔✔Converts AC to pulsating DC. Power supply filter - ✔✔Changes pulsating DC to smooth DC. Power supply regulator - ✔✔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. What component changes color to indicate an element change is needed in dry air systems? - ✔✔Telltale oil filters. What type of cooling is used in sealed enclosures? - ✔✔Air-to-air. What cooling system uses chilled water for both standby and normal operation? - ✔✔Type 3. Signal tracing - ✔✔If no fault found after voltage or current measurements, next trace signal with a logic probe.
