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HOW TO FACE VIVA VOCE EDC/WS LABS. Prof. K.APPA RAO ME(IISc),FIETE,MCSI. Email: apparao_kotha@hotmail.com Web site: www.freewebs.com/apparao_kotha Tel : 040-2774 9839, 040 3243 0039 (cell). COMMON QUESTIONS FOR EDC/WS LABS. WHAT IS THE DIFFERNECE BETWEEN
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HOW TO FACE VIVA VOCE EDC/WS LABS Prof. K.APPA RAO ME(IISc),FIETE,MCSI. Email: apparao_kotha@hotmail.com Web site: www.freewebs.com/apparao_kotha Tel : 040-2774 9839, 040 3243 0039 (cell)
COMMON QUESTIONS FOR EDC/WS LABS
WHAT IS THE DIFFERNECE BETWEEN THOERY AND PRACTICE ? Theory is abstract: Practical is specific and concrete. Example: Type: Carbon film CF Value : 1000 ohms Tolerance: 5 % Wattage: 1 watt. Style : axial. Size : 4 x 20mm…
BASIC COMPONENTS PASSIVE COMPONENTS R,L,C ACTIVE COMPONENTS D,Q,Z,FET,SCR etc. • COMMON QUESTIONS • SYMBOLS, PHYSICAL IDENTIFIATION • ELECTRICAL CHARECTERISTICS • VI CURVES, PARAMETERS ß, α, β, PIV, • RELATION BTWN PARAMETERS.
TOOLS USED NOSE PLIER, CUTTER, SOLDERING IRON etc INSTRUMENTS USED VOLT METERS,MILLI AMMETRS MULTIMETERS, DMM OSCILLOSCOPE, POWER SUPPLY, FUNTION GENERATOR etc.
QUESTIONS ON PASSIVE COMPONENTS *I HAVE ONLY 1/4 w RESITORS. I WANT 10K 1W. HOW CAN I MAKE ? SOLUTION: 2.5 K 1/4w RESITORS 4 IN SERIES. OR 40K 1/4w RESITORS 4 IN PARALLEL.
COLOR CODE OF RESISTORS. WHAT IS COLOR CODE FOR 1.5K 5 % (Br Gr, R , Gold) 82K 10% (Grey,R,Or Silver) 39 M 20 % (Or, Wh, Bl ) 2.2 OHM ? (R,R, Gold, Gold).
MEASUREMENTS ON PASSIVE COMPONENTS. • AN ELECTROLYTIC CAPACITOR • MFD measures 90 MFD. • IS IT ACCEPTABLE ? • YES • Electrolytic capacitors will have • Tolerance –20 % to + 40 %
A RESITOR IN DIODE CHARACTERISTIC EXPERIMENT AS SHOWN IS USED. What wattage rating is required ? Maximum current= 30/1=30ma Power dissipated in R= vxi=30x30 =900mw . Practical value 1watt Change V , max current find R & Wattage.
QUESTIONS ON AMMETERS AND VOLTMETERS WHAT IS INTERNAL RESISTANCE OF IDEAL AMMETER ? Ans: ZERO. IDEAL VOLTMETER ? ANS : INFINITY. why ? justify *
QUESTIONS ON MULTIMETRS, DMM IS ANALOG MULTI DC OR AC METER? HOW SEVERAL RANGES ARE ACHEIVED? HOW CAN YOU CONVERT AMMTER TO VOLTMETER ? WHAT IS LED / LCD ? WHAT CAN DMM MEASURE? WHAT DO U MEAN BY 3 ½ DIGIT DMM?
SPECIFIC QUESTIONS TO WORK SHOP LAB…MATERIALS WHAT IS PCB ? WHAT IS DICLAD,SINGLE CLAD/ WHAT IS CHEMICAL USED FOR ETCHING ? WHAT DRILL BIT HAVE USED FOR ‘R’. WHAT IS SPEC OF SOLDERING IRON. WHAT IS SOLDER MADE OF? WHAT IS FLUX ?WHY DO U USE ? TYPES OF RESISTORS ,CAPACITORS,INDUCTOR? SWICTHES,FERRITE CORES,KNOBS.
COMMON QUESTIONS TO EDC/WORK SHOP LAB…INSTRUMENTS OSCILLOSCOPE REGULATED POWER SUPPLY FUNCTION GENERATORS MULTIMETER,DMM DC MOVING COIL V,ma meters.
KNOWLEDGE OF ELECTROMECHANICAL COMPONENTS. FUSE, fast blow off/slow blow off. function,construction. What is fuse electrically? BINDING POST,SOCKETS,KNOBS, BANANA PLUGS,BNC,CONNECTORS. WIRES/CABLES…S/S,MULTI STRAND. SHIELDED CABLES,HOOK UP WIRES.
KNOBS: screw,collet, concentric, pointed, dials etc.for ¼,1/8 inch. SWITCHES: spst,dpst,sping loaded, rotary, slide,toggle,lever, etc.. TRANSFORMERS: power,audio,radio, pulse, winding wires,en cu wires. Coils: air core, rf, bifilar, RELAYS:function. HARDWARE: screws,nuts sizes(BA/mm),head styles. slot/star types.
KNOWLEDGE OF OSCILLOSCOPE SINGLE/DUAL TRACE modes XY, component tester modes. Band width,rise time relation. Uses: BLOCK Diagram of CRO. Double beam/dual trace Why sweep is saw tooth?
SHOW YOUR KNOWLEDGE IN REPORT ? How ? ? VERY SIMPLE … Make it more practical in aim, apparatus, procedure, description, curves, and choosing measurement points. see a simple example.
AIM: forward,reverse characteristics of given diode under its ratings. APPARATUS: Components: Si diode 1N 4007…. 1no. CF resistor 1K 5 % 1w..1no. insruments: DC regulated power supply0-30v..1no Dc moving coil milli ammeter 30mafsd. 1no 3 ½ digit DMM LCD type… 1no. others: Bread board, S/S hook up wires.
IMPORTANT HINTS. TALK POLITELY & CONFIDENTLY. EXPLAIN WITH FIGURES IF U CAN. BE PRECISE AND SHORT. DO NOT BE IN HURRY TO ANSWER. YOU CAN DO WELL.
ALL THE BEST.. BE PRACTICAL… GOOD LUCK.. Prof. K.Appa Rao.