Different types of Electronics Instruments and principles N Krishna Prakash 04-03-09 Nkp/eee skcet

UNIT - 2 ELECTRICAL AND ELECTRONICS INSTRUMENTS Principle and types of analog voltmeters Principle and types of digital voltmeters Principle and types of Multimeter Single and three phase wattmeter Single and three phase energy meters. Magnetic measurements Determination of B-H curve Measurements of iron loss Instrument transformers Instruments for measurement of frequency and phase 04-03-09 Nkp/eee skcet 2

Analog Instruments An analog device is one in which the output or display is a continuous function of time and bears a constant relation to its input. 04-03-09 Nkp/eee skcet

Classification Classified based upon the quantity they measure (ammeter, voltmeter) Classified according to the current that can be measured by them.(DC,AC) Classified according to the effects used for working. Classified as Indicating, Recording, Integrating. Classified on the basis of method used for comparing the unknown quantity. (Direct / Comparison measurement ) 04-03-09 Nkp/eee skcet

Principle of operation Magnetic Effect. Thermal Effect. Electrostatic Effect Induction Effect. Hall Effect. 04-03-09 Nkp/eee skcet

Magnetic Effect 04-03-09 Nkp/eee skcet

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Force Between Current carrying Magnet 04-03-09 Nkp/eee skcet

Force Between Two Current Carrying Coils 04-03-09 Nkp/eee skcet

Hall Effects 04-03-09 Nkp/eee skcet

Operating Forces Deflecting Force. Controlling Force. Damping Force. 04-03-09 Nkp/eee skcet

Supporting the moving element Suspension Taut Suspension Pivot and jewel bearings. 04-03-09 Nkp/eee skcet

Control Systems Gravity Control. Spring Control. 04-03-09 Nkp/eee skcet

Analog Ammeters Ammeters are connected in series in the circuit whose current is to be measured. The power loss in an ammeter is I2Ra.Therefore ammeters should have a low electrical resistance so that they cause a small voltage drop and consequently absorb small power. 04-03-09 Nkp/eee skcet

Analog Voltmeters Voltmeters are connected in parallel in the circuit whose voltage is to be measured. The power loss in an ammeter is V2/RV.Therefore voltmeters should have a high electrical resistance so that they cause a small voltage drop and consequently absorb small power. 04-03-09 Nkp/eee skcet

Types of Instruments Permanent magnet moving coil (PMMC). Moving Iron Electro-dynamometer type. Hot wire type. Thermocouple type. Induction type. Electrostatic type. Rectifier type. 04-03-09 Nkp/eee skcet

PMMC 04-03-09 Nkp/eee skcet

Moving Iron Instruments Attraction Type 04-03-09 Nkp/eee skcet

Repulsion Type Moving Iron Instruments 04-03-09 Nkp/eee skcet

Electrodynamometer Type 04-03-09 Nkp/eee skcet

Wattmeter 04-03-09 Nkp/eee skcet

Power Measurement in 3 phase 3 wire system 04-03-09 Nkp/eee skcet

Two wattmeter method 04-03-09 Nkp/eee skcet

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Energy meters 04-03-09 Nkp/eee skcet

Single Phase Energy Meter 04-03-09 Nkp/eee skcet

Poly Phase Energy Meter 04-03-09 Nkp/eee skcet

THANK YOU 04-03-09 Nkp/eee skcet