How would you use the output of the following circuit?

What is the purpose of the following circuit? 

Voltage regulators maintain a constant output voltage regardless of what 2 things? Mark 2

Slew rate determines how fast the output can change in response to a step input.

If you need a near perfect oscillation frequency, what must you employ? Its one word that starts with a ‘c’.  Be sure to spell correctly

Mark all components below that affect the upper cutoff frequency of a common emitter amplifier.

What is the following circuit called? (Hint: this is not the same as the previous circuit) What does it do? 

Calculate IF in the circuit. _______mA

Creating a Layout Design an XML layout for a login screen with fields for username, password, and a login button. The layout should be responsive to different screen sizes. Username field should be in plain text. Password should not be in plain text.      

Which file contains the user interface definition in an Android application?