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Can i use lm331 to measure the frequency of the supply ?

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hasiefac

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I am building a device that measures the frequency of the home power supply.Is lm331 is ideal for the purpose ? Since the output wave form of the supply is somewhat similar to a sinusoidal signal with distortions is it good to use lm331 or are there any other ic's i can use ?
 

crutschow said:
What type of "home supply'?
What frequency are you concerned about?
Click to expand...

220-235V and frequency 50-60Hz ....But from what i observed lm331 requires more circuit elements and i could do my job by a zero crossing detector.Is there any precision wise advancement in using lm331 for measuring frequency of a signal ?
 

LM331 or any other general purpose comparator is O.K. It should be used in a circuit with positive feedback to create some hysteresis. A low pass in front of the comparator might be necessary in some cases to filter higher frequency interferences.
 

Hi,

LM331 or any other general purpose comparator is O.K.
Click to expand...
LM331 is not a comparator, instead it is a voltage-to-frequency converter.

In the datasheet there are design examples of frequency-to-voltage converters.
I assume this is what the OP wants to do. But indeed he tells about nothing...

For mains frequency measurement I recommend a microcontroller with capture periferal.
(Measure time from one rising edge to the next rising edge, filter it and calculate frequency)
It needs a signal forming zero cross detection or a simple comparator in front of the capture input.
If the uC runs from a Xtal oscillator it is a very accurate and precise measurement device.

Klaus
 

Why do you want to measure the electrical frequency? If you live in a civilized country then the frequency should be extremely accurate, maybe more accurate than your measuring circuit.
Oh, your home is far from civilization and your electricity comes from a battery powered inverter? Then its frequency accuracy might be very poor.
My multimeter measures frequency with very good accuracy. Right now it measures 60.00Hz.
 

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