In the circuit in the Fig. below, reduce the resistance R3 will lead to a reducing of, * :choose all that possible options R1 V. R2 R3 None will be affected. Voltage across R3. O Current through R3. O Voltage across R1 Power dissipated in R2

2. An Automatic Night Light uses a photocell to detect the amount of available light in a room. Under strong light the resistance of the photocell is 1kn but goes up to 100k2 in total darkness. The photocell is put in series with a 4.7k2 resistor so as to make a voltage divider when the ends are connected between +5V and GND as shown. As it gets darker in the room, the resistance of the photocell goes up and raises the voltage on the "Sensor Voltage" line. At "dusk", the photocell has a resistance of 10k2. Automatic Night Light 5v Vdd a. What will the range of the sensor voltage be as the photocell +5V goes from 1k2 (bright light) to 100k2 (total darkness)? Photocell b. Write the equation for VoUT expressed in terms of the op-amp Sensor Voltage LM358AD Vout U1A mmarceau 5V inputs and gain. What is the maximum range for Vour? Reference R4 24.7ka Voltage (V) White LED C. Assuming the light is to come on at "dusk", what must the POTENTIOMETER reference voltage be set to to have the LED…

5. The resistors, labeled A through F, in the following circuit represent incandescent lightbulbs which are dimmable. By "dimmable," we mean the amount of light a bulb produces is proportional to the voltage across the bulb (or, correspondingly, the current through the bulb). The resistances of all these bulbs is constant and they all have the same resistance. Assuming the voltage source is sufficient to cause all these bulbs to produce at least some illumination, rank the bulbs from brightest to dimmest (if two bulbs are equally bright, note this fact). Justify your answer. You should be able to do this without using equations. (However, if you want to resort to an equation or two to help you sort this out or discuss your solution, that's okay.) V₂ + B E www www F M

Solve for 1, 12, and 13. R1 R5 1kQ 1kQ V1 R3 V2 10V 11 >1k2 12 -12V R2 R4 1k2 1k2 13 V3 R6 R7 1k2 20V 1k2 Hil in