Highpass Filter Selection for Blocking 60 Hz & Beyond

[m718]

Which type of highpass filter attenuates best?
I want to block 60 hz but its ok if there's some attenuation up to 250 hz.
I can't use notch filter.

 

[berkeman]

Which type of highpass filter attenuates best?
I want to block 60 hz but its ok if there's some attenuation up to 250 hz.
I can't use notch filter.

Depends on what you mean by "best". What are the constraints on your filter? What order filter? Passive or active? Gain tolerance in the passband? Tolerance on the corner frequency?

 

[chaoseverlasting]

You could use two Butterworth filters, highpass and lowpass (the order depends on you constraints as berkeman said) and choose their cutoff frequencies such that the 60 Hz frequency is blocked.

 

[m718]

I made three different notch filters to block 60 hz from pickup coil that goes to a single opamp amplifier, I put the filter before the amplifier and it doesn't blockout 60 hz, it just attenuates all frequencies about 10%. why is this happening?

 

[berkeman]

I made three different notch filters to block 60 hz from pickup coil that goes to a single opamp amplifier, I put the filter before the amplifier and it doesn't blockout 60 hz, it just attenuates all frequencies about 10%. why is this happening?

Please post a schematic if you can. Also, maybe the 60Hz pickup is getting into the circuit some other way?