# Ohm's Law Quiz 2 of 5

#### T.Jackson

Joined Nov 22, 2011
328
Rich (BB code):
                         o <---- 1.35V ----> o
|                   |
|                   |
|                   |
5v o--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--o GND
R1        R2        R3        R4        R5        R6
Calculate R1 to R6. Choose your own IT or RT.

#### DerStrom8

Joined Feb 20, 2011
2,390
This is looking suspiciously like you're having us do your homework......

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#### T.Jackson

Joined Nov 22, 2011
328
This is looking suspiciously like you're having us do your homework......

#### T.Jackson

Joined Nov 22, 2011
328
Soon I think we create a special forum with an entry exam.

We don't want ya if you don't know what you're talking about.

#### Georacer

Joined Nov 25, 2009
5,182

These threads don't seem to constitute any project. They will be move to the General Electronics Chat forum.

#### thatoneguy

Joined Feb 19, 2009
6,359
Soon I think we create a special forum with an entry exam.

We don't want ya if you don't know what you're talking about.
Who crowned you hall monitor?

#### bountyhunter

Joined Sep 7, 2009
2,512
Rich (BB code):
                         o <---- 1.35V ----> o
|                   |
|                   |
|                   |
5v o--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--o GND
R1        R2        R3        R4        R5        R6
Calculate R1 to R6. Choose your own IT or RT.
DEFINE IT and RT

#### Jony130

Joined Feb 17, 2009
5,351
R3 = R4 = 10K;

R3+R4 = 20K

IT = 1.35V/20k = 67.5uA

R1 + R2 + R5 + R6 = (5V - 1.35V)/67.5uA = 54.074K

R1 = R2 = 10K

R5 = 1K and R6 = 33K

#### Wendy

Joined Mar 24, 2008
22,931
If you go to my blog you can find a set of templates for drawing electronics I call Paint CAD. Your drawing could be redrawn thusly...

Without more information the problem is insoluble, or to phase it differently, there are an infinite number of solutions. Total current (It) is critical, but then you need to know the relationship between R1 and R2, R3 and R4, and R5 and R6.

I suspect the OP is trying to get a feel for the skill levels here. We have a spread of members from PHDs to complete beginners (some of the latter are children) who all are interested in electronics. All of the guys who have responded so far can do this in their sleep.

We have a couple of new projects in the Completed Projects area, check them out.

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#### SgtWookie

Joined Jul 17, 2007
22,226
Well, looks like T.Jackson composed the ASCII divider in WordPad or the like instead of Notepad. Proportional fonts just don't work well with ASCII graphics.

Here's how it's supposed to look:
Rich (BB code):
                         o <---- 1.35V ----> o
|                   |
|                   |
|                   |
5v o--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--+--/\/\/--o GND
R1        R2        R3        R4        R5        R6

#### SgtWookie

Joined Jul 17, 2007
22,226
One way to do it:
Rich (BB code):
It = 0.1 Amperes (declared)
Junction between R4 and R5 is now declared as node N1
Junction between R2 and R3 is now declared as node N2
Vt = 5 Volts          (known; given in problem statement)
Rt = Vt/It            (50 Ohms)
VN2N1 = 1.35          (V(N2)-V(N1), known; given as 1.35V in problem statement, given a name for calculation purposes.)
R3R4pct = VN2N1/Vt    (27%; calculate percent of total)
RR3R4 = Rt * R3R4pct  (R3+R4 = 13.5 total resistance)
R6 = RANDOM(Rt-RR3R4)         (R6 is a random number between 0 and 36.5 inclusive)
R5 = RANDOM(Rt-(RR3R4+R6))    (R5 is a random number between 0 and the sum of R6, R4, and R3)
R2 = RANDOM(Rt-(RR3R4+R5+R6)) (R2 is a random number between 0 and the sum of R6, R5, R4, and R3)
R1 = Rt - (R2+RR3R4+R5+R6)    (R1 is the remaining resistance, if any)
R4 = RANDOM(RR3R4)            (R4 is a random number between 0 and RR3R4)
R3 = RR3R4 - R4               (R3 is whatever's left of RR3R4 after R4)

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#### THE_RB

Joined Feb 11, 2008
5,438
Is this one of those psych homework assignments where they ask people annoying questions and then log how people respond and how annoyed they get as the situation escalates?