Electronic Device And Electronic Circuit

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Tuesday, July 04, 2006

Circuit for receive signal 4-20mA

Differential amp are the simplest circuit for receive signal 4-20mA
where a signal source flow to resistor 100 ohm will create voltage has
both of its terminals biased at several volts above ground, you need to
amplify the difference between the terminals. What about noise that
adds an unwanted voltage equally to both terminals of a sensor?
The differential amp reject the noise and rescue the signal.

Filtering is done to eliminate unwanted content in signal
A low pass filter can be formed by placing a capacitor in the feedback
loop of a differential amp
gain stage

gain = R2/R1
fo = 1/(2*Pi*R2*C1)