In the voltage reference circuit shown in the figure, the op-amp is ideal and the transistors Q₁, Q₂,….., Q₃₂ are identical in all respects and have infinitely large values of common – emitter current gain $$\beta $$. The collector current (I_C) of the transistors is related to their base emitter voltage (V_BE) by the relation I_C = I_S exp (V_BE/V_T); where I_s is the saturation current. Assume that the voltage V_P shown in the figure is 0.7 V and the thermal voltage V_T=26mV

The output voltage V_out (in volts) is _____.

An opamp has a finite open loop voltage gain of 100. Its input offset voltage V_ios (= +5mV) is modeled as shown in the circuit below. The amplifier is ideal in all other respects. V_input is 25 mV.

The output voltage (in millivolts) is ________.

In the opamp circuit shown, the Zener diodes Z1 and Z2 clamp the output voltage V_o to +5 V or -5 V. The switch S is intially closed and is opened at time t = 0

The time t = t_{1 (in seconds) at which Vo changes state is _____.}

A p-i-n photo diode of responsivity 0.8A/W is connected to the inverting input of an ideal opamp as shown in the figure, +V_CC = 15V, - V_CC = -15V, Load resistor R_L = 10 k$$\Omega $$ . If 10$$\mu $$W of power is incident on the photodiode, then the value of the photocurrent (in $$\mu $$A) through the load is _____.