Active and passive Instruments
Active and Passive Instruments: Active and passive Instruments Passive Instruments: The instruments where the output is produced completely by the quantity that is measured are called passive instruments. The example of passive instrument is a pressure gauge.Fig shows a pressure gauge. Passive Instrument As the pressure in the liquid changes, the piston moves.The pointer is connected to the piston. No other source of energy is used. The liquid pressure is the only source. Thus,the piston and pointer movement while measurement is entirely dependent on the liquid pressure. Active Instruments: Active instruments are the instruments in which the quantity to be measured activates the magnitude of external power input source that produces the measurement. The liquid level indicator is an example of an active instrument.Fig.1.4.2 shows a liquid level indicator. Active Instruments The power source is required in or...
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