# Need help on a electric circuit.. details to follow!

#### curly123

Joined Jan 23, 2018
4
The homework is:
To draw and to project an electronic circuit to stabilize the tension of 5 resistors with different sums to 3.3 V.

THE DIFFERENT SUMS EXPLANATION:
Sums of resistors are e.x. these number 567890: then the first resistor has 5 kΩ, the second resistor has 6 kΩ etc., ( if the number has a 0, let the resistance be 10kΩ)

The resistors can be connected in any kind of form and different kinds of elements and components from electric to electronics can be used, the purpose here is to stabilize the tension of each resistor to 3.3 V, where the resistance of the power source is 2kΩ, the sum of the power source can be set by desire and the circuit must have a minimum of 20% -/+ voltage tolerance. In the end calculate the power of the source which is needed to stabilize the tension of all resistors. save me please.. short deadline coming!!!!!

#### MrAl

Joined Jun 17, 2014
8,873
The homework is:
To draw and to project an electronic circuit to stabilize the tension of 5 resistors with different sums to 3.3 V.

THE DIFFERENT SUMS EXPLANATION:
Sums of resistors are e.x. these number 567890: then the first resistor has 5 kΩ, the second resistor has 6 kΩ etc., ( if the number has a 0, let the resistance be 10kΩ)

The resistors can be connected in any kind of form and different kinds of elements and components from electric to electronics can be used, the purpose here is to stabilize the tension of each resistor to 3.3 V, where the resistance of the power source is 2kΩ, the sum of the power source can be set by desire and the circuit must have a minimum of 20% -/+ voltage tolerance. In the end calculate the power of the source which is needed to stabilize the tension of all resistors. save me please.. short deadline coming!!!!!
Hi,

I think you are going to have to explain this problem a little better. Perhaps even draw a schematic.

#### dl324

Joined Mar 30, 2015
14,324
Welcome to AAC!

You're encouraged to use the search function before posting. Someone else appears to have posted the same question yesterday. Progress has been slow because the person posting the question has not answered questions seeking clarification.

It would be helpful if you posted the complete text of the problem and your solution attempt.

This forum isn't appropriate for problems that are time critical. You'll be expected to do most of the work.

#### curly123

Joined Jan 23, 2018
4
Hi,

I think you are going to have to explain this problem a little better. Perhaps even draw a schematic.
does this one help!?

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#### WBahn

Joined Mar 31, 2012
26,398
Nope. Doesn't help at all.

What would help quite a bit would be for you to show YOUR best attempt to solve YOUR homework problem. That will go a long way toward helping us figure out just what you are being asked to do. You are using the term "sum" in a way that makes little since. The "sum" is the result from adding a bunch of things up. So it makes no sense to talk about using resistors that have different sums. What is the "sum" of a resistor? Then, what is the "sum" of a power supply?

The best I can figure out is that each student is given a different set of resistors and the goal is to design a circuit that results in 3.3 V being dropped across each of those resistors (at the same time) given an adjustable voltage supply that has a 2 kΩ output resistance. You get to hook up the resistors in whatever arrangement you want and you can specify the voltage of the supply.

Is that correct?

If so, then you might consider what circuit configuration ensures that the same voltage appears across all of the resistors?

#### curly123

Joined Jan 23, 2018
4
it should look smth like this, and believe me Ive been trying anything that came to my head

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#### curly123

Joined Jan 23, 2018
4
it should look smth like this, and believe me Ive been trying anything that came to my head
Nope. Doesn't help at all.

What would help quite a bit would be for you to show YOUR best attempt to solve YOUR homework problem. That will go a long way toward helping us figure out just what you are being asked to do. You are using the term "sum" in a way that makes little since. The "sum" is the result from adding a bunch of things up. So it makes no sense to talk about using resistors that have different sums. What is the "sum" of a resistor? Then, what is the "sum" of a power supply?

The best I can figure out is that each student is given a different set of resistors and the goal is to design a circuit that results in 3.3 V being dropped across each of those resistors (at the same time) given an adjustable voltage supply that has a 2 kΩ output resistance. You get to hook up the resistors in whatever arrangement you want and you can specify the voltage of the supply.

Is that correct?

If so, then you might consider what circuit configuration ensures that the same voltage appears across all of the resistors?

it should look smth like this, and believe me Ive been trying anything that came to my head

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• 9.1 KB Views: 10

#### WBahn

Joined Mar 31, 2012
26,398
it should look smth like this, and believe me Ive been trying anything that came to my head
But since we are not mind readers, what have no idea what has or has not come into your head. That makes it really hard to help you figure out what you are doing right and what you are doing wrong.

Your circuit has a zener in it, which wasn't mentioned in your original post. I guess it falls under the umbrella of "different kinds of elements and components from electric to electronics can be used." But if that's the case, then why not just use a 3.3 V regulator IC or a 3.3 V power supply and be done with it?

What is and what is not fair game? Remember, we only know what YOU tell us.

If you want to use a zener in the circuit as you've shown (and where does this 0.91 kΩ load resistor come from?), then what does the current in the 2 kΩ resistor need to be?

#### MrAl

Joined Jun 17, 2014
8,873
it should look smth like this, and believe me I`ve been trying anything that came to my head
Hello again,

It looks like you are attempting to place resistors 1k, 2k, to 5k, in series parallel in order to get 3.3v output without having the zener conduct any current. Is this correct?
We have to guess because you are not explaining the goal of the problem very clearly yet. I guess just keep trying.