Electrical Resistance

JMJ MARIST BROTHERS NOTRE DAME OF DADIANGAS UNIVERSITY MARIST AVENUE, planetary SANTOS CITY MULTITESTER Instrumentation and Control CpE 511 surname KURT RUSSEL C. CHUASeptember 01, 2012 CYNTHIA C. GONZAGADate of Submission INSTRUCTOR ENGR. JAY S. VILLAN, MEP-EE Introduction A multitester or multimeter is a art which outhouse be employ to gather entropy about galvanizing circuits. A base multitester shtup cake foe, emf, and continuity bandage more advanced versions may be able to provide additional data.This implement can be very reclaimable to find around the house, and anyone who plans on doing electricalal repairs should most definitely use a multitester for safety reasons. Multitesters can be used with the authoritative off or on in most cases, although victimization the device with the received on can sometimes result in damage to the device. possible action Ammeters are employed for measuring stream in a circuit and affiliated in series with the circuit. A s ammeter is affiliated in series, the voltage befuddle across ammeter terminals should be as baseborn as possible.This requires that the impedance of the ammeter should be as first gear as possible. The current coil of ammeter has low current carrying capacity whereas the current to be measured may be kind of postgraduate. For this reason a low tube is connected in parallel to the current coil. Voltmeters are employed to measure the dominance difference across any ii points of the circuit these are connected in the parallel to the circuit. The resistance of voltmeter is kept very high by connecting a high resistance in series of the voltmeter with the current coil of the instrument.The actual voltage drop across the current coil of the voltmeter is except a fraction of the total voltage applied across the voltmeter which is to be measured. An ohmmeter is a measuring instrument used to measure the resistance placed among its leads. The resistance reading is indicated th rough a robotlike meter travail which operates on electric current. The ohmmeter must then have an immanent source of voltage to create the unavoidable current to operate the movement, and also have appropriate ranging resistors to allow just the secure amount of current through the movement at any given resistance.One major(ip) problem with this design is its reliance upon a stable battery voltage for absolute resistance reading. If the battery voltage decreases, the ohmmeter home will lose accuracy. Conclusion deflection from using devices lots(prenominal) asmultitester, the resistance value of aresistor can be determined by its seeming coding. There are small differences between measured and color coded values of the resistances. These differences may be caused by some factors such as the multitester used in the audition and some mistakes made by the experimenters.It is much easier to read the resistance value of a resistor through a digital multitester than by using a n analog multitester and by color coding. In addition, in using an analog multitester, you have to first contract the range of the resistance and make the zero-ohm limiting in each and every reading. In that case, that is the only time youcan flummox the resistance value after aslight inconvenient process. Pictorial reckoning For Ammeter * 0. 25A R1=99mV0. 25A R1= 0. 96 ? * 25mA R2=99mV25mA-R1 R2= 3. 564 ? * 2. 5mA R3=99mV2. 5mA-R2-R1 R3= 35. 64 ? For DC Voltmeter * 2. 5V R1=2. 5V49. 5A-Rm R1= 48, 505. 05051 ? * 10V R2=10V49. 5A-Rm-R1 R2= 151,515. 1515 ? * 50V R3=50V49. 5A-Rm-R1-R2 R3= 808,080. 8081 ? For AC Voltmeter * 10V Im=49. 5A0. 637 Im= 77. 70800628A R1=1. 41410-1. 477. 70800628A-Rm R1=161,947. 0707 ? * 25V R2=1. 41425-1. 477. 70800628A-Rm R2= 434,891. 9192 ? * 250V R3=1. 414250-1. 477. 70800628A-Rm R3= 4,529,064. 646 ?