Wednesday 8 February 2012

The Butterworth Second Order High Pass Filter Circuit

The Butterworth Second Order High Pass Filter Circuit

This is a circuit for high pass filter. This circuit is similar to low-pass filter circuit, but the position for resistors and capacitor are interchanged. This circuit is based on op-amp for the operation. LM833 IC is the op-amp that is used in the circuit. This is the figure of the circuit.


Similar with low pass design guide, the resistor and capacitor should be chosen according to the formula, and the resistor value should be:
· Much higher than equivalent leakage resistance of the capacitor.
· Much higher than the operational-amplifier’s (op-amp’s) input impedance.
· Doesn’t draw excessive current-violating the maximum allowed op-amp’s output current.

In general, for higher capacitor value, it is leakage current would be higher and you must use lower resistors to compensate the capacitor’s current leakage. [Schematic source: National Semiconductor's LM833 Application Notes]

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