Question

The following questions pertain to the circuits shown below. ЗmA 6mA 30 M2 ? 15 ΜΩ In an amplifier design, your company has a non-ideal current source. The amplifier acts like a resister of 15MS2 but can only take 3mA as input or it will overheat and cease function. It was discovered in testing e that the above schematic delivered 4mA to the amplifier and most of the amps burned out. Over 1000 of these amps have already been built with such tight space requirements that there is only enough room for one component to be placed in parallel with the amplifier.

Answer 1

17)

according to quetion,

amplifier works safely for current 3mA only and amplifier works like a resistor of 15 M ohm

when given source (6mA with 30 M ohm internal resiatance, amplifier draws 4mA which is not safe for operation).

when source is replace by 5 mA current with 15 M ohm internal resistance

Internal reistance of 15 M ohm appears in parallel with aplifier( amplifier works like a resistor of 15 M ohm)

current divided into equal parts in both the resistors

now, applifier is supplied with current= 5/2= 2.5 mA

2.5 mA which is not equal to 3mA  

hence, this current source does not works in this design.

18)

when parellel combination of internal resisatce 30 M ohm and the component gives equavalent resistance equal to the amplifioer resistance(15 M ohm) amplifier works safely

6mA 7 Зона SR 15 M2

WHEN resistance  R=30 M ohm which is parallel connected with internal resistance of source

equavelent resistance= 15 M ohm (combination of R and 30M ohm)

I=3mA 15M2 15MR 6m A

now, current in amplifier supplied is 3mA which solves the problem

option (c) is correct.