the voltages at the base of transistors q1 and q3 are substantially equal in addition feedback transistor q5 is used to drive resistor r1 amplifier 22 is configured to have a gain of two and therefore typical values for load resistors r1 and r3 are 50 ohms and 100 ohms respectively a first feedback path consists of diodes d1 and d5 that are biased on in the normal condition and are connected between the emitter of the feedback transistor q5 and the base of transistor q3 the junction of the cathodes of diodes d1 and d5 is coupled to resistor r1 a second feedback path consists of diode d3 that is biased on in an overdrive condition connected between the emitter of the feedback transistor q5 and the base of transistor q3 diode d3 is biased on during the overdrive condition by current source i5 that is coupled to the anode of diode d3 the value of current source i5 is typically set to a low value such as 500 u03bca similarly fig1 also shows a second amplifier half 24 that includes a differential pair of transistors q2 and q4 the base of transistor q2 being coupled to a single ended input voltage v2 the bases of transistors q2 and q4 form positive and negative inputs and the collectors of transistors q2 and q4 form negative and positive outputs a tail current source i2 and a load current source i4 provide bias current for the differential pair of.