# Series-Parallel Circuit

Discussion in 'Homework Help' started by MrBadVoodoo, Apr 10, 2006.

Apr 10, 2006
5
0
I was wondering if someone could show me a way to build a Series-Parallel Circuit using light bulbs. I have four light bulbs, They are:
6.3V @ 150mA
6.3V @ 250mA
2.5V @ 500mA
2V @ 60mA
I have to use at least one of each bulb, but I can use more than one, if I want to. The applied voltage is 9V. The hard part about making this circuit is that it has to be somewhat power efficient. The bulbs should use at least around 60+% of the circuit. the smallest resistor I can use is a 2.7 Ω. I have come up with some circuits that will work but they are not very power efficient. The highest power efficiency I can come up with is about 45%. Anyone's help on this will be greatly appreciated.

2. ### paultwang Well-Known Member

Mar 8, 2006
80
0
Do you mean Light Emitting Diodes?

3. ### windoze killa AAC Fanatic!

Feb 23, 2006
605
24
I certainly hope not, not with 500mA flowwing through one them. I am guessing he is using small liliput bulbs.

Apr 10, 2006
5
0
CM 40 - 6.3V @ 150mA
CM 46 - 6.3V @ 250mA
CM 43 -2.5V @ 500mA
CM 49 - 2V @ 60mA

They are just small little bulbs that you might use in a car (lights for your dash board/ lights for your overhead light etc.)

5. ### paultwang Well-Known Member

Mar 8, 2006
80
0
so they have fixed resistances at the given voltage level?

6. ### pebe AAC Fanatic!

Oct 11, 2004
628
3
I can get a max efficiency of about 46.5% by only using 1 of each bulb. But you say you can use more than 1 of each and you don't give a maximum or any current limitation.

So you could wire extra banks of 2v and 2.5 v bulbs in a series/parallel arrangement wiithout series resistors to get an overall efficiency approaching 100%

Apr 10, 2006
5
0
The current for this circuit is 1A ≤and I can use however many of each bulb I want. I at least have to use one of each bulb. Thanks for trying to help me.

Apr 10, 2006
5
0
They have no fixed resistances on them that I know of. The CM # is what it says on the bulbs themselves. I hope that answers your question. Thanks

9. ### pebe AAC Fanatic!

Oct 11, 2004
628
3
You can get over 75% efficiency. As it's homework I won't give the answer, but I'll give you a hint.

Use one of each of the 6.3v bulbs, 2 of 2.5V and 8 of 2V bulbs.