Figure shows a circuit suitable for op-amp applications. For all transistors β = 100, VBE = 0.7 V, and ro =∞.
(a) For inputs grounded and output held at 0 V (by negative feedback) find the collector currents of all transistors. Neglect base currents.
(b) Calculate the input resistance.
(c) Calculate the gain of the amplifier with a load of 5 k Ω.
(d) With load as in (c) calculate the value of the capacitor C required for a 3-dB frequency of 100 Hz.
