in fig1 curve 101 varies up to a maximum signal strength of max db curve 101 achieves a signal of max u2212 3 db at a frequency f lf the frequency at a point 106 at which a frequency response curve e g curve 101 is at a u2212 3 db signal level at the left end of the frequency response is commonly referred to as the low corner frequency of the frequency response curve frequency f lf is the low corner frequency of frequency response curve 101 in designing an amplifier circuit for a sensor such as a read head it is advantageous to establish low corner frequency f lf as low as possible to permit the amplifier to respond to as low a frequency signal from the sensor as can be achieved without passing dc signals fig2 is an electrical schematic illustration of a first example of a prior art differential amplifier for use with a read head in fig2 a read amplifier circuit 10 sometimes also referred to as a read front end is attached to a magneto resistive element 12 via connection leads 14 16 connected in parallel a capacitor 18 is coupled with connection lead 14 a capacitor 20 is coupled with connection lead 16 capacitors 18 20 block low frequency signals that appear on connection leads 14 16 metal oxide silicon mos transistor 30 has a source 32 a drain 34 and a gate 36 metal oxide.