voltage across capacitor 117 is also coupled to the input of an amplifier 118 whose output is connected to the gates of mosfets 105 and 106 amplifier 118 simply inverts the potentials available on capacitor 117 with low optical signal levels and a near zero voltage on capacitor 117 amplifier 118 presents a potential of about 5 volts to the gates of mosfets 106 and 107 under this condition resistor 104 is completely shorted out and resistor 103 is fully in the circuit resulting in maximum amplification in the preamplifier of fig1 as the potential on capacitor 117 increases with stronger optical signals the potential at the output of amplifier 118 decreases towards zero thereby decreasing the value of r c and permitting r c to track the decreases in the feedback resistance r f in accordance with the above relationship as a result the ratio of the poles p2 p1 can be kept more than 2 75 and stability maintained for even greater decreases in the feedback resistance than in the prior art the presence of mosfet 106 permits the dynamic range to be widened even further as pointed out hereinabove for small signal levels mosfet 106 completely shorts out the emitter resistor 104 and the open loop gain is not affected in the large signal mode mosfet 106 operates in the off mode resulting in the introduction of resistance r e in the emitter of transistor 102 the inclusion of mosfet 106 and resistor 104 serves several purposes first in the large signal mode it reduces the open loop gain a of the preamplifier thereby limiting the increase in the frequency of the.