Apply diodes and operational amplifiers to common applications

Require worked solutions to attached questions for self checking - Only Q's 1 & 3 required please.

Solve electrical network problems

Require a logic circuit designing for the attached solution, as much help as possible please as i am lost. The problem does not specify, what valves are a hazardous system, it is a closed system that serves no purpose as far as i can see. I have not studied any thermofluid systems as yet, it seems too much of a jump in knowledge expected to myself. So far only studied some electrical resistors and static & dynamics!

DC Circuits: Time Varing current and Voltages

See the attached file with 4 circuit problems.

An amplifier has a voltage gain of 50 V/V and a current gain of 500 A/A. What is the power gain in decibels?

An amplifier has a voltage gain of 50 V/V and a current gain of 500 A/A. What is the power gain in decibels? a. 4.398 b. 8.795 c. 43.98 d. 87.95

An amplifier with a voltage gain of +30db, an input resistance of 8 k ohms, and an output resistance of 2 k ohms is used to drive

An amplifier with a voltage gain of +30db, an input resistance of 8 k ohms, and an output resistance of 2 k ohms is used to drive a 2 k ohm load. What is the value of Avo? a. 3.162 b. 31.62 c. 100 d. 1000